黄粉虫蛋白替代豆粕影响尼罗罗非鱼肝肠健康的机制探究

Effects of yellow mealworm(Tenebrio molitor)meal replacing soybean meal on the hepatic and intestinal health of Nile tilapia(Oreochromis niloticus)and mechanism exploration

为探究黄粉虫蛋白替代豆粕对鱼类肝肠健康的影响及其机制,以尼罗罗非鱼为试验鱼,使用黄粉虫蛋白粉分别替代饲料中0、15%、30%和45%的豆粕,制成4组等氮(320 g/kg粗蛋白)等能(16.8 MJ/kg)的饲料,开展为期10周养殖试验,并对鱼体肝肠健康相关指标进行检测分析。结果显示:黄粉虫蛋白能够替代尼罗罗非鱼饲料中15%的豆粕而不显著影响其肝肠健康;当替代比例达到30%,尼罗罗非鱼肠道肌层厚度变薄,肠道绒毛变短,肠道跨上皮电阻下降,肠道屏障相关基因表达上调;当替代比例增加至45%,肠道损伤进一步加剧,肝脏发生损伤,表现为血清谷丙转氨酶活力显著升高,肝细胞边界模糊、脂滴蓄积,肝脏总脂、甘油三酯、游离脂肪酸和糖原含量显著升高。转录组测序分析结果显示:45%替代组的尼罗罗非鱼肝脏中糖原合成和凋亡相关通路显著上调;肝脏和肠道组织中的氧化应激相关基因klf9均显著上调,说明在黄粉虫蛋白高比例替代组存在氧化应激。

To evaluate the effects of yellow mealworm meal(YM)as a partial replacement for soybean meal(SBM)on the hepatic and intestinal health of fish,four groups of isonitrogenous(320 g/kg crude protein)and isoenergetic(16.8 MJ/kg)experimental diets were formulated using YM to replace 0,15%,30%,and 45%SBM in an SBM-based diet for Nile tilapia(Oreochromis niloticus).A ten-week feeding experiment was conducted and the parameters related to the hepatic and intestinal health were analyzed.The results indicated that YM could replace 15%SBM in tilapia feed without negative effects on the hepatic and intestinal health.However,when the replacement ratio was up to 30%,decreased intestinal muscular thickness,shorter intestinal villi,lower intestinal transepithelial electrical resistance and higher mRNA expression level of tight junction protein-related genes were observed.When the replacement ratio was up to 45%,the intestinal injury was further exacerbated,and hepatic injury occurred.Hepatic injury was manifested by a significant increase in serum alanine transaminase activity,blurred hepatocyte boundaries,lipid droplet accumulation,and a significant increase in total lipids,triglycerides,non-esterified free fatty acids,and glycogen content.Transcriptome analysis revealed that genes related to glycogen synthesis and apoptosis were significantly enhanced in liver in YM45.Further analysis revealed that klf9,an oxidative stress-related gene,was significantly upregulated in both liver and intestine,suggesting that oxidative stress occurred in YM45 group.