Comparative Effects of Antibiotic and Antimicrobial Peptide on Growth Performance, Gut Morphology, Intestinal Lesion Score, Ileal Microbial Counts, and Immune Status in Broilers Challenged with Necrotic Enteritis

This experiment aimed to compare the efficacy of an antimicrobial peptide (AMP) with a conventional antibiotic growth promoter (AGP) during necrotic enteritis (NE) challenge in broilers. In total, 720 1-day-old exclusively male broiler chicks (Ross-308) were allocated to five treatments, each with six replicates of 24 birds (n = 144/treatment), for 35 days. The treatments were as follows: (1) uninfected control (UC) with basal diet, (2) infected control (IC) with C. perfringens challenge and basal diet, (3) CP-AGP with C. perfringens challenge and 200 g/ton enramycin throughout trial, (4) CP-AMP1 with C. perfringens challenge and 200 g/ton AMP in all phases, and (5) CP-AMP2 with C. perfringens challenge and 300 g/ton AMP throughout experiment. To induce NE, the birds were predisposed with 10 x coccidia vaccine (day 15) followed by oral gavage of C. perfringens type G (1 ml; 1 x 10(8) CFU/ml/bird) at days 19 and 20. The results showed that AMP supplemented at 300 g/ton of diet improved body weight gain and FCR in both non-challenge (days 1-14) and challenge phases (days 15-35) as compared to the infected control (P < 0.05). Moreover, it also enhanced the livability and production efficiency factor (P < 0.0001). AMP at 300 g/ton also reduced NE lesion scores, and coccidia oocyst shedding, and positively affected intestinal morphology, gut microbial balance, immune organ weights, and HI titers against Newcastle disease (P < 0.0001). These findings suggest that AMP at 300 g/ton of diet could effectively mitigate NE and may be used as a viable substitute for AGPs in broiler diets during the NE challenge.