Abstract：
The study evaluated the effects of dietary phosphorus supplementation on the fishmeal replacement with Clostridium autoethanogenum protein (CAP) in the diet of L. vannamei. Four isonitrogenous and isolipid diets were formulated: the PC diet contains 25% fishmeal, the NC, P1 and P2 diets were replaced 40% fishmeal with CAP and supplemented with 0, 0.8 and 1.6% NaH2PO4 respectively (equivalent to dietary phosphorus level of 0.96%, 1.12% and 1.27%). Sampling and V. parahaemolyticus challenge test were conducted after 50-day-feeding (initial shrimp weight 1.79 ± 0.02 g). The results showed that there were no significant differences in the growth performance of shrimp among the 4 groups. The expressions of dorsal in the gut were significantly lower in shrimp fed the P1 and P2 diets than shrimp fed the NC diet and the expression of peroxinectin in the gut was lower in shrimp fed the NC diet than others. The cumulative mortality of shrimp after V. parahaemolyticus challenge was significantly lower in shrimp fed the P2 diet than those fed the NC diet. After the challenge, genes expressions related to the prophenoloxidase activating system (proPO, lgbp, ppaf) were inhibited in the hepatopancreas of shrimp fed NC diet but activated in shrimp fed the P1 diet compared to those fed the PC diet. The AKP and T-AOC activities were higher in shrimp fed the P2 diet than those fed the other diets. The thickness of muscle layer of shrimp fed the P1 diet was thicker than that in the other groups, and significant stress damage happened in the midgut of the shrimp fed the NC diet. The abundance of Pseudoalteromonas, Haloferula and Ruegeria in shrimp fed the P1 diet was higher than those fed the other diets, while Vibrio in shrimp fed the P2 diet was higher than those fed the other diets. This indicated that a low fishmeal diet with dietary phosphorus level of 1.12% could improve the histology, enhance immune response, and increase the abundance of beneficial bacteria in the gut of shrimp. The low fishmeal diet with dietary phosphorus level of 1.27% could improve disease resistance and antioxidant capacity, but there was a possibility of damage to the gut histology as well as increasing abundance of Vibrio in the gut microbiota of shrimp.
摘要：
该研究评估了日粮磷补充对南美白对虾日粮中自产乙醇梭菌蛋白（CAP）替代鱼粉的影响。配制了四种同氮和异脂饮食：PC饮食中含有25％的鱼粉，NC,P1和P2日粮用CAP代替40％的鱼粉，并分别补充0、0.8和1.6％的NaH2PO4（相当于0.96％的日粮磷水平，1.12%和1.27%）。在饲喂50天后进行取样和副溶血弧菌攻击测试(初始虾重量1.79±0.02g)。结果表明，4个群体对虾的生长性能差异不显著。饲喂P1和P2日粮的虾在肠道中的背侧表达明显低于饲喂NC日粮的虾，饲喂NC日粮的虾在肠道中的过氧化物酶素表达低于其他日粮。饲喂P2饮食的虾在副溶血性弧菌攻击后的虾的累积死亡率明显低于饲喂NC饮食的虾。挑战之后,与酚氧化酶原激活系统相关的基因表达(proPO，lgbp,ppaf）在饲喂NC饮食的虾的肝胰腺中受到抑制，但与饲喂PC饮食的虾相比，饲喂P1饮食的虾被激活。饲喂P2日粮的虾的AKP和T-AOC活性高于饲喂其他日粮的虾。饲喂P1日粮的虾的肌肉层厚度比其他组厚，饲喂NC日粮的虾中肠发生了明显的应激损伤。大量的假交替单胞菌，饲喂P1日粮的虾中的Haloferula和Ruegeria高于饲喂其他日粮的虾，而饲喂P2日粮的虾中的弧菌含量高于其他日粮。这表明低鱼粉饮食中磷水平为1.12％可以改善组织学，增强免疫反应，并增加虾肠道中有益细菌的丰度。低鱼粉日粮磷水平为1.27%,能提高抗病性和抗氧化能力,但是对虾的肠道微生物群中弧菌的丰度增加以及肠道组织学受损的可能性。
