谷氨酰胺对热应激肉鸡抗氧化性能的影响

目的研究运输前灌服谷氨酰胺(Gln)对运输应激肉仔鸡生长性能、血液激素水平及抗氧化能力的影响。方法选取健康初生AA肉仔鸡300只，随机分为5组，A、B组灌服1 mL生理盐水，C、D和E组按肉鸡体重分别灌服1 mL质量分数为0.50、0.75和1.00 g/kg的Gln。随后B、C、D和E组进行5 h的运输处理，A组为对照组。5 h运输应激处理后，称重并采集血液测定血清皮质酮(CORT)、丙二醛(MDA)、谷胱甘肽过氧化物酶(GSH-Px)、超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、乳酸脱氢酶(LDH)、肾上腺皮质激素(ACTH)和活性氧(ROS)水平；此后常规饲养14 d，测定采食量和日增重。结果(1) 5 h运输应激后，B组显著失重(P<0.05)，而灌服Gln肉仔鸡则未出现失重。饲养至7日龄时，运输应激B组肉仔鸡平均日增重、平均采食量和饲料转化率仍显著低于对照组(P<0.05)，但灌服不同剂量Gln可有效改善肉仔鸡平均日增重和平均采食量，其中D组平均采食量与饲料转化率恢复到了对照组水平。14日龄时，运输应激B组肉仔鸡平均日增重、平均采食量和饲料转化率仍显著低于对照组(P<0.05)，灌服不同剂量Gln均可有效提高肉仔鸡平均日增重和平均采食量(P<0.05)；其中D组平均日增重和平均采食量与E组平均日增重可恢复到对照组水平，而饲料转化率仍低于对照组(P<0.05)。(2)与对照组相比，运输应激可导致B组血清CORT、ACTH、ROS、MDA和LDH水平显著升高(P<0.05)，而GSH-Px、SOD和CAT活性显著下降(P<0.05)，运前灌服不同剂量Gln可改善上述激素水平和酶的活性，其中C组MDA水平并没有显著改善(P>0.05)，D组肉仔鸡的ROS水平可恢复至对照组水平。结论5 h运输会导致肉仔鸡生长性能下降，血液激素水平和抗氧化能力发生改变；运前灌服Gln可有效缓解运输应激造成的上述影响，其中0.75 g/kg的灌服水平改善效果较好。

Effects of transport stress on blood metabolism,glycolytic potential,and meat quality in meat-type yellow-feathered chickens

PurposeTo study the effects of glutamine (Gln) administration before transportation on growth performance, blood hormone levels and antioxidant capacity of stressed broilers. Method300 healthy AA newborn broilers were selected and randomly divided into five groups. Group A and B were given 1 mL of normal saline, while group C, D and E were given 1 mL of normal saline with the concentration of 0.50, 0.75 and 1.00 g Gln per kg body weight of broilers respectively. Subsequently B, C, D and E were transported for five hours, and group A was the control group. After five hours of stress treatment, the chicks were weighed and blood samples were collected to assess the levels of corticosterone (CORT), malondialdehyde (MDA), glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), catalase (CAT), lactate dehydrogenase (LDH), adrenocorticosteroid (ACTH) and reactive oxygen species (ROS). During the followed 14 days routine feeding, food intake and daily weight gain were determined. Result(1) After five hours of transportation stress, weight loss was significantly observed in group B (P<0.05), but no weight loss was observed in broilers administrated Gln. At seven days of age, the average daily gain and average feed intake and feed efficiency of broilers in group B were significantly lower than those in control group (P<0.05), but compared with group B, Gln administration improved the average daily gain and average feed intake of broilers (P<0.05), the average feed intake and feed efficiency of the broilers in group D restored to the similar level of the control group. At fourteen days of age, the average daily gain, feed intake and feed efficiency of broilers in groups B were still significantly lower than those in control group (P<0.05), the improvement of Gln administration on the average feed intake and average daily gain was still observed (P<0.05), especially group D and E had restored to the level of control group, but the feed efficiency of group D and E was still lower than those in control group (P<0.05). (2) Compared with the control group, transport stress significantly increased the levels of CORT, ACTH, ROS, MDA and LDH in serum (P<0.05), while the activities of GSH-PX, SOD and CAT in serum were significantly decreased (P<0.05). Gavage of Gln before transport significantly improved the above hormone levels and enzyme activities (P<0.05), except for MDA concentration in group C (P>0.05), ROS concentration in group D was restored to the level of control group.ConclusionFive hours transportation stress had negative impact on broiler growth performance, blood hormone level and antioxidant capacity. Administration of Gln before tramsportation could effectively alleviate the above effect of transportation stress, and 0.75 g/kg of Gln was the recommended dose to relieve the stress.