投喂蚕豆对草鱼肝脏脂肪蓄积及脂肪代谢的影响

Effects of feeding broad bean on fat accumulation and metabolism in grass carp (Ctenopharyngodon idellus) liver

为了研究摄食蚕豆后草鱼(Ctenopharyngodon idellus)肝脏脂肪蓄积情况以及形成原因,采集了摄食蚕豆的草鱼(试验组)和摄食配合饲料的草鱼(对照组)的肝脏样本后,通过H&E染色、油红O染色和透射电镜分别对两组草鱼肝脏进行病理学特征、脂质蓄积情况和肝细胞的超显微结构观察,同时检测与脂肪代谢相关的生理生化指标,并分析与脂肪酸合成相关的基因表达情况。结果发现:与对照组草鱼相比,试验组草鱼肝脏发生明显的脂肪变性,线粒体形态异常且数量减少;试验组草鱼血清中甘油三脂(TG)、总胆固醇(TC)、低密度脂蛋白胆固醇(LDL-C)、谷丙转氨酶(ALT)和谷草转氨酶(AST)含量显著升高(P<0.05);试验组草鱼肝脏中TG、TC和过氧化氢(H2O2)含量显著增加,但过氧化氢酶(CAT)和谷胱甘肽(GSH)显著降低(P<0.01);试验组草鱼肝脏脂肪酸合成相关基因(acc和fas)的mRNA表达量极显著高于对照组(P<0.01)。研究表明,长期摄食蚕豆的草鱼肝脏会发生脂肪变性,其可能与脂肪酸从头合成(DNL)增加、氧化应激增强及线粒体结构破坏等有关。研究结果将为脆肉鲩营养调控和预防鱼类肝脏脂肪变性提供一定的理论依据。

To explore the liver fat accumulation and its possible reasons of grass carp(Ctenopharyngodon idellus) fed with broad bean, liver samples of grass carp fed with broad bean(treatment group) and artificial feed(control group) were collected. The pathological feature, fat accumulation and hepatic structure were observed by H&E, oil red O staining and transmission electron microscopy method, respectively. The expression leads of genes associated with fatty acid synthesis were further analyzed. Additionally, some biochemical indexes were also detected both in liver and serum. The results showed that: hepatic steatosis was observed accompanying the abnormal morphology and decreased number of mitochondria in the treatment group;Triglyceride(TG), total cholesterol(TC), low-density lipoprotein cholesterol(LDL-C), alanine aminotransferase(ALT) and aspartate aminotransferase(AST) in the serum of treatment group were significantly higher than those of the control group(P<0.05);TG, TC and hydrogen peroxide(H2O2) in the liver of treatment group were extremely higher than those of the control group(P<0.01), but catalase(CAT) activity and glutathione(GSH) were extremely lower(P<0.01);The mRNA expression levels of fatty acid synthesis(acc and fas) in treatment group were extremely higher than those in the control group(P<0.01). The results demonstrated that long-term feeding broad bean could cause fat accumulation in the liver of grass carp, which may be related to the increase of fatty acid synthesis, oxidative stress and collapse of mitochondrial structure. This study would provide scientific data for nutritional regulation of crisp grass carp and prevention from fish hepatic steatosis.