饲料中预添加不同水平牛磺酸对热应激虹鳟血清生化指标的影响

Effects of different levels of taurine in feed on serum biochemical indexes of rainbow trout(Oncorhynchus mykiss) under heat stress

研究基础饲料中预添加不同水平牛磺酸对慢性热应激条件下虹鳟血清生化指标的影响,为牛磺酸在虹鳟抗热应激研究与应用提供参考依据。挑选平均体重(203.26±2.01)g的虹鳟450尾,分成3组,分别在18℃条件下预先投喂不同水平牛磺酸(0、600.0、1200.0 mg/kg)饲料,饲养30 d后,对虹鳟进行慢性热应激(24、25℃)处理,研究基础饲料中预添加不同水平牛磺酸对热应激虹鳟血清生化指标的变化规律。结果表明:①热应激条件下,虹鳟血清中总超氧化物歧化酶(T-SOD)、过氧化氢酶(CAT)、谷胱甘肽过氧化物酶(GSH-Px)活性随牛磺酸添加量的增加先增加后趋于稳定,其中1200.0 mg/kg牛磺酸组显著高于其它组(P<0.05);②热应激条件下,虹鳟血清中白蛋白(ALB)和总蛋白(TP)含量随牛磺酸添加量的增加先增后减,其中600.0 mg/kg牛磺酸组显著高于其它组(P<0.05);③热应激条件下,虹鳟血清中溶菌酶(LZM)活性随牛磺酸添加量的增加呈逐渐增大趋势但差异不显著(P>0.05),且25℃虹鳟血清中LZM活性显著低于24℃(P<0.05);虹鳟血清中谷草转氨酶(AST)活性随牛磺酸添加量的增加呈逐渐降低的趋势,且25℃虹鳟血清中AST活性显著高于24℃(P<0.05)。因此,热应激条件下,预添加1200.0 mg/kg牛磺酸组虹鳟抗氧化能力、部分非特异性免疫能力及抗损伤能力均高于未添加组,说明牛磺酸可作为虹鳟抗热应激的备选添加剂。

The present experiment is conductedto study the effect of taurine pre-added to feedon serum biochemical indexes of rainbow troutunder chronic heat stress,and provide referencefor the research and application of taurine in an-ti-heat stress of rainbow trout.450 healthy rainbow trout with body weight of(203.26±2.01)g were selected and randomly divided into three groups.Different levels of taurine feed(0,600.0,1200.0 mg/kg)were pre-fed at 18℃.After feeding for30 days,rainbow trout was treated with chronic heat stress(24,25℃).The changes of serum biochem-ical indexes of rainbow trout under heat stress were studied by preadding different levels of taurine inbasic diet.(1)Under a condition of heat stress,the activities of total-superoxide dismutase(T-SOD),catalase(CAT),glutathione peroxidase(GSH-Px)in rainbow trout serum increased at first and then sta-bilized with the increase of taurine concentration.Among them,1200.0 mg/kg taurine group was sig-nificantly higher than other groups(P<0.05);(2)Under a condition of heat stress,the content of albu-min(ALB)and total protein(TP)in rainbow trout serum increased at first and then decreased with theincrease of taurine concentration.Among them,600.0 mg/kg taurine group was significantly higherthan other groups(P<0.05);(3)Under a condition of heat stress,the activity of lysozyme(LZM)in rain-bow trout serum increased gradually with the increase of taurine concentration,but the difference wasnot significant(P>0.05).The activity of LZM in serum of rainbow trout at 25℃was significantly lowerthan that at 24℃(P<0.05).The activity of aspartate aminotransferase(AST)in serum of rainbow troutdecreased gradually with the increase of taurine concentration.The activity of AST in serum of rain-bow trout at 25℃was significantly higher than that at 24℃(P<0.05).Under the condition of heatstress,the antioxidant capacity,partial non-specific immune capacity and anti-injury capacity of rain-bow trout in taurine group pre-added with 1200.0 mg/kg were higher than those in the non-addedgroup.The results showed that taurine could be used as an alternative additive for resistance to heatstress in rainbow trout.