Yang Linlin, Cai Minglang, Zhong Lei, Shi Yong, Xie Shouqi, Hu Yi, Zhang Junzhi
College of Animal Science and Technology, Hunan Agricultural University, Changsha 410128, China.
College of Fisheries, Hunan Agricultural University, Changsha 410128, China.
Animals (Basel). 2023 Jul 12;13(14):2274. doi: 10.3390/ani13142274.
() powder is a novel non-grain single-cell protein with enormous potential to be a protein source. However, it is poorly studied in aquatic animals. The purpose of the present study was to explore the optimum replacement ratio of powder and the influence of the substitution of soybean meal with on grass carp () in terms of growth performance, intestinal integrity and the microbial community. Five isonitrogenous and isolipidic diets were formulated by replacing 0% (SM, containing 30% soybean meal), 25% (X25), 50% (X50), 75% (X75) and 100% (X100) soybean meal with The feeding trial period lasted 8 weeks. At the end of the experimental trial, the X50 group showed higher FW, WGR and PER than the SM group ( < 0.05). The feed conversion ratio (FCR) of the X50 group was significantly lower than that of the SM group ( < 0.05). The X50 group showed the highest value of the goblet cell number, intestinal amylase and trypsin activities when compared with the SM group (). Replacing 50% soybean meal with improved the intestinal barrier integrity, as evidenced by upregulating , and transcript ( < 0.05), and alleviated oxidative stress by an increased SOD enzymatic activity and transcript level, probably mediated through the - signaling pathway ( < 0.05). Meanwhile, the X50 group enhanced intestinal immunity, as manifested by increased ACP and LZM activities ( < 0.05), and downregulated the , , and through the pathway ( < 0.05). The functionally predicting pathways related to the nitrate respiration and nitrogen respiration were observably activated in the X50 group ( < 0.05). The X50 group improved the biological barrier, as manifested by increased and ( < 0.05). In conclusion, dietary powder could promote the growth performance of grass carp by restoring intestinal morphology, increasing digestive enzyme activities, improving antioxidant properties and immunity and optimizing the microflora structure. A powder replacement of 50% soybean meal was recommended as feed for grass carp.
（）粉是一种新型的非谷物单细胞蛋白，作为蛋白质来源具有巨大潜力。然而，其在水生动物中的研究较少。本研究的目的是探讨（）粉的最佳替代比例以及用（）替代豆粕对草鱼（）生长性能、肠道完整性和微生物群落的影响。通过用（）替代0%（SM，含30%豆粕）、25%（X25）、50%（X50）、75%（X75）和100%（X100）的豆粕，配制了五种等氮和等脂的饲料。饲养试验期持续8周。在试验结束时，X50组的终末体重（FW）、增重率（WGR）和蛋白质效率（PER）均高于SM组（P<0.05）。X50组的饲料系数（FCR）显著低于SM组（P<0.05）。与SM组相比，X50组的杯状细胞数量、肠道淀粉酶和胰蛋白酶活性最高（P<0.05）。用（）替代50%豆粕可改善肠道屏障完整性，上调（）、（）和（）转录水平可证明这一点（P<0.05），并通过提高超氧化物歧化酶（SOD）活性和转录水平减轻氧化应激，这可能是通过（）信号通路介导的（P<0.05）。同时，X50组增强了肠道免疫力，表现为酸性磷酸酶（ACP）和溶菌酶（LZM）活性增加（P<0.05），并通过（）途径下调（）、（）、（）和（）（P<0.05）。在X50组中，与硝酸盐呼吸和氮呼吸相关的功能预测途径明显被激活（P<0.05）。X50组改善了生物屏障，表现为（）和（）增加（P<0.05）。总之，日粮（）粉可通过恢复肠道形态学、提高消化酶活性、改善抗氧化性能和免疫力以及优化微生物区系结构来促进草鱼的生长性能。建议用50%豆粕替代的（）粉作为草鱼饲料。
