The objective of this research was to determine the optimal level of an encapsulated butyric acid (ButiPEARL) based on the performance of male Cobb broilers reared to 42 d of age and to investigate its effects on intestinal morphology. Experiment 1 ( EXP 1: ) consisted of 4 treatments with 12 replicate pens that contained 45 broilers, and Experiment 2 ( EXP 2: ) consisted of 6 treatments with 8 replicate pens that contained 50 broilers. Birds were weighed by pen on d 0, 21, 35, and 42. In EXP 1, the treatments were as follows: 1) control ( C: ); 2) C + 100 g ButiPEARL/ton; 3) C + 200 g ButiPEARL/ton; and 4) C + 300 g ButiPEARL/ton. In EXP 2, the treatments were identical to EXP 1, with 2 additional treatments: 5) C + 400 g ButiPEARL/ton and 6) C + 500 g ButiPEARL/ton. In EXP 1, two 42-d-old broilers per pen were randomly selected for duodenal and jejunal tissue collection. Only the samples from the broilers fed the C or 300 g ButiPEARL treatments were analyzed for histology in EXP 1. For EXP 2, on d 21 and 35, two broilers per pen were randomly selected for duodenal, jejunal, and ileal tissue collection. For EXP 1 and 2, BW gain increased linearly with increasing butyric acid levels (P < 0.027 and P < 0.001, respectively). For EXP 1 and 2, feed conversion linearly improved with increasing butyric acid from 0 to 42 d (P < 0.001 and P < 0.001, respectively). In EXP 1, there were no differences in any intestinal morphology at 42 d between broilers fed the C or 300 g ButiPEARL treatments. In EXP 2, there were no differences in villus height at 21 or 35 d of age with any level of butyric acid. Based on the results of this research related to BW gain and feed conversion, the recommended optimum dosage level for ButiPEARL in broilers reared to 42 d of age is up to 500 g/ton.
Keywords: ButiPEARL; body weight gain; broiler; butyric acid; feed conversion.
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