In this trial, a 3 × 2 factorial design with different dietary crude protein levels (CP, 17, 19 and 21%) and two levels of exogenous protease (0 and 30,000 IU/kg) was used. A total of 540 two-week old broilers (Ross-308) was randomly allocated to experimental diets over 15–28 days of age. The interaction between dietary protein levels and enzyme supplementation showed that body weight gain was significantly (p < 0.05) higher in birds fed CP-19 (1114.7 g) and CP-21 (1108.8 g) with enzymes supplementation. Feed intake was higher (p < 0.05) in broilers fed with CP-17 than CP-19 with supplementation of the protease enzyme. Results also revealed that the feed conversion ratio (FCR) was significantly (p < 0.05) improved in birds fed with CP-19 and CP-21 and protease supplementation. Total tract N retention was lower (p < 0.05) in birds fed CP-17 with no enzyme than the other dietary groups. Similarly, the gross energy (GE) was significantly (p < 0.05) lower in birds fed CP-17 with or without the protease enzyme. Abdominal fat was higher (p < 0.05) in CP-17 (0.96%) without the protease enzyme. It was concluded that a diet at 19% CP with the protease enzyme improved the performance and nutrient digestibility in broilers over 15–28 days.

A total of 300 day old broiler chicks (Hubbard) were assigned to 30 floor pens (10 birds per pen) under cyclic heat stress. Three diets including a control, as well as two levels of grape seed powder (GSP) and zinc (OZ) at the rates of 2.5 g/kg GSP + 50 mg/kg OZ and 5 g/kg GSP + 50 mg/kg OZ, were supplied to the broilers for 35 days. According to the results, broiler feed intake improved (p < 0.05) in GSP + OZ groups from 3–5 weeks and on an overall basis compared to the control diet. Body weight increased (p < 0.05) in GSP-5 + OZ-50 during weeks 2–5 and on an overall basis. The findings indicated that feed conversion ratio (FCR) decreased (p < 0.05) during week 5 in broilers supplemented with GSP-5 + OZ-50. The antibody titer (HI) against Newcastle disease (ND) was higher (p < 0.05) in GSP + OZ groups compared to control treatment. The value of malondialdehyde (MDA) decreased (p < 0.05) under GSP + OZ diets compared to control. Moreover, paraoxonase (PON1) was higher (p < 0.05) in GSP + OZ groups compared to untreated broilers. In conclusion, GSP + OZ positively supported growth traits, reduced MDA, and augmented PON1 and HI titer against ND in broilers exposed to heat stress.

The objective of the present study was to evaluate the impact of inclusion of wild cumin seeds (WCS) on performance, nutrient digestibility and blood profile in broilers during the finisher phase. For this purpose, 360, 14 days old chicks were randomly divided into four groups designated as CONT (control), 0.5WCS, 1.0WCS and 1.5WCS with 5 replicates, which were supplemented with WCS at the rate of 0, 0.5, 1, and 1.5% respectively. On the overall, feed intake was significantly (p < 0.01) higher in the CONT compared to the 1.0WCS. At the end of the finisher phase, and overall basis, body weight and feed conversion ratio were significantly (p < 0.05) higher in 0.5WCS. Crude protein apparent digestibility in the ileum was significantly (p < 0.05) higher in 0.5WCS compared to the CONT, while crude fat digestibility was significantly (p < 0.01) higher in 0.5WCS and 1.5WCS compared to the control. Similarly, serum triglyceride was significantly (p < 0.05) lower in 0.5WC but high density lipoprotein was significantly (p < 0.05) higher in the same group. It was concluded that wild Cumin at the rate of 0.5% was superior compared to the other treatments in the diet to improve the performance, nutrient digestibility and blood metabolites in broiler during the finisher phase.