Abstract
The effect of dry yeast (DY) (Saccharomyces cerevisiae) supplementation in a high-concentrate diet was evaluated for rumen fermentation, blood parameters, microbial populations, and growth performance in fattening steers. Sixteen crossbred steers (Charolais x American Brahman) at 375 ± 25 kg live weight were divided into four groups that received DY supplementation at 0, 5, 10, and 15 g/hd/d using a completely randomized block design. Basal diets were fed as a total mixed ration (roughage to concentrate ratio of 30:70). Results showed that supplementation with DY improved dry matter (DM) intake and digestibility of organic matter (OM), neutral detergent fiber (NDF), and acid detergent fiber (ADF) (p < 0.05), but DM and crude protein (CP) were similar among treatments (p > 0.05). Ruminal pH (>6.0) of fattening steer remained stable (p > 0.05), and pH was maintained at or above 6.0 with DY. The concentration of propionic acid (C3) increased (p < 0.05) with 10 and 15 g/hd/d DY supplementation, while acetic acid (C2) and butyric acid (C4) decreased. Methane (CH4) production in the rumen decreased as DY increased (p < 0.05). Fibrobacter succinogenes and Ruminococcus flavefaciens populations increased (p < 0.05), whereas protozoal and methanogen populations decreased with DY addition at 10 and 15 g/hd/d, while Ruminococcus albus did not change (p > 0.05) among the treatments. Adding DY at 10 and 15 g/hd/d improved growth performance. Thus, the addition of DY to fattening steers with a high concentrate diet improved feed intake, nutrient digestibility, rumen ecology, and growth performance, while mitigating ruminal methane production.
Highlights
The results showed that dry yeast (DY) addition enhanced final body weight (BW), Average daily gain (ADG), and dry matter (DM) feed intake of total mixed ration compared to the control group (p < 0.05)
Feeding with a high concentrate diet without DY addition resulted in lower fiber digestion in the rumen and, lower ruminal pH
Our results showed that DY supplementation consistently increased final BW, ADG, and DMI, with feed efficiency improving compared to the control [4,32,33,34,35]
Summary
Fattening beef production systems enhance animal growth and profitability by feeding high-concentrate diets with minimal roughage [1]. Preventive measures include modifying feeding management and/or incorporating additives into the total mixed ration (TMR) [4]. Yeast products, such as Saccharomyces cerevisiae, have been employed as antibacterial feed additive substitutes [5]. Yeast supplementation improved nutrient digestibility [15], decreased methane (CH4 ) production [7,16], and improved dairy cow performance [17,18,19,20]. Supplementation of active dry yeast (ADY) with a high-concentrate diet improves nutrient utilization via enhanced digestibility and rumen ecology while reducing CH4 production in fattening steers
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