Effects Of Four Plant Protein Supplementation Upon Growth, Body Composition And Digestive Enzyme Activities Of Juvenile Turbot (Scophthalmus Maximus)

This study investigated the effects of four plant protein supplementation upon growth performance, body composition and digestive enzyme activities of juvenile turbot (Scophthalmus maximus). Four experimental diets were isonitrogenous and isocaloric, which included separately different source of plant protein, extruded soybean, fermented soybean meal, corn gluten or their mixture, and other feed stuffs, white fish meal, squid liver meal, a-starch, fish oil etc. The growth, body composition, digestibility and digestive enzyme activities of juvenile turbot were determined among 4 feed of different plant protein source, in order to select a plant protein stuff which is more available for juvenile turbot. The juvenile turbot were fed the four experimental diets for 8 weeks, each treatment three replicates of 200 individuals, the water temperature is 13-14℃, salinity is 25-28‰. In the end, we analyzed the effects of different plant protein sources on the growth performance, body composition and digestive enzyme activities of juvenile turbot. The results and conclusions can be summarized as follows:1. There were no significant difference to the feeding rate among 4 groups.(P=0.39)2. There were significant effects on the final body weight, weight gain, weight gain rate and special growth rate(P<0.01). The extruded soybean meal group was higher significantly than the mixture of three sources of plant protein group and the corn gluten protein group(P <0.05), also higher than fermented soybean group, but no significant difference.3. There were significant effects on the feed conversion ratio among 4 groups(P<0.05), The extruded soybean meal group was lower significantly than corn gluten protein group.4. There was no significant effect on the protein efficient rate among all groups. The extruded soybean meal group was the highest.5.The body moistures were affected significantly by the different plant protein groups. The extruded soybean group was lower significantly than the others(P<0.05); The fermented soybean group was lower significantly than the corn gluten group (P<0.05). There were significant effects on the crude fat content (P<0.01). The extruded soybean group was the highest. There was no significant effect on ash content and crude protein content in all groups.6. The apparent digestibility coefficients of dry matter, protein and fat were significantly affected by the different plant protein groups(P<0.01). The corn gluten group was the lowest and the extruded soybean was the highest significantly in all groups.7. Protease activities in intestine were significantly different among all diets (P<0.01), The extruded soybean group and the fermented soybean group were significantly higher than the other groups(P<0.01). No significant difference was observed in amylase activities of intestine among four groups. There were significantly different in the lipase activities of intestine(P<0.05). The extruded soybean group was lower significantly than the corn gluten group(P<0.05).8. In a word, there were different effects on juvenile turbot among different plant protein groups.(1)From the point of growth and feeding intake, the extruded soybean group were the best. The worst is the corn gluten group. The ordering by feed performance is extruded soybean> fermented soybean> corn gluten. The mixture of three sources of plant protein is better than the corn gluten group, but less than the other two groups.(2)From the point of digestive physiology, the extruded soybean group was the best. The ordering is as same as the growth.9. There were no significant effects on the growth and feeding in different premix content.10. The growth and feeding were different significantly among the different growth promoters (P<0.05). Probiotics mixed Chinese materia medica is significantly higher than Potassium Diformate in SGR、body weight and protein efficient rate (P<0.05)...