Abstract

Aim: The present study aimed to explore the effects of different levels of dietary supplementation of Alpinia galangal rhizomes extracts (AGRE) on blood biochemical components, antioxidant status biomarkers, lipid peroxidation, productive performance (growth performance and mortality rate), and carcass characteristics of broilers under heat stress conditions (temperature-humidity index 87.5 – 93.5).

Materials and Methods: One day old Cobb broilers (n = 1000, body weight mean (44, 58 g) were randomly allotted to four dietary groups. The control group was fed a basal diet without AGRE; the experimental groups received the basal diet with 250, 500 and 750 mg AGRE/kg (groups 250 AGRE, 500 AGRE, and 750 AGRE, respectively). The experimental period lasted for 6 weeks.

Results: In groups, 500 AGRE and 750 AGRE, plasma total protein, albumin, and globulin were significantly (P=0.0001) increased. In contrast, all supplementation levels of AGRE reduced (P=0.022, 0.0001, 0.007 and 0.0024) the plasma concentrations of total lipids, total cholesterol, triglycerides, and low-density lipoproteins, respectively. Antioxidant enzymes of broilers; superoxide dismutase, catalase, glutathione peroxidase, glutathione S-transferase and total antioxidant capacity in the blood were increased (P=0.0005, 0.05, 0.03, 0.02 and 0.0001) by adding dietary AGRE, respectively. However, malondialdehyde was reduced (P=0.0001) with increasing AGRE levels. Compared with other groups, chickens of group 750 AGRE had the best body weight gain and feed conversion ratio and the lowest mortality. Carcass traits cut up parts and yields significantly increased for chicks fed different levels of AGRE, Also group fed on AGRE recorded the highest abdominal fat compared with control group. Additional, liver, heart and gizzard weight was increased significantly in the group of chickens that received different levels of AGRE as compared with the control group. Ascending levels of AGRE treatments influenced the carcass meat, which was observed an increase in crude protein contents (P=0.004), increase in moisture and ether extract contents (P=0.0013 and 0.004) in breast meat compared to control group, respectively. However, Ascending levels of AGRE treatments caused downward in crude protein contents (P=0.004) of thigh meat compared to the control group.

Conclusion: AGRE can be considered as a rich source of phenolic and flavonoid compounds. The results of the study revealed that all tested levels of AGRE were useful as natural protection against heat stress to maintain performance, carcass traits and antioxidant status and could reduce the negative effects of heat stress in broilers.

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