循环禁食对黄鳝血清溶菌酶活力和替代补体溶血活性的影响

Effect of Food Restriction on Lysozyme Activity and Alternative Complement Pathway Activity of the Rice-field Eel,Monopterus albus

研究循环性禁食后黄鳝(Monopterus albus)非特异性免疫力的变化,为生产实践中制定可行的禁食投喂方案提供更好的依据。试验用幼鳝体重(19.5±2.0)g,饲养在实验室的塑料水族箱(70 cm×55 cm×36 cm)中,正式试验前进行1周饱食投喂适应性暂养,暂养和试验期间的饵料为鲜活的水蚯蚓。循环禁食处理分2种:一种为不同比例的禁食时间与投喂时间的循环性禁食处理,即不同水平的循环性禁食处理;另一种为禁食时间与投喂时间的比例一致但禁食与投喂的时间间隔不同的循环性禁食,即不同时间间隔循环性禁食处理。结果表明,不同水平循环禁食试验组黄鳝其血清溶菌酶活力均显著低于对照组(P<0.05),试验组之间无显著差异(P>0.05);血清替代补体溶血活性显著高于对照(P<0.05),试验组之间无显著差异(P>0.05)。不同时间间隔循环禁食试验组黄鳝血清溶菌酶活力均显著低于对照组(P<0.05),随着禁食持续时间延长溶菌酶活力呈逐渐下降趋势;血清替代补体溶血活性均显著高于对照组(P<0.05),试验组之间无显著差异(P>0.05)。采取特定投喂模式促使鱼类获得生长补偿效应的同时其非特异性免疫力不受影响是有可能实现的。

Appropriate food restriction can induce growth compensation in fish and this phenomenon is of great significance for reducing feed and labor costs,improving water quality and increasing husbandry efficiency. However,the effect of restricted food on the immune response of fish has not yet been assessed. The rice-field eel（ Monopterus albus） is an economic freshwater species cultured on a large-scale in the middle and lower reaches of the Yangtze River. The objective of this study was to determine the effects of different feeding protocols on lysozyme activity and the alternative complement pathway（ ACP） activity of the rice-field eel. Young rice-field eels with body mass of（ 19. 5 ± 2. 0） g were acclimated for one week in a tank and fed live tubificid worms（ Limnodrilus hoffmeisteri） daily. After acclimation,test eels were fed using different fasting-feeding regimes for 60 d. Two trials were designated. The trial with different restriction levels were divided into three treatments： S1F2,1 d fasting,2 d feeding for20 cycles; S1F3,1 d fasting,3 d feeding for 15 cycles; S1F4,1 d fasting,4 d feeding for 12 cycles; The trial with different restriction intervals were also divided into three treatments： S1F2,1 d fasting,2 d feeding for 20 cycles; S2F4,2 d fasting,4 d feeding for 10 cycles; S4F8,4 d fasting,8 d feeding for 5 cycles. Each fasting-feeding regime was run in triplicate,with a control group（ daily feeding） for each treatment. The rice-field eels were tested at（ 25 ± 1） ℃,dissolved oxygen 〈5. 2 mg / L,ammonia nitrogen〈 0. 09 mg / L and p H 6. 5- 7. 2. After the 60 d trials,changes in lysozyme activity and alternative complement pathway（ ACP） activity in the fish were measured. Results shows that rice-field eels in all test groups had significantly lower lysozyme activities than in the controls（ P〈 0. 05） and lysozyme activity decreased significantly with the duration of food deprivation（ P 〈0. 05）.However,treated rice-field eels had significantly higher ACP activities than controls（ P 〈0. 05） and ACP activity increased gradually with the duration of food deprivation,probably due to refeeding,which enhances the non-specific immune function. This study indicates that it is possible to use feeding regimes that include food deprivation to achieve desirable growth compensation in rice-field eels without simultaneously compromising their nonspecific immunity.