卵内注射亮氨酸对慢性热应激雌性肉鸡生长性能、肠道组织形态和抗氧化能力的影响

Effects of in Ovo Leucine Injection on Growth Performance,Intestinal Tissue Morphology and Antioxidant Capacity of Female Broilers under Chronic Heat Stress

本试验旨在探讨卵内注射亮氨酸对慢性热应激雌性肉鸡生长性能、肠道组织形态和抗氧化能力的影响。试验选取罗斯308种蛋200枚,随机分为2组(每组平均蛋重64.9 g),在胚胎期第7天进行卵内注射,对照组和亮氨酸组分别注射超纯水(0.5 mL/枚)和亮氨酸水溶液(0.5 mL/枚,含9.06 mg L-亮氨酸)。在雏鸡2日龄时通过快慢羽鉴别法筛选出雌性雏鸡分笼饲养,饲养至15日龄时2组各选择体重相近的24只雌性雏鸡,分成8个重复,每个重复3只。2组雌性雏鸡在21~39日龄连续19 d(每天10:00—16:00)进行热处理[(30±2)℃],结束后在正常温度环境下饲养1周至46日龄。结果显示:与对照组相比,1)卵内注射亮氨酸对雌性肉鸡的生长性能没有显著影响(P>0.05);2)卵内注射亮氨酸极显著提高了39日龄雌性肉鸡脾脏指数(P<0.01);3)卵内注射亮氨酸极显著提高了39日龄雌性肉鸡十二指肠绒毛高度和回肠隐窝深度(P<0.01),极显著降低了空肠隐窝深度(P<0.01),且卵内注射亮氨酸显著或极显著提高了46日龄雌性肉鸡回肠和空肠绒毛高度(P<0.05或P<0.01),同时极显著降低了空肠隐窝深度(P<0.01);4)卵内注射亮氨酸极显著降低了46日龄雌性肉鸡血清丙二醛(MDA)的含量(P<0.01),且极显著提高了血清超氧化物歧化酶(SOD)的活性(P<0.01);5)卵内注射亮氨酸使39日龄雌性肉鸡空肠组织MDA含量降低了46.7%(P=0.134),且使空肠组织过氧化氢酶(CAT)和谷胱甘肽过氧化物酶(GSH-Px)活性分别提高了4.9%(P=0.886)和53.2%(P=0.102)。综上所述,卵内注射亮氨酸可改善慢性热应激雌性肉鸡肠道组织形态和脾脏指数,提高血清抗氧化能力。

In this study,the effects of in ovo leucine injection on the growth performance,intestinal tissue morphology and antioxidant capacity of female broilers under chronic heat stress were investigated.A total of 200 fertilized Ross 308 eggs were randomly divided into 2 groups,and the average egg weight of each group was 64.9 g.The eggs were in ovo injected with leucine aqueous solution(0.5 mL/egg,containing 9.06 mg L-leucine)or ultrapure water(0.5 mL/egg)on embryonic day(ED)7.Female chicks were selected by feather identification and were reared at 2 days of age.At 15 days of age,twenty-four female broilers of each group were chosen and assigned 8 replicates with 3 birds per replicate.Female broilers of 2 groups were exposed to a chronic heat cyclic and continued heat stress[(30±2)℃]for 19 days(10:00—16:00 of every day).After heat stress,female broilers were reared from 1 week to 46 days of age for normal temperature.The results showed as follows:compared with the control group,1)in ovo leucine injection had no significant effect on the growth performance of female broilers(P>0.05).2)Spleen index of 39-day-old female broilers was extremely significantly increased by in ovo leucine injection(P<0.01).3)The height of duodenum villus and the depth of ileum crypt of 39-day-old female broilers were extremely significantly increased(P<0.01)and the depth of jejunum crypt was extremely significantly decreased by in ovo leucine injection(P<0.01),respectively;meanwhile;in ovo leucine injection significantly or extremely significantly increased the heights of ileum and jejunum villus of 39-day-old female broilers(P<0.05 or P<0.01),and extremely significantly reduced the depth of jejunum crypt(P<0.01).4)Serum malondialdehyde(MDA)content of 46-day-old female broilers was extremely significantly reduced(P<0.01)and serum superoxide dismutase(SOD)activity was extremely significantly increased by in ovo leucine injection(P<0.01).5)The content of MDA in jejunum tissue of 39-day-old female broilers was reduced by 46.7%(P=0.134),and the activities of catalase(CAT)and glutathione peroxidase(GSH-Px)in jejunum tissue were increased by 4.9%(P=0.997)and 53.2%(P=0.102)by in ovo leucine injection,respectively.In conclusion,in ovo leucine injection can improve the intestinal tissue morphology,spleen index and serum antioxidant capacity of female broilers under chronic heat stress.