复合蛋白替代鱼粉对花鲈生长、消化能力和肠道健康的影响

Effects of Replacing Fish Meal with Composite Protein on Growth, Diet Digestibility, and Gut Health in Japanese Seabass (Lateolabrax maculatus)

中文关键词: 复合蛋白  花鲈  生长  消化  肠道组织结构  炎性因子

英文关键词: Composite protein  Japanese seabass (Lateolabrax maculatus)  Growth performance  Digestibility  Gut morphology structure  Inflammatory genes

中文摘要:

      以初均重为(5.80±0.07) g的花鲈(Lateolabrax maculatus)幼鱼为实验对象，研究复合蛋白替代鱼粉对花鲈生长、消化和肠道健康的影响。用复合蛋白分别替代对照组饲料中0、20%、40%、60%和80%的鱼粉，配制成5种等氮等脂的实验饲料，分别用这5种饲料投喂花鲈70 d；养殖实验期间水温为(29.5±1.5)℃，盐度为29±1，溶解氧≥6.5 mg/L。养殖实验结束后采集样品进行分析，结果显示，20%替代组花鲈生长性能与对照组无显著差异(P>0.05)，但随鱼粉替代比例的升高，花鲈增重率(WGR)、存活率(SR)、饲料效率(FE)以及蛋白质效率(PER)显著下降(P<0.05)，花鲈肠道蛋白酶活性以及饲料干物质、粗蛋白与粗脂肪表观消化率皆显著降低(P<0.05)，且花鲈后肠黏膜组织结构出现损伤，肠道促炎因子TNF-α、IL-1β基因表达量升高，抗炎因子基因IL-4、IL-10表达量相应降低。研究表明，复合蛋白替代花鲈饲料中鱼粉比例不宜超过20%。

英文摘要:

      This study was conducted to evaluate the effects of replacing fish meal with composite protein on growth performance, diet digestibility, and gut health in Japanese seabass (Lateolabrax maculatus). Five isonitrogenous and isolipidic diets were formulated by replacing 0, 20%, 40%, 60%, or 80% of fish meal in the basic diet with composite protein. Quadruplicate groups of 30 fish [initial body weight (5.80±0.07) g] were fed the test diets to apparent satiation twice daily (08:00 and 16:30), and the experiment continued for 70 days. During the feeding trial, water temperature, salinity, and dissolved oxygen values were maintained at (29.5±1.5)℃, 29±1, and ≥6.5 mg/L, respectively. Samples were collected for analysis after the feeding trial. The main indexes including the growth performance, diet digestibility, intestinal digestive enzymes activities, posterior intestine morphology structure, and expression of inflammation-related genes of the proximal intestine, mid-intestine, and posterior intestine were analyzed to investigate the appropriate replacement proportion of fish meal by composite protein. The results showed that substituting 20% of fish meal with composite protein did not significantly affect growth performance compared to that of the control group (P>0.05), while further increment of fish meal replacement levels resulted in significant reduction of weight gain, survival rate, feed efficiency, and protein efficiency ratio (P<0.05). Moreover, as the replacement level of fish meal with composite protein exceeded 20%, intestinal protease activity and apparent digestibility coefficients of feed dry matter, crude protein, and crude lipid also significantly decreased with increasing level of fish meal replacement by composite protein (P<0.05). Meanwhile, increasing replacement of fish meal with composite protein damaged posterior intestine morphology structure and up-regulated expression of gut inflammatory genes such as TNF-α and IL-1β, while an opposite trend was observed for the expression of anti-inflammatory genes, IL-4 and IL-10. In conclusion, it was recommended that the replacement proportion of fish meal with composite protein should not exceed 20%.