Sustainable use of sodium butyrate as a source of bioactive additive: impact on calf growth performance, rumen fermentation characteristics, and microbial count

Butyrate is a short-chain fatty acid derived from the microbial fermentation of dietary fibers in the foregut or hindgut, and the impact on gut is dependent on the concentration and availability of butyrate produced from diet. However, the objective of this study was to determine the effect of sodium butyrate (SB) addition in milk replacement on the productive performance, energy metabolism, and rumen microbiota in Holstein calves. Twenty-four calf Holstein males at 3 days of age were distributed in a randomized complete block design, of three experimental groups (n = 8). Calves were fed on milk replacement added with 0 (SB0, control), 5 (SB5), and 10 (SB10) g of sodium butyrate/day for 49 days, and fed on starter and water ad libitum during the experimental period (i.e., 49 days), coinciding with weaning. The addition of 5 and 10 g SB to the milk replacement reduced (P < 0.05) feed conversion ratio compared with the control group with an observed significant (P < 0.05) variation in the dry matter intake among the treatment groups. The SB5 calves had higher average daily gain while animals supplemented with 10 g (SB10) were similar to the control, whereas the best feed efficiency was observed in SB10 calves. Calves supplemented with 5 and 10 g of SB increased (P < 0.05) the blood total protein as well as a reduction (P < 0.05) in their ruminal pH. The ruminal bacteria load increased (P < 0.0001) with increasing SB levels in milk calves, whereas ruminal protozoa were not affected by the treatments. The volatile fatty acids, dry matter and organic matter digestibility were increased (P < 0.05) by the SB supplementation in the milk replacer. The inclusion of 5 g SB enhanced (P < 0.05) fermentation and gas production compared to SB0 and SB10 calves. This indicated that SB could be included in the calf’s milk replacement to enhance rumen microbial development, feed conversion efficiency, and energy metabolism.