Abstract：
This study aims to evaluate the effects of substituting soybean meal with fermented rapeseed meal (FRM) on growth, antioxidant capacity, and liver and intestinal health of the genetically improved farmed tilapia (GIFT, Oreochromis niloticus). A total of 450 tilapia (7.22 ± 0.15 g) were fed with five experimental diets, including a basal diet containing 40% soybean meal (CP0), which was subsequently replaced by 25% (CP25), 50% (CP50), 75% (CP75), and 100% (CP100) FRM in a recirculated aquiculture system for 9 weeks (30 fish per tank in triplicates). The results showed that the weight gain, specific growth rate, feed intake, feed efficiency, hepatosomatic index, and viscerosomatic index of fish in both CP75 and CP100 groups were significantly lower than those in CP0 group (P < 0.05). The fish in CP100 group had the lower content of muscle crude protein while the higher level of muscle crude lipid (P < 0.05). Activities of serum aspartate aminotransferase, alanine aminotransferase along with total triglyceride in CP100 group were significantly higher than those in CP0 group (P < 0.05). There were no significant differences in the contents of liver protease, amylase, and lipase among five groups (P > 0.05). The activities of liver total antioxidant capacity and superoxide dismutase exhibited the increased tendency with the increase of FRM replacement levels from 25 to 50% (P < 0.05), while then significantly decreased from 75 to 100% (P < 0.05). Histological morphology indicated that the fish in between CP75 and CP100 groups had poor liver and intestine health. Intestinal microbial diversity analysis showed that the relative abundance of Cetobacterium and Alcaligenaceae in both CP75 and CP100 groups were lower than that in other three groups. In conclusion, the maximum replacement level of soybean meal with FRM in the diet was determined to be 50% without compromising the growth performance, antioxidant status, and liver and intestinal health of tilapia under the current experimental conditions. The observed decrease in food intake and subsequent retarded growth performance in the CP75 and CP100 groups can be attributed directly to a reduction in feed palatability caused by FRM.
摘要：
本研究旨在评估用发酵菜籽粕（FRM）替代豆粕对生长的影响。抗氧化能力，以及遗传改良的养殖罗非鱼的肝脏和肠道健康(GIFT，尼罗罗非鱼）。共饲喂罗非鱼450只(7.22±0.15克)5种实验日粮,包括含40%豆粕（CP0）的基础日粮，随后被25%(CP25)取代，50%（CP50），75%（CP75），和100％（CP100）FRM在循环水产养殖系统中进行9周（每缸30条鱼，一式三份）。结果表明，体重增加，比增长率，饲料摄入量，饲料效率，肝细胞指数，CP75和CP100组鱼的内脏指数均明显低于CP0组（P<0.05）。CP100组鱼的肌肉粗蛋白质含量较低，而肌肉粗脂肪含量较高（P<0.05）。血清天冬氨酸转氨酶活性,谷丙转氨酶和总甘油三酯在CP100组明显高于CP0组(P<0.05)。肝脏蛋白酶的含量没有显著差异，淀粉酶，5组之间的脂肪酶（P>0.05）。肝脏总抗氧化能力和超氧化物歧化酶活性随着FRM替代水平从25％增加到50％而呈上升趋势（P<0.05）。然后从75%下降到100%(P<0.05)。组织学形态表明，CP75和CP100组之间的鱼肝脏和肠道健康状况不佳。肠道微生物多样性分析表明，CP75和CP100组的细菌和食环菌的相对丰度均低于其他三组。总之,在不损害生长性能的情况下，确定在日粮中使用FRM的豆粕的最大替代水平为50％，抗氧化状态，在目前的实验条件下，罗非鱼的肝脏和肠道健康。在CP75和CP100组中观察到的食物摄入量的减少和随后的生长性能的延迟可以直接归因于由FRM引起的饲料适口性的降低。
