Showing papers in "Journal of Dairy Research in 2015"
TL;DR: The findings suggest that the purified dipeptide has the potential to be used as ion-binding ingredient in dietary supplements and sequestered calcium percentage experiment has proved that EG-Ca is significantly more stable than CaCl2 in human gastrointestinal tract in vitro.
Abstract: The bioavailability of dietary ionised calcium is affected by intestinal basic environment. Calcium-binding peptides can form complexes with calcium to improve its absorption and bioavailability. The aim of this study was focused on isolation and characterisation of a calcium-binding peptide from whey protein hydrolysates. Whey protein was hydrolysed using Flavourzyme and Protamex with substrate to enzyme ratio of 25:1 (w/w) at 49 °C for 7 h. The calcium-binding peptide was isolated by DEAE anion-exchange chromatography, Sephadex G-25 gel filtration and reversed phase high-performance liquid chromatography (RP-HPLC). A purified peptide of molecular mass 204 Da with strong calcium binding ability was identified on chromatography/electrospray ionisation (LC/ESI) tandem mass spectrum to be Glu-Gly (EG) after analysis and alignment in database. The calcium binding capacity of EG reached 67·81 μg/mg, and the amount increased by 95% compared with whey protein hydrolysate complex. The UV and infrared spectrometer analysis demonstrated that the principal sites of calcium-binding corresponded to the carboxyl groups and carbonyl groups of glutamic acid. In addition, the amino group and peptide amino are also the related groups in the interaction between EG and calcium ion. Meanwhile, the sequestered calcium percentage experiment has proved that EG-Ca is significantly more stable than CaCl2 in human gastrointestinal tract in vitro. The findings suggest that the purified dipeptide has the potential to be used as ion-binding ingredient in dietary supplements.
57 citations
TL;DR: On dairies with optimum colostral feeding practices, serum IgG and TP concentrations of 2001–2500 mg/dl and 5·8–6·3 g/dl are recommended as endpoints to indicate adequate passive immunity in dairy calves.
Abstract: Colostral administration practices on dairy farms have significantly improved over the last 15-20 years resulting in prevalence of calves ingesting insufficient colostrum decreasing from 35-40% to 19%. Despite these improvements, the serum immunoglobulin G (IgG) concentration of ≥ 1000 g/dl and serum total protein (TP) concentrations of ≥ 5. 2 g/dl are considered indicative of adequate transfer of immunity. We hypothesised that the current serum IgG concentrations of ≥ 1000 mg/dl is too low to indicate adequate transfer of colostral immunity on modern dairies. The objective of this study was to determine the serum IgG and TP concentrations indicating adequate transfer of passive immunity in dairy heifer calves. A cohort study of 1290 heifers from a calf raising facility for 48 dairy farms was performed. Heifers were assigned into strata based on serum IgG and TP concentrations. Mortality events were recorded for the heifers for 4 months. Interval likelihood ratios for mortality were calculated for heifers in each stratum of serum IgG or TP concentrations. Logistic regression to predict probability of mortality events was performed. Estimates of probability of survival were evaluated using survival analysis. Serum strata of ≤ 1500, 1501-2000 or >2500 were not significant predictors of mortality during the 120 d of rearing. Serum IgG concentration was not a significant predictor of hazard for mortality. In contrast to previous studies, serum IgG and TP concentrations of 2001-2500 mg/dl and 5.8-6.3 g/dl respectively, were considered optimum for indicating adequate passive transfer of colostral immunity in dairy calves based on the likelihood ratios. On dairies with optimum colostral feeding practices, serum IgG and TP concentrations of 2001-2500 mg/dl and 5.8-6.3 g/dl are recommended as endpoints to indicate adequate passive immunity in dairy calves.
50 citations
TL;DR: β-CN(94-123) is a multifunctional molecule but only the sequence of 30 amino acids has a stimulating effect on the production of MUC2, a crucial factor of intestinal protection.
Abstract: We recently reported the identification of a peptide from yoghurts with promising potential for intestinal health: the sequence (94-123) of bovine β-casein This peptide, composed of 30 amino acid residues, maintains intestinal homoeostasis through production of the secreted mucin MUC2 and of the transmembrane-associated mucin MUC4 Our study aimed to search for the minimal sequence responsible for the biological activity of β-CN(94-123) by using several strategies based on (i) known bioactive peptides encrypted in β-CN(94-123), (ii) in silico prediction of peptides reactivity and (iii) digestion of β-CN(94-123) by enzymes of intestinal brush border membranes The revealed sequences were tested in vitro on human intestinal mucus-producing HT29-MTX cells We demonstrated that β-CN(108-113) (an ACE-inhibitory peptide) and β-CN(114-119) (an opioid peptide named neocasomorphin-6) up-regulated MUC4 expression whereas levels of the secreted mucins MUC2 and MUC5AC remained unchanged The digestion of β-CN(94-123) by intestinal enzymes showed that the peptides β-CN(94-108) and β-CN(117-123) were present throughout 1·5 to 3 h of digestion, respectively These two peptides raised MUC5AC expression while β-CN(117-123) also induced a decrease in the level of MUC2 mRNA and protein In addition, this inhibitory effect was reproduced in airway epithelial cells In conclusion, β-CN(94-123) is a multifunctional molecule but only the sequence of 30 amino acids has a stimulating effect on the production of MUC2, a crucial factor of intestinal protection
39 citations
TL;DR: Fat, protein fractions, true protein, casein and whey proteins, P and titratable acidity of V-milk were positively correlated with its 24 h ACY, while chloride, pH and SCS showed a negative correlation.
Abstract: The aim of this study was to determine the influence of the somatic cell content (SCC) of milk on Parmigiano-Reggiano cheese yield, produced in commercial cheese factories under field conditions. The study was carried out following the production of 56 batches of Parmigiano-Reggiano in 13 commercial cheese factories by processing milk collected from Italian Friesian cattle herds. The vat-milk (V-milk) used for making each cheese batch was obtained by mixing evening milk (partially skimmed following spontaneous separation of fat overnight, natural creaming) and morning milk. The batches of cheese produced were divided into 5 classes according to the SCC value of the evening milk determined prior to natural creaming (class 1, from 0 to 200 000; 2, 201 000–300 000; 3, 301 000–400 000; 4, 401 000–500 000; 5, over 501 000 cells/ml). The cheese yield was calculated as the amount of 24-h cheese, expressed in kilograms, obtained from 100 kg of V-milk (24 h ACY). The values of fat, crude protein, true protein, casein and 24 h ACY of V-milk were negatively correlated with the somatic cell score (SCS) of the evening milk. Conversely, a positive correlation was observed between chloride and SCS. Fat, protein fractions (crude protein, casein and whey proteins), P and titratable acidity of V-milk were positively correlated with its 24 h ACY, while chloride, pH and SCS showed a negative correlation. A significant drop in 24 h ACY was observed in classes 3, 4 and 5, therefore when the SCC of the evening milk exceeded 300 000 cells/ml. Finally a lower recovery of milk fat in cheese was observed as SCC of evening milk increase.
39 citations
TL;DR: Using PCR as the only microbiological method for mastitis diagnostics, clinical relevance of the results should be carefully considered before further decisions, for instance antimicrobial treatment, especially when minor pathogens with low amount of DNA have been detected.
Abstract: Reliable identification of the aetiological agent is crucial in mastitis diagnostics. Real-time PCR is a fast, automated tool for detecting the most common udder pathogens directly from milk. In this study aseptically taken quarter milk samples were analysed with a real-time PCR assay (Thermo Scientific PathoProof Mastitis Complete-12 Kit, Thermo Fisher Scientific Ltd.) and by semi-quantitative, in-depth bacteriological culture (BC). The aim of the study was to evaluate the diagnostic performance of the real-time PCR assay in routine use. A total of 294 quarter milk samples from routine mastitis cases were cultured in the national reference laboratory of Finland and examined with real-time PCR. With BC, 251 out of 294 (85.7%) of the milk samples had at least one colony on the plate and 38 samples were considered contaminated. In the PCR mastitis assay, DNA of target species was amplified in 244 samples out of 294 (83.0%). The most common bacterial species detected in the samples, irrespective of the diagnostic method, was the coagulase negative staphylococci (CNS) group (later referred as Staphylococcus spp.) followed by Staphylococcus aureus. Sensitivity (Se) and specificity (Sp) for the PCR assay to provide a positive Staph. aureus result was 97.0 and 95.8% compared with BC. For Staphylococcus spp., the corresponding figures were 86.7 and 75.4%. Our results imply that PCR performed well as a diagnostic tool to detect Staph. aureus but may be too nonspecific for Staphylococcus spp. in routine use with the current cut-off Ct value (37.0). Using PCR as the only microbiological method for mastitis diagnostics, clinical relevance of the results should be carefully considered before further decisions, for instance antimicrobial treatment, especially when minor pathogens with low amount of DNA have been detected. Introducing the concept of contaminated samples should also be considered.
35 citations
TL;DR: The suitability of this methodology to produce mixtures of dietary non-digestible carbohydrates with prebiotic properties from WP has been demonstrated, which is interesting for the food industry since it increases the value and the applicable of this by-product from cheese manufacture.
Abstract: This work was funded by projects Consolider Ingenio 2010 (FUN-C-FOOD CSD2007-00063), Network Consolider AGL2014-58205-REDC and AGL2011-27884. Beatriz Padilla and Ana I. Ruiz Matute thank their JAE Predoc and JAE Doc contracts from CSIC.
33 citations
TL;DR: The blood metabolite profiles in Majorera and Palmera goats were analysed to establish the differential responses to feed restriction between the two breeds and to characterise their metabolite standard values under control conditions.
Abstract: Feed restriction, and seasonal weight loss (SWL), are major setbacks for animal production in the tropics and the Mediterranean. They may be solved through the use of autochthonous breeds particularly well adapted to SWL. It is therefore of major importance to determine markers of tolerance to feed restriction of putative use in animal selection. Two indigenous breeds from the Canary Islands, Palmera and Majorera, are commonly used by dairy goat farmers and, interestingly, have different phenotype characteristics albeit with a common ancestry. Indeed, Majorera is well adapted to feed restriction whereas the Palmera is susceptible to feed restriction. In addition, regardless of their importance in dairy production, there are only a limited number of reports relating to these breeds and, to the best of our knowledge, there is no description of their blood metabolite standard values under control conditions or as affected by feed restriction. In this study we analysed the blood metabolite profiles in Majorera and Palmera goats aiming to establish the differential responses to feed restriction between the two breeds and to characterise their metabolite standard values under control conditions. We observed significant differences in creatinine, urea, non-esterified fatty acids (NEFAs), cholesterol, IGF-1 and T3 due to underfeeding. Furthermore, a PCA analysis, revealed that animals submitted to undernutrition could be distinguished from the control groups, with the formation of three separate clusters (Palmera individuals after 22 d of subnutrition (PE22); Majorera individuals after 22 d of subnutrition (ME22) and animals assigned to control conditions (MC0, MC22, PC0 and PC22)), highlighting different responses of the two breeds to undernutrition.
32 citations
TL;DR: Changes in the pixel brightness of mammary gland ultrasound images were significantly influenced by MP:ME ratios in the diet of heifers that were subjected to accelerated growth rates, and it is not recommended to use diets of less than 38 g MP/Mcal ME in diets to heifer allowed to gain more than 1 kg/d.
Abstract: This study was conducted to evaluate the development of the mammary gland in Holstein heifers subjected to different dietary metabolisable protein (MP): metabolisable energy (ME) ratios. Twenty-five Holstein heifers (initial body weight (BW) 213±13·5 kg and initial average age 7·8±0·5 months) were divided into five treatments. The treatments were designed to provide MP:ME ratios equal to 33, 38, 43, 48, and 53 g of MP per Mcal of ME. All diets were formulated to have the same energy content (2·6 Mcal ME/kg dry matter). Actual MP:ME ratios were 36·2, 40·2, 46·2, 47·1, and 50·8 g MP/Mcal ME. The experiment was conducted in a randomised block design, while considering initial BW as a blocking factor to evaluate pre- and post-pubertal periods. Block effect was not observed for all variables evaluated; hence it was considered that the diets had the same influence both on pre- and post-pubertal phases. Dry matter and nutrient intake did not change between treatments, excepting protein intake and digestibility. Serum concentrations of insulin-like growth factor 1 increased linearly across treatments. Changes in the pixel brightness of mammary gland ultrasound images, which are associated with lipid content, were significantly influenced by MP:ME ratios in the diet of heifers that were subjected to accelerated growth rates. It is not recommended to use diets of less than 38 g MP/Mcal ME in diets to heifers allowed to gain more than 1 kg/d.
32 citations
TL;DR: It was observed that Lb.
Abstract: In this study, the chemical composition, proteolysis and in vitro angiotensin-converting enzyme-(ACE)-inhibitory and antioxidant activities of white cheeses made using probiotic adjunct cultures (Bifidobacterium bifidum DSMZ 20456 and Lactobacillus acidophilus DSMZ 20079) were investigated. The cheeses were ripened in a vacuum package or brine for 120 d at 4 °C. The cheese samples maintained the probiotic characteristics of the viable cells as >106 cfu/g even after ripening for 120 d. The proteolysis degrees in terms of water-soluble nitrogen/total nitrogen (WSN/TN), trichloroacetic acid-soluble nitrogen/total nitrogen (TCA-SN/TN) and phosphotungstic acid-soluble nitrogen/total nitrogen (PTA-SN/TN) values in the cheeses increased throughout the ripening. The highest levels of proteolysis were found in cheese made using Lb. acidophilus DSMZ 20079 and ripened in a vacuum package. ACE-inhibitory activity of the water soluble extracts (WSEs) of the cheeses increased significantly (P < 0·05) throughout the ripening (IC50 values 82·78–140·99 μg/ml). Use of Lb. acidophilus DSMZ 20079 and packaging under vacuum significantly increased the percentage of ACE inhibiting activity. WSEs had DPPH scavenging activity (the IC50 values were 2·41–5·39 mg/ml and the inhibition values were 5·10–10·38%), increasing up to 60 d ripening. In the present study, it was observed that Lb. acidophilus DSMZ 20079 was more effective than Bifido. bifidum DSMZ 20456 in terms of the cheese characteristics investigated.
29 citations
TL;DR: The obtained results show that the goats of higher parity display higher levels of metabolism intensity and consequently, varying levels of oxidative stress during the peripartum period.
Abstract: The aim of this study was to research changes in metabolic and antioxidative status of Saanen goats of different parity occurring during the peripartum period. Blood samples were taken on 10-7 and 3-1 d prepartally and 1-3, 14 and 28 d postpartally from goats allocated in three groups according to their parity: primiparous (PRIM), goats that kidded the 2nd or 3rd time (MID), and goats that kidded 4 or more times (MULTI)). Metabolic profile parameters (non-esterified fatty acids (NEFA), β-hydroxybutyrate (BHB), glucose, triglycerides, albumin and urea) and indicators of oxidative stress ((superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and malondialdehyde (MDA)) were determined. Intense metabolic changes associated with late pregnancy and onset of lactation were pronounced the most in MULTI goats that also had the biggest litter per goat. Significant differences were found in metabolic parameters NEFA, BHB, glucose, triglycerides within groups during peripartum period, as well as between them (the effect of parity). MDA concentrations were indicative of increased lipid peroxidation around parturition, especially pronounced in MULTI group 1-3 d prepartally, when the highest GSH-Px/SOD ratio was also found. Postpartally, antioxidant enzymes ratio in MID and MULTI group decreased while MDA concentrations remained high, suggesting antioxidant system inefficiency. Significant time × group interaction was observed for most of the parameters. The obtained results show that the goats of higher parity display higher levels of metabolism intensity and consequently, varying levels of oxidative stress during the peripartum period. Further studies should determine applicability of NEFA and BHB in periparturient metabolic profiling in dairy goats as well as establish normal ranges and cut-off levels for these biomarkers.
28 citations
TL;DR: The present investigation increases the panel of SNPs and adds new information about the effects of the caprine LALBA gene polymorphism as well as observing an effect of the three SNPs on milk yield and lactose content.
Abstract: The variability of the promoter region and the 3'UTR (exon-7) of the BLG gene, encoding the β-lactoglobulin, was investigated by sequencing in 263 lactating Sarda goats in order to assess its association with milk traits. Milk traits included: milk yield, fat, total protein and lactose content, pH, daily fat and protein yield (DFPY), freezing point, milk energy, somatic cell count, total microbial mesophilic count, rennet coagulation time (RCT), curd firming rate (k20) and curd firmness (a30). A total of 7 polymorphic sites were detected and the sequence analysed was given accession number KM817769. Only three SNPs (c.-381C>T, c.-323C>T and c.*420C>A) had minor allele frequency higher than 0.05. The effects of farm, stage of lactation and the interaction farm × stage of lactation significantly influenced all the milk traits (P T and c.*420C>A (P T (P < 0.001). The c.-381TT homozygous goats showed lower pH, RCT and k20 than c.-381CT (P < 0.05). In conclusion the polymorphism of the goat BLG gene did not affect the total protein content of the Sarda goat milk, and only weakly influenced RCT and k20. On the other hand, an interesting effect on milk yields and DFPY emerged in two SNPs. This information might be useful in dairy goat breeding programs.
TL;DR: Iranian White cheese was manufactured from ultrafiltered cows’ milk using different concentrations of salt consisting of 1, 2·5, 4% and salt free to find that the use of different salt concentrations significantly influenced all chemical composition, proteolysis, total number of lactic acid bacteria and sensory characteristics of the cheeses.
Abstract: Iranian White cheese was manufactured from ultrafiltered cows' milk using different concentrations of salt consisting of 1, 2.5, 4% and salt free. Chemical composition, proteolysis, counts for lactic acid bacteria and sensory evaluation were examined during 90 d of ripening. It was found that the use of different salt concentrations significantly influenced all chemical composition, proteolysis, total number of lactic acid bacteria and sensory characteristics of the cheeses. Increasing the salt concentrations caused a proportional decrease in proteolysis determined by both urea-PAGE of caseins and RP-HPLC of peptides. With increased salt concentration, total number of lactic acid bacteria decreased. Cheeses with 1 and 2.5% salt were suitable and acceptable in odour and flavour that may be due to the proportional level of proteolysis products. In conclusion, reducing salt concentration from 4 to 2.5 and 1% had no ineligible effect on the quality and acceptability of the cheese.
TL;DR: The multivariate approach was able to discriminate beyond doubt mountain cheeses from those of indoor feeding and part-time valley grazing, and those of α-tocopherol andα-tocotrienol of milk and cheese.
Abstract: Fatty acids (FAs), tocopherols and retinoids were analysed in raw milk and cheese from six commercial sheep flocks monitored from early lactation in winter to late lactation in summer. In winter, animals received concentrate and forage indoors; in early spring, animals grazed part-time on cultivated or natural valley grasslands; and from mid spring on, animals were kept outdoors constantly on mountain natural pastures. Mountain grazing in late lactation significantly increased the amount of healthy desirable unsaturated FAs such as C18:1t11 (VA), C18:2c9t11 (RA), C18:2t11c13, C18:3c9c12c15 (ALA) and C20:5c5c8c11c14c17 (EPA), and those of α-tocopherol and α-tocotrienol of milk and cheese. Stepwise discriminant analysis was applied to classify cheese samples according to seasonal feeding management. The multivariate approach was able to discriminate beyond doubt mountain cheeses from those of indoor feeding and part-time valley grazing.
TL;DR: Prebiotic galactooligosaccharides was found to improve the levels of antioxidative enzymes (superoxide dismutase, catalase and glutathione peroxidase) in liver and blood and it was found that improvement in lactobacilli count along with a concomitant decrease in coliform count was observed in GOS fed groups.
Abstract: This study was conducted to assess the effect of prebiotic galactooligosaccharides (GOS) on alloxan-induced diabetes in male Sprague-Dawley (SD) rats. Diabetes was induced by administration of alloxan (100 mg/kg) and rats were divided in 4 groups: normal control group (NCG), prebiotic control group (PCG), diabetic control group (DCG) and diabetic prebiotic group (DPG). While PCG and DPG were fed with GOS supplemented (10% w/w) diet, NCG and DCG were administered with basal diet. Rats were sacrificed after 42 d for collection of blood and liver. Faecal samples were collected at the interval of 7 d throughout the study for measurement of lactobacilli and coliform count. Feeding of GOS decreased or delayed the severity of diabetes by amelioration of diabetes associated markers including fasting blood glucose, haemoglobin, glycosylated haemoglobin triglycerides, total cholesterol, low density lipoproteins, creatinine and urea. GOS was also found to improve the levels of antioxidative enzymes (superoxide dismutase, catalase and glutathione peroxidase) in liver and blood. Improvement in lactobacilli count along with a concomitant decrease in coliform count was observed in GOS fed groups.
TL;DR: The results indicate that the efficiency of feed protein utilisation for milk protein is not impaired if concentrates are reduced in a moderate- to low-input dairy production system.
Abstract: An experiment was conducted during 6 weeks to evaluate effects of a reduced dietary level of protein-rich concentrates in a moderate dairy production system on cows' performance, protein efficiency and milk quality including fatty acid profiles. Twenty-three lactating cows (Swiss Fleckvieh) were assigned either to a group receiving on average 2.4 kg/d individually fed concentrates (Prot+, n = 12) or to a group receiving no individually fed concentrates (Prot-, n = 11). All cows had ad-libitum access to a total mixed ration (TMR) mainly based on grass and maize silage, hay and little potatoes and soybean cake. In weeks 4-6 of the experiment, part of the hay was excluded from the TMR, and fed separately in the morning. Individual feed intake and milk yield were recorded during weeks 3 and 6 of the experiment; at the same time feed, faeces and milk samples were collected twice per week for analyses. Data were processed in linear mixed models. Omission of individual concentrates in Prot- was fully compensated by higher roughage intake in terms of dry matter. Crude protein (CP) and net energy intake was almost maintained. Despite a lower apparent CP digestibility in Prot-, the ratio of milk protein to ingested CP was the same in both groups, indicating a higher ruminal utilisation of degraded CP in Prot-. This corresponded with lower milk urea concentrations in Prot-. Milk quality was affected in terms of lower concentrations of linoleic and conjugated linoleic acid in milk fat of Prot-. Concentrations of odd- and branched-chain fatty acids in milk were increased in Prot-. Sequential offer of hay and TMR did not lead to considerable effects in intake, efficiency and milk quality. In conclusion, the results indicate that the efficiency of feed protein utilisation for milk protein is not impaired if concentrates are reduced in a moderate- to low-input dairy production system.
TL;DR: Analysis of the effect of heat treatment and skimming on precipitation of proteins in caprine and bovine milk found that a centrifugal force of 600 g appeared to be the most appropriate, in order to avoid protein loss and a possible error in the interpretation of results.
Abstract: Caprine and bovine milks have a similar overall gross composition, but vary considerably in the ratios of their casein components. These differences in colloidal casein micelles could affect directly or indirectly the heat stability of caprine and bovine milks at their natural pH. In the present work, the differences in colloidal stability of caprine and bovine milk have been studied by analysing the effect of heat treatment and skimming on precipitation of proteins. Raw and heated milk samples (70 °C/5 min, 80°C/5 min and 90°C/5 min) were centrifuged at 600, 2000, and 4500 g . The amount of precipitate formed after skimming was measured and the protein composition of both precipitates and supernatants analysed using the SDS-PAGE (sodium dodecyl sulphate polyacrylamide gel electrophoresis) and densitometry. In caprine milk, the heat treatment prior to skimming had a statistically significant effect on protein precipitation. Centrifugal force had a statistically significant effect on amount of precipitate for both milks, but the amount was 2 to 4 times higher for caprine milk. When defatting the milk for electrophoresis, a centrifugal force of 600 g appeared to be the most appropriate, in order to avoid protein loss and a possible error in the interpretation of results. Results of this study could also serve as the basis for further investigations on adjusting the skimming conditions for caprine milk in industrial dairy processing environment.
TL;DR: The present study provided new insights into S. dysgalactiae IMIs, including distinct lymphocyte profiles, and a tendency toward an inhibition of apoptosis in milk neutrophils.
Abstract: Streptococcus dysgalactiae is a bacterium that accounts for a notable proportion of both clinical and subclinical intramammary infections (IMIs). Thus, the present study explores the function of milk neutrophils and the lymphocyte profile in mammary glands naturally infected with Streptococcus dysgalactiae. Here, we used 32 culture-negative control quarters from eight clinically healthy dairy cows with low somatic cell counts and 13 S. dysgalactiae-infected quarters from six dairy cows. Using flow cytometry, we evaluated the percentage of milk monocytes/macrophages and neutrophils, expression of CD62L, CD11b and CD44 by milk neutrophils, the levels of intracellular reactive oxygen species (ROS) production and phagocytosis of Staphylococcus aureus by milk neutrophils, and neutrophil viability. Furthermore, the percentages of B cell (CD21(+)) and T lymphocyte subsets (CD3(+)/CD4(+)/CD8(-); CD3(+)/CD8(+)/CD4(-); and CD3(+)/CD8(-)/CD4(-)), and the expression of CD25 by T milk lymphocytes (CD3(+)) and T CD4(+) milk cells were also assessed by flow cytometry using monoclonal antibodies. The present study showed a higher SCC and percentage of milk neutrophils, and a decrease in the percentage of milk monocytes/macrophages from S. dysgalactiae-infected quarters when compared to uninfected ones. We also observed a higher expression of CD11b by milk neutrophils and a tendency toward a decrease in neutrophil apoptosis rate in S. dysgalactiae-infected quarters. In addition, the S. dysgalactiae-infected quarters had higher percentages of milk T cells (CD3(+)) and their subset CD3(+)CD8(+)CD4(-) cells. Overall, the present study provided new insights into S. dysgalactiae IMIs, including distinct lymphocyte profiles, and a tendency toward an inhibition of apoptosis in milk neutrophils.
TL;DR: In this paper, the two copies of the sheep growth hormone (GH) gene (GH1/GH2-N and GH2-Z) were entirely sequenced in one 106 ewes of Sarda breed, in order to highlight sequence polymorphisms and investigate possible association between genetic variants and milk traits.
Abstract: Growth hormone (GH) is encoded by the GH gene, which may be single copy or duplicate in sheep. The two copies of the sheep GH gene (GH1/GH2-N and GH2-Z) were entirely sequenced in one 106 ewes of Sarda breed, in order to highlight sequence polymorphisms and investigate possible association between genetic variants and milk traits. Milk traits included milk yield, fat, protein, casein and lactose percentage. We evidenced 75 nucleotide changes. Transcription factor binding site prediction revealed two sequences potentially recognised by the pituitary-specific transcription factor POU1FI at the GH1/GH2-N gene, which were lost at the promoter of GH2-Z, which might explain the different tissues of expression of GH1/GH2-N (pituitary) and GH2-Z (placenta). Significant differences in milk traits were observed among genotypes at polymorphic loci only for the GH2-Z gene. Sheep with homozygote genotype ss748770547 CC had higher fat percentage (P < 0·01) than TT. SNP ss748770547 was part of a potential transcription factor binding site for C/EBP alpha (CCAAT/Enhancer Binding Protein), which is involved in the regulation of adipogenesis and adipoblast differentiation. SNP ss748770547, located in the GH2-Z gene 5′ flanking region, may be a causal mutation affecting milk fat content. These findings might contribute to the knowledge of the sheep GH locus and might be useful in selection processes in sheep.
TL;DR: This preliminary study showed 76 variables across 3 dimensions produced a model with greater than 90% sensitivity, specificity, and area under the receiver operating curve (AUC), a marked improvement on the 52% sensitivity and 85% specificity previously observed with the 1 dimensional model or the 45% sensitivities reported with visual observations.
Abstract: Lameness remains a significant cause of production losses, a growing welfare concern and may be a greater economic burden than clinical mastitis . A growing need for accurate, continuous automated detection systems continues because US prevalence of lameness is 12.5% while individual herds may experience prevalence's of 27.8-50.8%. To that end the first force-plate system restricted to the vertical dimension identified lame cows with 85% specificity and 52% sensitivity. These results lead to the hypothesis that addition of transverse and longitudinal dimensions could improve sensitivity of lameness detection. To address the hypothesis we upgraded the original force plate system to measure ground reaction forces (GRFs) across three directions. GRFs and locomotion scores were generated from randomly selected cows and logistic regression was used to develop a model that characterised relationships of locomotion scores to the GRFs. This preliminary study showed 76 variables across 3 dimensions produced a model with greater than 90% sensitivity, specificity, and area under the receiver operating curve (AUC). The result was a marked improvement on the 52% sensitivity, and 85% specificity previously observed with the 1 dimensional model or the 45% sensitivities reported with visual observations. Validation of model accuracy continues with the goal to finalise accurate automated methods of lameness detection.
TL;DR: Yeast extract and SM were by far the best ingredient and the best medium, respectively, allowing for a BLIS production at the late exponential phase of 2000 AU/ml.
Abstract: Bacteriocins are natural compounds used as food biopreservatives instead of chemical preservatives. Bifidobacterium animalis subsp. lactis (Bifid. lactis) was shown to produce a bacteriocin-like inhibitory substance (BLIS) able to inhibit the growth of Listeria monocytogenes selected as an indicator microorganism. To enhance this production by the strain Bifid. lactis BL 04, skim milk (SM) was used as a fermentation medium either in the presence or in the absence of yeast extract, Tween 80 or inulin as stimulating additives, and the results in terms of bacterial growth and BLIS production were compared with those obtained in a traditional high cost complex medium such as Man, Rogosa and Sharpe (MRS). To this purpose, all the cultivations were carried out in flasks at 200 rpm under anaerobic conditions ensured by a nitrogen flowrate of 1.0 L/min for 48 h, and BLIS production was quantified by means of a modified agar diffusion assay at low values of both temperature and concentration of List. monocytogenes. Although all these ingredients were shown to exert positive influence on BLIS production in both media, yeast extract and SM were by far the best ingredient and the best medium, respectively, allowing for a BLIS production at the late exponential phase of 2000 AU/ml.
TL;DR: The carriage of fnb could enhance the accumulation of biofilm, but the lack of lukD/E and splA, B or E might decrease the invasiveness of strain, so bap-positive Staph.
Abstract: The biofilm-associated protein (Bap) of Staphylococcus aureus is a high molecular weight cell-wall-anchored protein involved in biofilm formation, first described in bovine mastitis strains from Spain. So far, studies regarding Bap were mainly based on the Spanish strain V329 and its mutants, but no information on the genetic variability of bap-positive Staph. aureus strains is yet available in the literature. The present study investigated the molecular characteristics of 8 bap-positive Staph. aureus strains from subclinical bovine mastitis, isolated in 5 herds; somatic cell counts (SCC) of milk samples were also registered. Strains were characterised using MLST, SPA typing and microarray and the results were compared with V329. All isolates from this study and V329 were assigned to ST126, t605, but some molecular differences were observed. Only herd A and B strains harboured the genes for β-lactams resistance; the leukocidin D/E gene, a type I site-specific deoxyribonuclease subunit, 3rd locus gene and serin-protease A and B were carried by all strains, but not by V329, while serin-protease E was absent in V329 and in another isolate. Four isolates and V329 harboured the fibronectin-binding protein B gene. SCC showed the highest value in the milk sample affected by the only strain carrying all the virulence factors considered. Potential large variability of virulence was evidenced among V329 and all bap-positive Staph. aureus strains considered: the carriage of fnb could enhance the accumulation of biofilm, but the lack of lukD/E and splA, B or E might decrease the invasiveness of strain.
TL;DR: The current results using quarter-milking reinforces the importance of accurate IMI detection in relation to economic and welfare factors, and moreover, emphasises the need for technical sensing and constant reporting to the farmer about changes in the milk quality of every animal.
Abstract: Intramammary infection (IMI), comprises a group of costly diseases affecting dairy animals worldwide. Many dairy parlours are equipped with on-line computerised data acquisition systems designed to detect IMI. However, the data collected is related to the cow level, therefore the contribution of infected glands to the recorded parameters may be over estimated. The present study aimed at evaluating the influence of single gland IMI by different bacteria species on the cow's overall milk quality. A total of 130 cows were tested 239 times; 79 cows were tested once and the others were examined 2-8 times. All of the analysed data refer to the number of tests performed, taking into account the repeated testing of the same cows. Of the cows tested ~50% were free of infection in all 4 glands and the others were infected in one gland with different coagulase negative staphylococci (CNS), Streptococcus dysgalactiae, or were post infected with Escherichia coli (PIEc), i.e., free of bacterial infection at the time of sampling but 1-2 months after clinical infection by E. coli. Overall, infection with bacteria had significant effects on somatic cell count (SCC) and lactose concentration. Examining each bacterium reveals that the major influence on those parameters was the sharp decrease in lactose in the PIEc and curd firmness in PIEc and Strep. Individual gland milk production decreased ~20% in Strep. dysgalactiae- and ~50% in PIEc-infected glands with respect to glands with no bacterial findings. Significant differences were found in lactose, SCC, rennet clotting time and curd firmness in the milk of infected glands and among those, these parameters were significantly higher in Strep. dysgalactiae and PIEc than in CNS infected cows. The current results using quarter-milking reinforces the importance of accurate IMI detection in relation to economic and welfare factors, and moreover, emphasises the need for technical sensing and constant reporting to the farmer about changes in the milk quality of every animal.
TL;DR: Investigation of antioxidant capacity of milk was investigated with two competing TAC assays, namely CUPRAC and ABTS (2,2′-azinobis(3-ethylbenzothiazoline-6-sulphonic acid), because only these assays were capable of evaluating protein contribution to the observed TAC value.
Abstract: Most milk-applied antioxidant assays in literature are based on the isolation and quantification of individual antioxidative compounds, whereas total antioxidant capacity (TAC) gives a more holistic picture due to cooperative action of antioxidants. Recently, the cupric reducing antioxidant capacity (CUPRAC) method has been modified to measure the antioxidant capacities of thiol-containing proteins, where the classical ammonium acetate buffer - that may otherwise precipitate proteins- was replaced with concentrated urea buffer (able to expose embedded thiol groups of proteins to oxidative attack) adjusted to pH 7.0. Thus, antioxidant capacity of milk was investigated with two competing TAC assays, namely CUPRAC and ABTS (2,2'-azinobis(3-ethylbenzothiazoline-6-sulphonic acid))/persulphate, because only these assays were capable of evaluating protein contribution to the observed TAC value. As milk fat caused turbidity, experiments were carried out with skim milk or defatted milk samples. To determine TAC, modified CUPRAC method was applied to whole milk, separated and redissolved protein fractions, and the remaining liquid phase after necessary operations. Both TAC methods were investigated for their dilution sensitivity and antioxidant power assessment of separate milk fractions such as casein and whey. Proteins like β-lactoglobulin and casein (but not simple thiols) exhibited enhanced CUPRAC reactivity with surfactant (SDS) addition. Addition of milk protein fractions to whole skim milk produced significant 'negative-biased' deviations (up to -26% relative standard error) from TAC absorbance additivity in the application of the ABTS method, as opposed to that of the CUPRAC method less affected by chemical deviations from Beer's law thereby producing much smaller deviations from additivity (i.e. the property of additivity is valid when the measured TAC of a mixture is equal to the sum of individual antioxidant capacities of its constituents).
TL;DR: Positive results showed the ability to produce antioxidant-enriched edible coatings to increase food protection and phenol nutritional intake and the possibility of protecting phenols against oxidation and digestive alteration by entrapment in CN and Na-CN coating films.
Abstract: Active films were developed for food coating applications. Entrapped phenol susceptibility to digestion was studied. Sodium caseinate (Na-CN) coatings were formulated with 0, 10, 20% Casein (CN) incorporating selected phenols as model antioxidants. This study investigated phenol/CN/Na-CN interactions, in vitro bioaccessibility of phenols and CN role in phenols retention during in vitro gastric and pancreatic digestion. The antioxidant activity of catechin (CAT), rutin (RUT), chlorogenic acid (CHL), gallic acid (GAL), and tannic acid (TA) in coatings varied with the phenolic compound type and CN concentration and was related to phenol hydrophobic binding to CN. ABTS method gave activities ranged from 412 down to 213, and DPPH method gave values from 291·7 to 190·9. An inverse relationship was found with CN content due to CN/phenol interaction. During digestion, a part of phenols was degraded by alkaline pH of pancreatic fluid. Simultaneously, CN proteolysis led to release of phenols and the bioaccessibility index remained above 80% for all phenols. The results suggested the possibility of protecting phenols against oxidation and digestive alteration by entrapment in CN and Na-CN coating films. These positive results showed the ability to produce antioxidant-enriched edible coatings to increase food protection and phenol nutritional intake.
TL;DR: Differences between group A and group B in all other haemodynamic parameters studied were not significant, neither throughout the last month of pregnancy, nor during the first week of lactation.
Abstract: Objective of the study was to record, by means of ultrasonographic examination, changes occurring during lactogenesis in the udder of healthy ewes and of ewes with pregnancy toxaemia. The work was carried out in 28 ewes, 16 with pregnancy toxaemia (group A) and 12 healthy controls (group B). B-mode and Doppler ultrasonographic examination of the udder of ewes was performed. During the last month of pregnancy, grey-scale intensity values of mammary parenchyma in group A were significantly greater than in group B (P = 0.007), as was also the progressive increase in grey-scale intensity values in both groups (P 0.35). Differences between group A and group B in all other haemodynamic parameters studied were not significant, neither throughout the last month of pregnancy (P > 0.25), nor during the first week of lactation (P > 0.06). However, their progressive changes during the last month of pregnancy were significant (P < 0.02).
TL;DR: The increase of blood components in milk during inflammation follows two different patterns: There is a rapid increase for IgG1, IgG2, or LDH, before the increase of SCC, and their concentrations reach a plateau within 3 h, and SCC and L-lactate show a slower but consistent increase not reaching a plateauWithin 5 h after LPS challenge.
Abstract: This study aimed to describe chronological patterns of changes of various candidate blood components in milk during the acute phase of a mammary immune response in detail. Eight dairy cows were challenged with Escherichia coli lipopolysaccharide in one udder quarter. Milk from challenged and control quarters and blood samples were taken before, and 1 and 2 h after challenge and then every 15 min until 5 h after challenge. The SCC, serum albumin, immunoglobulin (Ig)G1, IgG2, lactate dehydrogenase (LDH), and L-lactate in milk and blood, and α-lactalbumin in blood were analysed. All selected parameters in milk increased in challenged quarters but did not increase in control quarters. Milk IgG1, IgG2, serum albumin, and LDH were already significantly increased at 2 h after challenge whereas a significant increase of SCC was detectable at 2.75 h and L-lactate was increased at 2.25 h after challenge. In blood L-lactate was increased at 3.75 h after challenge, however, other factors in blood did not change significantly within the 5 h of experiment. In conclusion, the increase of blood components in milk during inflammation follows two different patterns: There is a rapid increase for IgG1, IgG2, or LDH, before the increase of SCC, and their concentrations reach a plateau within 3 h. On the other hand, SCC and L-lactate show a slower but consistent increase not reaching a plateau within 5 h after LPS challenge. L-lactate increases to higher concentrations in milk than in blood. This clearly shows that the increase of blood components follows different patterns and is therefore a controlled and compound-specific process and not exclusively an unspecific type of leakage.
TL;DR: A significant influence of the type of coagulant enzyme was observed, especially in the nitrogen fractions and peptide profiles, which demonstrated that camel chymosin was slightly less proteolytic; however, these differences were lower than those caused by the scalding temperature.
Abstract: In this work, we studied the influence of the type of coagulant enzyme and the curd scalding temperature on the proteolysis and residual coagulant and plasmin activities of a cooked cheese, Reggianito, in the interest of reducing ripening time. A two-factor experimental design was applied in two levels: type of coagulant enzyme, bovine chymosin or camel chymosin, and curd scalding temperature, 50 or 56 °C. The experimental treatments were applied in Reggianito cheese making experiments, and the samples were ripened for 90 d at 12 °C. Scalding temperature influenced residual coagulant activity; the cheeses cooked at 50 °C had significantly higher activity than those treated at 56 °C. In contrast, scalding temperature did not modify plasmin activity. Proteolysis was primarily affected by curd cooking temperature because chymosin-mediated hydrolysis of αs1 casein was slower in cheeses treated at 56 °C. Additionally, the nitrogen content in the cheese soluble fractions was consistently lower in the cheeses scalded at 56 °C than those cooked at 50 °C. A significant influence of the type of coagulant enzyme was observed, especially in the nitrogen fractions and peptide profiles, which demonstrated that camel chymosin was slightly less proteolytic; however, these differences were lower than those caused by the scalding temperature.
TL;DR: The results of the study indicated that microbial fermentation with tested strains is a valuable method for reducing the immunoreactivity of mare's milk proteins, but further studies with other bacterial strains are needed to gain a higher level of elimination or total reduction.
Abstract: The similarity of mare's milk to breast milk makes it an interesting substrate for the creation of dairy beverages. The aim of this study was to determine the immunoreactivity of the digested mare's milk products carried out by lactic acid fermentation with Lactobacillus casei LCY, Streptococcus thermophilus MK10 and Bifidobacterium animalis Bi30. Simulation of digestion with saliva, pepsin and pancreatin/bile salts was carried out. The immunoreactivity of the milk proteins was assessed by competitive ELISA. The separation of proteins was studied using a tricine SDS-PAGE method. It has been demonstrated that lactic acid fermentation significantly decreases the immunoreactivity of β-lactoglobulin, β-casein, κ-casein and bovine serum albumin. The level of reduction was connected to the type of bacterial strain. The simulated digestion processes caused the decline of immunoreactivity, and the decreases obtained in the experiment were as follows: lactoferrin: 95%, β-lactoglobulin: 94%, β-casein: 93%, α-lactalbumin: 82%, α-casein: 82%, bovine serum albumin: 76% and κ-casein: 37%. The results of the study indicated that microbial fermentation with tested strains is a valuable method for reducing the immunoreactivity of mare's milk proteins. However, further studies with other bacterial strains are needed to gain a higher level of elimination or total reduction of mare's milk immunoreactivity to possibly introduce fermented mare's milk into the diet of patients with immune-mediated digestive problems.
TL;DR: SRLV infection proved to be a statistically significant independent factor reducing cheese yield – when other covariates were held constant cheese yield was reduced by 4·6 g per each 1 kg milk in an infected goat compared with an uninfected goat.
Abstract: Three-year cohort study was carried out to investigate the influence of small ruminant lentivirus (SRLV) infection on cheese yield in goats. For this purpose records of milk yield, milk composition and cheese yield were collected in a dairy goat herd. Cheese yield was recorded as the amount of fresh cheese obtained from 1 kg milk. All goats were serologically tested for SRLV infection twice a year. The analysis included 247 records in total (71 for seropositive and 176 from seronegative individuals) and was carried out with the use of the four-level hierarchical linear model (α = 0·05). SRLV infection proved to be a statistically significant independent factor reducing cheese yield (P = 0·013) – when other covariates were held constant cheese yield was reduced by 4·6 g per each 1 kg milk in an infected goat compared with an uninfected goat. Other statistically significant covariates positively associated with cheese yield were protein contents, fat contents and the 3rd stage of lactation (P < 0·001 for all).
TL;DR: The pH decrease in situ upon heating from 25–90 °C was similar for all the modified skim milks with the same starting pH, suggesting that the pH changes to milk on heating were primarily mediated by the initial mineral composition of the serum and were unaffected by the casein : whey protein ratio or the total protein content of the milk.
Abstract: The heat-induced changes in pH, Ca activity and viscosity after heating at 90 °C for 10 min of five modified skim milks were studied as a function of the initial pH of the milks at 25 °C. The milks had (i) different ratios of casein : whey protein (0.03, 1.74, 3.97, 5.27 and 7.25), (ii) the same total solids concentration (9% w/w) and (iii) prior to the adjustment of the pH, similar values of pH (6.67-6.74), concentration of serum calcium, and calcium activity, suggesting that the sera have similar mineral composition. The total protein concentrations of the milks differ (2.8-4.0%, w/w). The pH decrease in situ upon heating from 25-90 °C was similar for all the modified skim milks with the same starting pH, suggesting that the pH changes to milk on heating were primarily mediated by the initial mineral composition of the serum and were unaffected by the casein : whey protein ratio or the total protein content of the milk. The heat-induced changes in pH and calcium activity were largely reversible on cooling. The two milks with the lowest ratios of casein to whey protein gelled on heating to 90 °C for 10 min and cooling to 25 °C when the pH was adjusted to pH = 6.2 prior to heating. The viscosities of all other milks with casein to whey protein ratio of 3.97, 5.27 and 7.25 and/or pH ≥6.7 prior to heating did not change significantly. The effect of casein : whey protein ratio and the pH are the dominant factors in controlling the susceptibility to thickening of the milks on heating in this study.