Effects of Dietary Onion Peel Powder (Allium cepa L.) on Ileal Digestive Enzyme Activity and Nutrient Digestibility in Broiler Chickens

This study aimed to evaluate the effect of onion peel powder as a feed additive on digestive enzyme activity and nutrient digestibility in broilers. A total of 144 unsexed Lohmann strain DOC broilers were reared for 35 days (24 units, 6 birds/unit); 1 bird per unit (n = 24) was sampled for ileal digestive enzyme activity, then randomly selected 24 male chickens for digestibility analysis at 36-41 days. This study was arranged using a Completely Randomized Design (CRD) with 6 treatments and 4 replications. The variables observed included digestive enzyme activity (amylase, protease, lipase) and nutrient digestibility (crude protein digestibility, nitrogen retention, and metabolizable energy). Data were analyzed using ANOVA and continued with Duncan's test if there was a significant effect. The results showed that the treatment had a highly significant effect (P<0.01) on digestive enzyme activity and nutrient digestibility. The addition of onion peel powder at a dose of 0.25% increased amylase enzyme activity (89.43 U/mL), AME (3112.26 kcal/kg), and AMEn (3039.90 kcal/kg), indicating its potential for use as a sustainable natural feed additive.