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

Abstract

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 quantita-tive 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.

Yeast Products Mediated Ruminal Subenvironmental Microbiota, and Abnormal Metabolites and Digestive Enzymes Regulated Rumen Fermentation Function in Sheep

“…ne3005 decreased significantly with the addition of YP at the species level, and we found no relevant reports of this rumen bacterium in other studies. Prevotella ruminicola is known to be an important starch- and protein-degrading bacterium, and it has been reported that yeast can reduce the abundance of rumen starch-utilizing bacteria and maintain rumen pH at a healthy level [ 26 ], which is consistent with our results. However, it is also reported that live yeast can increase the relative abundance of amylolytic microorganisms [ 8 ]; therefore, the specific mechanism may need further study.…”

“…Starch is known to be an important energy source in monogastric animals, but for ruminants, too much starch is a challenge to the rumen. Previous studies in dairy cows have shown that yeast can reduce the relative abundance of amylolytic bacteria, such as Ruminobacter amylophilus and Succinimonas amylolytica , and thus reduce the digestibility of starch in the rumen, which might partially promote a more neutral rumen pH [ 25 , 26 ]. These results are consistent with the fact that the addition of YP reduced rumen amylase activity.…”

“…can use starch and fiber to produce VFAs, thereby improving the production performance of ruminants. R. flavefaciens is a very important cellulose-degrading bacterium in the rumen, and many studies have reported the growth-promoting effect of yeast on this bacterium [ 1 , 3 , 26 ]. Prevotella sp.…”

Alterations in the rumen bacterial communities and metabolites of finishing bulls fed high-concentrate diets supplemented with active dry yeast and yeast culture

“…Previous studies showed that both ADY and YC supplementation stabilize rumen pH in ruminants fed high-concentrate diets ( Erasmus et al, 1992 ; Thrune et al, 2009 ). The underlying mechanism of the regulation of rumen pH by ADY and YC under high-grain diets in beef cattle was the reduction of lactic acid production rather than the enhancement of its consumption, which agreed with Halfen et al (2021) and Lynch and Martin (2002) . ADY and YC supplementation both caused numerical increases in rumen pH value, but these were not statistically significant ( Supplementary Table 5 ).…”

Isolation and Characterization of Ruminal Yeast Strain with Probiotic Potential and Its Effects on Growth Performance, Nutrients Digestibility, Rumen Fermentation and Microbiota of Hu Sheep

“…Moreover, the addition of yeast provides nutrients (vitamins, peptides and growth factors) for the host, thereby stimulating the growth of ruminal microorganisms [5]. The regulation of yeast on ruminal microorganisms is reflected in increasing fiber-degrading and lactate-utilizing bacteria, which improves further rumen fermentation efficiency and subsequent production capacity [6,7]. In ruminant production, Saccharomyces cerevisiae is the most commonly used yeast additive [8].…”