The use of probiotics for farm animals has increased considerably over the last 15 years. Probiotics are defined as live microorganisms which can confer a health benefit for the host when administered in appropriate and regular quantities. Once ingested, the probiotic microorganisms can modulate the balance and activities of the gastrointestinal microbiota, whose role is fundamental to gut homeostasis. It has been demonstrated that numerous factors, such as dietary and management constraints, can strongly affect the structure and activities of the gut microbial communities, leading to impaired health and performance in livestock animals. In this review, the most important benefits of yeast and bacterial probiotics upon the gastrointestinal microbial ecosystem in ruminants and monogastric animals (equines, pigs, poultry, fish) reported in the recent scientific literature are described, as well as their implications in terms of animal nutrition and health. Additional knowledge on the possible mechanisms of action is also provided.

Probiotics in animal nutrition and health.

Yeast and yeast derivatives in feed additives and ingredients: Sources, characteristics, animal responses, and quantification methods

We aimed to determine the effects of variations in dietary composition on equine gut microbiota and their fermentation products, and proposed that dietary modifications profoundly affect microbial ecosystems and their metabolites. Bacterial communities within the large intestine of three groups of horses were compared using oligonucleotide-RNA hybridisation methodology. Each group consisting of six horses was maintained on (1) a grass-only diet, (2) a concentrate diet (i.e. supplemented with hydrolysable carbohydrates) and (3) a concentrate diet but horses were affected by simple colonic obstruction and distension (SCOD), a prevalent form of dietary-induced intestinal disease. We show that in response to dietary change and intestinal disease, there is a progressive and significant increase in Lachnospiraceae, the Bacteroidetes assemblage and the lactic acid-producing, Bacillus-Lactobacillus-Streptococcus (BLS) group. In contrast, there is a corresponding decrease in the proportion of obligate fibrolytic, acid-intolerant bacteria, Fibrobacter and Ruminococcaceae. Assessment of monocarboxylic acids indicated that there are significantly higher concentrations of lactic acid in the colonic contents of horses maintained on a concentrate diet and those suffering from SCOD, correlating with the observed increase in the population abundance of the BLS group. However, the population size of the Veillonellaceae (lactate utilisers) remained constant in each study group. The inability of this group to respond to increased lactic acid may be a contributory factor to the build-up of lactic acid observed in horses fed a concentrate diet and those suffering from SCOD.

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Alterations in microbiota and fermentation products in equine large intestine in response to dietary variation and intestinal disease.

A first group of three horses was given diet 1 (D1) allowing 1180 g per 100 kg body weight (BW) of a pelleted food rich in fibre (P1) and 556 g per 100 kg BW of straw during a 20-day period to allow for adaptation. A second group of four horses were given diet 2 (D2) allowing 1180 g per 100 kg BW of a pelleted food rich in cereals (P2) and 1000 g per 100 kg BW of meadow hay during the same period. Digesta was collected from the stomach, duodenum, jejunum, ileum, caecum, right ventral colon, left ventral colon, left dorsal colon, right dorsal colon, and small colon, and faeces were collected under general anaesthesia 2·5 h after the ingestion of the morning pelleted meal. The concentration of total anaerobic, cellulolytic and lactic acid-utilizing bacteria, lactobacilli and streptococci were determined in all these segments except for the duodenum, left ventral colon, right dorsal colon and small colon. D-/L-lactic acid, volatile fatty acids and pH were measured in all anatomic segments of the digestive tract (from stomach to small colon). The caecal concentration of total anaerobic bacteria was the lowest (7·9 5 107 colony-forming units (c f. u.) per ml), whereas that of the stomach was the highest (1·4 5 109 c f. u. per ml) (P < 0·001). Cellulolytic bacteria did not exceed 3·0 5 102 c f u. per ml in the ante-caecal segments whereas in the hindgut the average concentration was 5·3 x 105 c f u. per ml (P < 0·001). Likewise, VFA concentrations were also greater in the large intestine (on average, 96·3 mmol/l v. 8·8 mmol/l in the ante-caecal segments) (P < 0·001), confirming the limited extent of fibre degradation in these ante-caecal segments. Lactobacilli, streptococci and lactate-utilizing bacteria colonized all the digestive tract; the stomach and the small intestine tended to host the greatest numbers of these bacteria, which suggests a high interference of micro-organisms with the digestion of readily fermentable carbohydrates. Compared with the other ante-caecal segments, the stomach ecosystem seemed the most affected by the composition of the last pelleted meal ingested: the concentrations of lactobacilli and lactate-utilizing bacteria were higher (P < 0·05) with P2. The lower concentration of D-/L-lactate with P2 (P < 0·05) was concomitant with a greater proportion of propionate (P < 0·05), probably related to a greater fermentation of lactate. In the large intestine of horses given D2, cellulolytic bacteria tended to be lower, whereas VFA concentrations were higher (P < 0·05). The lower [NDF/starch] ratio of D2 was probably less propitious for the proliferation of cellulolytic bacteria but was compensated by the higher cellulose intake brought by the hay.

Characterization of the microbial and biochemical profile of the different segments of the digestive tract in horses given two distinct diets

Summary
Reasons for performing study: Diets rich in readily fermentable carbohydrates, fed traditionally to meet the increased energy requirements of the performance horse, are associated with a number of gastrointestinal disorders that involve disturbances in the intestinal microbiota, however, these changes are poorly understood.

Objectives: With the long-term objective of improving intestinal health and to increase understanding of the relationship between diet and microbiota, the effect of feeding Standardbred horses a high-energy forage-only (F) diet was studied compared to a more traditional forage-concentrate (C) diet on faecal microbiota.

Methods: Diets were fed in a cross-over design to 6 mature geldings on a scheduled training regime, both periods consisting of 29 days. DNA was extracted from faecal samples collected at 4 time points from each period, bacterial 16S rRNA genes were amplified and community composition assessed by terminal-restriction fragment length polymorphism, cloning and sequencing. Faecal pH and cultivable lactic acid bacteria (LAB) and enterobacteria were also assessed on the final collection day of each period.

Results: Diet F resulted in a microbial composition that was more stable between sampling periods and had lower counts (P<0.05) of cultivable LAB and specifically members of the Streptococcus bovis/equinus complex. Motile and swarming Lactobacillus ruminis was present in all horses on diet C and not in horses on diet F. Diet C also resulted in the increase (P<0.05) in members of Clostridiaceae cluster III and a concomitant reduction (P<0.05) in an unknown group of Bacteroidales.

Conclusions and potential relevance: The greater microbial stability and reduction in LAB and members of the Streptococcus bovis/equinus complex on diet F indicate an opportunity to develop feeding strategies that support equine health and welfare. Novel changes identified in the faecal microbiota that resulted from carbohydrate inclusion merit further investigation.

Changes in faecal bacteria associated with concentrate and forage-only diets fed to horses in training.

Eight horses were allotted into pairs consisting of one cecum- and right ventral colon-fistu- lated animal and one cecum-fistulated animal They were fed daily at the same level of intake either a high- fiber (HF) or a high-starch (HS) diet without or with 10 go f aSaccharomyces cerevisiae preparation, in a 4 × 4 Latin square design The HS diet provided a starch overload (ie, 34 g starchkg −1 BWmeal −1 ) while main- taining a high amount of fiber intake (ie, dietary NDF/ starch ratio was 10) A 21-d period of adaptation to the treatments occurred before cecal and colonic contents were withdrawn 4 h after the morning meal to count total anaerobic, cellulolytic, and lactic acid-utilizing bacteria, lactobacilli, and streptococci Lactic acid, vola- tile fatty acids, ammonia concentrations, and pH were measured on cecal and colonic fluid samples collected hourly during the first 12-h postfeeding When the HS diet was fed, the concentration of total anaerobic and lactic acid-utilizing bacteria increased (P < 0001), whereas that of cellulolytic bacteria decreased (P < 005) in the cecum The concentration of lactobacilli and streptococci increased (P < 0001) in the cecal and co- lonic contents These alterations of the microbial pro- files were associated with decreases (P < 0001) of pH, (acetate + butyrate)/propionate ratio and with an in- crease (P < 0001) of lactic acid concentration Supple- menting the S cerevisiae preparation increased (P < 001) the concentration of viable yeast cells, averaging 43 × 10 6 and 45 × 10 4 cfu/mL in the cecal and colonic contents, respectively Yeast supplementation had al- most no effect on microbial counts in the cecum and colon The supplementation of S cerevisiae appeared to modify (P < 005) pH, concentrations of lactic acid and ammonia, molar percentages of acetate and buty- rate with the HS diet and ((acetate + butyrate)/propio- nate) ratio when the HF diet was fed The effects of the S cerevisiae preparation were greater in the cecum than in the colon, which coincided with the abundance of yeast cells When the digestion of starch in the small intestine was saturated, the effect of the addition of a S cerevisiae preparation appeared to limit the extent of undesirable changes in the intestinal ecosystem of the horse

Effect of a preparation of Saccharomyces cerevisiae on microbial profiles and fermentation patterns in the large intestine of horses fed a high fiber or a high starch diet.

Eight crossbred male horses aged 12 +/- 5 yr and with BW of 305 +/- 18 kg were used in pairs in a 4 x 4 Latin square design with 4 ground and pelleted diets. Each pair included a cecum and right ventral colon-fistulated animal and a cecal-fistulated animal. The 4 horse diets were a high-fiber diet (HF+0) based on dehydrated alfalfa, a high-starch diet based on barley and wheat bran (HS+0), and the HF or HS diets supplemented with Saccharomyces cerevisiae (SC) CBS 493.94 (HF+SC and HS+SC). The probiotic preparation contained 4.5 x 10(9) cfu/g of live yeast mixed with the culture medium, and was top-dressed onto the feed pellets at a rate of 10 g/d, equally distributed between the 2 daily meals. All 4 diets were offered in the same quantities (18.0 g of pelleted feed DM + 3.5 g of long wheat straw/kg of BW per d). Each of the 4 experimental treatments was divided into a 21-d period of diet adaptation followed by a 10-d period of total fecal collection for digesta flow rate and apparent digestibility measurements. Three markers were used to measure mean retention time (MRT) of the feed particles: Yb bound to the pelleted feeds for MRT in the whole digestive tract (MRT(Yb)), Eu bound to the pelleted feeds, and Dy bound to the fecal particles for MRT in the hindgut (MRT(Eu) and MRT(Dy)). Apparent digestibilities of DM, OM, and CP were greater (P < 0.001) in the HS than HF diet, independently of SC supplementation, whereas ADF digestibility was greatest in the HF diet (P = 0.035). Cellulolytic activity estimated through the in vitro disappearance rate of the dietary ADF fraction (IVAD(ADF)) was less (P < 0.001) in the HS than the HF diet. There was no dietary effect on NDF digestibility due to the longer MRT(Eu) of small particles in the hindgut (P = 0.036), which compensated for the lower fibrolytic activity expressed per unit of time in the HS compared with the HF diet. Supplementation with SC improved ADF digestibility (P = 0.038) and stimulated DM (P = 0.030) and NDF (P = 0.038) intakes, but had no effect on the MRT of solid digesta. The absence of any significant diet x SC interaction supports the strategy of using SC to stimulate cellulose digestion and improve the nutritional status of horses under both HF and HS diets.

Effect of live yeast culture supplementation on apparent digestibility and rate of passage in horses fed a high-fiber or high-starch diet.

Four cecum and right ventral colon-fistulated horses were assigned in a 4 x 4 Latin square design and fed a high-fiber (HF) or a high-starch (HS) diet with or without 10 g of Saccharomyces cerevisiae (SC; CBS 493.94) containing 4.5 x 10(9) cfu/g. The HF and HS diets consisted of pelleted feeds and long wheat straw (18.0 and 3.5 g of DM.kg(-1) of BW.d(-1), respectively) given in 2 equal meals to provide an NDF:starch ratio of 3.5 and 1.0, respectively. After a 21-d adaptation period intestinal contents were collected 4 h after the morning meal on d 23 and 25 to determine bacterial and SC concentrations. Polysaccharidase activities (CMCase, xylanase, amylase) and activities of glycoside hydrolases (alpha-l-arabinosidase, beta-d-cellobiosidase, beta-d-glucosidase, beta-d-xylosidase) were determined in liquid-associated bacteria (LAB) and solid-adherent bacteria (SAB) isolated from both compartments. Lactobacilli were increased in the cecum (P = 0.012) and colon (P = 0.086) when starch intake increased, whereas total anaerobes, cellulolytics, and streptococci did not change in either compartment. In yeast-supplemented horses, SC concentrations were greater in cecum (4.4 x 10(6) cfu/mL) than in right-ventral colon (5.6 x 10(4) cfu/mL) and did no change with diet. Concentrations of lactobacilli and lactic-acid utilizers were greater (P = 0.099 and 0.067, respectively) in the cecum but remained similar in the colon of SC-supplemented horses. The CMCase activities of SAB were not affected by diet. Colonic xylanase activities of SAB were reduced (P = 0.046) by starch addition, but no change was seen in the cecum. All SAB glucoside hydrolase activities in the cecum and colon, except beta-d-xylosidase in the cecum, were decreased when starch intake was increased. The LAB CMCase (P = 0.049 in the colon) and xylanase (P = 0.021 in the cecum; P < 0.001 in the colon) activities decreased with starch intake. No effect of starch on LAB or SAB amylase activity was observed. Addition of SC improved SAB CMCase in the cecum (P = 0.019) and colon (P = 0.037) as well as beta-d-cellobiosidase (P = 0.002) and beta-d-glucosidase (P = 0.041) in the cecum. Only xylanase in the cecum (P = 0.015) and beta-d-xylosidase in the cecum (P = 0.028) were improved with SC, whereas colonic LAB alpha-amylase activity was significantly decreased (P = 0.046). Most enzymes involved in plant cell wall digestion were increased after SC addition. This fact may contribute to explain a better digestion of fiber that has been previously reported in SC-supplemented horses.

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Effect of live yeast culture supplementation on hindgut microbial communities and their polysaccharidase and glycoside hydrolase activities in horses fed a high-fiber or high-starch diet.


 Feed supplementation with vitamin E increases antioxidant capacity, essential to cope with cellular oxidative process that may happen during meat length of storage. This last decades, polyphenol rich botanicals content were widely investigated as new antioxidant chain links able to spare and/or strengthen Vitamin E inclusion. Therefore, this study designed on broiler meat model aims to determine any preservative and positive effects of a novel proprietary blend of polyphenols extracts [BoreOX® (BX500), Probiotech International Inc.]. A total of 840 Ross 308 male broilers were distributed on two dietary treatments: standard (SVE) with 84, 56 and 50 ppm of expected vit. E in starter (S), grower (G) and finisher (F) stages, respectively and a polyphenols-supplemented diet with the same levels of vit. E added with 25, 50 and 100 ppm of (BX500) in S, G and F phases, respectively (SVEBX). The same 3-phase diets were offered ad libitum to 6 replicated pens of 70 birds from 0 to 42 days of age with robenidine as anticoccidial agent. At slaughterhouse, meat samples (breast and thigh muscle from 1 bird/pen) were cooled down for 24 hours and stored at +3°C before completing some selected analysis (chemical, rheological and microbiological) at 2, 6 and 10 days of storage (72 samples/treatment). Treatment effect was compared an analysis of variance performed in Statistica, version 7.1 (StatSoft, Czech Republic). The monitored parameters of chicken meat changed mainly due to the length of storage - TBA, dripping and microorganism counts increased, on the other hand, antioxidant capacity, meat firmness and water activity decreased. The presence of the polyphenols leaded to higher thigh meat lightness (p = 0.059). In conclusion, although the effect of the tested supplement in the feed was slightly positive in terms of protection of fat against oxidative changes. Apart from meat lightness, the other parameters monitored were not significantly affected.

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B. Medina

Papers

Effect of a preparation of Saccharomyces cerevisiae on microbial profiles and fermentation patterns in the large intestine of horses fed a high fiber or a high starch diet.

Effect of live yeast culture supplementation on apparent digestibility and rate of passage in horses fed a high-fiber or high-starch diet.

Effect of live yeast culture supplementation on hindgut microbial communities and their polysaccharidase and glycoside hydrolase activities in horses fed a high-fiber or high-starch diet.

PSIII-A-6 Boreox, a Proprietary Blend of Polyphenols Alters Positively Broiler Meat Quality During Storage