Punicic Acid as a Potential Antibiotic Replacements in Broiler Diets

The move to reduce antibiotic growth promoters (AGP) in animal diets has hindered the control of enteric disease and reduced broiler performance. Thus, dietary punicic acid (PA) from pomegranate seed oil (PSO) was screened as a potential AGP replacer on performance, necrotic enteritis (NE) intestinal lesions, and footpad dermatitis (FPD) on broilers from 1 to 42 d of age. A total of 1,280 birds were randomly distributed across 8 treatments with 8 replicates of 20 birds each. The treatments were: Positive Control (PC; basal diet with antibiotic), Negative Control (NC; basal diet without antibiotic), and six increasing doses of PA (NC diet + either 0.1, 0.25, 0.5, 1, 1.5, or 2% of the feed). A sub-clinical NE challenge model was applied to all birds (15 X coccidiosis vaccine dose at 12 d and a 24-hour feed removal at 18 d). Feed intake (FI), body weight gain (BWG), and feed conversion ratio (FCR) were measured in the starter, grower, and finisher phases. Intestinal NE lesion scores were measured at 20 and 40 d, while FPD scores were measured at 42 d. No significant difference between the PC and NC treatment for performance was found at any phase. Increasing doses of PA quadratically reduced BWG (P<0.01), FI (P<0.01), and increased FCR (P=0.01) before and after the challenge. For the entire period (0 – 41 d), no significant difference for BWG or FCR among treatments was found; however, NC+2% had the lowest FI (85.54 ± 5.54 g/day/bird). The PC treatment had the lowest NE gross lesions, while the treatment NC+2% had the highest number of lesions at 20 d. The NC group had a higher frequency of severe FPD (P<0.01) compared with other treatments. The lack of difference between the PC and NC group indicate that the challenge used may not have been severe enough to detect differences in performance and test PA efficacy. The reduction in performance in treatments with higher PA concentrations may be related to other characteristics of PSO. A baker's yeast enriched with PA is being developed to be used in future experiments, eliminating the potential confounding effects of PSO composition. Therefore, PA may still have the potential to be developed as an alternative for the reduced use of AGP in the poultry industry; however, further studies are required to evaluate the exclusive effects of PA in broilers.

Key words: Antibiotic replacers; broilers; necrotic enteritis; performance; punicic acid.

Presented at the 2021 Animal Nutrition Conference of Canada. For information on the next edition, click here.