外源褪黑素对羔羊生长发育的影响

Effects of exogenous melatonin on the growth and development of lambs

为了研究不同褪黑素处理方式对断奶羔羊生长发育的影响,试验随机将50只体重相近的3月龄多胎细毛羊公羔分为五组,即对照组(无外源褪黑素刺激)、试验1组(一次性背部皮下埋植30 mg/只褪黑素缓释颗粒)、试验2组(背部皮下埋植10 mg/只褪黑素缓释颗粒,每30 d埋植1次)、试验3组(一次性肌肉注射30 mg/只褪黑素凝胶)、试验4组(肌肉注射10 mg/只褪黑素凝胶,每30 d注射1次),每组10只,预试期10 d,正试期90 d。试验前(第0天)及每30 d测定体重和血液中褪黑素含量,计算日增重;试验前及结束时进行体尺指标(体高、体长、胸围、管围、腰角宽)的测定,分析外源褪黑素对试验羊只体重和体尺指标的影响,以及褪黑素含量与体重之间的相关性。结果表明:试验结束时,试验2组体重和日增重显著高于其他四组(P<0.05),对照组和试验2组体高显著高于其他三组(P<0.05),试验1组和试验4组体长显著高于其他三组(P<0.05),试验2组胸围显著高于其他四组(P<0.05),五组试验羊只管围和腰角宽差异不显著(P>0.05);第30天时,试验4组的褪黑素含量显著高于其他四组(P<0.05);第60天时,对照组和试验3组的褪黑素含量显著高于其他三组(P<0.05);第90天时,试验1组和试验2组的褪黑素含量显著高于其他三组(P<0.05),其中试验2组平均褪黑素含量最高,为29.23 ng/mL。褪黑素含量与多胎细毛羊体重呈极显著相关关系(P<0.01)。说明给予多胎细毛羊羔羊适量外源褪黑素可促进其生长发育,但与处理方式有关,相较之下每30 d埋植1次10 mg/只褪黑素缓释颗粒、共埋植3次的方式最好。

In order to study the effects of different melatonin treatments on the growth and development of weaned lambs,50 three-month-old male multifetal fine-wool lambs with similar body weights were randomly selected and divided into 5 groups:control group(no exogenous melatonin stimulation),experimental group 1(one-time subcutaneous implantation of 30 mg/only melatonin sustained-release granules in the back),experimental group 2(subcutaneous implantation 10 mg/only melatonin sustained-release granules in the back,once every 30 days during the test period),experimental group 3(one-time intramuscular injection of 30 mg/only melatonin gel),and experimental group 4(intramuscular injection 10 mg/only of melatonin gel,once every 30 days during the test period).There were 10 animals in each group.The pre-test period of 10 days,and the test period was 90 days.The body weight and blood melaton in content were measured before the test(day 0)and every 30 days,and the daily weight gain was calculated.Body size indexes(body height,body length,chest circumference,tube circumference,waist angle width)were measured at the beginning and end of the experiment,and the effects of exogenous melatonin on body weight and body size of experimental sheep were analyzed,as well as the correlation between melatonin content and body weight.The results showed that at the end of experiment,the body weight and daily gain in the experimental group 2 were significantly higher than those in the other four groups(P<0.05);the body heights in the control group and the experimental group 3 were significantly higher than those in the other three groups(P<0.05);the body length in the experimental group 1 and the experimental group 4 was significantly higher than that in the other three groups(P<0.05),and the chest circumference in the experimental group 2 was significantly higher than that in the other four groups(P<0.05),there was no significant difference in the tube circumference and waist angle width of the 6-month-old sheep among the five groups(P>0.05).On the 30 th day,the melatonin content of the multiple parity fine wool sheep in the experimental group 4 was significantly higher than that in the other four groups(P<0.05).On the 60 th day,the melatonin content in the control group and the experimental group 3 was significantly higher than that in the other three groups(P<0.05).On the 90 th day,the melatonin content in the experimental group 1 and the experimental group 2 was significantly higher than that in the other three groups(P<0.05),and the content in the test group 2 was the highest,with an average melatonin content of 29.23 ng/mL.The content of melatonin was significantly correlated with the weight of multiple litters of fine wool sheep(P<0.01).The results indicated that giving an appropriate amount of exogenous melatonin could promote the growth and development of multiple fine-wool lambs,but it was related to the way of treatments.In contrast,the way of implanting 10 mg/only melatonin sustained-release granules,and 3 times was the best.