Showing papers in "Journal of Animal Science in 2018"

BIG DATA ANALYTICS AND PRECISION ANIMAL AGRICULTURE SYMPOSIUM: Machine learning and data mining advance predictive big data analysis in precision animal agriculture.

Abstract: Precision animal agriculture is poised to rise to prominence in the livestock enterprise in the domains of management, production, welfare, sustainability, health surveillance, and environmental footprint. Considerable progress has been made in the use of tools to routinely monitor and collect information from animals and farms in a less laborious manner than before. These efforts have enabled the animal sciences to embark on information technology-driven discoveries to improve animal agriculture. However, the growing amount and complexity of data generated by fully automated, high-throughput data recording or phenotyping platforms, including digital images, sensor and sound data, unmanned systems, and information obtained from real-time noninvasive computer vision, pose challenges to the successful implementation of precision animal agriculture. The emerging fields of machine learning and data mining are expected to be instrumental in helping meet the daunting challenges facing global agriculture. Yet, their impact and potential in "big data" analysis have not been adequately appreciated in the animal science community, where this recognition has remained only fragmentary. To address such knowledge gaps, this article outlines a framework for machine learning and data mining and offers a glimpse into how they can be applied to solve pressing problems in animal sciences.

Supplementation of Bacillus subtilis-based probiotic reduces heat stress-related behaviors and inflammatory response in broiler chickens.

Abstract: Probiotics reduce stress-related inflammation and abnormal behaviors in humans and rodents via regulation of the microbiota-gut-brain axis. The objective of this study was to determine if probiotic, Bacillus subtilis, has similar functions in broiler chickens under heat stress (HS). Two hundred forty 1-d-old broiler chicks were assigned to 48 pens with 4 treatments: Thermoneutral (TN)-RD (regular diet), TN-PD (the regular diet mixed with 1 × 106 CFU/g feed probiotic), HS-RD and HS-PD. Probiotic (Sporulin) was fed from day 1; and HS at 32°C for 10 h daily was initiated at day 15. The data showed that final BW, average daily gain , and feed conversion efficiency were improved in PD groups as compared to RD groups regardless of the ambient temperature (P HS-PD > TN-RD > TN-PD birds (P < 0.01). Compared to TN birds, HS birds spent more time in wing spreading, panting, squatting close to the ground, drinking, sleeping, dozing, and sitting but spent less time in eating, standing, and walking (P < 0.05 or 0.01). In addition, HS birds had greater levels of hepatic IL-6, IL-10, heat shock protein (HSP)70, and HSP70 mRNA expression (P < 0.01) and greater levels of cecal IgA and IgY (P < 0.01) compared to TN birds. Within TN groups, TN-PD birds had greater concentrations of hepatic IL-10 (P < 0.05) and cecal IgA (P < 0.01) than TN-RD birds. Within HS groups, HS-PD birds spent less time in wing spreading, panting, squatting close to the ground, drinking, sleeping, dozing, and sitting but spent more time in eating, foraging, standing, and walking than HS-RD birds (P < 0.05 or 0.01). The HS-PD birds also had lower concentrations of hepatic IL-6 and HSP70 (P < 0.01), whereas greater levels of IL-10 (P < 0.05) and lower concentrations of cecal IgA and IgY (P < 0.01). These results indicate that broilers fed the probiotic, B. subtilis, are able to cope with HS more effectively by ameliorating heat-induced behavioral and inflammatory reactions through regulation of microbiota-modulated immunity.

Dietary chlorogenic acid improves growth performance of weaned pigs through maintaining antioxidant capacity and intestinal digestion and absorption function

Abstract: Chlorogenic acid (CGA) is a natural phenolic acid, which is an important component of biologically active dietary phenols isolated from various species. Two experiments were conducted to investigate the effects of CGA on growth performance, antioxidant capacity, nutrient digestibility, diarrhea incidence, intestinal digestion and absorption function, and the expression levels of intestinal digestion and absorption-related genes in weaned pigs. In Exp. 1, 200 weaned pigs were randomly allotted to four dietary treatments and fed with a basal diet or a basal diet supplemented with 250, 500, or 1,000 mg/kg CGA, respectively, in a 14-d trial. Pigs on the 1,000 mg/kg CGA-supplemented group had greater (P < 0.05) G:F compared with those on the control (CON) group. In Exp. 2, 24 weaned pigs were randomly allotted to two groups and fed with a basal diet (CON group) or a basal diet supplemented with 1,000 mg/kg CGA (the optimum does from Exp. 1; CGA group). After a 14-d trial, 8 pigs per treatment were randomly selected to collect serum and intestinal samples. Compared with the CON group, the ADG, G:F, as well as the apparent total tract digestibility of CP, crude fat, and ash were increased (P < 0.05), whereas the diarrhea incidence was decreased (P < 0.05) in the CGA group. Pigs on the CGA group had greater (P < 0.05) serum albumin and IGF-1, and lower (P < 0.05) serum urea nitrogen than pigs on the CON group. Furthermore, dietary CGA supplementation enhanced (P < 0.05) the activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) in the serum, the activity of maltase in the jejunum and ileum, as well as the activities of sucrase and alkaline phosphatase (AKP) in the jejunum. The mRNA levels of sodium glucose transport protein-1 (SGLT1) and zinc transporter-1 (ZNT1) in the duodenum and the mRNA levels of SGLT1, glucose transporter-2 (GLUT2), and divalent metal transporter-1 (DMT1) in the jejunum were upregulated (P < 0.05) in pigs fed the CGA diet. These results suggested that dietary CGA supplementation has the potentials to improve the growth performance and decrease the diarrhea incidence of the weaned pigs, possibly through improving the antioxidant capacity and enhancing the intestinal digestion and absorption function.

Microbiome profiling of commercial pigs from farrow to finish.

Abstract: Balanced bacterial communities within the gastrointestinal (GI) tract of animals are a key component of gut health, resulting in optimal performance and the prevention of disease. The purpose of this study was to characterize the commercial pig's baseline bacterial microbiome over time and across anatomical site. Several anatomical sites (duodenum/jejunum, ileum, cecum, and colon) were examined across multiple ages (days 0, 10, 21, 33, 62, 84, and market) for bacterial microbiome structure using 16S rRNA V4 region sequencing with Illumina MiSeq. General trends in the succession of the bacterial microbiome were observed over age, such as increasing populations of Clostridia and decreasing populations of Gammaproteobacteria (P < 0.05). However, apparent disruptions in the microbiome were also observed that did not follow these trends, specifically at sampling 24 h post-weaning where Lactobacillaceae were drastically reduced in relative abundance (P < 0.05). The introduction of solid feed between days 21 and 33 had the greatest overall impact on bacterial community structure as compared with the effects of age, changes in solid feed type, and pig movement. A core bacterial microbiome was identified across all anatomical sites consisting of the dominant operational taxonomic units (OTUs); samples were only differentiated based upon anatomical site when considering less abundant OTUs and differences in relative abundance. When considering mucosal vs. digesta samples from the cecum and ileum, several taxa were of significantly higher relative abundance in the mucosa (P < 0.05), including Anaerovibrio, Bacteroides, Desulfovibrio, Helicobacter, Oscillospira, Phascolarctobacterium, and Prevotella. Correlations between several genus-level taxa and pig weight were observed. Overall, this study provides an expanded view of the dynamic pig GI microbiome from farrow to finish.

Diquat-induced oxidative stress increases intestinal permeability, impairs mitochondrial function, and triggers mitophagy in piglets

Abstract: In the present study, we investigated the influence of diquat-induced oxidative stress on intestinal barrier, mitochondrial function, and the level of mitophagy in piglets. Twelve male Duroc × Landrace × Yorkshire 35-d-old pigs (weaned at 21 d of age), with an average body of 9.6 kg, were allotted to two treatments of six piglets each including the challenged group and the control group. The challenged pigs were injected with 100 mg/kg bodyweight diquat and control pigs injected with 0.9% (w/v) NaCl solution. The results showed that diquat injection decreased ADFI and ADG. Diquat decreased (P < 0.05) the activities of superoxide dismutase and glutathione peroxidase and increased (P < 0.05) the malondialdehyde concentrations. The lower (P < 0.05) transepithelial electrical resistance and higher (P < 0.05) paracellular permeability of fluorescein isothiocyanatedextran 4 kDa were found in diquat challenged piglets. Meanwhile, diquat decreased (P < 0.05) the protein abundance of claudin-1, occluding, and zonula occludens-1 in jejunum compared with the control group. Diquat-induced mitochondrial dysfunction, as demonstrated by increased (P < 0.05) reactive oxygen species production and decreased (P < 0.05) membrane potential of intestinal mitochondria. Diquat-injected pigs revealed a decrease (P < 0.05) of mRNA abundance of genes related to mitochondrial biogenesis and functions, PPARg coactivator-1α, mammalian-silencing information regulator-1, nuclear respiratory factor-1, mt transcription factor A, mt single-strand DNA-binding protein, mt polymerase r, glucokinase, citrate synthase, ATP synthase, and cytochrome coxidase subunit I and V in the jejunum. Diquat induced an increase (P < 0.05) in expression of mitophagy-related proteins, phosphatase and tensin homologue deleted on chromosome 10-induced putative kinase, and Parkin in the intestinal mitochondria, as well as an enhancement of the ratio of light chain 3-II (LC3-II) to LC3-I content in the jejunal mucosa. These results suggest that oxidative stress disrupted the intestinal barrier, caused mitochondrial dysfunction, and triggered mitophagy.

Influence of bull age, ejaculate number, and season of collection on semen production and sperm motility parameters in Holstein Friesian bulls in a commercial artificial insemination centre.

Abstract: In the current era of genomic selection, there is an increased demand to collect semen from genomically selected sires at a young age. The objective of this study was to assess the effect of bull age, ejaculate number, and season of collection on semen production (ejaculate volume, sperm concentration, and total sperm number; TSN) and sperm motility (prefreeze and post-thaw total and gross motility) parameters in Holstein Friesian bulls in a commercial artificial insemination (AI) center. The study involved the interrogation of a large dataset collected over a 4-yr period, (n = 8,983 ejaculates; n = 176 Holstein Friesian bulls aged between 9 mo and 8 yr). Bulls aged less than 1 yr had the poorest semen production and sperm motility values for all parameters assessed compared with bulls older than 1 yr (P < 0.01). First ejaculates had greater semen production and greater prefreeze motility values than second consecutive ejaculates (P < 0.01), but despite this, there was no difference in post-thaw motility. When subsequent ejaculates were collected from bulls aged less than 1 yr, semen production and sperm motility did not differ compared with mature bulls. Semen collected in winter was poorest in terms of sperm concentration and TSN, but best in terms of post-thaw motility (P < 0.01). In conclusion, second ejaculates can be collected, particularly from bulls aged less than 1 yr, without a significant decrease in post-thaw sperm motility, thus may be a useful strategy to increase semen availability from young genomically selected AI bulls in high demand.

Impact of sow energy status during farrowing on farrowing kinetics, frequency of stillborn piglets, and farrowing assistance.

Abstract: Farrowing duration is rather long in sows most likely due to selection for large litters, and we hypothesized that prolonged farrowings would compromise sow energy status during farrowing and in turn the farrowing process. Two studies were performed as follows: 1) to evaluate whether sow energy status during farrowing compromise the farrowing kinetics (FK, i.e., farrowing duration and birth intervals) and 2) to study the underlying mechanisms potentially affecting stillbirth rate and farrowing assistance. In study-1, parameters affecting FK were characterized based on data from a total of 166 farrowings from 7 feeding trials focused on sow colostrum production. The data were screened for associations with FK using the CORR procedure of SAS. Traits that were correlated with the FK at P 6 h) to evaluate the impact on birth intervals, farrowing assistance, and stillbirth rate. Birth intervals (P 6 h, respectively. In study-2, blood samples were collected once or twice each week in late gestation and each hour during farrowing to measure arterial concentrations and uterine extractions of plasma metabolites. Time since last meal was strongly negatively correlated with arterial glucose 1 h after the onset of farrowing (r= -0.96; n = 9; P < 0.001). Glucose appeared to be the key energy metabolite for oxidative metabolism of gravid uterus. In conclusion, the present study strongly suggests that a substantial proportion of sows suffer from low-energy status at the onset farrowing and that this negatively affects the farrowing process. Transferring this knowledge into practice, the results suggest that sows should be fed at least 3 daily meals in late gestation.

The combined effects of supplementing monensin and 3-nitrooxypropanol on methane emissions, growth rate, and feed conversion efficiency in beef cattle fed high-forage and high-grain diets.

Abstract: The study objective was to evaluate the combined effects of supplementing monensin (MON) and the methane (CH4) inhibitor 3-nitrooxypropanol (NOP) on enteric CH4 emissions, growth rate, and feed conversion efficiency of backgrounding and finishing beef cattle. Two hundred and forty crossbred steers were used in a 238-d feeding study and fed a backgrounding diet for the first 105 d (backgrounding phase), transition diets for 28 d, followed by a finishing diet for 105 d (finishing phase). Treatments were as follows: 1) control (no additive); 2) MON (monensin supplemented at 33 mg/kg DM; 3) NOP (3-nitrooxypropanol supplemented at 200 mg/kg DM for backgrounding or 125 mg/kg DM for finishing phase); and 4) MONOP (33 mg/kg DM MON supplemented with either 200 mg/kg DM or 125 mg/kg DM NOP). The experiment was a randomized complete block (weight: heavy and light) design with 2 (NOP) × 2 (MON) factorial arrangement of treatments using 24 pens (8 cattle/pen; 6 pens/treatment) at the main feedlot and 8 pens (6 cattle/pen; 2 pens/treatment) at the controlled environment building (CEB) feedlot. Five animals per treatment were moved to chambers for CH4 measurements during both phases. Data were analyzed using a Mixed procedure of SAS with pen as experimental unit (except CH4). Location (Main vs. CEB) had no significant effect and was thus omitted from the final model. Overall, there were few interactions between MON and NOP indicating that the effects of the 2 compounds were independent. When cattle were fed the backgrounding diet, pen DMI was decreased by 7%, whereas gain-to-feed ratio (G:F) was improved by 5% with NOP supplementation (P < 0.01). Similarly, MON improved G:F ratio by 4% (P < 0.01), but without affecting DMI. During the finishing phase, DMI tended (P = 0.06) to decrease by 5% with both MON (5%) and NOP (5%), whereas ADG tended (P = 0.08) to decrease by 3% with MON. Gain-to-feed ratio for finishing cattle was improved with NOP by 3% (P < 0.01); however, no effects were observed with MON. 3-Nitrooxypropanol decreased CH4 yield (g/kg DMI) by 42% and 37% with backgrounding and finishing diets (P ≤ 0.01), respectively, whereas MON did not lower CH4 yield. Overall, these results demonstrate efficacy of NOP in reducing enteric CH4 emissions and subsequently improving feed conversion efficiency in cattle fed high-forage and high-grain diets. Furthermore, effects of NOP did not depend on whether MON was included in the diet.

Effects of hydrolyzable tannin with or without condensed tannin on methane emissions, nitrogen use, and performance of beef cattle fed a high-forage diet.

Abstract: Sustainability of animal agriculture requires efficient use of energy and nitrogen (N) by ruminants fed high-forage diets. Thus, there is a need to decrease methane (CH4) emissions and prevent excessive N release into the environment. Therefore, this experiment examined the long-term effects of feeding hydrolyzable tannin (HT) with or without condensed tannin (CT) on animal performance, rumen fermentation, N use, and CH4 production in beef cattle fed a high-forage diet. A total of 75 weaned crossbred steers (292 ± 4.1 kg) were grouped by body weight (BW), housed in individual pens, and randomly assigned to 1 of 5 dietary treatments (15 animals/treatment) in a completely random design. The animals were fed a basal diet of alfalfa:barley silages (50:50; dry matter [DM] basis) with a crude protein content of 17.1% and supplemented with HT extract (chestnut, CN) or a combination (50:50) of HT and CT extracts (quebracho, Q) in a powdered form at different levels of dietary DM. The treatments for determining animal performance and N use were control (no tannin), 0.25% CN, 1.5% CN, combination of CN and Q at 0.125% each (0.25% CNQ), and CN and Q at 0.75% each (1.5% CNQ) of dietary DM. The treatments for the CH4 measurement were control, 1.5% CN, and 1.5% CNQ of dietary DM. The first 84 d of the study were used to measure animal performance, rumen fermentation, and N use, and the next 30 d were used to measure CH4 emissions with the tracer gas technique. There were no effects of treatment on DM intake (DMI), BW, average daily gain, and gain: feed (P ≥ 0.10). The plasma urea N concentration was greater (P 0.05) from animals fed control or 0.25% CN (117.2 and 117.5 mg/L, respectively). Tannin inclusion did not affect rumen pH, total volatile fatty acid concentration, proportions of acetate and propionate, and total protozoa populations (P ≥ 0.16). Tannin, irrespective of type or dose, decreased (P < 0.01) ruminal ammonia concentration. Tannin type and dose did not affect (P = 0.54) daily CH4 production (154 ± 5.9 g/d) but 1.5% CNQ tended to decrease CH4 yield compared with control (20.6 vs. 22.0 g/kg DMI; P = 0.094). HT from CN alone or in combination with CT from Q can be added at a low (0.25% DM) or high (1.5% DM) level to a forage-based diet to decrease ruminal ammonia concentration in growing beef cattle fed a high-protein diet without adverse effects on animal performance. A combination of HT and CT at a concentration of 1.5% dietary DM also tended to decrease CH4 emissions without negatively affecting performance.

Rumen bacterial community structure impacts feed efficiency in beef cattle

Abstract: The importance of the rumen microbiota on nutrient cycling to the animal is well recognized; however, our understanding of the influence of the rumen microbiome composition on feed efficiency is limited. The rumen microbiomes of two large animal cohorts (125 heifers and 122 steers) were characterized to identify specific bacterial members (operational taxonomic units [OTUs]) associated with feed efficiency traits (ADFI, ADG, and G:F) in beef cattle. The heifer and steer cohorts were fed a forage-based diet and a concentrate-based diet, respectively. A rumen sample was obtained from each animal via esophageal tubing and bacterial community composition was determined through 16S rRNA gene sequencing of the V4 region. Based on a regression approach that used individual performance measures, animals were classified into divergent feed efficiency groups. Within cohort, an extreme set of 16 animals from these divergent groups was selected as a discovery population to identify differentially abundant OTUs across the rumen bacterial communities. The remaining samples from each cohort were selected to perform forward stepwise regressions using the differentially abundant OTUs as explanatory variables to distinguish predictive OTUs for the feed efficiency traits and to quantify the OTUs collective impact on feed efficiency phenotypes. OTUs belonging to the families Prevotellaceae and Victivallaceae were present across models for heifers, whereas OTUs belonging to the families Prevotellaceae and Lachnospiraceae were present across models for steers. Within the heifer cohort, models explained 19.3%, 25.3%, and 19.8% of the variation for ADFI, ADG, and G:F, respectively. Within the steer cohort, models explained 27.7%, 32.5%, and 26.9% of the variation for ADFI, ADG, and G:F, respectively. Overall, this study suggests a substantial role of the rumen microbiome on feed efficiency responses.

Sodium propionate and sodium butyrate effects on histone deacetylase (HDAC) activity, histone acetylation, and inflammatory gene expression in bovine mammary epithelial cells.

Abstract: Histone deacetylase (HDAC) inhibition attenuates inflammation in rodents and short-chain fatty acids (SCFAs) are effective HDAC inhibitors. Therefore, the objective of this study was to evaluate the role of the SCFAs sodium propionate (SP) and sodium butyrate (SB) as HDAC-dependent regulators of inflammatory gene expression in bovine mammary epithelial cells (MAC-Ts). We postulated that SP and SB would decrease inflammation in MAC-Ts by inhibiting HDAC activity and increasing histone H3 acetylation and consequently decreasing inflammatory gene expression. For this study, MAC-Ts stimulated with lipopolysaccharide (LPS) were used as a model for bovine mammary epithelial cell inflammation. MAC-Ts were cultured in a basal medium. Cell lysates were incubated with SP or SB (0 to 5 mM) for 2 h prior to HDAC substrates incubation for an additional 2 h and HDACs activity was determined. Next, cells were pretreated with SP or SB (0 to 3.0 mM) for 2 h prior to LPS (1 µg/mL) stimulation for an additional 2 h and assessed for histone H3 acetylation. Then, cells were pretreated with SP or SB (1 mM) for 24 h prior to LPS (1 µg/mL) stimulation for an additional 2 h and RNA was isolated for inflammatory gene expression evaluation by PCR array and gene validation was performed using quantitative real-time PCR. One-way ANOVA followed by Tukey post hoc analysis was conducted and statistical significance set at P 0.05) overall inflammatory gene expression. Under our experimental conditions, findings suggest that in MAC-Ts, SCFAs regulate epigenetic markers on nucleosomal DNA in addition to regulation of inflammatory gene events independent of HDAC activity. Nevertheless, examination of SCFAs and/or HDACs inhibitors in bovine mammary gland is worth being further investigated to delineate the potential impact of HDAC inhibition and histones hyperacetylation on mammary gland tissue inflammation.

Weaning disrupts intestinal antioxidant status, impairs intestinal barrier and mitochondrial function, and triggers mitophagy in piglets.

Abstract: In the present study, we investigated the influence of weaning on antioxidant status, intestinal integrity, mitochondrial function, and the mitophagy level in piglets (weaned at 21 d) during the 1 wk after weaning. The redox status was measured by antioxidant enzymes activities, related genes expression, and malondialdehyde (MDA) content in jejunum. The intestinal barrier function was assessed by the Ussing chamber and expression of tight junction proteins in the jejunum. The function of intestine mitochondria was measured by mitochondrial DNA (mtDNA) content and activities of mitochondria oxidative phosphorylation complexes. The levels of light chain 3-1 (LC3-I), light chain 3-II (LC3-II), PTEN-induced putative kinase 1 (PINK1), and Parkin were determined to investigate whether mitophagy is involved in the weaning process. The results showed that, as compared with the preweaning phase (d 0), weaning suppressed (P < 0.05) the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) on d 3 and d 7 postweaning, decreased (P < 0.05) the expression of copper and zinc superoxide dismutase (Cu/Zn-SOD), manganese-containing superoxide dismutase (Mn-SOD) on d 3 postweaning, declined (P < 0.05) the level of glutathione peroxidase 1 (GPX-1) and glutathione peroxidase 4 (GPX-4) on d 3 and d 7 postweaning, and increased (P < 0.05) MDA content in jejunum on d 3 and d 7 postweaning. The jejunal transepithelial electrical resistance and levels of occludin, claudin-1, and zonula occludens-1 on d 3 and d 7 postweaning were reduced (P < 0.05), and paracellular flux of fluorescein isothiocyanatedextran (4 kDa) on d 3 and d 7 postweaning was increased (P < 0.05). Weaning induced mitochondrial dysfunction, as demonstrated by decreased (P < 0.05) content of mtDNA on d 3 and d 7 postweaning and declined (P < 0.05) activities of mitochondria complexes (I, II, III, IV) in jejunum on d 1, d 3, and d 7 postweaning. Weaning led to an increased (P < 0.05) expression level of mitophagy-related proteins, PINK1 and Parkin, in the intestinal mitochondria, as well as an enhancement (P < 0.05) of the ratio of LC3-II to LC3-I content in the jejunal mucosa on d 1, d 3, and d 7 postweaning. These results suggest that weaning disrupted intestinal oxidative balance, and this imbalance may impair intestinal barrier and mitochondrial function and trigger mitophagy in piglets.

Animal production and soil characteristics from integrated crop-livestock systems: toward sustainable intensification.

Abstract: Sustainable intensification of land-use practices has never been more important to ensure food security for a growing world population. When combined under thoughtful management, cover cropping and crop-livestock integration under no-till systems can benefit from unexpected synergies due to their unique features of plant-animal diversification and complex agroecosystem functions. Mimicking the nutrient coupling/decoupling processes of natural ecosystems by diversifying plant and animal components of no-till integrated crop-livestock operations is an essential feature of the design of agroecological systems that support self-regulating feedbacks and lend resilience while increasing productivity and ecosystem service provision. Focusing on grazing animals as drivers of agroecosystem change, we highlight the benefits of grazed cover crops in rotation with cash crops for primary and secondary production and for soil physical, chemical, and biological parameters. However, careful management of grazing intensity is imperative; overgrazing drives soil deterioration, while light to moderate grazing enhances overall system functioning and allows for the generation of emergent properties.

Genetic parameters of methane emissions determined using portable accumulation chambers in lambs and ewes grazing pasture and genetic correlations with emissions determined in respiration chambers.

Abstract: Methane (CH4) emission traits were previously found to be heritable and repeatable in sheep fed alfalfa pellets in respiration chambers (RC). More rapid screening methods are, however, required to increase genetic progress and to provide a cost-effective method to the farming industry for maintaining the generation of breeding values in the future. The objective of the current study was to determine CH4 and carbon dioxide (CO2) emissions using several 1-h portable accumulation chamber (PAC) measurements from lambs and again as ewes while grazing ryegrass-based pasture. Many animals with PAC measurements were also measured in RC while fed alfalfa pellets at 2.0 × maintenance metabolizable energy requirements (MEm). Heritability estimates from mixed models for CH4 and CO2 production (g/d) were 0.19 and 0.16, respectively, when measured using PAC with lambs; 0.20 and 0.27, respectively, when measured using PAC with ewes; and 0.23 and 0.34, respectively, when measured using RC with lambs. For measured gas traits, repeatabilities of measurements collected 14 d apart ranged from 0.33 to 0.55 for PAC (combined lambs and ewes) and were greater at 0.65 to 0.76 for the same traits measured using RC. Genetic correlations (rg) between PAC in lambs and ewes were 0.99 for CH4, 0.93 for CH4 + CO2, and 0.85 for CH4/(CH4 + CO2), suggesting that CH4 emissions in lambs and ewes are the same trait. Genetic correlations between PAC and RC measurements were lower, at 0.62 to 0.67 for CH4 and 0.41 to 0.42 for CH4 + CO2, likely reflecting different environmental conditions associated with the protocols used with the 2 measurement methods. The CH4/(CH4 + CO2) ratio was the most similar genetic trait measured using PAC (both lambs and ewes, 63% and 66% selection efficiency, respectively) compared with CH4 yield (g/kg DMI) measured using RC. These results suggest that PAC measurements have considerable value as a rapid low-cost method to estimate breeding values for CH4 emissions in sheep.

Effect of feeding condensed tannins in high protein finishing diets containing corn distillers grains on ruminal fermentation, nutrient digestibility, and route of nitrogen excretion in beef cattle

Abstract: Eight ruminally cannulated crossbred beef heifers (427 ± 41.2 kg, body weight) were used in a replicated 4 × 4 Latin square to determine the effects of feeding a condensed tannin (CT) extract with high protein diets containing corn dried distillers grains and solubles (DG) on ruminal fermentation, nutrient digestibility, and route of nitrogen (N) excretion. Dietary treatments included [dry matter (DM) basis]: 0 (0DG), 20 (20DG), and 40% DG (40DG), and 40% DG with 2.5% CT extract (1.33% CT) from Acacia mearnsii (40DGCT). The DG and CT extract were substituted for grain in a barley-based diet that contained 91% concentrate and 9% silage (DM basis) and was fed as a total mixed ration once daily. The crude protein concentrations of the diets were 12.9, 16.8, 20.4, and 20.5% for 0DG, 20DG, 40DG, and 40DGCT, respectively. Periods were 5 wk with 2 wk for transition to the DG level of the diets, 1 wk for adaptation to CT, and 2 wk for measurements. Feed offered and refused were measured daily. Total urine and fecal output were collected daily for 4 d consecutively. Data were analyzed using a mixed linear model with diet and period as fixed effects and square and animal within square as random effects. There was no effect (P ≥ 0.22) of CT on DM intake, but 40% DG in the diet (40DG and 40DGCT) decreased (P ≤ 0.015) DM intake compared with 20DG. As a result, nitrogen (N) intake was not different (P > 0.15) among heifers fed 20DG, 40DG, and 40DGCT (313 g N/d) and was less (P ≤ 0.001) for heifers fed 0DG (220 ± 18 g N/d). Apparent total tract N digestibility was less (P ≤ 0.001) in heifers fed 40DGCT (70.6 ± 1.07%) compared with to 0DG, 20DG, and 40DG (78.4%). There was no effect (P = 0.84) of CT (40DGCT vs. 40DG) on the total N output, however, feeding 40DGCT decreased (P ≤ 0.001) the excretion of total urinary N and urea N in urine by 17 and 21%, respectively, compared with heifers fed 40DG and was equivalent (P ≥ 0.12) to the amount excreted by heifers fed 20DG. The reduction of N digestibility reflected the protein binding effects of CT within the gastrointestinal tract and the shift in excess N excretion from labile urea N in urine to bound NDIN and ADIN in feces (P ≤ 0.001) in heifers fed 40DGCT compared with 40DG. Supplementation of CT in high protein diets fed to feedlot cattle reduced urinary N and increased the capture of N in manure to potentially lesson the loss of N as ammonia and provide opportunities for improved nutrient management of beef production.

BOARD-INVITED REVIEW: Arginine nutrition and metabolism in growing, gestating, and lactating swine.

Abstract: Arginine (Arg) has traditionally not been considered as a deficient nutrient in diets for gestating or lactating swine due to the assumption that these animals can synthesize sufficient amounts of Arg to meet their physiological needs. The lack of full knowledge about Arg nutrition has contributed to suboptimal efficiency of pork production. Over the past 25 yr, there has been growing interest in Arg metabolism in the pig, which is an agriculturally important species and a useful model for studying human biology. Arginine is a highly abundant amino acid in tissues of pigs, a major amino acid in allantoic fluid, and a key regulator of gene expression, cell signaling, and antioxidative reactions. Emerging evidence suggests that dietary supplementation with 0.5% to 1% Arg maintains gut health and prevents intestinal dysfunction in weanling piglets, while enhancing their growth performance and survival. Also, the inclusion of 1% Arg in diets is required to maximize skeletal muscle accretion and feed efficiency in growing pigs, whereas dietary supplementation with 1% Arg reduces muscle loss in endotoxin-challenged pigs. Furthermore, supplementing 0.83% Arg to corn- and soybean meal-based diets promotes embryonic/fetal survival in swine and milk production by lactating sows. Thus, an adequate amount of dietary Arg as a quantitatively major nutrient is necessary to support maximum growth, lactation, and reproduction performance of swine. These results also have important implications for improving the nutrition and health of humans and other animals.

Risk factors associated with animal mortality in pasture-based, seasonal-calving dairy and beef herds.

Abstract: Animal mortality is indicative of animal health and welfare standards, which are of growing concern to the agricultural industry. The objective of the present study was to ascertain risk factors associated with mortality at multiple life stages in pasture-based, seasonal-calving dairy and beef herds. Males and females were stratified into seven life stages based on age (0 to 2 d, 3 to 7 d, 8 to 30 d, 31 to 182 d, 183 to 365 d, 366 to 730 d, and 731 to 1,095 d) whereas females with ≥1 calving event were further stratified into five life stages based on cow parity number (1, 2, 3, 4, and 5). Mortality was defined as whether an animal died during each life stage; only animals that either survived the entire duration or died during a life stage were considered. The data, following edits, consisted of 4,404,122 records from 1,358,712 animals. Multivariable logistic regression was used to estimate the logit of the probability of mortality in each life stage separately. The odds of a young animal (i.e., aged ≤ 1,095 d) dying was generally greater if veterinary assistance was required at their birth relative to no assistance (odds ratio [OR]: 3.10 to 31.85), if the animal was a twin relative to a singleton (OR: 1.46 to 2.31) or if the animal was male relative to female (OR: 1.14 to 6.15). Moreover, the odds of a cow (i.e., females with ≥1 calving event) dying were greater when she required veterinary assistance at calving (OR: 2.69 to 7.55) compared with a cow that did not require any assistance, if she produced twin relative to singleton progeny (OR: 1.59 to 2.03) or male relative to female progeny (OR: 1.09 to 1.20). Additionally, the odds of a first or second parity cow dying when she herself had received veterinary assistance at birth were only 0.63 to 0.66 times that of a cow that was provided no assistance at birth. For both young animals and cows, the odds of dying generally increased with herd size, whereas animals residing in expanding herds had lower odds of dying. Results from the present study indicate that the risk factors associated with mortality in pasture-based, seasonal-calving herds are similar to those reported in literature in confinement, nonseasonal-calving herds. Moreover, the present study identifies that these risk factors are similar in both dairy and beef herds, yet the magnitude of the association often differs and also changes with life stage.

Curcumin attenuates hepatic mitochondrial dysfunction through the maintenance of thiol pool, inhibition of mtDNA damage, and stimulation of the mitochondrial thioredoxin system in heat-stressed broilers.

Abstract: The aim of this study was to investigate the effects of dietary curcumin supplementation on the performance, mitochondrial redox system, mitochondrial DNA (mtDNA) integrity, and antioxidant-related gene expression in the liver of broiler chickens after heat stress treatment. At day 21, a total of 400 Arbor Acres broiler chickens with similar body weight (BW) were divided into 5 groups with 8 replicates per group and then reared either at a normal temperature (22 ± 1 °C) or at a high ambient temperature (34 ± 1 °C for 8 h and 22 ± 1 °C for the remaining time) for 20 d. Broilers in the 5 groups were fed a basal diet at a normal temperature (NT group) and a basal diet with 0, 50, 100, and 200 mg/kg curcumin at a high ambient temperature (HT, CUR50, CUR100, and CUR200 groups), respectively. The serum and liver samples were analyzed for the parameters related to hepatic damage, mitochondrial function, and redox status. The results showed that the G:F was increased in the CUR50 and CUR100 groups, and the final BW was increased in CUR100 group in comparison with the HT group (P < 0.05). When compared with those in the HT group, both serum aspartate and alanine aminotransferase activities were decreased in the curcumin-supplemented groups (P < 0.05). Curcumin decreased the reactive oxygen species (ROS) production but increased the mitochondrial membrane potential in the hepatocytes of the broilers after heat stress (P < 0.05). The broilers in curcumin-supplemented groups had lower malondialdehyde and protein carbonyl concentrations as well as greater thiol concentrations (P < 0.05). The mitochondrial manganese superoxide dismutase (MnSOD) activity in the liver was increased (P < 0.05) in the CUR100 group compared with the HT group. Compared with the heat-stressed broilers, the broilers that were fed curcumin had greater (P < 0.05) mtDNA copy number and ATP concentrations than those in the HT group. Curcumin supplementation attenuated the depression of the thioredoxin 2 and peroxiredoxin-3 gene expressions (P < 0.05). The MnSOD gene expression was increased in the CUR100 and CUR200 groups, and the thioredoxin reductase 2 gene expression was increased in the CUR50 group in comparison with the HT group (P < 0.05). In conclusion, curcumin mitigated the mitochondrial dysfunction in heat-stressed broilers, as evidenced by the suppression of the ROS burst, the maintenance of the thiol pool and mtDNA content, and the enhanced mitochondrial antioxidant gene expression.

Fecal microbial composition associated with variation in feed efficiency in pigs depends on diet and sex

Abstract: Dietary fiber content and composition affect microbial composition and activity in the gut, which in turn influence energetic contribution of fermentation products to the metabolic energy supply in pigs. This may affect feed efficiency (FE) in pigs. The present study investigated the relationship between the fecal microbial composition and FE in individual growing-finishing pigs. In addition, the effects of diet composition and sex on the fecal microbiome were studied. Fecal samples were collected of 154 grower-finisher pigs (3-way crossbreeds) the day before slaughter. Pigs were either fed a diet based on corn/soybean meal (CS) or a diet based on wheat/barley/by-products (WB). Fecal microbiome was characterized by 16S ribosomal DNA sequencing, clustered by operational taxonomic unit (OTU), and results were subjected to a discriminant approach combined with principal component analysis to discriminate diets, sexes, and FE extreme groups (10 high and 10 low FE pigs for each diet by sex-combination). Pigs on different diets and males vs. females had a very distinct fecal microbiome, needing only 2 OTU for diet (P = 0.020) and 18 OTU for sex (P = 0.040) to separate the groups. The 2 most important OTU for diet, and the most important OTU for sex, were taxonomically classified as the same bacterium. In pigs fed the CS diet, there was no significant association between FE and fecal microbiota composition based on OTU (P > 0.05), but in pigs fed the WB diet differences in FE were associated with 17 OTU in males (P = 0.018) and to 7 OTU in females (P = 0.010), with 3 OTU in common for both sexes. In conclusion, our results showed a diet and sex-dependent relationship between FE and the fecal microbial composition at slaughter weight in grower-finisher pigs.

Supplementation of fructooligosaccharides to suckling piglets affects intestinal microbiota colonization and immune development.

Abstract: Emerging knowledge shows the importance of early life events in programming the intestinal mucosal immune system and development of the intestinal barrier function. These processes depend heavily on close interactions between gut microbiota and host cells in the intestinal mucosa. In turn, development of the intestinal microbiota is largely dependent on available nutrients required for the specific microbial community structures to expand. It is currently not known what the specificities are of intestinal microbial community structures in relation to the programming of the intestinal mucosal immune system and development of the intestinal barrier function. The objective of the present study was to investigate the effects of a nutritional intervention on intestinal development of suckling piglets by daily oral administration of fructooligosaccharides (FOS) over a period of 12 d (days 2-14 of age). At the microbiota community level, a clear "bifidogenic" effect of the FOS administration was observed in the colon digesta at day 14. The former, however, did not translate into significant changes of local gene expression in the colonic mucosa. In the jejunum, significant changes were observed for microbiota composition at day 14, and microbiota diversity at day 25. In addition, significant differentially expressed gene sets in mucosal tissues of the jejunum were identified at both days 14 and 25 of age. At the age of 14 d, a lower activity of cell cycle-related processes and a higher activity of extracellular matrix processes were observed in the jejunal mucosa of piglets supplemented with FOS compared with control piglets. At day 25, the lower activity of immune-related processes in jejunal tissue was seen in piglets supplemented with FOS. Villi height and crypt depth in the jejunum were significantly different at day 25 between the experimental and control groups, where piglets supplemented with FOS had greater villi and deeper crypts. We conclude that oral FOS administration during the early suckling period of piglets had significant bifidogenic effects on the microbiota in the colon and on gene expression in the jejunal mucosa by thus far unknown mechanisms.

Excessive backfat of sows at 109 d of gestation induces lipotoxic placental environment and is associated with declining reproductive performance.

Abstract: This study investigated the influence of sow backfat thickness at 109 d of gestation on sow and piglet performance. Data from 846 farrowing multiparous Yorkshire sows with parity from 3 to 5 were collected from a pig breeding farm. Sows were divided into six groups based on backfat thickness (≤16, 17-18, 19-20, 21-22, 23-24, and ≥25 mm) at 109 d of gestation. The evaluation of reproductive performance included the litter size, litter weight at birth and at weaning of 21 d, weight of placenta at parturition, placental efficiency, and sow daily feed intake of lactation. Parameters related to plasma lipids and the placental-lipid concentration were measured. Data were analyzed to determine the relationships among backfat thickness, placental lipids, and piglet performance. No differences were observed in the number of piglets born, born alive, after cross-foster, and at weaning among groups (P > 0.05). The litter weight at birth and weaning, piglet birth weight, weaning weight, placental efficiency, and the number and percentage of piglets born with weight of <800 g showed a significantly quadratic effect of the backfat thickness (P < 0.05). During lactation, sow daily feed intake linearly decreased with increased backfat thickness at 109 d of gestation (P < 0.05). Although triglycerides and low-density lipoprotein cholesterol (LDL-C) showed no significant difference, cholesterol and high-density lipoprotein cholesterol (HDL-C) and free fatty acid (FFA) concentrations significantly increased (P < 0.05) in both maternal and umbilical cord blood with increased backfat thickness of sow. Placental-lipid concentrations also significantly increased (P < 0.05) with increased backfat thickness. Moreover, backfat thickness and placental-lipid concentration were positively correlated with the number of piglets weighing <800 g (P < 0.01) but negatively correlated with birth weight, litter birth weight, and piglet weaned weight (P < 0.01). In conclusion, backfat thickness of sow at end of gestation correlates with birth and weaning weight of piglets. Placental ectopic lipid accumulation-induced lipotoxicity is likely responsible for such correlation.

Immunomodulatory potential of dietary soybean-derived isoflavones and saponins in pigs.

Abstract: In this review, the potential for use of soy-derived bioactive compounds as immunomodulatory feed additives in pigs is discussed. Soy is a major component of the modern U.S. swine diet in today's commercial industry, providing the bulk of dietary AA necessary for growth and production. However, soy use has generally been limited in early growth phases, during which the risks of immunological insult and disease are among the highest. Improvements of soybean processing and development of soy protein products with little to no antinutritional factors have made soy more appropriate for use in young pigs but additional processing may affect bioactive compound levels in the feed. The bioactive compounds of interest for this review are soy isoflavones and soy saponins. Soy isoflavones are flavonoid compounds with a range of biological activity including moderate estrogenic effects at low biological concentrations. Although estrogenic effects are of more interest in human medical research, isoflavones are also known for their anti-inflammatory, antioxidative properties at cellular levels, engaging several receptors and pathways including inhibition of NF-κB activation and inducible-nitric oxide synthase enzymes, thereby ascribing antiviral properties. Saponins, amphipathic glycoside compounds, also engage anti-inflammatory pathways, though their biological activity in pigs has not been well investigated and seem to mainly be observed on the mucous membrane in the gastrointestinal tract. Regarding use as an immunomodulatory feed additive, supplemental soy isoflavones have been shown to improve immunological status of pigs and produce mild improvements of growth performance under certain disease challenges including porcine reproductive and respiratory syndrome virus. Although more in vivo research in pigs is needed to fully understand biological activity of these compounds in the live animal, soy-derived bioactive compounds show great potential as a health promoting feed additive for the modern swine industry.

Dietary tea polyphenol supplementation improved egg production performance, albumen quality, and magnum morphology of Hy-Line Brown hens during the late laying period.

Abstract: The aim of this study was to investigate how dietary supplementation of tea polyphenols (TP) and tea catechins (TC) affect laying performance, albumen quality, ovomucin composition, and magnum morphology of laying hens in the late phase of production. Two hundred seventy Hy-Line Brown laying hens (64 wk old) were assigned to a basal diet (the control), the basal diet supplemented with 200 mg/kg tea polyphenols (TP200) or 200 mg/kg tea catechins (TC200). Each treatment had 6 replicates with 15 hens each. The feeding trial lasted 10 wks. Over the course of the trial, dietary supplementation with TP200 significantly increased the egg production (EP) and improved the feed conversion ratio (FCR) in wk 6 to 10 and wk 1 to 10 (P 0.05). The SDS-PAGE analysis indicated that bands of the ovomucin fractions in the TP200 group had the highest intensity compared with those of the control and TC200 groups. Compared with the control, there was a significant increase in protein sulfhydryl (SH) content of the albumen in the TP200 group at the end of experiment, while a significant decrease in protein carbonyl content and protein surface hydrophobicity (P < 0.05). There were also obvious increase in the height and width of the primary folds, epithelial cell height, and cilia height of the simple columnar epithelium in the TP200 group compared with the control and TC200 groups (P < 0.05). In conclusion, dietary supplementation with 200 mg/kg TP can improve performance, albumen quality, and magnum morphology of aged hens. In addition, TP rather than TC could improve the health status of the magnum for aged layers.

Preslaughter handling practices and their effects on animal welfare and pork quality.

Abstract: At all times, prior to slaughter, pigs may experience stress from a range of handling practices, such as fasting, loading and transport, mixing, and interaction with humans. These factors can affect the welfare of pigs and carcass and meat quality, both individually and collectively. Preslaughter stress is both an animal welfare and a meat quality issue. Behavioral and physiological studies have revealed that poor handling practices at the farm, during transport and at the slaughter plant, have an adverse effect on pigs and may result in the loss of profits due to animal losses during transport and in lairage. Also, poor preslaughter handling can also lead to losses in carcass value as a result of reduced yield, the presence of lesions and bacterial contamination, and meat quality defects (e.g., pale, soft, exudative and dark, firm, dry pork). These economic losses can be limited by improving the design of facilities, controlling the environmental conditions, and implementing training programs for the correct animal handling at any stage preslaughter. The objective of this review was to review research findings on the effects of preslaughter practices on ante-mortem behavioral and physiological response in pigs, including muscle metabolism, and to provide recommendations aimed at limiting the impact of preslaughter handling on animal losses and pork quality.

Effect of engineered biocarbon on rumen fermentation, microbial protein synthesis, and methane production in an artificial rumen (RUSITEC) fed a high forage diet

Abstract: The objective of this study was to investigate the effects of adding engineered biocarbon to a high-forage diet on ruminal fermentation, nutrient digestion, and enteric methane (CH4) production in a semi-continuous culture artificial rumen system (RUSITEC). The experiment was a completely randomized block design with four treatments assigned to sixteen fermentation vessels (four/treatment) in two RUSITEC apparatuses. The basal diet consisted of 60% barley silage, 27% barley grain, 10% canola meal, and 3% supplement (DM basis) with biocarbon added at 0, 0.5, 1, and 2% of substrate DM. The study period was 17 d, with a 10-d adaptation and 7-d sample collection period. Increasing biocarbon linearly increased (P 0.05) in production of total gas, large or small peptides, or in the number of protozoa as a result of addition of biocarbon to the diet. Addition of biocarbon to a forage diet increased DM digestibility by up to 2%, while lowering enteric CH4 production and enhancing microbial protein synthesis in in vitro semi- continuous culture fermenters.

A genome-wide association study of growth and fatness traits in two pig populations with different genetic backgrounds.

Abstract: Improvement in growth and fatness traits are the main objectives in pig all breeding programs. Tenth rib backfat thickness (10RIBBFT) and days to 100 kg (D100), which are good predictors of carcass lean content and growth rate, respectively, are economically important traits and also main breeding target traits in pigs. To investigate the genetic mechanisms of 10RIBBFT and D100 of pigs, we sampled 1,137 and 888 pigs from 2 Yorkshire populations of American and British origin, respectively, and conducted genome-wide association study (GWAS) through combined analysis and meta-analysis, to identify SNPs associated with 10RIBBFT and D100. A total of 11 and 7 significant SNPs were identified by combined analysis for 10RIBBFT and D100, respectively. And in meta-analysis, 8 and 7 significant SNPs were identified for 10RIBBFT and D100, respectively. Among them, 6 and 5 common significant SNPs in two analysis results were, respectively, identified associated with 10RIBBFT and D100, and correspondingly explained 2.09% and 0.52% of the additive genetic variance of 10RIBBFT and D100. Further bioinformatics analysis revealed 10 genes harboring or close to these common significant SNPs, 5 for 10RIBBFT and 5 for D100. In particular, Gene Ontology analysis highlighted 6 genes, PCK1, ANGPTL3, EEF1A2, TNFAIP8L3, PITX2, and PLA2G12, as promising candidate genes relevant with backfat thickness and growth. PCK1, ANGPTL3, EEF1A2, and TNFAIP8L3 could influence backfat thickness through phospholipid transport, regulation of lipid metabolic process through the glycerophospholipid biosynthesis and metabolism pathway, the metabolism of lipids and lipoproteins pathway. PITX2 has a crucial role in skeletal muscle tissue development and animal organ morphogenesis, and PLA2G12A plays a role in the lipid catabolic and phospholipid catabolic processes, which both are involved in the body weight pathway. All these candidate genes could directly or indirectly influence fat production and growth in Yorkshire pigs. Our findings provide novel insights into the genetic basis of growth and fatness traits in pigs. The candidate genes for D100 and 10RIBBFT are worthy of further investigation.

Volatile flavor compounds vary by beef product type and degree of doneness.

Abstract: This study aimed to determine how quality grade and degree of doneness (DOD) influence the development of volatile compounds among beef whole muscle and ground patties. Volatile compounds were quantified via head space solid phase microextraction from samples tempered in refrigerated temperatures (3 to 5 °C), room temperature (24 to 26 °C), or cooked on an electric clamshell-style grill to an endpoint temperature of 55, 60, 71, or 77 °C. Collected samples were subsequently determined by gas chromatography mass spectrometry. Prominent compounds known to be the result of the Maillard reaction or lipid degradation were retained for comparison. Four Strecker aldehydes, 4 pyrazines, and one ester had a 3-way interaction between quality grade, DOD, and product type (each P 0.05) in ground patties and was comparably greater (P < 0.05) in steaks; in Prime and Low Choice steaks, pyrazine concentration increased (P < 0.05) as DOD increased. A 2-way interaction between quality grade and product type was observed for acetaldehyde, dimethyl disulfide, 1-penten-3-ol, butanoic acid, hexanal, octanal, nonanal, and 2-heptanone. Among which, octanal and nonanal were greater (P < 0.05) in Prime steaks compared with ground patties. Another 2-way interaction, quality grade and DOD, was observed in 2 ketones, an alcohol, 2 esters, and 2 aldehydes. For example, 2,3-butanedione was greater (P < 0.05) in concentration in Prime 4 °C samples compared with Low Choice and Standard. The final 2-way interaction of DOD and product type was observed in 3 ketones, 2 sulfur compounds, 2 esters, 5 aldehydes, 2 carboxylic acids, and a ketone. For example, 2-heptanone was greater (P < 0.05) in concentration in ground patties compared to steaks in all degrees of doneness except 4 °C. Overall, these results indicate that the volatile flavor profile of beef is greatly influenced by product type and DOD. Generally, consumers select beef based on product type and determine their cookery approach. Therefore, consumers may greatly influence final beef flavor profile.

Development and validation of a small SNP panel for feed efficiency in beef cattle.

Abstract: The objective of this study was to develop and validate a customized cost-effective single nucleotide polymorphism (SNP) panel for genetic improvement of feed efficiency in beef cattle. The SNPs identified in previous association studies and through extensive analysis of candidate genomic regions and genes, were screened for their functional impact and allele frequency in Angus and Hereford breeds used as validation candidates for the panel. Association analyses were performed on genotypes of 159 SNPs from new samples of Angus (n = 160), Hereford (n = 329), and Angus-Hereford crossbred (n = 382) cattle using allele substitution and genotypic models in ASReml. Genomic heritabilities were estimated for feed efficiency traits using the full set of SNPs, SNPs associated with at least one of the traits (at P ≤ 0.05 and P < 0.10), as well as the Illumina bovine 50K representing a widely used commercial genotyping panel. A total of 63 SNPs within 43 genes showed association (P ≤ 0.05) with at least one trait. The minor alleles of SNPs located in the GHR and CAST genes were associated with decreasing effects on residual feed intake (RFI) and/or RFI adjusted for backfat (RFIf), whereas minor alleles of SNPs within MKI67 gene were associated with increasing effects on RFI and RFIf. Additionally, the minor allele of rs137400016 SNP within CNTFR was associated with increasing average daily gain (ADG). The SNPs genotypes within UMPS, SMARCAL, CCSER1, and LMCD1 genes showed significant over-dominance effects whereas other SNPs located in SMARCAL1, ANXA2, CACNA1G, and PHYHIPL genes showed additive effects on RFI and RFIf. Gene enrichment analysis indicated that gland development, as well as ion and cation transport are important physiological mechanisms contributing to variation in feed efficiency traits. The study revealed the effect of the Jak-STAT signaling pathway on feed efficiency through the CNTFR, OSMR, and GHR genes. Genomic heritability using the 63 significant (P ≤ 0.05) SNPs was 0.09, 0.09, 0.13, 0.05, 0.05, and 0.07 for ADG, dry matter intake, midpoint metabolic weight, RFI, RFIf, and backfat, respectively. These SNPs contributed to genetic variation in the studied traits and thus can potentially be used or tested to generate cost-effective molecular breeding values for feed efficiency in beef cattle.

Low-protein diet improves meat quality of growing and finishing pigs through changing lipid metabolism, fiber characteristics, and free amino acid profile of the muscle.

Abstract: The objective of the study was to investigate the effect of feeding reduced CP, AA-supplemented diets on meat quality in growing and finishing pigs as well as the related mechanism. In experiment 1, 18 growing pigs (36.5 kg BW) were assigned randomly and fed 1 of 3 corn-soybean meal diets containing either 18% CP (normal protein, NP), 15% CP (low protein, LP), or 12% CP (very low protein, VLP). In experiment 2, 18 finishing pigs (62.3 kg BW) were allotted randomly into 1 of the following diets: 16% CP (NP), 13% CP (LP), or 10% CP (VLP). In both experiments, the LP and VLP diets were supplemented with crystalline AA to achieve equal content of standardized ileal digestible lysine, methionine, threonine, and tryptophan. At the end of each experiment, all pigs were slaughtered to collect longissimus dorsi muscle (LM) samples. Samples were used for determining meat quality, intramuscular fat (IMF) content, fatty acid composition, free AA profile, and expression of genes for myosin heavy chain isoforms. Results showed that growing and finishing pigs fed the LP diets increased (P < 0.05) redness value of LM, while finishing pigs fed the LP and VLP diets decreased (P < 0.05) the shear force values. Compared with the NP diet, growing and finishing pigs fed lower CP diets had higher (P < 0.05) contents of IMF and MUFA, and lower (P < 0.05) contents of PUFA. Besides, higher (P < 0.05) expression levels of type I and/or IIa muscle fibers were observed in LP diet-fed growing and finishing pigs, and greater concentrations of taurine and tasty AA in VLP diet-fed growing and finishing pigs. Taken together, our results indicate that low-protein diets could positively affect meat quality of growing and finishing pigs, and likely through regulation of IMF content and fatty acid composition, fiber characteristics, and free AA profile in the muscle.