Abstract:
A 12-wk trial was conducted to compare the tolerance of tilapia to high carbohydrate and high lipid diets. Three isonitrogenous and isoenergetic diets, whose carbohydrate and lipid levels were the following: 35.0% and 8% (control), 44.2% and 4% (D1, high carbohydrate), and 25.8% and 12% (D2, high lipid), respectively. Three hundred tilapias (27 ± 0.11 g) were fed the diets for 10 wk (4 replicates per group); 72 fish from the D1 group were continually fed the D1 (D1D1) and 72 fish from the D2 were continually fed the D2 (D2D2) diet for 2 wk (3 replicates each group) to evaluate the tilapia\'s capacity to tolerate high carbohydrate and high lipid diets, respectively. Another 36 fish from D1 group were continually fed D2 (D1D2) for comparison with D1D1 and D2D2 groups. In phase 1, hepatosomatic index, liver triglycerides (TG), glucose tolerance (GT) and crude protein in the whole body in D1 group were higher than those in D2 group (P < 0.05). During phase 2, D1D1 group had lower feed intake and weight gain, as well as lower serum total protein and albumin than that of D2D2 group (P < 0.05), while its liver glycogen was significantly higher than that in D1D2 and D2D2 groups (P < 0.05). Moreover, serum glucose and GT were higher in D1D1 and D1D2 groups than those in D2D2 group (P < 0.05). By contrast, D2D2 group had significantly higher intraperitoneal fat, subcutaneous adipose tissue (SCAT) and liver TG than those in D1D1 group (P < 0.05). The mRNA expression of brain npy, hepatic nrf2, gst1 and hepatic transcriptomic data showed that immune-related genes (gama, mrc2, mhc2 and cd163), were downregulated in D1D1 group compared to D2D2 and D1D2 groups. Taken together: 1) tilapia have higher tolerance to a high lipid diet than high carbohydrate diet; 2) despite retention of glucose tolerance, the continuous feeding of D1 diet impaired tilapia\'s appetite, weight gain rate and host immune response; 3) specific distribution of fat in intraperitoneal regions, SCAT and liver may be a risk-avoidance strategy in tilapia in response to a continuous D2 diet.
摘要:
进行了12周的试验,以比较罗非鱼对高碳水化合物和高脂饮食的耐受性。三种同氮和等能量饮食,其碳水化合物和脂质水平如下:35.0%和8%(对照),44.2%和4%(D1,高碳水化合物),25.8%和12%(D2,高脂),分别。饲喂300只罗非鱼(27±0.11g)10周(每组4个重复);D1组的72条鱼连续饲喂D1(D1D1),D2组的72条鱼连续饲喂D2(D2D2)2周(每组3个重复),以评估罗非鱼耐受高碳水化合物和高脂饮食的能力,分别。D1组的另外36条鱼连续饲喂D2(D1D2),以与D1D1和D2D2组进行比较。在第一阶段,肝细胞指数,肝脏甘油三酯(TG),D1组大鼠体内葡萄糖耐量(GT)和粗蛋白含量均高于D2组(P<0.05)。在第2阶段,D1D1组的采食量和体重增加较低,血清总蛋白和白蛋白低于D2D2组(P<0.05),而肝糖原显著高于D1D2和D2D2组(P<0.05)。此外,D1D1和D1D2组的血糖和GT高于D2D2组(P<0.05)。相比之下,D2D2组腹腔脂肪明显增高,皮下脂肪组织(SCAT)和肝脏TG高于D1D1组(P<0.05)。脑npy的mRNA表达,肝nrf2、gst1和肝转录组数据显示,免疫相关基因(gama,mrc2、mhc2和cd163),与D2D2和D1D2组相比,D1D1组下调。总之:1)罗非鱼对高脂饮食的耐受性高于高碳水化合物饮食;2)尽管保留了葡萄糖耐量,D1日粮的连续饲喂损害了罗非鱼的食欲,体重增加率和宿主免疫反应;3)脂肪在腹腔区域的特异性分布,SCAT和肝脏可能是罗非鱼应对连续D2饮食的风险规避策略。