Dietary Yeast Culture Supplementation Research Articles

Effect of Adding Yeast Cultures to High-Grain Conditions on Production Performance, Rumen Fermentation Profile, Microbial Abundance, and Immunity in Goats.

It is a common practice among farmers to utilize high-grain diets with the intention of promoting ruminant growth. However, this approach bears the risk of inducing rumen disorders and nutrient metabolism diseases. Yeast culture (YC) showed advantages in ruminant applications. The objective of this study was to evaluate the effects of adding two different types of YC to high-grain conditions on production performance, rumen fermentation profile, microbial abundance, and immunity in goats. A total of 30 male goats with similar body condition were randomly distributed into 3 dietary treatments with 10 replicates per treatment as follows: basic diet group (CON); basic diet + 0.5% yeast culture 1 (YC1) group; basic diet + 0.5% yeast culture 2 (YC2) group. The trial lasted for 36 days. The results demonstrated that dietary YC supplementation led to an increase in the average daily gain and a reduction in feed intake and weight gain ratio in goats. It increased the apparent digestibility of crude protein, NDF, and ADF (p < 0.05). The serum concentrations of interleukin (IL)-1β, IL-6, and Tumor Necrosis Factor-α in the control group were significantly higher than those of the YC groups (p < 0.05). The serum concentrations of Immunoglobulin (Ig)A and IgG in the control group were significantly lower than those in the YC groups (p < 0.05). The rumen concentration of microbial protein (MCP) in the control group was significantly lower than that in the YC groups (p < 0.05). There was a negative correlation between the concentration of IL-10 and Bacteroidota, Spirochaetota, and Succinivibrio, while there was a positive correlation between concentrations of IL-10 and Firmicutes. Nevertheless, discrepancies were observed in the impact of the two different types of YC on the physiological and biochemical indicators of the animals. The concentration of triglyceride in the YC1 group was significantly higher than that of the CON and YC2 groups, while the concentration of urea in the YC2 group was significantly higher than that of the CON and YC1 groups (p < 0.05). At the phylum level, the addition of YC2 to the diet significantly increased the relative abundance of Bacteroidota and Fibrobacterota and significantly decreased Firmicutes compared to the control. At the genus level, the addition of YC1 to the HGD significantly reduced the relative abundance of Rikenellaceae_RC9_gut_group, while the addition of YC2 to the HGD significantly increased the relative abundance of Prevotellace-ae_UCG-001, Fibrobacter, and Prevotellaceae_UCG-003 (p < 0.05). The addition of YC significantly improved growth performance, increased nutrient digestibility, beneficially manipulated ruminal fermentation and microbial diversity, and improved immune function. The choice of yeast cultures can be customized according to specific production conditions.

Effects of yeast cultures on meat quality, flavor composition and rumen microbiota in lambs

Since the banning of antibiotics, the use of feed additives to improve meat quality to satisfy people's pursuit of high quality has become a research hotspot. Yeast culture (YC) is rich in proteins, mannan oligosaccharides, peptides, and yeast cell metabolites, etc., and its use as a feed additive has a positive impact on improving meat quality. So the study aimed to provide a theoretical basis for YC improving mutton flavor and quality by detecting and analyzing the effects of YC on muscle physicochemical properties, amino acids, fatty acids, flavor composition, expression of related genes, and rumen microbiota of lambs. A total of 20 crossbred F1 weaned lambs (Australian white sheep♂ × Hu sheep♀; average 23.38 ± 1.17 kg) were randomly assigned to 2 groups, the control group (CON) and the 1.0% YC supplemented group (YC) (n = 10), and were reared in separate pens. The experiment had a pre-feeding period of 10 d and a treatment period of 60 d. After the experiment, 6 lambs in each group were randomly selected for slaughtering. The results showed that dietary YC supplementation increased rumen total VFA and acetate concentrations (p < 0.05), and muscle carcass fat (GR), a∗ value, intramuscular fat (IMF), lysine (Lys), arginine (Arg), nonessential amino acid (NEAA), oleic acid (C18:1n9c), and eicosanoic acid (C20:1) contents were significantly increased (p < 0.05), while cooking loss and γ-linolenic acid (C18: 3n6) were decreased (p < 0.05). Furthermore, we found that dietary YC improved the types of flavor compounds, and the key flavor substances such as hexanal, nonanal, styrene, benzaldehyde, p-xylene, and 1-octen-3-ol contents were changed (p < 0.05). Additionally, the expression of fat metabolism related genes PPARγ, FASN, and FABP4 were increased. Adding 1% YC to lamb diets increased profits by 47.70 CNY per sheep after 60 d of fattening. All of which indicated that YC could improve meat quality, especially flavor, which may be related to the regulation of the relative abundance of rumen microorganisms Bacteroidota, Prevotella_7, Succiniclasticum and Lachnospiraceae_NK3A20_group.

Effect of Yeast Culture on Reproductive Performance, Gut Microbiota, and Milk Composition in Primiparous Sows.

The objective of this study was to evaluate the effects of yeast culture (YC) on reproductive performance, gut microbiota, and milk composition in primiparous sows. A total of 60 primiparous sows were randomly assigned to the control group (CON) and YC group (0.5% YC during gestation and 0.8% YC during lactation) consisting of 30 replicates, with one sow in each. The results showed that dietary YC supplementation increased the piglet birth weight and backfat thickness at 28 d of lactation (p < 0.05). Dietary YC supplementation increased the apparent total tract digestibility (ATTD) of gross energy and calcium during lactation, the content of acetic acid and propionic acid at 110 d of gestation, and the content of acetic acid and butyric acid at 28 d of lactation in feces (p < 0.05). Furthermore, dietary YC supplementation decreased the abundance of Firmicutes, Lachnospiraceae_XPB1014_group, and Terrisporobacter (p < 0.05), and increased the abundance of Prevotellaceae_NK3B31_group and Rikenellaceae_RC9_gut_group (p < 0.05). Compared to the control group, dietary YC supplementation increased the fat and lactose content of the colostrum (p < 0.05). Metabolomics analysis showed that YC increased 26 different metabolites in the colostrum. Among them were mainly pantothenic acid, proline, isoleucine, phenylalanine, acylcarnitine, and other metabolites. In conclusion, these results suggested that dietary YC supplementation improves reproductive performance and gut health and increases the nutrient content in the colostrum of primiparous sows.

An Evaluation of Yeast Culture Supplementation in the Diet of Pseudobagrus ussuriensis: Growth, Antioxidant Activity, Nonspecific Immunity, and Disease Resistance to Aeromonas hydrophila

An 8-week feeding trial was conducted to evaluate the effects of dietary yeast culture (YC) supplementation on growth performance, antioxidant activity, nonspecific immunity, and disease resistance of Pseudobagrus ussuriensis (average initial weight6.01±0.01 g). Four isonitrogenous and isolipidic diets were formulated to contain 0 (Y0), 10 (Y1), 20 (Y2), and 30 (Y3) g/kg YC, respectively. After the feeding experiment, the challenge test of injecting Aeromonas hydrophila was executed. Results showed that appropriate YC supplementation level in the diet could improve growth performance, digestive enzyme activities, nonspecific immunity capacity, antioxidant capacity, and disease resistance of P. ussuriensis. And the highest weight gain, feed intake, specific growth rate, and IGF-1 gene expression level were observed in fish fed the Y2 diet. The activities of protease and amylase in intestine in fish fed the Y2 diet were enhanced compared with that in fish fed the Y0 diet significantly (P&lt;0.05). Simultaneously, fish fed the Y2 diet had significantly higher serum lysozyme activity and significantly lower serum alanine amino transferase activity (P&lt;0.05). Dietary 20 g/kg YC supplementation increased the activity of catalase and total antioxidant capacity in liver and reduced malondialdehyde content in the liver and intestine of P. ussuriensis significantly (P&lt;0.05). Fish fed the Y2 diet had the highest disease resistance under the condition of A. hydrophila challenge (P&lt;0.05). The quadratic regression analysis based on weight gain against dietary YC levels indicated that the appropriate dietary YC supplementation level is 13.4 g/kg diet.

Effect of dietary yeast culture supplementation on the cecal microbiota modulation of geese

One of the most extensively applied animal feed additives is yeast culture ( YC ), which can increase production efficiency by altering gastrointestinal tract ( GIT ) microbiota. Geese are the ideal model to study the interaction between diet and GIT, due to their adaptation to consume different roughage sources. Here, we fed geese with 0 (control), 0.5% (treat1), 1.0% (treat2), 2.0% (treat3), and 4.0% (treat4) of YC for 10 wk. The GIT microbiota was analyzed by 16S rRNA gene V3–V4 region via high-throughput sequencing. The results showed that YC supplementation did not significantly affect α-diversity ( P >0.05). However, dietary YC at 2.0% had the highest species richness (quadratic, P < 0.05). Principal coordinates analysis showed an obvious separation between control and 4.0% group. The dominant phyla were Firmicutes and Bacteroidetes whereas the predominant genera were Alistipes and Desulfovibrionaceae . The relative abundance of phyla Firmicutes significantly increased in 0.5, 1.0, and 2.0% group and decreased in 4.0% group ( P < 0.05). YC supplementation increased the relative abundance of Bacteroidetes (linear, P = 0.04) and genus Bacteroides (linear, P = 0.02; quadratic, P = 0.05). 1.0% group contained the highest proportion of the beneficial bacteria, such as Parabacteroides, Enterococcus, Streptococcus , and Pseudomonas . 0.5% group obviously improved the capacity of amino acid and carbohydrate metabolism. Collectively, these findings demonstrate the beneficial effects of YC feeding on gut microbiota for geese, which suggested that dietary strategy based on feed additives is an effective method to maintain the health of geese.

Effects of Yeast Culture Supplementation on Growth Performance, Nutrient Digestibility, Blood Metabolites, and Immune Response in Geese.

Simple SummaryAntibiotics benefit animal growth performance and health. However, an overuse of antibiotics can lead to antibiotic residue and the development of drug-resistant bacteria. Considering the possible serious consequences of antibiotic overuse, non-antibiotic alternatives, such as yeast and yeast products, are widely used in animal diets to improve growth and productive performance. Geese are important poultry, and their meat provides high-quality protein to humans, but studies showing how yeast culture affect geese are limited. On this basis, the effects of dietary yeast culture supplementation on growth performance, nutrient digestibility, blood metabolites, and immune functions of geese were studies. The results showed that the dietary addition of yeast culture could improve growth performance and nutrient digestibility and can modulate the immune response of geese. This dietary strategy based on feed additives is an effective method for improving the growth efficiency of the geese.The present study was conducted to investigate the effects of dietary yeast culture (YC) supplementation on growth performance, nutrient digestibility, blood metabolites, and immune functions in geese. One-day-old Sichuan white geese (n = 300) were randomly divided into five groups containing 0 (control), 0.5%, 1.0%, 2.0%, and 4.0% of YC in the diet for 70 days. In general, the dietary supplementation of YC significantly increased the average daily gain and feed conversion ratio (p < 0.05) in which the 1.0% or 2.0% levels were better and significantly reduced the average daily feed intake at the 2.0% level (p < 0.05). YC supplementation increased digestibility of P (quadratic, p = 0.01) and gross energy (quadratic, p = 0.04) from days 23 to 27 and crude protein from days 23 to 27 and days 64 to 68 (quadratic, p ≤ 0.05), with the 2.0% level being the most effective. Serum metabolites were significantly affected by dietary YC (p < 0.05). Supplemental YC increased IL-2 on day 28 (linear, p = 0.01; quadratic, p = 0.04) and lysozyme on day 70 (quadratic, p = 0.04) and decreased complement C4 on day 70 (linear, p = 0.05). Interferon-γ, interleukin-2, and tumor necrosis factor-α genes were mostly up-regulated after YC supplementation, and interferon-γ and interleukin-2 gene expression levels were significantly increased at the 2.0% level (p < 0.05). Taken together, dietary YC supplementation improved growth performance and affected nutrient digestibility, serum metabolites, and immune function in geese, which was optimized at the 2% YC level in the present study.

Effects of yeast culture supplementation from late gestation to weaning on performance of lactating sows and growth of nursing piglets

Dietary yeast culture supplementation can contribute to the performance and health of sows and piglets, but few studies have focused on the relationships between the effects of yeast culture and gut microbiota. This study investigated the effect of yeast culture (Saccharomyces cerevisiae) supplementation from late gestation to weaning on the reproductive performance of lactating sows and their faecal microbiota. One hundred and six purebred Landrace sows, of parities two to six were selected and randomly assigned to a control (CON) and yeast culture supplementation (YC) groups based on parity and back fat thickness. The YC sows were individually fed with yeast culture at a dose of 24 g/d from day 90 of gestation to parturition and 40 g/d during lactational period. Blood samples were collected from sows on d 110 of gestation and at weaning at day 21 of lactation for plasma hormone and immunoglobulin analysis. Colostrum and milk on day 20 of lactation were collected for composition analysis. Faecal samples from sows on day 110 of gestation and day 20 of lactation were collected for short-chain fatty acid and faecal microbial analysis. Results showed that the farrowing performance of YC sows did not differ significantly from the CON group (P > 0.05). The average daily feed intake by the YC group during the lactation period was significantly increased by 9.98% (P = 0.004), the weaning-to-oestrus interval was shortened by 0.96 d (P = 0.046) and average daily weight gain of piglets increased by 7.14% (P = 0.036) compared with the CON group. Yeast culture supplementation also significantly improved the average daily milk yield in the first week of lactation (P = 0.035), lactose content in colostrum (P = 0.046), protein (P = 0.033) and DM (P < 0.001) content of milk. In the YC group, concentrations of plasma ghrelin (P = 0.02) and IgG (P = 0.015) were increased compared with the CON group, while that of glucagon-like peptide-1 was decreased (P = 0.006) on d 110 of gestation. The 16S rRNA gene sequencing showed that faecal microbiota changed at taxonomic levels with yeast culture addition (P < 0.05). Dietary yeast culture supplementation from late gestation to lactation improved feed intake, immunity status, milk yield, milk quality and faecal microbiota of sows, resulting in the improved growth performance of piglets.

Effects of dietary yeast culture supplementation on the meat quality and antioxidant capacity of geese

Summary This study aimed to evaluate the effects of dietary yeast culture (YC) supplementation on the meat quality and antioxidant capacity of geese. Three hundred geese (live weight: 95.57 ± 2.42 g) were fed a basal diet (control), or diets supplemented with 0.5, 1.0, 2.0, or 4.0% YC for 70 d. Compared with the control, dietary YC supplementation increased (P

Effects of reducing dietary fishmeal with yeast supplementations on Litopenaeus vannamei growth, immune response and disease resistance against Vibrio harveyi

The aim of this experiment was to investigate the effects of reducing dietary fishmeal (FM) with yeast culture (SYC) supplementation on growth, immune response, intestinal microbiota, intestinal morphology, and disease resistance of Litopenaeus vannamei. A total of 480 shrimps with an average initial body weight of 0.35 ± 0.002 g were randomly distributed into twelve tanks. Three isonitrogenous (40.00 crude protein) and isolipidic (8.00 crude lipids) diets with yeast culture supplementing fishmeal were formulated. The groups were divided into two (2) namely control group and experimental groups. The formulations of the groups were control (0 %, without yeast culture) and the experiment groups (SYC) [(1 % of yeast culture), and (2 % of yeast culture)]. Each diet was delivered in four replicate per treatment group. The results indicate significant improvement on the growth indices (specific growth rate, weight gain rate, survival rate and lower feed conversion ratio) with yeast culture treatment group after 56 days feeding trials (P < 0.05). Total hemolymph protein, superoxide dismutase, catalase, alkaline phosphatase, acid phosphatase, lysozyme and phenoxidase were enhanced but low aspartate aminotransferase, alanine aminotransferase, and glucose were observed in shrimp fed yeast culture diets (P < 0.05). The SYC groups showed insignificant differences in hemolymph cholesterol and triglyceride. Proteobacteria, Bacteroidetes, and Actinobacteria were the dominant bacteria found in all the SYC groups. At the genus level, Vibrio was significantly decreased (P < 0.05) in 2 % yeast culture diets supplemented group whereas the beneficial bacteria Pseudoalteromonas was significantly enhanced. Moreover, intestinal villus length and width in shrimps fed yeast culture diets were improved (P < 0.05). Dietary yeast culture supplementation can improve growth, intestinal health, immune response, and resistance against Vibrio harveyi infections in L. vannamei.

Yeast culture promotes the production of aged laying hens by improving intestinal digestive enzyme activities and the intestinal health status

Yeast culture (YC) positively affects the performance of laying hens. The purpose of the present study was to explore the underlying mechanism for the YC-mediated performance improvement. Sixty 67-week-old Hy-Line Brown laying hens were randomly allocated into 2 experimental groups with 5 replicates of 6 birds each. One group was fed a control diet, whereas the other received the control diet supplemented with YC at 3.0 g/kg; treatment lasted for 8 wk. The results showed that dietary YC supplementation increased (P < 0.05) the total egg weight (11.2–13.6%) and egg-laying rate (13.0–13.5%) but decreased (P < 0.05) the feed/egg ratio by 9.3 to 11.0% during weeks 5 to 6 and 7 to 8 compared with the control. However, egg quality, including eggshell strength, eggshell thickness, egg weight, albumen height, egg yolk color, and Haugh unit, was not affected (P > 0.05) by YC supplementation. Furthermore, dietary YC supplementation increased (P < 0.05) chymotrypsin and ɑ-amylase activities by 54.8 to 62.5% in the duodenal chyme and reduced (P < 0.05) plasma endotoxin by 44.1%. YC dietary supplementation also upregulated (P < 0.05) the mRNA levels of intestinal barrier–related genes (occludin and claudin 1) and antimicrobial peptides genes (β-defensin 1 and 7 and cathelicidin 1 and 3) in the duodenum or jejunum compared with the control. In conclusion, dietary YC supplementation improved the performance of aged laying hens, potentially through the upregulation of intestinal digestive enzyme activities and intestinal health-related gene expression.

Yeast cultures alleviate gossypol induced inflammatory response in liver tissue of Ussuri catfish (Pseudobagrus ussuriensis)

The present study explored the mechanisms of gossypol induced inflammatory response in liver tissue of Ussuri catfish (Pseudobagrus ussuriensis), and investigated whether the yeast culture could relieve the inflammatory response of fish. For this purpose, Ussuri catfish were fed two diets with or without yeast culture for 8 weeks, and then fish were treated with 300 mg gossypol/kg body weight by intragastric administration for 15 days. Fish pre-fed diet without yeast culture supplementation and treated with gossypol oral administration (Gos group) had higher interleukin-1β (IL-1β) and interleukin 8 (IL-8) mRNA levels compared with fish pre-fed diet without yeast culture supplementation and treated with sodium carboxymethylcellulose solution oral administration (control group) and pre-fed yeast culture diet and treated with gossypol oral administration (Gos/YC group), but had lower interleukin 10 mRNA level than the control group (P < .05). Simultaneously, hepatic toll-like receptor 2 (TLR2), myeloid differentiation factor 88 (MyD88) and nuclear transcription factor kappa B p65 (NF-κB p65) mRNA levels of fish in Gos group were also up-regulated. However, dietary yeast culture supplementation remarkably prevented the increase of IL-1β and IL-8 mRNA levels and the decrease of IL-10 mRNA level by inhibiting the excessive activation of TLR2-MyD88-NF-κB signaling pathway through down-regulating TLR2, NF-κB p65 (P < .05) and MyD88 (P > .05) mRNA levels. Besides, the lowest serum lysozyme and alkaline phosphatase activities were observed in fish of Gos group. There was an increased trend in immunoglobulin M content among the groups. Fish in Gos group had significantly lower hepatic catalase, superoxide dismutase and total antioxidant capacity compared with those fish in the control group (P < .05). Higher occurrences of the dilatation in sinusoids, karyolysis, hydropic degenerations and nuclei shifting to the cellular periphery were detected in Gos group compared with those in the control group, coupled with increased serum aspartate aminotransferase activity. Lower occurrences of these histopathological symptoms were observed in the Gos/YC group compared with those of fish in the Gos group. Overall, the results mentioned above indicated that gossypol could result in immune and oxidative damage, liver injury and inflammatory response and dietary yeast culture supplementation could alleviate these negative responses for Ussuri catfish.

Effects of yeast culture supplementation on growth performance, intestinal health, and immune response of nursery pigs1

A total of 216 weaning pigs were used in 2 experiments to determine the effects of dietary supplementation of yeast culture (YC) at different dose levels on the growth performance, nutrient digestibility, intestinal morphology, intestinal microflora, and immune response in weanling pigs and to determine whether YC can be a candidate to replace antibiotic growth promoters (AGP). In Exp. 1, 192 pigs (7.5 +/- 0.2 kg of BW) weaned at 28 d of age were randomly allotted to 6 treatments: 1) control (without AGP or YC); 2) AGP (chlortetracycline, 80 mg/kg); 3) 2.5 g/kg of YC (Diamond V XP Yeast Culture); 4) 5 g/kg of YC; 5) 10 g/kg of YC; and 6) 20 g/kg of YC. Each treatment had 8 replicated pens with 4 pigs per pen. Pigs were fed the experimental diets for 21 d. Average daily gain of pigs fed 5 g/kg of YC was greater (P < 0.05) than that of pigs in the control and other YC groups. However, there was no difference between the YC and AGP group. Pigs supplemented with 5 g/kg of YC, 10 g/kg of YC, and AGP had a greater (P < 0.01) ADFI than the control; however, G:F was not affected by treatment. Thus, 5 g/kg of YC supplementation level was chosen for Exp. 2. In Exp. 2, to elucidate the mode of action of YC, 24 nursery pigs (5.8 +/- 0.1 kg of BW; 21 d of age) were randomly allotted into 3 treatments for a 21-d trial. Treatments consisted of 1) control (without AGP or YC), 2) AGP, and 3) 5 g/kg of YC. Blood samples were collected weekly to measure CD4(+), CD8(+) percentage, and blood cytokine content. All pigs were harvested to determine treatment effects on gut microbiota, morphology, and immune function. Dietary supplementation of 5 g/kg of YC improved (P < 0.05) ADG of pigs compared with the control group, but performance of pigs fed YC was similar to those fed AGP. Pigs receiving 5 g/kg of YC had greater (P < 0.05) digestibility of DM, CP, GE, and jejunal villus height and villus height:crypt depth ratio (P < 0.05) compared with pigs fed the control diet. However, no differences in performance, digestibility, or gut morphology were observed between pigs fed YC and AGP. Gut interferon (IFN)-gamma concentrations were greater (P < 0.01) for pigs supplemented with YC compared with control pigs and pigs supplemented with AGP on d 21. However, plasma IFN-gamma concentrations were decreased (P < 0.01) in pigs supplemented with YC and AGP compared with control pigs on d 7, and CD4(+) was decreased (P < 0.01) in pigs supplemented with YC and AGP on d 14. Results indicate that dietary YC supplementation at 5 g/kg had a positive effect on growth performance of nursery pigs by improving jejunal villus height and villus height:crypt depth ratio and by modulating gut immune response. The comparable effect of 5 g/kg of YC supplementation and AGP on the growth performance of nursery pigs indicates that YC may be a good candidate as an antibiotic alternative.

Effects of Yeast Culture Supplementation to Gestation and Lactation Diets on Growth of Nursing Piglets

A total of 335 sows at a commercial operation (Hitch Pork Producers Inc, Guymon, OK) was used to determine dietary effects of yeast culture supplementation (XPC™, Diamond V Mills) on litter performance. Sows were grouped by parity (parity 1 to 12). Pigs within a group were then allotted to treatments. Treatments consisted of: CON (no added yeast culture) and YC (12 and 15 g/d XPC during gestation and lactation, respectively). Sows were housed individually and fed their assigned gestation and lactation diets from d 35 of gestation to d 21 of lactation. Sows were fed 2.0 kg/d during gestation and ad libitum during lactation. Voluntary feed intake was measured daily during lactation. At farrowing, numbers of pigs born total and alive were measured. Weights of litters were measured at birth and weaning on d 21 of lactation. Litter weight gain of the YC treatment was 6.9% greater (p<0.01) than that of the CON. However, voluntary feed intake of sows and litter size did not differ between treatments. This study indicates that dietary yeast culture supplementation benefits sow productivity by improving litter weight gain. At present, it is not confirmed if improved litter weight gain was due to milk production, which remains to be investigated.

Dietary yeast culture supplementation improves initial rearing of McConaughy strain rainbow trout

The addition of a yeast culture food supplement (DVAqua from Diamond V. Mills, Cedar Rapids, IA, USA) was evaluated during feeding of McConaughy strain rainbow trout Oncorhynchus mykiss. Two trials were run consecutively, starting with initial feeding, and were replicated over 2 years. The yeast culture was added to commercial trout starter at levels of 0.125 and 0.25 g kg−1. The number of rainbow trout that died during the first 4 weeks of rearing was significantly reduced in the tanks receiving either of the yeast culture-supplemented diets compared with the tanks receiving a control starter diet. Ending tank weights and gain were significantly and consistently greater in the tanks fed the 0.25 g kg−1 yeast culture diet. Individual fish weights were also significantly heavier in the fish-fed yeast culture containing diets in each year of the study at the end of 27 days. In the trials from 4 to 8 weeks postinitial feeding, mortality rates were significantly less only in the tanks receiving 0.25 g kg−1 yeast culture supplementation. Individual fish lengths and weights at the end of the second trial were significantly greater in the tanks receiving either level of yeast culture compared with the control diet only in 1 year. Total tank weights and feed conversion were not significantly different between any of the treatments. The inclusion of DVAqua yeast culture provided significant increases in trout survival and growth through the first 4 weeks of feeding, with continued benefits for the next 4 weeks.

Effects of dietary yeast culture supplementation of lactating mares on the digestibility and retention of the nutrients delivered to nursing foals via milk

Summary Eight pregnant Thoroughbred mares were randomly allotted to 2 diets, 4 weeks prior to their anticipated dates of foaling. The diets consisted of 30% timothy hay, 20% alfalfa hay, 17.5% whole corn, 17.5% oats, 9% barley, 2.5% molasses, 2.5% soybean mean and 1% calcium carbonate, with or without 20 g/day of a commercial yeast culture preparation. The digestibilities of dietary energy, crude protein, hemicellulose, cellulose and phosphorus were significantly greater in the supplemented mares. The supplemented mares produced 12% more milk during the third week of lactation (p

Dietary yeast culture supplementation of mares during late gestation and early lactation

Summary Pregnant mares were fed diets with or without 20 g/day of added dried live yeast culture from 4 weeks before foaling through 8 weeks of lactation. Total plasma free amino acid concentrations increased in all mares at the onset of lactation. In addition, yeast culture supplementation was associated with significant additive increases in plasma alanine, argin- ine, glutamine, glycine, isoleucine, leucine, methionine and valine concentrations. In contrast, plasma 3-methylhistidine concentrations tended to be lower in the supplemented mares. Lactation was also accompanied by increased plasma hy- droxyproline concentrations in all mares. However, this in- crease was significantly smaller in the supplemented mares. At 2 weeks of age, the foals of supplemented mares exhibited significantly greater steady-state plasma concentrations of triglycerides and total free amino acids, alanine, arginine, aspartic acid, glutamic acid, glutamine, glycine, histidine, isoleucine, leucine, lysine, methionine, tryptophan, tyrosine and valine than did the foals nursing unsupplemented mares. These differences continued through 8 weeks of life. A nursing bout resulted in transient increases in plasma metab- olite concentrations in all foals. Thyroid hormone (T3 and T4) concentrations tended to be significantly higher in both sup- plemented mares and their foals. These data suggest that supplementing lactating mares with yeast culture causes changes in circulating energy substrate and amino acid con- centrations which may be mediated through changes in thy- roid hormone metabolism.

Dietary yeast culture supplementation of mares during late gestation and early lactation: Effects on milk production, milk composition, weight gain and linear growth of nursing foals

Summary This study examined the effects of dietary supplementation of pregnant and lactating mares with concentrated dried live yeast culture on the nutrient content and rate of production of milk during early lactation and on the growth of their nursing foals. Pregnant mares were fed the same diets, with or without 20 g/day of yeast culture, from 4 weeks before foaling through the eighth week of lactation. Milk production at the onset of lactation, as measured by the weigh-suckle-weigh technique, was significantly stimulated by yeast culture supplementation, although the effect was only temporary. However, the nutrient composition of mares milk was altered by continued yeast culture supplementation through at least the eighth week of lactation. Gross energy (kcal/100 g milk), sugar, fat, protein and total amino acid contents (g/100 g milk) were significantly increased. The concentrations of a number of individual amino acids tended to be greater in the milk of supplemented mares, but most of these individual differences were not statistically significant. The intakes of energy (Mcal/day), sugars, fat, protein, total amino acids, leucine, lysine, serine and valine (g/day) were significantly greater by the foals nursing supplemented mares through 8 weeks. The foals nursing supplemented mares exhibited significantly greater rates of gain by the fourth week of life, and faster growth at the withers after 6 weeks. The efficiency of converting mare feed to neonatal body mass was 24% greater in the foals of supplemented mares, These data indicate that supplementing mares with dietary yeast culture during early lactation resulted in more efficient and rapid growth of their nurslings.

Dietary yeast culture supplementation of mares during late gestation and early lactation Effects on dietary nutrient digestibilities and fecal nitrogen partitioning

This study explored the hypothesis that dietary supplementation of mares during late gestation and early lactation with small amounts of a concentrated dried live yeast culture preparation would increase the digestibility of the components of their feed. Ten pregnant mares were randomly allotted to 2 groups which were fed the same diets, except for supplementation of one group with 20 g/day of yeast culture, from 4 weeks before foaling to 8 weeks after foaling. After 2 weeks of supplementation, the supplemented mares exhibited increases (p<.05) in the digestibilities of dietary energy, dry matter, NDF, ADF, hemicellulose, cellulose, calcium and phosphorus, compared to the digestibilities of these nutrients before supplementation began. In addition, the digestibilities of crude protein,NDF- bound nitrogen and the nutrients listed above were increased (p<.05) when compared to the digestibilities exhibited by the unsupplemented mares. Increased nutrient digestibilities (p<.05) were observed in the supplemented mares 4 weeks after foaling. These data indicate that the supplementation of gestating and lactating mares with yeast culture will increase the nutritional value of a 50% rough- age, 50% concentrate diet.

Effects of dietary yeast culture supplementation during the conditioning period on equine exercise physiology

Two groups of previously unconditioned young adult horses participated in 6 weeks of gradually increasing exercise on an inclined plane treadmill while receiving a cornoats-hay diet with or without a commercially available dietary yeast culture preparation. Forced treadmill exercise at a workload of 11.98 j/kg/m, equivalent to a workrate of 18.34 j/sec/kg and an estimated ground speed of 5.36 m/sec, began at 5 minutes per day (2.75 Mjoules/500 kg body-weight) and was increased by 5 minutes per week to a maximum of 35 minutes per day (19.25 Mjoules/500 kg) after 6 weeks. Treadmill exercise increased venous plasma lactate concentrations in direct proportion to the duration of an exercise bout, but the increases tended to be smaller after a given amount of work as the horses became conditioned. At the end of 35 minutes of exercise, plasma lactate concentrations averaged 30.08 mg/dl in the supplemented horses and 41.29 mg/dl in the unsupplemented horses (p<.01). Plasma glucose concentrations decreased significantly and triglyceride concentrations increased significantly in both groups as exercise duration exceed 10 minutes. Changes in plasma glucose concentrations were not significantly affected by yeast culture supplementation, while the supplemented horses exhibited somewhat slower rates of increased plasma triglyceride concentrations. During the 35-minute exercise bouts, significantly lower heart rates were recorded in the supplemented horses during the first 5 and the final 10 minutes of the workouts (p<.01), suggesting an enhanced state of athletic fitness. The digestible energy required for work (Mcal/500 kg bodyweight) was calculated to be 0.454 (Mcal/Mjoule) (Mjoules of work/500 kg bodyweight) + 0.024 Mcal/500 kg bodyweight (r2=0.95), with an efficiency of converting dietary DE to work of 53% for both groups of horses. Although the exercise challenges to these horses were not severe, these results suggest that dietary yeast culture supplementation of horses entering into conditioning programs may well enhance athletic training.