| Asian red-tailed catfish(Hemibagrus wyckioides) is an omnivorous freshwater fish of wide distribution in the Lancang-Mekong River Basin with possessing very high culture potential because of its fleshy delicious meat. But there is no complete formula feed of H.wyckioides in normal growth and development demand on the market. Six feeding trials were conducted to find the optimum level of dietary replacement of fish meal and the proportion of animal protein plant protein sources and that could produce the effect of different plant protein sources on growth performance, feed utilization, digestive enzymes, protein metabolism, anti-oxidation and body composition of juvenile Asian red-tailed catfish Hemibagrus wyckioides.1. There were apparent nutrient digestibilities of eight common protein sources for H.wyckioides: fish meal was the highest of all, then the rapeseed meal, cottonseed meal, soybean meal, corn gluten meal, rubber seed.2. With the increase of soybean meal replacement ratio, growth performance descended significantly. The 30% level of replacement by soybean meal significantly increased the growth performance and feed utilization of Hemibagrus wyckioides, pepsase, plasma INS, GH and GDH, liver and plasma AMPD activity, liver and plasma ALT, serum IGM. Protein efficiency rate, daily gain coefficient induced with the level replacement by soybean meal up to 45%, but it is contrary to the feed coilversion rate and plasma MDA.When the level replacement fish meal by soybean meal up to 30%, it increased the growth performance, feed utilization, digestive enzymes and protein metabolism, and it does not affect the an-ti-oxidation and immunity.3. With the increase of meal replacement, growth performance was not significant. 36% replacement group had no significant difference in feed coefficient, and the intestinal lipase, pepsin, blood ammonia, urea nitrogen, IGF 1, in the liver and serum AST and ALT, liver, and plasma of GDH and AMPD, AKP, POD, SOD, gsh-px and MDA, LDH, etc. The 48% level of replacement of fish meal protein by rapeseed meal was lower in protein efficiency rate, the activity of gut trypsase and pepsase, serum albumin, plasma IGF-1, the activity of liver ALT, GDH, AMPD, CAT, SOD, LDH, GSH-Px, but ie is higher in feed coilversion rate, serum ammonia. In a word, the level replacement by rapeseed meal up to 48% significantly influenced feed utilization, digestive enzymes, protein metabolism and anti-oxidation. The 36% level is the optimum level.4. With the increase of cottonseed meal replacement ratio, the growth performance showed a trend of decline. When the level replacement by cottonseed meal up to 36%, it is significantly increased protein efficiency rate, weight gain rate, specific growth rate, pepsase, Plasma and liver AMPD,the activity of GR and GH,IGF-1,AST, ALT. Compared with control group, there is no obvious difference in the activity of liver CAT、SOD、LDH、GSH-Px and plasma MDA. In short, the 48% level replacement by cottonseed meal significantly influenced growth performance, feed utilization, digestive enzymes, whereas, in contrast with the protein metabolism, anti-oxidation and body composition. Therefore, 36% is best replacement ratio by cottonseed meal.5. With the increase of corn protein powder replacement ratio, growth performance significantly reduced. The group of 24% level replacement by corn gluten meal is lower in weight gain rate, plasma ALT, and higher in feed coilversion rate, there is no significant difference compared with the control group in AST、 ALT、GDH、AMPD、γ-GT、LDH γ-GT. The group of 24% level has significant difference in gut trypsase, liver IGF-1, plasma ALT, and serum IGM.In brief, the 24% level is the optimum level replacement fish meal by corn gluten meal.6. With the increase of rubber seed cake replacement ratio, growth performance dropped significantly. The group of 16% level of rubber seed meal showed an observably raise in weight gain rate, specific growth rate, protein efficiency rate, feed coilversion rate. There is no significant effect in digestive enzyme, the liver and plasma ALT,AST, the liver CAT、SOD、LDH、GSH-Px, plasma MDA and body composition compared the control diet. As the alternative to 24%, the body weight gain, specific growth rate, protein efficiency, protein deposition rate, daily gain coefficient dropped significantly. Significantly it decreased the activity of trypsin, NO content, significantly increased gamma GT, affecting the fish protein metabolism.16% is the optimum proportion rubber seed cake instead of fish meal protein.In conclusion, fish meal is the highest in eight protein sources digestibility of dry matter and energy, protein and phosphorus. Consider nutrition and amino acid balance under the condition of fully, applicable soybean meal, rapeseed dregs, cottonseed meal, corn protein powder, rubber seed cake partly replace fish meal protein feed formula. Broken-line regression analysis showed that the optimum dietary requirement of fish meal by plant protein sources for maximum weight gain rate of juvenile H. wyckioides under these experimental conditions was 22.17% of soybean meal,36.00% of rapeseed meal、36.00% of cottonseed meal,30.76% of corn gluten meal, 16.00% of rubber seed meal.The optimum proportion of animal protein plant protein sources were 16.04% of soybean meal, 33.60% of rapeseed meal、25.74% of cottonseed meal, 17.64% of corn gluten meal, 30.00% of rubber seed meal. |
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