Performance, carcass yield, and intestinal morphology of broilers supplemented with Saccharomyces boulardii or Saccharomyces cerevisiae and reared on different litter substrates

Aim of study: To evaluate the performance, carcass yield, and intestinal morphology of broilers supplemented with the yeasts Saccharomyces boulardii or Saccharomyces cerevisiae and housed on wood shavings, rice husk, or a 50% mixture of these substrates. Area of study: South Brazil. Material and methods: A total of 270 one-day-old Cobb 500 broilers were housed, in a 3x3 factorial scheme within a completely randomized design, distributed in 45 experimental pens (experimental units) resulting in 9 treatments with 5 replications each. Feed consumption, weight gain, and feed conversion of birds were evaluated in the period from 1 to 21 days of age, 22 to 42 days, and over the entire experimental period. Additionally, the weight of cuts and viscera was assessed after euthanasia at 42 days of age. A part of the ileum of approximately one centimeter was sampled to evaluate the height of the villi, depth of the crypts, and villus:crypt ratio. Main results: No significant interactions were found on performance variables. Birds raised on rice husk showed higher weight gain and longer ileum villi compared to other litters. Yeast supplementation influenced the weight of cuts and viscera, with notable interactions between substrate types, crypt length and villus ratios remained unaffected. Research highlights: These findings emphasize the importance of considering rice husk as an effective alternative litter, as it improved body weight gain and intestinal villus length in broilers. Additionally, dietary yeast supplementation influenced cut and viscera weight interactions, with significant effects observed in different substrate combinations.