Review: Utilization of yeast of Saccharomyces cerevisiae origin in artificially raised calves

Feeding a Saccharomyces cerevisiae Fermentation Product to Mares in Late Gestation Alters the Biological Activity of Colostrum

The quality of equine colostrum is typically defined by refractometry or the concentration of maternal antibodies. However, the activity of other equine colostral bioactive molecules has not yet been investigated. This study analyzed whether the administration of a Saccharomyces cerevisiae fermentation product (SCFP) influences the biological activity of mare colostrum and whether the biological activity of colostrum has a lasting immunomodulating effect for foals. A total of fourteen pregnant mares received 20 g/day of a SCFP for a period of twelve weeks prior to the calculated date of birth (SCFP-group). Twelve pregnant mares without supplementation served as controls (CON). Colostral Brix values were determined within three hours after parturition. The concentration of IgG in blood sera and colostrum samples was determined with an ELISA. The biological activity was determined in a cell growth assay with a porcine epithelial cell line (IPEC-J2). Mares (at three weeks before the calculated date of birth) and foals (at the age of 5-8 months) received a parenteral active vaccination against influenza and tetanus. The administration of SCFP did not alter the mare's serum and colostrum IgG concentrations and did not exert a significant influence on the mares' early response to the vaccination. Growth and diarrhea episodes were comparable between foals of supplemented mares (SCFP) and foals of mares without supplementation (CON). Colostrum samples from SCFP-supplemented mares exhibited heightened biological activity. While SFCP and CON foals did not differ in their early response to vaccination, the vaccination-induced alterations in circulating neutrophilic granulocyte numbers were significantly correlated with the biological colostrum activity. These findings suggest that the supplementation of mares in late gestation with SCFP can enhance the biological activity of colostrum, which subsequently influences the innate immune responses of their offspring in later life.

Microbial feed additives in ruminant feeding

The main purposes of feed additives administration are to increase feed quality, feed utilization, and the performance and health of animals. For many years, antibiotic-based feed additives showed promising results; however, their administration in animal feeds has been banned due to some public concerns regarding their residues in the produced milk and meat from treated animals. Some microorganisms have desirable properties and elicit certain effects, which makes them potential alternatives to antibiotics to enhance intestinal health and ruminal fermentation. The commonly evaluated microorganisms are some species of bacteria and yeasts. Supplementing microorganisms to ruminants boosts animal health, feed digestion, ruminal fermentation, animal performance (meat and milk), and feed efficiency. Moreover, feeding microorganisms helps young calves adapt quickly to consume solid feed and prevents thriving populations of enteric pathogens in the gastrointestinal tract which cause diarrhea. Lactobacillus, Streptococcus, Lactococcus, Bacillus, Enterococcus, Bifidobacterium, Saccharomyces cerevisiae, and Aspergillus oryzae are the commonly used microbial feed additives in ruminant production. The response of feeding such microorganisms depends on many factors including the level of administration, diet fed to animal, physiological status of animal, and many other factors. However, the precise modes of action in which microbial feed additives improve nutrient utilization and livestock production are under study. Therefore, we aim to highlight some of the uses of microorganisms-based feed additives effects on animal production, the modes of action of microorganisms, and their potential use as an alternative to antibiotic feed additives.

Probiotics in milk replacer affect the microbiome of the lung in neonatal dairy calves

Introduction

Probiotics have been investigated for their many health benefits and impact on the microbiota of the gut. Recent data have also supported a gut-lung axis regarding the bacterial populations (microbiomes) of the two locations; however, little research has been performed to determine the effects of oral probiotics on the microbiome of the bovine respiratory tract. We hypothesized that probiotic treatment would result in changes in the lung microbiome as measured in lung lavage fluid. Our overall goal was to characterize bacterial populations in the lungs of calves fed probiotics in milk replacer and dry rations from birth to weaning.

Methods

A group of 20 dairy calves was split into two treatment groups: probiotic (TRT; N = 10, milk replacer +5 g/d probiotics; Bovamine Dairy, Chr. Hansen, Inc., Milwaukee, WI) and control (CON; N = 10, milk replacer only). On day 0, birth weight was obtained, and calves were provided colostrum as per the dairy SOP. On day 2, probiotics were added to the milk replacer of the treated group and then included in their dry ration. Lung lavages were performed on day 52 on five random calves selected from each treatment group. DNA was extracted from lavage fluid, and 16S ribosomal RNA (rRNA) gene hypervariable regions 1-3 were amplified by PCR and sequenced using next-generation sequencing (Illumina MiSeq) for the identification of the bacterial taxa present. Taxa were classified into both operational taxonomic units (OTUs) and amplicon sequence variants (ASVs).

Results

Overall, the evaluation of these samples revealed that the bacterial genera identified in the lung lavage samples of probiotic-fed calves as compared to the control calves were significantly different based on the OTU dataset (p < 0.05) and approached significance for the ASV dataset (p < 0.06). Additionally, when comparing the diversity of taxa in lung lavage samples to nasal and tonsil samples, taxa diversity of lung samples was significantly lower (p < 0.05).

Discussion

In conclusion, analysis of the respiratory microbiome in lung lavage samples after probiotic treatment provides insight into the distribution of bacterial populations in response to oral probiotics and demonstrates that oral probiotics affect more than the gut microbiome.

Yeast culture repairs rumen epithelial injury by regulating microbial communities and metabolites in sheep

This study delves into the impact of yeast culture (YC) on rumen epithelial development, microbiota, and metabolome, with the aim of investigating YC's mechanism in regulating rumen fermentation. Thirty male lambs of Hu sheep with similar age and body weight were selected and randomly divided into three groups with 10 lambs in each group. Lambs were fed a total mixed ration [TMR; rough: concentrate (R:C) ratio ≈ 30:70] to meet their nutritional needs. The experiment adopted completely randomized design (CRD). The control group (CON) was fed the basal diet with high concentrate, to which 20 g/d of YC was added in the low dose YC group (LYC) and 40 g/d of YC in the high dose YC group (HYC). The pretrial period was 14 days, and the experimental trial period was 60 days. At the end of a 60-day trial, ruminal epithelial tissues were collected for histomorphological analysis, and rumen microorganisms were analyzed by 16S rDNA sequencing and rumen metabolites by untargeted liquid chromatography-mass spectrometry (LC-MS) metabolomics techniques. The results showed that YC improved rumen papilla development and increased rumen papilla length (p < 0.05), while decreased cuticle thickness (p < 0.05). The 16S rDNA sequencing results showed that YC reduced the relative abundance of Prevotella_1 (p < 0.05), while significantly increased the relative abundance of Ruminococcaceae_UCG-005, uncultured_bacterium_f_Lachnospiraceae, and Ruminococcus_1 genus (p < 0.05). Metabolomics analysis showed that YC changed the abundance of metabolites related to amino acid metabolism, lipid metabolism and vitamin metabolism pathways in the rumen. In summary, YC might maintain rumen health under high-concentrate diet conditions by changing rumen microbiota structure and fermentation patterns, thereby affecting rumen metabolic profiles and repairing rumen epithelial injury.

Supplemental organic trace minerals and a yeast culture product in newly weaned steers: effects of use and delivery method on growth performance and hepatic trace mineral content

The objective of this study was to determine if supplementation and delivery method of a "stress pack" composed of organic trace minerals and Saccharomyces cerevisiae yeast culture product influenced growth performance, feed efficiency, and hepatic trace mineral concentration in newly weaned steers. Crossbred steers (n = 192; 256 ± 14.0 kg) were used in a 49-day receiving phase experiment. Within 36 hours of weaning, steers were weighed, allotted to 24 pens (n = 8 steers/pen; 8 pens/treatment), and randomly assigned to treatments: 1) a traditional receiving diet (CON), 2) a traditional receiving diet plus the "stress-pack" directly in the diet (FORCE), and 3) a traditional receiving diet plus a low-moisture, cooked molasses block fortified with the "stress-pack" (TUB). The "stress-pack" was offered the first 28 day of the 49-day receiving period. Due to adverse weather conditions forecasted on day 1, biopsy samples were collected from a subsample of steers (n = 14 steers) on day 1 to establish hepatic trace mineral concentration baseline. Steers were selected based on the mean body weight (BW) from allotment (day -1) of the pen for collection of subsequent samples (n = 1 steer/pen) on days 14, 28, and 49 for hepatic trace mineral concentration determination. Cumulative dry matter intake (DMI) (P = 0.01) was greater for FORCE compared to CON and TUB. Final BW and average daily gain (ADG) tended (P ≤ 0.10) to be greater for FORCE compared to TUB and CON by 5.4% and 9.4%, respectively. Feed efficiency did not differ between treatments (P = 0.28). A treatment × day interaction (P ≤ 0.01) for hepatic Cu concentration was noted. The FORCE treatment had greater hepatic Cu compared to TUB and CON for the entire period. The steers that received TUB had greater hepatic Cu compared to CON on days 14 and 28, but similar to CON on day 49. The addition of a "stress-pack" to diets offered to newly weaned cattle enhanced hepatic trace mineral concentration, and delivery method influences DMI and daily gain.

Graduate Student Literature Review: The problem of calf mortality on dairy farms

Calf mortality can be used as an indicator of animal health and welfare on dairy farms. However, several challenges surround the estimation and reporting of this metric, specifically: (1) lack of records or reliable data, (2) methods of data collection, and (3) inconsistencies in calculation and definitions used. Therefore, despite its importance, the lack of consensus on a definition of calf mortality makes it difficult to compare mortality rates between dairy farms or studies. Monitoring factors associated with calf mortality is vital to create preventative strategies. Although common strategies have been set about how to raise dairy calves and manage dairy calves, discrepancies among studies evaluating factors associated with calf mortality still exist. This review summarizes research on the evaluation of calf mortality and associated risk factors, specifically, the lack of reliable data and standardization of the definition of calf mortality. In addition, current strategies to monitor and prevent calf mortality will be presented in this review.

Research Progress of Biological Feed in Beef Cattle

Biological feed is a feed product developed through bioengineering technologies such as fermentation engineering, enzyme engineering, protein engineering, and genetic engineering. It possesses functional characteristics of high nutritional value and good palatability that can improve feed utilization, replace antibiotics, enhance the health level of livestock and poultry, improve the quality of livestock products, and promote a better breeding environment. A comprehensive review is provided on the types of biological feed, their mechanism of action, fermenting strains, fermenting raw material resources, and their current status in animal production to facilitate in-depth research and development of applications.

Characterization of controlled trials on probiotic supplementation to dairy calves: A scoping review

The objective of this scoping review was to identify, describe, and characterize the literature on probiotic supplementation in dairy calves. Eligible studies were nonrandomized, quasi-randomized and randomized controlled trials in English, Spanish, or Portuguese that evaluated the effect of probiotic supplementation on growth and health of dairy calves. The search strategies were based on a modification of the PICO (Population, Intervention, Comparator, Outcome) framework and used synonyms and words related to "dairy calves" (population), "probiotics" (intervention), and "growth and health measurements" (outcomes). No restrictions for publication year or language were applied. Searches were conducted in Biosis, CAB Abstracts, Medline, Scopus, and the Dissertations and Theses Database. In total, the search identified 4,467 records, of which 103 studies (110 controlled trials) met the inclusion criteria. The studies were published between 1980 and 2021 and originated from 28 countries. Trials were randomized (80.0%), nonrandomized (16.4%), and quasi-randomized (3.6%), ranging in sample size from 5 to 1,801 dairy calves (mode = 24; average = 64). Enrolled calves were frequently Holstein (74.5%), males (43.6%), and younger than 15 d at the beginning of probiotic supplementation (71.8%). Often, trials were conducted in research facilities (47.3%). Trials evaluated probiotics with single or multiple species of the same genus: Lactobacillus (26.4%), Saccharomyces (15.4%), Bacillus (10.0%), Enterococcus (3.6%), or multiple species of various genera (31.8%). Eight trials did not report the probiotic species used. Lactobacillus acidophilus and Enterococcus faecium were the species most supplemented to calves. The duration of probiotic supplementation ranged from 1 to 462 d (mode = 56; average = 50). In trials with a constant dose, it ranged from 4.0 × 106 to 3.7 × 1011 cfu/calf per day. Most probiotics were administered mixed solely into feed (88.5%; whole milk, milk replacer, starter, or total mixed ration) and less frequently orally as a drench or oral paste (7.9%). Most trials evaluated weight gain (88.2%) as a growth indicator and fecal consistency score (64.5%) as a health indicator. Our scoping review summarizes the breadth of controlled trials evaluating probiotic supplementation in dairy calves. Differences in intervention design (mode of probiotic administration, dose, and duration of probiotic supplementation) and outcomes evaluation (type and methods) justify future efforts toward standardized guidelines in clinical trials.

Use of a commercial feed supplement based on yeast products and microalgae with or without nucleotide addition in calves

The use of feed additives with antioxidant and immune response modulatory activity could be a useful strategy in suckling calves to reduce morbidity and mortality. This strategy is based on several feed additives tested for these purposes. The aim of the paper is the examination of a commercial feed additive for adult cows for use in calves, with and without nucleotide supplementation. Seventy-five Holstein Friesian male calves were divided in 3 groups, with each calf randomly assigned to a group according to birth order. All calves received 2 L of pooled colostrum within 2 h of birth. The commercial feed supplement group was orally administered with 5 g/head of Decosel (dried brewer's yeast lysate (Saccharomyces cerevisiae), brewer's yeast walls (Saccharomyces cerevisiae), diatoms, spirulina, barley flour, calcium carbonate; Agroteam srl, Torrimpietra, Italy) and the nucleotides + commercial feed supplement group was orally administered with 5 g/head of an additive containing 2.5 g of Decosel and 2.5 g of nucleotides once daily from birth to 25 d. The control group was orally administered 20 mL of fresh water/head once daily. Calves that received the supplement and the nucleotides showed lower rates of protein and metabolizable energy conversion, with longer villi and greater crypt depth in duodenum. Moreover, the commercial feed supplement alone increased antioxidant capacity [2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) and ferric-reducing antioxidant power] in plasma some activity of antioxidant liver enzymes, and peripheral blood mononuclear cell viability after in vitro concanavalin A and H₂O₂ stimuli. Dietary supplementation with a commercial feed supplement containing yeast products (yeast cell walls and hydrolyzed yeast) and microalgae enhanced the redox balance and gut morphology in calves, allowing calves to improve their immune response, increasing resistance to stress. Moreover, these beneficial effects were strongly potentiated when dietary nucleotides were added to the supplement.

Invited review: Rumen modifiers in today's dairy rations

Our aim was to review feed additives that have a potential ruminal mechanism of action when fed to dairy cattle. We discuss how additives can influence ruminal fermentation stoichiometry through electron transfer mechanisms, particularly the production and usage of dihydrogen. Lactate accumulation should be avoided, especially when acidogenic conditions suppress ruminal neutral detergent fiber digestibility or lead to subclinical acidosis. Yeast products and other probiotics are purported to influence lactate uptake, but growing evidence also supports that yeast products influence expression of gut epithelial genes promoting barrier function and resulting inflammatory responses by the host to various stresses. We also have summarized methane-suppressing additives for potential usage in dairy rations. We focused on those with potential to decrease methane production without decreasing fiber digestibility or milk production. We identified some mitigating factors that need to be addressed more fully in future research. Growth factors such as branched-chain volatile fatty acids also are part of crucial cross-feeding among groups of microbes, particularly to optimize fiber digestibility in the rumen. Our developments of mechanisms of action for various rumen-active modifiers should help nutrition advisors anticipate when a benefit in field conditions is more likely.

Active dry yeast supplementation benefits ruminal fermentation, bacterial community, blood immunoglobulins, and growth performance in young dairy goats, but not for intermittent supplementation

This study evaluated the effects of active dry yeast (ADY) supplementation and supplementation strategies on ruminal fermentation, bacterial community, blood metabolites, and growth performance in young dairy goats. Sixty young female Guanzhong dairy goats of similar age (4.00 ± 0.50 months) and BW (19.65 ± 0.41 kg) were randomly divided into 3 groups (n = 20): (1) basal diet group (CON); (2) basal diet continuously supplemented with 3.0 g/goat per day commercial ADY (a proprietary strain of Saccharomyces cerevisiae with 5.0 × 10⁹ cfu/g) group (CSY); (3) basal diet with intermittently supplemented ADY group (ISY; 5 d supplementation with ADY at 4.5 g/goat per day following 5 d of no supplementation). The experiment lasted 67 d with the first 7 d as an adaptive period. Rumen fluid and blood samples were collected bi-weekly. Data were analyzed using the MIXED procedure combined with the SLICE option in SAS. Specific orthogonal contrasts of ADY vs. CON and CSY vs. ISY were also analyzed. During the experimental period, ADY supplementation resulted in greater DMI (P = 0.03), ruminal acetate proportion (P < 0.01) and acetylesterase activity (P = 0.01), and blood contents of glucose (P = 0.01) and IgM (P = 0.02) and tended to have greater ADG (P = 0.05) and paunch girth (P = 0.06) than the CON, despite the propionate proportion (P = 0.03) and contents of total protein (P = 0.04) and IgA (P = 0.03) being lower. The lower ruminal NH₃-N (P < 0.01) and blood urea nitrogen (P = 0.07) contents indicated greater nitrogen utilization with ADY supplementation. ADY supplementation showed persistent effects after it was stopped because the BW at 12 months of age (P = 0.03) and birth weight of lambs (P = 0.02) were greater than the CON. However, the ISY did not show those benefits and had significantly lower relative abundances of fiber-degrading related bacteria than the CSY. In conclusion, ADY supplementation, especially continuously supplemented, may enhance ADG and ADG:DMI ratio by improving DMI, ruminal cellulolytic bacteria abundance and enzyme activity, nitrogen utilization, and immune status. These findings provide a theoretical basis for the rational application of ADY and have important practical implications for the design of nutritional strategies in growing dairy goats.

Yeast (Saccharomyces cerevisiae) Culture Promotes the Performance of Fattening Sheep by Enhancing Nutrients Digestibility and Rumen Development

Paraprobiotics are potential agents for improving animal health and performance. This experiment investigated the effect of dietary supplementation of yeast (Saccharomyces cerevisiae) culture (YC) on the growth performance, nutrient digestibility, rumen development and microbiome of fattening sheep. Ninety male Hu sheep weighed 38 ± 1.47 kg were randomly assigned to three treatments: CON diet (basal diet), LYC diet (basal diet supplied with 10 and 20 g/d yeast culture at the early and late stages, respectively), and HYC diet (basal diet supplied with 20 and 40 g/d yeast culture at the early and late stages, respectively). Treatments (LYC or HYC) were sprinkled on the feed surface according to the required dosage before feeding the basal diet to each sheep throughout the trial. The trial included early (60 days) and later (30 days) fattening periods. The results showed that average daily gain and feed efficiency were higher (p < 0.05) in the LYC group compared with CON in later and whole stages. Digestibility of DM, OM, CP, NDF and ADF were higher (p < 0.05) in LYC and HYC compared with CON. The retained N, the utilization efficiency of N and the biological value of N were higher (p < 0.05) in LYC compared with CON and HYC. Rumen NH3-N was higher (p < 0.05) in LYC and HYC. The papillary height of the rumen was higher (p < 0.05) in LYC when compared with CON and HYC, whereas rumen wall thickness and muscular layer thickness were higher (p < 0.05) in HYC compared with CON and LYC. The dressing percentage of LYC and HYC was higher (p < 0.05) compared with CON. The diversity, richness and structure of rumen microbiota showed no significant difference (p > 0.05); however, still observed remarkable increases in the relative abundance of several specific genera including Succiniclasticum and Fibrobacter with increasing doses of yeast culture. In addition, at the ASV level, ASV83, ASV123 (Succiniclasticum), and ASV148, ASV250 (Fibrobacter) were increased in YC groups. In conclusion, we confirmed that the supplementation of YC in diet could improve the growth and slaughter performance of fattening Hu sheep through improving nutrient digestion, especially nitrogen utilization, rumen microbial environment and the development of rumen epithelium, which proves the benefits of paraprobiotics in animal production.

Effects of Autolyzed Yeast Supplementation in a High-Starch Diet on Rumen Health, Apparent Digestibility, and Production Variables of Lactating Holstein Cows

Fifteen multiparous rumen-cannulated Holstein cows were assigned to one of five treatments in a replicated 5 × 5 Latin square design. The treatments were low-starch (LS) (22.8 ± 1% of dry matter; DM) without autolyzed yeast (AY; LS0, control), high-starch (HS) (31.2 ± 4% of DM) without AY (HS0), and HS with either 15 g (HS15), 30 g (HS30), or 45 g (HS45) of AY supplementation. Cows in HS0 had increased (p < 0.03) dry matter intake (DMI; 24.9 kg/d) and energy-corrected milk (ECM; 34.4 kg/d) compared to cows in LS0 (19.9 and 31.3 kg/d, respectively). There was a tendency for a quadratic treatment effect for feed efficiency (ECM/DMI, p = 0.07) and crude protein (CP) apparent digestibility (AD) (p = 0.09). Cows in HS45 tended (p = 0.09) to have increased DMI (25.6 kg/d) compared to cows in HS0 (24.9 kg/d). Cows in HS0 had greater (p < 0.04) milk protein nitrogen (N; 166 g/d) and microbial N production (161 g/d) than those in LS0 (140 and 138 g/d, respectively). In conclusion, the addition of AY tended to improve DMI, feed efficiency, and CP AD when cows were fed the HS diet.

An Evaluation of Nutritional and Therapeutic Factors Affecting Pre-Weaned Calf Health and Welfare, and Direct-Fed Microbials as a Potential Alternative for Promoting Performance—A Review

The priority for calf rearing has been to maintain good health and welfare in order to promote and sustain future production. However, there have been numerous reports of undesirable levels of morbidity and mortality amongst pre-weaned calves. This may be mitigated or exacerbated by nutritional management practices. Some areas of concern include colostrum feeding, utilization of waste milk, and restrictive milk feeding regimes. Antibiotics may be prescribed at lethal or sub-inhibitory doses to treat or prevent disease. However, extensive antibiotic use may disrupt the gastrointestinal microbiota and aid in expanding the antibiotic resistant gene pool. In an attempt to reduce the use of antibiotics, there is a demand to find alternative performance enhancers. Direct-fed microbials, also known as probiotics, may comply with this role. A DFM consists of live microorganisms that are biologically active and able to confer health benefits onto the host. Lactic acid bacteria have been the most frequently investigated; however, this field of research has expanded to include spore-forming bacteria and live yeast preparations. This review aims to provide a comprehensive evaluation of the nutritional management strategies that may increase a calf’s susceptibility to morbidity and mortality, the efficacy and sustainability of antibiotics as a tool for managing calf health and welfare, and the potential for DFMs as a supportive strategy for promoting calf wellbeing.

Ruminal Microbiota Determines the High-Fiber Utilization of Ruminants: Evidence from the Ruminal Microbiota Transplant

The rumen, which contains a series of prokaryotes and eukaryotes with high abundance, determines the high ability to degrade complex carbohydrates in ruminants. Using 16S rRNA gene sequencing, we compared the ruminal microbiota of dairy goats with that in the foregut and colon of mice and found more Bacteroides identified in the rumen, which helps ruminants to utilize plant-derived polysaccharides, cellulose, and other structural carbohydrates. Furthermore, high-fiber diets did not significantly increase intestinal fiber-degrading bacteria in mice, but did produce higher levels of ruminal fiber-degrading bacteria in dairy goats. Through rumen microbe transplantation (RMT), we found that rumen-derived fiber-degrading bacteria can colonize the intestines of mice to exert their fiber-degrading function, but their colonization efficiency is affected by diet. Additionally, the colonization of these fiber-degrading bacteria in the colon may involve higher content of butyrate in the colon, protecting the colonic epithelial barrier and promoting energy metabolism. Overall, the fiber degradation function of rumen bacteria through RMT was verified, and our results provide new insights into isolating the functional and beneficial fiber-degrading bacteria in the rumen, providing a theoretical basis for the role of dietary fiber in intestinal health. IMPORTANCE Ruminants have a powerful progastric digestive system that converts structural carbohydrates into nutrients useful to humans. It is well known that this phenomenon is due to the fact that the rumen of ruminants is a natural microbial fermenter, which can ferment structural carbohydrates such as cellulose and hemicellulose and transform them into volatile fatty acids to supply energy for host. However, monogastric animals have an inherent disadvantage in utilizing fiber, so screening rumen-derived fiber-degrading bacteria as a fermentation strain for biological feed is needed in an attempt at improving the fiber digestibility of monogastric animals. In this study, a ruminal microbiota transplant experiment from goats to mice proves that ruminal microbiota could serve as a key factor in utilization of high-fiber diets and provides a new perspective for the development of probiotics with fiber degradation function from the rumen and the importance of the use of prebiotics during the intake of probiotics.

Effects of supplementation with Saccharomyces cerevisiae products on dairy calves: A meta-analysis

Saccharomyces cerevisiae products (SCP) have the potential to promote the growth and development of the gastrointestinal tract and immunity in young livestock animals. However, the effects of SCP supplementation on calves are inconsistent among the reported studies in the literature. Hence, we performed a meta-analysis to comprehensively assess the effects of SCP on the growth performance, ruminal fermentation parameters, nutrients digestibility, ruminal histological morphology, serum immune response, and fecal pathogen colony counts in calves. We searched the Web of Science, ScienceDirect, PubMed, and China National Knowledge Infrastructure for relevant studies published up to October 1, 2021. After screening against a set of criteria, the data of 36 studies were included in our meta-analysis (2,126 calves in total). We evaluated the quality of the data using sensitivity analysis and assessed publication bias. Our meta-analysis revealed several important findings. First, SCP supplementation increased the ruminal short-chain fatty acid concentration, ruminal papilla height, and fiber digestibility, pointing toward stimulation of the development of the rumen in calves. Second, SCP supplementation increased the serum concentrations of total protein, IgA, and IgG but decreased fecal pathogen colony counts, suggesting that SCP could help calves to promote immunity (especially maintaining circulating concentrations of immunoglobulins in preweaning calves) and resistance to pathogens. Third, a subgroup analysis between preweaning and postweaning calves showed that SCP increased average daily gain and dry matter intake preweaning but not postweaning, suggesting that SCP is better supplemented to preweaning calves to achieve the best results. Forth, based on the dose-response curve, 24 to 25 g/d might be the optimal dose range of SCP supplementation (into starter feed) preweaning to achieve the best overall effect, meanwhile, we need more studies to improve the consistency and accuracy of the dose-response curve prediction. Overall, SCP supplementation improved growth performance, rumen development, and immunocompetence in calves, particularly in preweaning calves.

An Electro-Microbial Process to Uncouple Food Production from Photosynthesis for Application in Space Exploration

Here we propose the concept of an electro–microbial route to uncouple food production from photosynthesis, thereby enabling production of nutritious food in space without the need to grow plant-based crops. In the proposed process, carbon dioxide is fixed into ethanol using either chemical catalysis or microbial carbon fixation, and the ethanol created is used as a carbon source for yeast to synthesize food for human or animal consumption. The process depends upon technologies that can utilize electrical energy to fix carbon into ethanol and uses an optimized strain of the yeast Saccharomyces cerevisiae to produce high-quality, food-grade, single-cell protein using ethanol as the sole carbon source in a minimal medium. Crops performing photosynthesis require months to mature and are challenging to grow under the conditions found in space, whereas the electro–microbial process could generate significant quantities of food on demand with potentially high yields and productivities. In this paper we explore the potential to provide yeast-based protein and other nutrients relevant to human dietary needs using only ethanol, urea, phosphate, and inorganic salts as inputs. It should be noted that as well as having potential to provide nutrition in space, this novel approach to food production has many valuable terrestrial applications too. For example, by enabling food production in climatically challenged environments, the electro–microbial process could potentially turn deserts into food bowls. Similarly, surplus electricity generated from large-scale renewable power sources could be used to supplement the human food chain.

Performance and microbiota of the digestive tract of Nellore calves supplemented with fungi isolated from bovine rumen

Background and Aim

In tropical semiarid regions, supplementation with fungi could contribute to rumen modulation, promoting greater production of fibrolytic enzymes and degradation of forage. The objective of this study was to analyze the effect of supplementation with fungi, isolated from the bovine rumen, on the performance and microbiota of the digestive tract of Nellore calves.

Materials and Methods

The experiment was conducted in randomized blocks evaluating eight Nellore calves that were daily supplemented with isolates of Aspergillus terreus and Trichoderma longibrachiatum, along with eight calves that were not supplemented. After 55 days, the animals were weighed, and samples of rumen fluid and feces were collected for analysis. The characteristics that showed normal distribution were subjected to analysis of variance and compared using Tukey's test. Whereas, the variables that did not show normal distribution were subjected to the Kruskal-Wallis test, and the frequencies of the bacterial and fungal genera were compared using the Chi-square test.

Results

Supplementation with fungi promoted the reduction in ruminal pH (p<0.05). However, the final live weight; average daily weight gain; total weight gain; rumen protozoa; and the count of Enterobacteriaceae, mycelial fungi, and yeasts of ruminal fluid and feces were not influenced by supplementation (p>0.05). Moreover, the protozoa Eodinium spp. was identified only in supplemented calves (p<0.05).

Conclusion

Supplementation with the fungi presented the potential for use as possible additives because it did not alter the physiological parameters of the facultative anaerobic microbiota composition in the rumen and feces. In addition, it favored the presence of the ciliate genus Eodinium. However, further studies should be performed to better define suitable dosages for supplementation.

Does algae β-glucan affect the fecal bacteriome in dairy calves?

β-glucans has been reported to be associated with many health-promoting and improvements in animal performance, however, information about their effects on the bacterial community remains unknown. This study aimed to investigate how the addition of β-glucans can affect the fecal bacterial community with possible consequences on animal growth and health. For this, newborn Holstein calves (n = 14) were individually housed in tropical shelters and blocked according to sex, date, and weight at birth and randomly assigned to one of the following treatments: (1) Control: milk replacer (14% solids, 24% CP, 18.5% fat); (2) β-glucans: milk replacer supplemented with β-glucans (2 g/d). All calves were bucket fed 6 L/d of milk replacer and received water and starter concentrate ad libitum starting on d 2. To evaluate the bacteriome, fecal samples were collected at weeks 1, 2, 4, and 8. The bacterial community was assessed through sequencing of the V3-V4 region of the 16S rRNA gene on the Illumina MiSeq platform and analyzed using the DADA2 pipeline. No differences for Shannon and Chao1 indexes were observed for treatments, but both indexes increased with age (P < 0.001). There were dissimilarities in the structure of the bacterial community during the pre-weaning period (P = 0.01). In a deeper taxonomic level, Collinsella (Actinobacteriota), Prevotella (Bacteroidota), and Lactobacillus (Firmicutes) were the most abundant genera (9.84, 9.54, and 8.82% of the sequences, respectively). β-glucans promoted a higher abundance of Alloprevotella and Holdemanella, which may indicate a beneficial effect of supplementation on dairy calves. The bacterial community was highly correlated with the fecal score at weeks 1 and 2 and with starter concentrate intake at week 8. In conclusion, algae β-glucan supplementation could be beneficial to fecal bacteriome and consequently to the health and performance of dairy calves.

Effects of yeast culture supplementation on lactation performance and rumen fermentation profile and microbial abundance in mid-lactation Holstein dairy cows

The continuous trend for a narrowing margin between feed cost and milk prices across dairy farms in the United States highlights the need to improve and maintain feed efficiency. Yeast culture products are alternative supplements that have been evaluated in terms of milk performance and feed efficiency; however, less is known about their potential effects on altering rumen microbial populations and consequently rumen fermentation. Therefore, the objective of this study was to evaluate the effect of yeast culture supplementation on lactation performance, rumen fermentation profile, and abundance of major species of ruminal bacteria in lactating dairy cows. Forty mid-lactation Holstein dairy cows (121 ± 43 days in milk; mean ± standard deviation; 32 multiparous and 8 primiparous) were used in a randomized complete block design with a 7-d adaptation period followed by a 60-d treatment period. Cows were blocked by parity, days in milk, and previous lactation milk yield and assigned to a basal total mixed ration (TMR; 1.6 Mcal/kg of dry matter, 14.6% crude protein, 21.5% starch, and 38.4% neutral detergent fiber) plus 114 g/d of ground corn (CON; n = 20) or basal TMR plus 100 g/d of ground corn and 14 g/d of yeast culture (YC; n = 20; Culture Classic HD, Cellerate Yeast Solutions, Phibro Animal Health Corp.). Treatments were top-dressed over the TMR once a day. Cows were individually fed 1 × /d throughout the trial. Blood and rumen fluid samples were collected in a subset of cows (n = 10/treatment) at 0, 30, and 60 d of the treatment period. Rumen fluid sampled via esophageal tubing was analyzed for ammonia-N, volatile fatty acids (VFA), and ruminal bacteria populations via quantitative PCR amplification of 16S ribosomal DNA genes. Milk yield was not affected by treatment effects. Energy balance was lower in YC cows than CON, which was partially explain by the trend for lower dry matter intake as % body weight in YC cows than CON. Cows fed YC had greater overall ruminal pH and greater total VFA (mM) at 60 d of treatment period. There was a contrasting greater molar proportion of isovalerate and lower acetate proportion in YC-fed cows compared with CON cows. Although the ruminal abundance of specific fiber-digesting bacteria, including Eubacterium ruminantium and Ruminococcus flavefaciens, was increased in YC cows, others such as Fibrobacter succinogenes were decreased. The abundance of amylolytic bacteria such as Ruminobacter amylophilus and Succinimonas amylolytica were decreased in YC cows than CON. Our results indicate that the yeast culture supplementation seems to promote some specific fiber-digesting bacteria while decreasing amylolytic bacteria, which might have partially promoted more neutral rumen pH, greater total VFA, and isovalerate.

Dietary Supplementation of Yeast Culture Into Pelleted Total Mixed Rations Improves the Growth Performance of Fattening Lambs

There is a growing interest in the use of yeast (Saccharomyces cerevisiae) culture (YC) for the enhancement of growth performance and general animal health. Grain-based pelleted total mixed rations (TMR) are emerging in intensive sheep farming systems, but it is uncertain if the process of pelleting results in YC becoming ineffective. This study aimed to examine the effects of YC supplemented to pelleted TMR at two proportions of corn in the diet on animal performance, feed digestion, blood parameters, rumen fermentation, and microbial community in fattening lambs. A 2 × 2 factorial design was adopted with two experimental factors and two levels in each factor, resulting in four treatments: (1) low proportion of corn in the diet (LC; 350 g corn/kg diet) without YC, (2) LC with YC (5 g/kg diet), (3) high proportion of corn in the diet (HC; 600 g corn/kg diet) without YC, and (4) HC with YC. Fifty-six 3-month-old male F2 hybrids of thin-tailed sheep and Northeast fine-wool sheep with a liveweight of 19.9 ± 2.7 kg were randomly assigned to the four treatment groups with an equal number of animals in each group. The results showed that live yeast cells could not survive during pelleting, and thus, any biological effects of the YC were the result of feeding dead yeast and the metabolites of yeast fermentation rather than live yeast cells. The supplementation of YC resulted in 31.1 g/day more average daily gain regardless of the proportion of corn in the diet with unchanged feed intake during the 56-day growth measurement period. The digestibility of neutral detergent fibre and acid detergent fibre was increased, but the digestibility of dry matter, organic matter, and crude protein was not affected by YC. The supplementation of YC altered the rumen bacterial population and species, but the most abundant phyla Bacteroidetes, Firmicutes, and Proteobacteria remained unchanged. This study indicates that YC products can be supplemented to pelleted TMR for improved lamb growth performance, although live yeast cells are inactive after pelleting. The improved performance could be attributed to improved fibre digestibility.

Pollution by Antibiotics and Antimicrobial Resistance in LiveStock and Poultry Manure in China, and Countermeasures

The demand for animal protein has increased considerably worldwide, especially in China, where large numbers of livestock and poultry are produced. Antibiotics have been widely applied to promote growth and prevent diseases. However, the overuse of antibiotics in animal feed has caused serious environmental and health risks, especially the wide spread of antimicrobial resistance (AMR), which seriously affects animal and human health, food safety, ecosystems, and the sustainable future development of animal protein production. Unfortunately, AMR has already become a worldwide challenge, so international cooperation is becoming more important for combatting it. China’s efforts and determination to restrict antibiotic usage through law enforcement and effective management are of significance. In this review, we address the pollution problems of antibiotics; in particular, the AMR in water, soil, and plants caused by livestock and poultry manure in China. The negative impact of widespread and intensive use of antibiotics in livestock production is discussed. To reduce and mitigate AMR problems, we emphasize in this review the development of antibiotic substitutes for the era of antibiotic prohibition.

Effects of Saccharomyces cerevisiae supplementation on growth performance, plasma metabolites and hormones, and rumen fermentation in Holstein calves during pre- and post-weaning periods

This study aimed to evaluate the effects of supplementing Saccharomyces cerevisiae (SC) during the pre- and post-weaning periods on growth, metabolic and hormonal responses, and rumen fermentation in calves. Three-week-old Holstein calves were assigned to either control (n = 12) or SC group (n = 12), the latter of which received 2 × 10⁹  cfu/day of SC. The experiment was conducted over a period of 7 weeks around weaning. Daily gain (DG) in the SC group was higher (p < .05) than that in the control group. In the SC group, plasma glucose, insulin, and growth hormone (GH) concentrations were higher (p < .05) and concentrations of glucagon and insulin-like growth factor 1 (IGF-1) tended to be higher (p < .1) than in the control group. Proportion of rumen propionate and concentration of rumen ammonia nitrogen at 10 weeks of age were greater (p < .05) in the SC group than that in the control group. Supplementation of SC around weaning may improve dietary nutrient and energy availability and increase plasma GH and IGF-1 concentrations. These changes observed in SC-supplemented calves could be closely related to the improvement of DG.

The effects of supplementing yeast fermentation products on gut permeability, hormone concentration, and growth in newborn dairy calves

The objectives of this study were to evaluate the effect of the use of yeast fermentation products (YFP) on growth, hormone concentration, and gut permeability in dairy calves. One hundred and twenty heifers were randomly assigned to one of three treatments: control group with no YFP supplementation (C), Saccharomyces cerevisiae fermentation products (SCFP) supplementation (1 g/head/d of SmartCare [Diamond V] in the milk and 0.7% on dry matter basis of NutriTek [Diamond V] on the starter feed), or Aspergillus oryzae fermentation extracts (AOFE) supplementation (3 g/head/d of LXtract1224 [Biozyme Inc.] in the milk). All calves received 6 L/d of pasteurized milk and had ad libitum access to water and dry feed along the study. Body weight (BW) was recorded at birth and on days 14, 30, and 45 and at weaning. Dry feed (starter) offered was measured daily and refusals twice a week to obtain starter intake (SI). Diarrhea events were recorded daily and fecal scores were classified by using a four-point scale. Blood was sampled on days 7 and 14 for plasma glucose, nonesterified fatty acids (NEFA), insulin, and IL-1β concentrations. Lactulose and D-mannitol were included in the morning feeding of day 14 and blood samples were taken an hour after feeding for assessment of intestinal permeability. On day 14, blood samples were taken for plasma glucagon-like peptide 2 (GLP-2) concentration. On day 30, fecal samples were collected for measurements of Salmonella and Escherichia coli concentration on feces. No treatment differences (P ≥ 0.13) were found for BW or SI. There was a time by treatment difference (P = 0.01) in average daily gain (ADG) on day 45 where C animals had a greater ADG when compared with SCFP and AOFE. Diarrhea incidence did not change between treatments (P = 0.97) and Salmonella and E. coli were not found in feces. There were no differences (P > 0.60) between treatments for plasma GLP-2, glucose, insulin, lactulose, nor D-mannitol concentrations. There was a time by treatment tendency (P = 0.06) for NEFA concentration which tended to be greater on day 7 for C and AOFE when compared with day 14. Plasma IL-1β concentration showed a treatment tendency which tended (P = 0.06) to be greater for SCFP when compared with C. Under the current conditions, supplementation with YFP did not improve performance parameters. Plasma GLP-2 concentration, intestinal permeability, and plasma metabolites did not differ after yeast fermentation products supplementation.

Feeding various forages and live yeast culture on weaned dairy calf intake, growth, nutrient digestibility, and ruminal fermentation

The objective of this study was to determine effects of various forages and live yeast culture on intake, growth, nutrient digestibility, and ruminal fermentation of weaned dairy calves. Holstein calves (n = 45) were randomly assigned to 2 × 3 factorial treatments: live yeast culture or no yeast and alfalfa haylage (AH), corn silage (CS), or grass hay (GH). Calves were weaned at 6 wk of age, housed individually, and studied from 7 to 16 wk of age. Rations, consisting of an 18% crude protein texturized grower (yeast or no yeast) and assigned forage, were offered as separate components until 9 wk of age. After 9 wk, diets were offered as a total mixed ration (TMR). Concentrate intake was capped at 2.25 kg of dry matter (DM)/d, and forage was offered ad libitum. The TMR contained equal forage neutral detergent fiber (8 ± 0.5%) on a DM basis for each basal diet. Calves were fed TMR to limit concentrate intake, and additional forage was offered ad libitum after 8 h if the entire TMR allotment was consumed. Total fecal collection (12 calves) was conducted for 4 d at 11 and 15 wk of age. Feeds and feces were evaluated for DM, neutral detergent fiber, acid detergent fiber, and starch to calculate digestibility. On the last day of fecal collection, rumen samples were collected to evaluate pH and volatile fatty acid (VFA) profile. Metabolizable energy and DM intake was least for calves consuming GH compared with other forages. Forage intake (% of DM intake) increased as calves aged (AH = 20 to 44.4%, CS = 24.5 to 37.6%, GH = 11.3 to 32.3% at 10 and 16 wk of age, respectively). Calves on CS had the greatest average daily gain and empty body weight gain, and calves on GH had the least. Calves on GH tended to have the lowest final body weight. There were no differences in structural growth. Digestibility of DM decreased with age. Fiber digestibility was least for calves on CS, and starch digestibility was least for calves on AH. Mean and minimum rumen pH increased with age. Forage offered changed VFA profile and there was an interaction between yeast and forage on VFA profile. These results indicated that recently weaned calves perform well on AH, CS, or GH and have minimal benefit from yeast supplementation. Feeding GH reduced weight gain, but all calves achieved a level of gain to meet growth goals for breeding and freshening. Furthermore, the ability to consume large portions of the ration as forage allows for more economical diets to be fed.

Impact of inulin and yeast containing synbiotic on calves' productivity and greenhouse gas production

Aim:

The research aimed to determine the impact of synbiotic: 6 g of prebiotic inulin and 5 g of probiotic Saccharomyces cerevisiae strain 1026 on calves’ productivity and greenhouse gas (GHG) production.

Materials and Methods:

The research was conducted with 10 Holstein Friesian and Red Holstein (Bos taurus L.) crossbreed calves of mean age 33±6 days and initial body weight 73.4±12.75 kg. We added the synbiotic into the diet of five dairy crossbreed calves (SynG) and five calves in control group (CoG) received non-supplemented diet. The duration of the experiment was 56 days. The weight of calves and amount of methane (CH₄) and carbon dioxide (CO₂) in the rumen were determined on day 1, 28, and 56. On day 56, three calves from each group were slaughtered. Meat samples were assessed for some indicators of meat quality. The main methanogens were detected in the rumen fluid and feces.

Results:

The weight gain during the whole experiment period of 56 days was higher in the SynG (62.6±13.75 kg) compared to CoG (36.8±7.98 kg) calves (p<0.01). There were no significant differences in the levels of protein (%), fat (unsaturated and saturated – %), and cholesterol (mg/100 g) in meat samples from both groups. At the end of the experiment, the amount of CH₄ in calves’ rumen in CoG was higher (Me=792.06 mg/m³, interquartile range [IQR] 755.06-873.59) compared to SynG (Me=675.41 mg/m³, IQR 653.46-700.50) group (p<0.01). The values for CO₂ were also increased in CoG (Me=4251.28 mg/m³, IQR 4045.58-4426.25) compared to SynG (Me=3266.06 mg/m³, IQR 1358.98-4584.91) group (p=0.001). There were no significant differences in the calves’ weight and certain methanogen species in rumen liquid and feces on the 56^th day of the experiment. Significantly higher results in the parameter total prokaryotes (V3) (bacteria+archaea) in rumen fluid were in SynG, whereas significantly higher results in the parameter total methanogens Met630/803 in rumen fluid were in CoG, p<0.05.

Conclusion:

The main results showed that the synbiotic can increase the daily weight gain in calves and decrease the amount of GHG in rumen but does not impact different methanogen species in rumen liquid and feces and meat protein, fat, and cholesterol levels.

Manipulating the rumen microbiome to address challenges facing Australasian dairy farming

As dairy production systems expand globally, there is an increasing need to reduce the impact of dairy wastes on the environment by decreasing urinary N output and reducing emissions of green-house gasses (GHG). An understanding of rumen microbiome composition can result in the development of strategies that reduce methane emissions and nitrogen leakage, ultimately lowering the impact of dairying on the environment, while improving animal productivity. The strongest driver of the composition of the rumen microbiome was found to be the diet of the host animal. Thus, dietary manipulation offers a viable solution to alter the microbiome to address present-day challenges faced by the dairy industry. In the present review, we discuss such strategies and provide insight into rumen microbiome changes that have resulted in reduced GHG emissions and improved animal productivity.

Supplementation of live yeast based feed additive in early life promotes rumen microbial colonization and fibrolytic potential in lambs

Rumen microbiota is of paramount importance for ruminant digestion efficiency as the microbial fermentations supply the host animal with essential sources of energy and nitrogen. Early separation of newborns from the dam and distribution of artificial milk (Artificial Milking System or AMS) could impair rumen microbial colonization, which would not only affect rumen function but also have possible negative effects on hindgut homeostasis, and impact animal health and performance. In this study, we monitored microbial communities in the rumen and the feces of 16 lambs separated from their dams from 12 h of age and artificially fed with milk replacer and starter feed from d8, in absence or presence of a combination of the live yeast Saccharomyces cerevisiae CNCM I-1077 and selected yeast metabolites. Microbial groups and targeted bacterial species were quantified by qPCR and microbial diversity and composition were assessed by 16S rDNA amplicon sequencing in samples collected from birth to 2 months of age. The fibrolytic potential of the rumen microbiota was analyzed with a DNA microarray targeting genes coding for 8 glycoside hydrolase (GH) families. In Control lambs, poor establishment of fibrolytic communities was observed. Microbial composition shifted as the lambs aged. The live yeast supplement induced significant changes in relative abundances of a few bacterial OTUs across time in the rumen samples, among which some involved in crucial rumen function, and favored establishment of Trichostomatia and Neocallimastigaceae eukaryotic families. The supplemented lambs also harbored greater abundances in Fibrobacter succinogenes after weaning. Microarray data indicated that key cellulase and hemicellulase encoding-genes were present from early age in the rumen and that in the Supplemented lambs, a greater proportion of hemicellulase genes was present. Moreover, a higher proportion of GH genes from ciliate protozoa and fungi was found in the rumen of those animals. This yeast combination improved microbial colonization in the maturing rumen, with a potentially more specialized ecosystem towards efficient fiber degradation, which suggests a possible positive impact on lamb gut development and digestive efficiency.

Dynamic role of single-celled fungi in ruminal microbial ecology and activities

In ruminants, high fermentation capacity is necessary to develop more efficient ruminant production systems. Greater level of production depends on the ability of the microbial ecosystem to convert organic matter into precursors of milk and meat. This has led to increased interest by animal nutritionists, biochemists and microbiologists in evaluating different strategies to manipulate the rumen biota to improve animal performance, production efficiency and animal health. One of such strategies is the use of natural feed additives such as single-celled fungi yeast. The main objectives of using yeasts as natural additives in ruminant diets include; (i) to prevent rumen microflora disorders, (ii) to improve and sustain higher production of milk and meat, (iii) to reduce rumen acidosis and bloat which adversely affect animal health and performance, (iv) to decrease the risk of ruminant-associated human pathogens and (v) to reduce the excretion of nitrogenous-based compounds, carbon dioxide and methane. Yeast, a natural feed additive, has the potential to enhance feed degradation by increasing the concentration of volatile fatty acids during fermentation processes. In addition, microbial growth in the rumen is enhanced in the presence of yeast leading to the delivery of a greater amount of microbial protein to the duodenum and high nitrogen retention. Single-celled fungi yeast has demonstrated its ability to increase fibre digestibility and lower faecal output of organic matter due to improved digestion of organic matter, which subsequently improves animal productivity. Yeast also has the ability to alter the fermentation process in the rumen in a way that reduces methane formation. Furthermore, yeast inclusion in ruminant diets has been reported to decrease toxins absorption such as mycotoxins and promote epithelial cell integrity. This review article provides information on the impact of single-celled fungi yeast as a feed supplement on ruminal microbiota and its function to improve the health and productive longevity of ruminants.

Invited Review: Nutritional regulation of gut function in dairy calves: From colostrum to weaning

Purpose

Published literature regarding calf nutrition was reviewed to create an information base for the implementation of proper nutritional management to maximize health and productivity.

Sources

The main source of data and information for this review was peer-reviewed literature.

Synthesis

Feeding a sufficient volume of colostrum during the first hours of life is crucial to calf health and survival; however, less is known about transition milk feeding and the potential benefits of the myriad of bioactive compounds it contains. After feeding colostrum and transition milk, calves are susceptible to diarrhea when moved onto high amounts of milk, and antibiotic use is often necessary to decrease disease. Feeding an elevated plane of milk nutrition results in increased ADG and, in some studies, increased future milk production. Thus, this nutritional strategy is recommended; however, weaning calves from high volumes of milk represents massive changes in the structure and microbiology of the gastrointestinal tract.

Conclusions and Applications

Colostrum and transition milk contain an abundance of bioactive molecules that can positively affect gut development and microbiota. There is significant potential for the use of novel feeding strategies and microbial-based products as alternatives to antibiotics. Calves fed an elevated plane of nutrition in the first month of life have greater productivity and growth. However, weaning should take place later in life. Moreover, applying a proper step-down feeding protocol is recommended, as it allows calves to intake and digest sufficient solid feed for growth and minimize distress at weaning.

Review: Are there indigenous Saccharomyces in the digestive tract of livestock animal species? Implications for health, nutrition and productivity traits

All livestock animal species harbour complex microbial communities throughout their digestive tract that support vital biochemical processes, thus sustaining health and productivity. In part as a consequence of the strong and ancient alliance between the host and its associated microbes, the gut microbiota is also closely related to productivity traits such as feed efficiency. This phenomenon can help researchers and producers develop new and more effective microbiome-based interventions using probiotics, also known as direct-fed microbials (DFMs), in Animal Science. Here, we focus on one type of such beneficial microorganisms, the yeast Saccharomyces. Saccharomyces is one of the most widely used microorganisms as a DFM in livestock operations. Numerous studies have investigated the effects of dietary supplementation with different species, strains and doses of Saccharomyces (mostly Saccharomyces cerevisiae) on gut microbial ecology, health, nutrition and productivity traits of several livestock species. However, the possible existence of Saccharomyces which are indigenous to the animals' digestive tract has received little attention and has never been the subject of a review. We for the first time provide a comprehensive review, with the objective of shedding light into the possible existence of indigenous Saccharomyces of the digestive tract of livestock. Saccharomyces cerevisiae is a nomadic yeast able to survive in a broad range of environments including soil, grass and silages. Therefore, it is very likely that cattle and other animals have been in direct contact with this and other types of Saccharomyces throughout their entire existence. However, to date, the majority of animal scientists seem to agree that the presence of Saccharomyces in any section of the gut only reflects dietary contamination; in other words, these are foreign organisms that are only transiently present in the gut. Importantly, this belief (i.e. that Saccharomyces come solely from the diet) is often not well grounded and does not necessarily hold for all the many other groups of microbes in the gut. In addition to summarizing the current body of literature involving Saccharomyces in the digestive tract, we discuss whether the beneficial effects associated with the consumption of Saccharomyces may be related to its foreign origin, though this concept may not necessarily satisfy the theories that have been proposed to explain probiotic efficacy in vivo. This novel review may prove useful for biomedical scientists and others wishing to improve health and productivity using Saccharomyces and other beneficial microorganisms.

Saccharomyces cerevisiae boulardii CNCM I-1079 affects health, growth, and fecal microbiota in milk-fed veal calves

The objective of this study was to investigate the effect of one specific strain of yeast, Saccharomyces cerevisiae boulardii CNCM I-1079 (SCB), on the growth performance, health, and fecal bacterial profile of veal calves. A total of 84 animals were enrolled in an experiment at a commercial veal farm for a total of 7 wk. Calves were fed twice a day with a milk replacer meal during the entire experiment and were randomly assigned to receive daily either SCB supplementation (10 × 10⁹ cfu/d) or a placebo (CON). Individual feed intake and body weight were monitored on a daily and weekly basis, respectively. Fecal samples were collected at arrival to the veal facility (wk 0) and additional samples were taken on d 14 (wk 2) and d 49 (wk 7). These samples were subjected to 16S rRNA gene amplicon sequencing using Illumina MiSeq (Illumina Inc., San Diego, CA) to examine the bacterial profiles and real-time quantitative PCR to quantify Saccharomyces cerevisiae and specific bacterial groups. The significant increase of S. cerevisiae in the feces of SCB calves at wk 2 and 7 compared with wk 0 (respectively 1.7 × 10⁷, 1.2 × 10⁷, and 2.2 × 10⁵ copy number of S. cerevisiae/g of feces) indicates a good survival of that yeast strain along the gastrointestinal tract. Supplementation of SCB did not improve overall growth performance with regard to average daily gain (ADG), final body weight, and feed intake. Nevertheless, a total of 69.1% of nonsupplemented calves had diarrhea and 28.6% experienced severe diarrhea, whereas 50.0% of the calves supplemented with SCB had diarrhea and 9.5% experienced severe diarrhea. With respect to antibiotic use, 89.7% of the diarrheic calves recorded in the CON group were treated, whereas only 66.7% of the SCB diarrheic calves received an antibiotic. In addition, diarrheic calves supplemented with SCB maintained an ADG similar to nondiarrheic animals, whereas the CON diarrheic calves had a significantly lower ADG in comparison with nondiarrheic CON calves. Fecalibacterium was the most predominant bacterial genus in fecal samples of nondiarrheic and diarrheic calves supplemented with SCB, whereas fecal microbiota was predominated by Collinsella in diarrheic calves from the CON group. Live yeast supplementation in milk replacer led to a decrease of diarrhea in milk-fed veal calves and the fecal microbiota of diarrheic calves maintained a healthy community similar to nondiarrheic animals, with Fecalibacterium being the predominant genus.

Effect of milk feeding strategy and lactic acid probiotics on growth and behavior of dairy calves fed using an automated feeding system1

Automated milk feeders offer flexibility to feed calves high milk allowances, to change the daily quantity of milk offered, and also to dispense additives like probiotics on an individual basis. Our objectives were to test the effects of 2 milk feeding protocols and a lactic acid bacterium probiotic on performance and behavior in calves. Heifer dairy calves (n = 96) were enrolled at birth in a 2 × 2 factorial study design comparing feeding (1) 2 milk feeding protocols and (2) a lactic acid bacterium-based probiotic program, or a placebo, using automated milk feeders. The early milk feeding strategy (EM) offered a maximum of 11 L/d on day 1 and a peak maximum allowance of 15 L/d on day 21. The late milk feeding strategy (LM) offered a maximum of 7 L/d on day 1 and increased slowly to its peak at 13 L/d on day 28. Both feeding strategies gradually weaned the calves after peak milk allowance until complete weaning at day 53, offering a total of 543 liters of milk. Probiotics or placebo were fed orally in a gel once after colostrum, and twice daily in the milk until weaning. Water and calf starter were provided ad libitum. The experimental period was divided into 3 periods: from day 1 on the automated feeder to day 28 (Period 1), from day 29 to day 53 (Period 2), and the week post-weaning (Period 3). For Period 1, the average daily gain (ADG) of the probiotic group was greater than that of the placebo group (0.84 ± 0.10 kg/d vs. 0.74 ± 0.10 kg/d, respectively), but was not different between milk feeding strategies. For Period 2, ADG was not affected by probiotic or milk feeding strategies. For Period 3, ADG was greater for EM compared to LM (1.27 ± 0.10 kg/d vs. 1.02 ± 0.10 kg/d, respectively), but not between probiotic and placebo groups. During the whole experimental period, LM calves consumed significantly more milk than the EM calves (431.84 ± 33.0 liters vs. 378.64 ± 34.2 liters, respectively). During Period 3, probiotics affected the frequency of visits to the calf starter feed bunk (37.72 ± 2.8 vs. 23.27 ± 2.8 visits per day for probiotic and placebo groups, respectively), but did not affect total time spent at the feed bunk. The supplementation of a lactic acid-based probiotic improved ADG during early life and altered some aspects of the feeding behavior of dairy calves. Calves receiving an early accelerated milk allowance had improved growth during post-weaning and consumed less milk in total, which may indicate better use of solid feed.

Addressing Global Ruminant Agricultural Challenges Through Understanding the Rumen Microbiome: Past, Present, and Future

The rumen is a complex ecosystem composed of anaerobic bacteria, protozoa, fungi, methanogenic archaea and phages. These microbes interact closely to breakdown plant material that cannot be digested by humans, whilst providing metabolic energy to the host and, in the case of archaea, producing methane. Consequently, ruminants produce meat and milk, which are rich in high-quality protein, vitamins and minerals, and therefore contribute to food security. As the world population is predicted to reach approximately 9.7 billion by 2050, an increase in ruminant production to satisfy global protein demand is necessary, despite limited land availability, and whilst ensuring environmental impact is minimized. Although challenging, these goals can be met, but depend on our understanding of the rumen microbiome. Attempts to manipulate the rumen microbiome to benefit global agricultural challenges have been ongoing for decades with limited success, mostly due to the lack of a detailed understanding of this microbiome and our limited ability to culture most of these microbes outside the rumen. The potential to manipulate the rumen microbiome and meet global livestock challenges through animal breeding and introduction of dietary interventions during early life have recently emerged as promising new technologies. Our inability to phenotype ruminants in a high-throughput manner has also hampered progress, although the recent increase in “omic” data may allow further development of mathematical models and rumen microbial gene biomarkers as proxies. Advances in computational tools, high-throughput sequencing technologies and cultivation-independent “omics” approaches continue to revolutionize our understanding of the rumen microbiome. This will ultimately provide the knowledge framework needed to solve current and future ruminant livestock challenges.

Direct-fed microbial supplementation influences the bacteria community composition of the gastrointestinal tract of pre- and post-weaned calves

This study investigated the effect of supplementing the diet of calves with two direct fed microbials (DFMs) (Saccharomyces cerevisiae boulardii CNCM I-1079 (SCB) and Lactobacillus acidophilus BT1386 (LA)), and an antibiotic growth promoter (ATB). Thirty-two dairy calves were fed a control diet (CTL) supplemented with SCB or LA or ATB for 96 days. On day 33 (pre-weaning, n = 16) and day 96 (post-weaning, n = 16), digesta from the rumen, ileum, and colon, and mucosa from the ileum and colon were collected. The bacterial diversity and composition of the gastrointestinal tract (GIT) of pre- and post-weaned calves were characterized by sequencing the V3-V4 region of the bacterial 16S rRNA gene. The DFMs had significant impact on bacteria community structure with most changes associated with treatment occurring in the pre-weaning period and mostly in the ileum but less impact on bacteria diversity. Both SCB and LA significantly reduced the potential pathogenic bacteria genera, Streptococcus and Tyzzerella_4 (FDR ≤ 8.49E-06) and increased the beneficial bacteria, Fibrobacter (FDR ≤ 5.55E-04) compared to control. Other potential beneficial bacteria, including Rumminococcaceae UCG 005, Roseburia and Olsenella, were only increased (FDR ≤ 1.30E-02) by SCB treatment compared to control. Furthermore, the pathogenic bacterium, Peptoclostridium, was reduced (FDR = 1.58E-02) by SCB only while LA reduced (FDR = 1.74E-05) Ruminococcus_2. Functional prediction analysis suggested that both DFMs impacted (p < 0.05) pathways such as cell cycle, bile secretion, proteasome, cAMP signaling pathway, thyroid hormone synthesis pathway and dopaminergic synapse pathway. Compared to the DFMs, ATB had similar impact on bacterial diversity in all GIT sites but greater impact on the bacterial composition of the ileum. Overall, this study provides an insight on the bacteria genera impacted by DFMs and the potential mechanisms by which DFMs affect the GIT microbiota and may therefore facilitate development of DFMs as alternatives to ATB use in dairy calf management.

Changes in the Rumen Epithelial Microbiota of Cattle and Host Gene Expression in Response to Alterations in Dietary Carbohydrate Composition

The inclusion of high-quality hay (HQH), in place of concentrates, shifts dietary carbohydrate intake, and the extent to which these shifts effect epimural microbiota and epithelial gene expression of the rumen has not yet been evaluated. Eight ruminally cannulated nonlactating Holstein cows were used in a replicated 4 by 4 Latin square design with four dietary treatments containing HQH, with either 0% concentrate/100% HQH (100HQH), 25% concentrate/75% HQH (75HQH), or 40% concentrate/60% HQH (60HQH). The fourth group (control [CON]) was fed 60% normal fiber-rich hay and 40% concentrate. The data showed that measures of diversity for the rumen epimural population, specifically the Shannon (P = 0.004) and Simpson (P = 0.003) indices, decreased with increasing levels of HQH in the diet. The feeding of HQH shifted the epimural population from predominantly Firmicutes to Proteobacteria Phylogenetic analysis revealed that HQH feeding markedly shifted the abundance of Campylobacter spp. from 7.8 up to 33.5% (P < 0.001), with greater ingestion of protein (r = 0.63) and sugars (r = 0.65) in HQH diet being responsible for this shift. The expression of genes targeting intracellular pH regulation, barrier function, and nutrient uptake of rumen epithelium remained stable regardless of the carbohydrate source. In conclusion, the data suggest strong alterations of the ruminal epimural microbiota in response to changes in the nutritive patterns of the diet. Further research is warranted to evaluate the long-term effects of these significant microbial changes on rumen health and food safety aspects in cattle at a transcriptional level.IMPORTANCE Feeding of forages versus starchy concentrates is a highly debated topic. Hay is believed to be healthier and more ecological sustainable for cattle than are concentrates, although the effects of feeding hay with enhanced sugar and protein content on epimural microbiota and host gene expression have not yet been evaluated. This research provides a report of the role of feeding hay with increased sugar and protein content in place of starchy concentrates in altering epimural microbiota and in generating a host response. Our research shows that the addition of high-quality hay to dairy rations shifted nutrient intake, resulting in strong alterations in the epimural microbiota in cattle. This work provides a background for further long-term research regarding the effects of feeding practices on the host-microbiome interaction and its role in rumen health and food safety in cattle.

Immunomodulatory effects of probiotics and prilled fat supplementation on immune genes expression and lymphocyte proliferation of transition stage Karan Fries cows

Background and Aim:

Probiotics are the living microorganism which when administered improves the digestion and health of the animal. Saccharomyces cerevisiae (SC) improves the humoral and innate immunity of the animal. Prilled fat is a hydrogenated palm oil triglyceride which has been reported to promote the release of cytokines from macrophages. The aim of the study was to evaluate the immunomodulatory effect of probiotic and prilled fat during transition stage in Karan Fries (KF) cows.

Materials and Methods:

A total of 12 KF cows at 21 days prepartum were selected and divided into two groups of six animals each. The control group was fed as per the standard feeding practices and the supplemented group cows were supplemented daily with prilled fat at 100 g/cow, SC at 25 g/cow, and sweetener at 1 g/cow in addition to the standard feeding practices from −30 days of prepartum to 21 days of lactation. The sweetener was added to improve the palatability of the feed. The natural sweetener of an African plant leave had 105 times more sweetness than glucose with good aroma. The dry matter intake of the animal was recorded. Plasma samples were collected weekly from all cows for the analysis of blood metabolite beta-hydroxybutyric acid (BHBA). Lymphocytes were isolated from the blood for studying the expression of tumor necrosis factor alpha (TNF-α) and interleukin-1β (IL-1β) and for estimating lymphocyte proliferation index (LPI).

Results:

The upregulated IL-1β and TNF-α around calving might be possibly associated to the metabolic changes occurring during the transition period and suggest a higher degree of inflammation around parturition. High concentrations of BHBA caused increased expression and synthesis of the pro-inflammatory factors such as TNF-α and IL-1β in supplemented group in primary calf hepatocytes. The LPI was higher in supplemented group as compared to control which suggests a stimulatory effect of unsaturated fatty acids on mitogen-stimulated T-cell proliferation.

Conclusion:

Dietary supplementation of probiotics, prilled fat, and sweetener alleviated negative energy balance by stimulating feed intake and modulating hepatic lipid metabolism; and both of these additives improved the postpartum health (antioxidant status and immune function) of transition dairy cows.