Document Type : Research Paper
Authors
1 1. Ph.D. Student, Department of Animal Science, Faculty of Animal Sciences and Fisheries, Sari Agricultural Sciences and Natural Resources University, Sari, Iran
2 Professor, Department of Animal Science, Faculty of Animal Sciences and Fisheries, Sari Agricultural Sciences and Natural Resources University, Sari, Iran
3 Associate Professor, Department of Animal Science, Faculty of Animal Sciences and Fisheries, Sari Agricultural Sciences and Natural Resources University, Sari, Iran
4 4. Associate Professor, Department of Animal Science, Faculty of Animal Sciences and Fisheries, Sari Agricultural Sciences and Natural Resources University, Sari, Iran
Abstract
Objective: Heat stress is one of the most challenging environmental stressors in the poultry industry, as it leads to reduced feed intake, body weight, and carcass quality, suppresses immune system activity, and consequently increases flock mortality. This study was conducted to evaluate the effects of basil and parsley seed powders on growth performance, carcass traits, the relative gene expression of heat shock protein 70 (HSP70) in blood and interleukin-two (IL-2) in liver tissue, as well as selected blood parameters of broiler chickens under heat-stress conditions.
Method: A total of 150 male Ross 308 broiler chicks were selected and weighed, then distributed into a completely randomized design consisting of five treatments with three replicates and 10 chickens per replicate. The experimental treatments included: 1) control (basal diet without basil or parsley seed powder); 2) basal diet supplemented with three g/kg basil seed powder; 3) basal diet supplemented with three g/kg parsley seed powder; 4) basal diet supplemented with 1.5 g/kg basil seed powder + 1.5 g/kg parsley seed powder; and 5) basal diet supplemented with neomycin as a positive control (0.2% in the drinking water). To induce heat stress, the temperature of the rearing house was set to 32°C for six hours daily from days 21 to 35. Performance traits (body weight gain, feed intake, and feed conversion ratio (FCR)) were measured throughout the trial. At the end of the experiment, three birds per replicate (closest to the treatment mean body weight) were selected, weighed, and slaughtered to evaluate carcass characteristics, blood biochemical parameters (glucose, cholesterol, HDL, triglycerides), and the relative expression of target genes (HSP70 in blood and IL-2 in liver tissue).
Results: The treatments had no significant effect on feed intake and weight gain; however; the FCR during days 1 to 35 was lowest in the neomycin group (P<0.05). No significant differences were observed among treatments for blood biochemical parameters. Supplementation with basil + parsley seed powder significantly affected gizzard weight and jejunum length compared with the control group (P<0.05). The relative expression of the HSP70 gene in blood was significantly reduced in the basil, parsley, and basil+parsley groups compared with the control and neomycin groups. The relative expression of the IL-2 gene in liver tissue was highest in the basil+parsley group and lowest in the control group (P<0.05).
Conclusions: Overall, this study indicates that the supplementation with basil and parsley seed powders in the diet of broiler chickens under heat stress conditions can reduce the relative expression of the HSP70 gene and increase the relative expression of the IL-2 gene in the birds.
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