Abstract

Soybean has been the key protein source for optimal broiler performance; however, due to rising costs and supply constraints, sunflower meal (SFM) is considered a viable substitute when supported by exogenous enzyme (ENZ) supplementation to mitigate its anti-nutritional factors. This study was designed to evaluate the effect of SFM supplementation with enzyme inclusion on broiler growth performance, gut morphometry, digesta viscosity, and nutrient absorption genes. For this purpose, six iso-caloric, iso-nitrogenous diets were formulated for starter phase (ME; 2850 kcal/kg, CP: 22%), grower phase (ME; 2950 kcal/kg, CP: 20.5%) and finisher (ME; 3050 kcal/kg, CP: 19%) phases. A total of 540, one day old, Ross308 broilers were randomly divided into 6 dietary treatments receiving 0%, 10%, and 20% sunflower meal (SFM) with or without supplementation of multicarbohydrase-protease blend, in a 3 × 2 factorial design. Data were analyzed using ANOVA and Tukey-HSD. Results revealed that enzyme supplementations significantly affected (P < 0.05) growth performance and interaction effects of SFM and ENZ showed the greatest improvement in body weight gain and feed conversion ratio 10% SFM with enzyme supplemented group. Gut morphological parameters were also positively affected by SFM and ENZ interactions in terms of villus heights; however, crypt depths and their ratios remained non-significant for interaction effects. Notably, digesta viscosity was significantly reduced (P < 0.05) by enzyme addition. Moreover, enzyme supplementations significantly upregulated the expression (P < 0.05) of nutrient transport genes (CLDN1, TJP1, MUC1, PEPT1) for main effects of SFM and ENZ supplementation but remained non-significant for their interaction effects. Hence, concluding that safe incorporation of SFM up to 20%, ideally around 10%, along with a blend of Multicarbohydrase-protease enzymes in poultry feeds can be an efficient replacement of SBM without compromising performance, gut functioning and overall health in broiler birds.