This experiment was conducted to study the effects of 7-aminobutyric acid (GABA) on the laying and reproductive performance of broiler breeders under heat stress, and to investigate the mechanism from an-tioxidation, immunologic function and liver-associated serum enzyme activities. A total of 360 Lingnan yellow broiler breeders (28-week-old) were randomly divided into 4 groups with 3 replicates in each group and 30 broiler breeders in each replicate. Diets of the four groups were supplemented with 0 (control group) , 25, 50 and 75 mg/kg GABA in a basal diet, respectively. The preliminary trial period lasted for 14 days; trial period lasted for 56 days. The results showed as follows; compared with the control group, 1) supplemented 75 mg/kg GABA significantly increased laying rate, average egg weight, feed/egg ratio of broiler breeders (P<0.05) , and also significantly increased fertilization and hatchability of eggs (P <0. 05) , birth weight (P <0. 05) and birth rate (P <0. 01) of chicks. Furthermore, supplemented 25 and 50 mg/kg GABA significantly increased hatchability and birth rate (P <0. 05) , and supplemented 25 GABA significantly increased birth rate of chicks (P <0. 05). 2) Supplemented 75 mg/kg GABA significantly increased the contents of serum immunoglobulin A (IgA) , immunoglobulin M (IgM) and complement C4 (P <0. 05) ; supplemented 25 mg/kg GABA significantly increased the serum IgM content (P <0. 05). 3) Supplemented 75 mg/kg GABA significantly increased the activities of serum superoxide dismutase, glutathione peroxidase (P <0. 05) and total antioxidant capability (P <0. 01) , and decreased the serum malondialdehyde concentration (P < 0.01); supplemented 25 mg/kg GABA also significantly decreased serum malondialdehyde concentration (P < 0.05). It is concluded that supplementation of GABA can improve the laying and reproductive performance of broiler breeders under heat stress.%本试验旨在研究γ-氨基丁酸( GABA)对热应激条件下肉种鸡产蛋性能和繁殖性能的影响,并从血清抗氧化和免疫功能及肝功能相关酶活等方面探讨其作用机理.选取360只28周龄岭南黄肉种鸡,随机分为4组,每组3个重复,每个重复30只鸡,分别在基础饲粮添加0(对照)、25、50、75 mg/kg GABA.预试期14 d,正试期56 d.结果显示:与对照组比,1)添加75 mg/kg GABA显著提高了肉种鸡产蛋率、平均蛋重和料蛋比(P＜0.05),并显著提高了种蛋的受精率、孵化率、雏鸡初生重(P＜0.05)及出雏率(P＜0.01)；添加25和50 mg/kg GABA也显著提高了种蛋孵化率和出雏率(P＜0.05),添加25 mg/kg GABA还显著提高了雏鸡初生重(P＜0.05).2)添加75 mg/kg GABA显著提高了血清免疫球蛋白A(IgA)和免疫球蛋白M(IgM)及补体C4含量(P＜0.05)；添加25 mg/kg GABA也显著提高了血清IgM含量(P＜0.05).3)添加75 mg/kg GABA显著提高了血清超氧化物歧化酶活性和血清谷胱甘肽过氧化物酶活性(P＜0.05)及总抗氧化能力(P＜0.01),降低了血清丙二醛浓度(P＜0.01)；添加25 mg/kg GABA也显著降低了血清丙二醛浓度(P＜0.05).结果提示,饲粮中添加GABA具有提高热应激条件下肉种鸡产蛋性能和繁殖性能的作用.
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