本试验旨在研究不同添加水平γ-氨基丁酸（GABA）对崇仁麻鸡生长性能和血液生理生化指标的影响。选用8日龄崇仁麻鸡280只，随机分为7组，每组4个重复，每个重复10只鸡，各组在基础日粮中分别添加0（对照组）、5、30、55、80、115和150 mg/kg的GABA，试验期6周。统计试验前期（8-28日龄）、后期（29-49日龄）和全期（8-49日龄）的生长性能指标，并测定29和50日龄血液相关生理生化指标。结果表明，30 mg/kg组全期的平均日增重显著高于对照组，提高了4.69%（P<0.05）；在试验前期、后期和全期，各组间的平均日采食量均无显著差异（P>0.05），但都以115 mg/kg组的数值最大；30 mg/kg组后期和全期的料重比显著降低（P<0.05），与对照组相比分别降低了5.90%和5.30%。在29和50日龄时，各组间血清总蛋白、白蛋白和尿酸含量均无显著差异（P>0.05）；各试验组血清谷草转氨酶和谷丙转氨酶的活性均低于对照组，其中50日龄时30 mg/kg组的谷丙转氨酶活性显著低于对照组（P<0.05）；血浆生长激素水平以30 mg/kg组为最高，分别比对照组提高了12.50%（P>0.05）和10.53%（P>0.05）；各组间血浆促甲状腺激素水平均无显著差异（P>0.05）；各试验组血浆三碘甲腺原氨酸水平均高于对照组，其中29日龄时30 mg/kg组显著高于对照组（P<0.05）；各试验组血浆甲状腺素水平均有不同程度的下降，其中29日龄时30 mg/kg组显著低于对照组（P<0.05）；GABA呈剂量依赖性地升高血浆神经肽Y水平，其中29日龄时150 mg/kg组显著高于对照组（P<0.05）。由此可知，本试验条件下，30 mg/kg GABA可提高崇仁麻鸡的生长性能，降低血清中谷丙转氨酶的活性和血浆中甲状腺素的浓度，升高血浆中三碘甲腺原氨酸水平，综合考虑以30 mg/kg GABA添加水平效果最佳。

This experiment was conducted to study the effects of γ-aminobutyric acid (GABA) on growth performance, blood biochemical and physiological parameters in Chongren chickens. Two hundred and eighty Chongren chickens at the age of 8 d were selected and divided into 7 groups with 4 replicates of 10 chicks in each replicate. Diets of groups were supplemented with 0 (control group), 5, 30, 55, 80, 115 and 150 mg/kg GABA in the basal diet, respectively. The experiment lasted for 6 weeks. The effects of GABA on the growth performance of Chongren chickens during 8-28 d, 29-49 d and 8-49 d were studied, and the blood biochemical and physiological parameters at the age of 29, 50 d were detected. The results showed that the ADG of 30 mg/kg group during 8-49 d was significantly enhanced by 4.69% compared with the control group (P<0.05); and there was no significant difference in ADFI during 8-28 d, 29-49 d and 8-49 d, with the 115 mg/kg group had the best effect (P>0.05); compared with the control group, the F/G of 30 mg/kg group during 29-49 d and 8-49 d was significantly lowered by 5.90% and 5.30%, respectively (P<0.05). At the age of 29 and 59 d, there was no significant difference between each group in the contents of TP, ALB and UA in the serum (P>0.05); the activities of serum GOT and GPT of each experimental group were lower than those in the control group, the GPT activity of 30 mg/kg group at the age of 50 d had significant difference (P<0.05); the 30 mg/kg group had the highest level of plasma GH which was increased by 12.5% (P>0.05) and 10.53% (P>0.05), respectively; compared with the control group, there was no significant difference between each group as for the level of plasma TSH (P>0.05); the level of T3 of each experimental group was higher than that of the control group, and the T3 level of 30 mg/kg group at the age of 29 d had significant difference (P<0.05). Interestingly, the level of T4 of each experimental group had the opposite effect to that of T3 GABA dose-dependently increased the level of plasma NPY, the NPY level of 150 mg/kg group at the age of 29 d was significantly higher than that of the control group (P<0.05). In conclusion, 30 mg/kg GABA could improve growth performance of Chongren chickens, reduce the activities of serum GPT and the level of plasma T4, and increase the levels of plasma T3. It was recommended that the optimal supplemental level of GABA in Chongren chickens production was 30 mg/kg.［Chinese Journal of Animal Nutrition, 2010，22（2）:452-459］