Assessing the effect of a yeast product (Pichia guilliermondii) on growth performance, carcass traits, gut morphology, intestinal microbial computation, and immune response in broilers.

This study evaluated the effects of Pichia guilliermondii supplementation on broiler growth performance, carcass traits, gut morphology, microbiota, and immune response over a 35-day period. A total of 240 chicks were randomly assigned to four dietary treatments: a control group and three experimental groups receiving 0.05%, 0.1%, and 0.15% yeast supplementation, each with six replicates of 10 birds each. Data were analyzed using a one-way ANOVA under a completely randomized design. Birds supplemented with 0.15% yeast tended to increase the weight gain, while all yeast-treated groups exhibited significantly improved feed conversion ratios (P < 0.05) compared to the control group. The 0.05% group showed significantly higher live weights and numerical increases in carcass weights, both with and without giblets. Leg quarter yield tended to improve in both the 0.05% and 0.15% groups, while gizzard weight significantly increased (P < 0.05) in the 0.05% group. Histological analysis revealed a marked increase in villus height and a reduction in crypt depth (P < 0.0001) in all yeast-treated groups, with higher inclusion levels enhancing the villus height-to-crypt depth ratio. All yeast-treated groups exhibited significantly elevated antibody titers against Newcastle disease on days 20 and 35. Microbial analysis indicated increased Lactobacilli and reduced Salmonella counts in the 0.15% group. Economically, the 0.05% yeast group yielded the highest profit per bird. Overall, Pichia guilliermondii supplementation—particularly at 0.05%—proved to be a cost-effective and sustainable strategy for improving broiler performance, health, and profitability.