补喂5-羟色氨酸、瘤胃保护性5-羟色氨酸对绵羊血浆中5-羟色氨酸、褪黑素含量的影响

摘要

本试验旨在研究补喂5-羟色氨酸、瘤胃保护性5-羟色氨酸对绵羊血浆中5-羟色氨酸、褪黑素含量的影响,探究通过5-羟色氨酸调节绵羊机体中褪黑素分泌模式及含量的可能性.试验选取1岁、平均体重为(55.78±3.24)kg的陶赛特母羊18只,按体重分为3组,每组6只,分别为对照组和试验Ⅰ组、试验Ⅱ组,每天每只羊的粉状精料饲喂量为体重的1％,玉米青贮饲喂量为0.6 kg,混合干草自由采食,在此基础上,试验Ⅰ组、试验Ⅱ组羊只分别补喂5-羟色氨酸50 mg/kg BW、瘤胃保护性5-羟色氨酸111 mg/kg BW,进行15 d的饲养试验.结果表明:在早上、下午饲喂后试验组血浆中5-羟色氨酸含量均高于对照组,且在下午饲喂后2个试验组血浆中5-羟色氨酸含量呈波动性上升,但试验Ⅰ组与试验Ⅱ组之间差异不显著(P>0.05).在早上饲喂后1.5 h,各组血浆中色氨酸含量均呈增加趋势;在下午饲喂后1.5～6.0 h,各组血浆中色氨酸含量呈下降趋势.在白天时,各组血浆中5-羟色胺含量差异不显著(P>0.05);在下午饲喂后1.5～6.0 h,各组血浆中5-羟色胺含量呈波动性上升.在早上饲喂后3.0～9.0 h,试验Ⅰ组与试验Ⅱ组血浆中褪黑素含量均高于对照组,其中在早上饲喂后6.0 h试验Ⅰ组和试验Ⅱ组与对照组的差异均达到了极显著水平(P<0.01).在下午饲喂后1.5～9.0 h,各组血浆中褪黑素含量均呈波动性上升,且在下午饲喂后1.5、3.0、6.0 h试验Ⅰ组和试验Ⅱ组极显著高于对照组(P<0.01),在下午饲喂后9.0 h试验Ⅱ组显著高于对照组(P<0.05).由此可知,补喂5-羟色氨酸(50 mg/kg BW)或瘤胃保护性5-羟色氨酸(111 mg/kg BW)均可显著提高绵羊血浆中5-羟色氨酸含量,改变白天机体中褪黑素分泌模式及含量,且瘤胃保护性5-羟色氨酸的作用更有效,但对血浆中色氨酸、5-羟色胺含量均无显著影响.%This experiment aimed to study the effects of diet supplemented with 5-hydroxytryptophan, rumen protected 5-hydroxytryptophan on plasma 5-hydroxytryptophan and melatonin contents of sheep, and to explore the possibility of regulating sheep melatonin secretion mode and content by 5-hydroxytryptophan. Eighteen 1-year-old Dorset sheep with the average body weight of (55.78±3.24) kg were divided into 3 groups accord-ing to the body weight, being control group, trial groupⅠand trial groupⅡ. Each sheep in all group was fed with 10％ of body weight powder concentrate, 0.6 kg corn silage every day, and had free continuous access to mixed hay, additionally, each sheep in trail group Ⅰ and trial group Ⅱ was fed with 5-hydroxytryptophan (50 mg/kg BW) and rumen protected 5-hydroxytryptophan (111 mg/kg BW), respectively. The supplemen-tary feeding experiment lasted for 15 days. The results showed that plasma 5-hydroxytryptophan content in trial groups were higher than that in control group after feeding in the morning and afternoon, and 5-hydroxytrypto-phan content in trial groups showed a fluctuating increasing trend after feeding in the afternoon, but the differ-ence between two trial groups was not significant ( P>0.05) . Plasma tryptophan content in all groups was in-creased at 1.5 h after feeding in the morning, but it was decreased at 1.5 to 6.0 h after feeding in the afternoon. During the daytime, there was no significant difference in plasma 5-hydroxytryptamine content among all groups (P>0.05). The content of 5-hydroxytryptamine in each group was volatility increased at 1.5 to 6.0 h after feeding in the afternoon. Plasma melatonin content in trail groupⅠand trial groupⅡwas higher than that in control group at 3.0 to 9.0 h after feeding in the morning. Among them, the differences between two trial groups and control groups at 6.0 h after feeding in the morning were significant ( P<0.01) . Plasma melatonin content in all groups showed a fluctuating increasing trend at 1.5 to 9.0 h after feeding in the afternoon, it in trial groups was significantly higher than that in control group at 1.5, 3.0 and 6.0 h after feeding in the after-noon ( P<0.01) , and it in trial groupⅡ was significantly higher than that in control group at 9.0 h after feed-ing in the afternoon (P<0.05). In conclusion, diet supplemented with 5-hydroxytryptophan (50 mg/kg BW) or rumen protected 5-hydroxytryptophan ( 111 mg/kg BW ) both can significantly elevate sheep plasma 5-hydroxytryptophan content, change melatonin secretion pattern and content in the daytime, and rumen pro-tected 5-hydroxytryptophan shows a better effect, but plasma tryptophan and 5-hydroxytryptamine contents are not be affected significantly.