Effects of probiotic and butyrate-based feed additives on growth performance, carcass yield and gut health of broiler chickens

An experiment was conducted to evaluate the effects of different feed additives on growth performance, carcass yield, blood biochemical parameters, and ileal microflora of broilers raised under warm temperatures (30.4°C). A total of 625 one-day-old Ross 308 broiler chicks were randomly allotted to five dietary treatment groups in a completely randomized design. The treatments comprised a control group (fed a basal diet) and four supplemented groups (each consisting of five replicates with 25 birds per replicate). The feed additives included Saccharomyces boulardii, Bacillus subtilis PB6, protected sodium butyrate, and a sodium–calcium butyrate blend, each incorporated into the basal diet at specified commercial doses. The results showed that the inclusion of protected sodium butyrate and sodium–calcium butyrate consistently enhanced broiler growth performance and increased feed intake without negatively affecting the feed conversion ratio. Mortality rates were slightly reduced in the additive-supplemented groups. Supplementation with sodium and calcium butyrate markedly improved carcass yield in broilers, as evidenced by the significantly higher dressing percentage compared with most other treatments. Reductions in total protein, globulin, ALT, and AST observed in the supplemented groups suggest that probiotics and butyrate exert beneficial modulatory effects on protein metabolism and liver function. Additionally, all tested feed additives improved intestinal development, as indicated by increased villus height and enhanced villus:crypt ratios, particularly in birds receiving Bacillus subtilis and sodium butyrate. A complete absence of harmful microorganisms was observed in birds receiving Bacillus subtilis or sodium butyrate.