Gross responses and apparent ileal digestibility of amino acids and minerals in broiler chicken fed vegetable-based starter diets supplemented with microbial enzymes

This study was conducted to investigate the effects of diet and exogenous enzymes on growth responses and micronutrient digestibility of broilers. Day-old broilers (n = 256) were distributed into a 2 x 2 factorial design and were fed on two basal diets: soybean (T₁) or canola (T₂) meals as such, or supplemented with enzymes up to 21 days. Feed intake (FI) and live weight (LW) to 21 days on the T₂ diet was higher (P < 0.001) than that on T₁. Feed conversion ratio (FCR) was better (P < 0.01) on T₁ than on T₂ at 21 days. Enzymes generally improved (P < 0.001) FI, FCR, and LW. The digestibility of histidine was higher (P < 0.05) on T₂ , but lysine digestibility was higher (P < 0.01) on T₁ at 21 days. Histidine, threonine, lysine, valine, isoleucine, and phenylalanine digestibility was improved (P < 0.05) in the supplemented diets. Mineral digestibility was unaffected (P > 0.05) by diet, but enzymes increased (P < 0.05) digestibility of P, K, Mn, and Cu at 21 days. The digestibility of Cu, Zn, and Mg was higher (P < 0.05) on T₂, whereas Ca digestibility was greater (P < 0.05) on the T1 diet. Broilers' growth responded positively to enzyme diets, probably due to improvement in nutrient digestibility.