Liu Dayin, Qu Peng, Huangfu Yingxu, Wang Xinyu, Pan Mingzhu, Wu Yang, Mai Kangsen, Zhang Wenbing
The Key Laboratory of Mariculture (Ministry of Education), Shenzhen Institute, Fisheries College, Ocean University of China, Qingdao 266003, China.
College of Marine and Biology Engineering, Yancheng Institute of Technology, Yancheng, 224051, China.
Fish Shellfish Immunol. 2025 Feb;157:110062. doi: 10.1016/j.fsi.2024.110062. Epub 2024 Nov 29.
The aim of the present study was to investigate the influence of supplementation of lysozyme (LZM) into diet on the growth performance, muscle quality, immunity, intestinal microbiota in large yellow croaker (Larimichthys crocea) with initial body weight of 194.5 ± 0.27 g. After a 70-day feeding trial, 6 experimental diets with LZM supplementation at 0 (LZM0), 10 (LZM10), 30 (LZM30), 50 (LZM50), 70 (LZM70) and 90 mg/kg (LZM90) were tested. Results showed that the fish in the LZM70 group exhibited the lowest feed conversion ratio and the highest weight gain (WG), along with the highest trypsin and Na/K ATPase activities in intestine (P < 0.05). The LZM activity in serum and intestine was significantly reduced in all dietary LZM supplemented groups compared to the LZM0 group (P < 0.05). Compared with that in the LZM0 group, the gene expressions of claudin 11, bcl-2, nlrp 3, tnf α, il-10 and tgf β in intestine in the LZM90 group were significantly elevated, while bax and caspase3 were significantly downregulated (P < 0.05). Meanwhile, the group supplemented with 90 mg/kg of dietary LZM also increased muscle crude lipid content, springiness and drip loss, along with decreased crude protein content, shear force and hardness compared with other groups (P < 0.05). Furthermore, the results of intestinal microbiota showed that compared to those in the LZM0 group, relative abundances of Fusobacterium in the LZM30 and LZM90 groups were decreased, and the relative abundances of Achromobacter, Mycoplasma and Cetobacterium were increased. In conclusion, appropriate supplementation of LZM in diet promoted the growth performance, improved immunity, adjusted intestinal microbiota and muscle quality of large yellow croaker. Furthermore, the optimal level of dietary LZM supplementation for large yellow croaker was estimated to be 67.14 mg/kg based on the quadratic regression for WG.
本研究旨在探讨在初始体重为194.5±0.27克的大黄鱼（Larimichthys crocea）日粮中添加溶菌酶（LZM）对其生长性能、肌肉品质、免疫力和肠道微生物群的影响。经过70天的饲养试验，测试了6种添加不同水平LZM的实验日粮，添加量分别为0（LZM0）、10（LZM10）、30（LZM30）、50（LZM50）、70（LZM70）和90毫克/千克（LZM90）。结果表明，LZM70组的鱼饲料转化率最低，增重（WG）最高，同时肠道中胰蛋白酶和钠钾ATP酶活性最高（P<0.05）。与LZM0组相比，所有添加LZM的日粮组血清和肠道中的LZM活性均显著降低（P<0.05）。与LZM0组相比，LZM90组肠道中claudin 11、bcl-2、nlrp 3、tnfα、il-10和tgfβ的基因表达显著升高，而bax和caspase3显著下调（P<0.05）。同时，与其他组相比，添加90毫克/千克日粮LZM的组还增加了肌肉粗脂肪含量、弹性和滴水损失，同时降低了粗蛋白含量、剪切力和硬度（P<0.05）。此外，肠道微生物群结果显示，与LZM0组相比，LZM30和LZM90组中梭杆菌的相对丰度降低，而无色杆菌、支原体和鲸杆菌的相对丰度增加。总之，日粮中适当添加LZM可促进大黄鱼的生长性能，提高免疫力，调节肠道微生物群和肌肉品质。此外，根据WG的二次回归分析，大黄鱼日粮中LZM的最佳添加水平估计为67.14毫克/千克。
