Optimization Of Protein Sources In Hybrid Wuling Compound Feed

Protein is not only an important nutrient that limits the growth of fish but also a key factor in determining the cost of feed formulations.So it is the focus of long-term commitment to nutritionists that how to effectively improve the efficiency of protein utilization or the development of new protein source.Hybrid snakehead is an important freshwater aquaculture fish in China,but in recent years,the rapid decline in farming efficiency,because of the lack of nutrition and feed parameters and high prices of fish meal.To this end,this experiment uses four different protein sources to replace part of the fish meal to evaluate its application effect;the application of fermented mulberry leaves in diet of hybrid snakehead was discussed;then,according to the existing research results,the cotton meal,rapeseed meal,silkworm pupa and mulberry leaf were fermented and formulated as a compound protein source to study its application effect,for the development of new protein source and aquatic feed preparation technology to provide new ideas.The results are as follows:1.On the basis of the application of feed(control group),five kinds of isonitrogenous and isocaloric(CP 42%,GE18 MJ/Kg)diet were formulated that 25% of the fish meal was replaced,respectively,with peeled soybean meal,cottonseed protein,Canadian rapeseed meal and poultry by-product group.To compare the effects of peeled soybean meal,cottonseed protein,Canadian meal and poultry by-product meal on the growth and body composition of hybrid snakehead(Channa maculata♀ × C.argus♂)fed with hybrid snakehead(initial weight 25g)for 8 weeks The results showed that the final average weight,specific growth rate and protein efficiency of treatment groups were significantly reduced(P<0.05),and the feed coefficient was significantly increased(P<0.05).The rapeseed meal group show the best feeding rate(P<0.05).In soybean meal group,cottonseed meal group and rapeseed meal group hybrid snakehead body protein content was significantly higher than that of control group and poultry by-product group(P<0.05).But the highest content of lysine,methionine,leucine,total essential amino acid and total amino acid in whole fish are both in rapeseed meal group,and the lowest in the cottonseed group(P<0.05).Four alternative group pepsin,trypsin and intestinal lipase activity were lower than in the control group,poultry by-product group performed the worst.Substitution of protein sources with partial fish meal significantly affect liver aspartate aminotransferase,alanine aminotransferase and catalase activity(P<0.05).There was no significant difference in MDA content,SOD and CAT activities between the test groups(P>0.05).In short,the soybean meal and rapeseed meal performance the best effect,cottonseed meal followed,the worst is poultry by-product meal.Single protein source instead of fish meal should not exceed 25%.2.In order to study the efficacy of fermented mulberry leaves,three kinds of isonitrogenous and isocaloric(CP41% GE19.5 MJ / Kg)were prepared by adding 0(control group),7.5%(low mulberry group)and 15%(high mulberry group),fed with hybrid snakehead(initial weight 26g)for 8 weeks.The specific growth rate,protein efficiency and feed coefficient were not affected by Low-level fermented mulberry leaves(P>0.05).While the high level of fermented mulberry leaves would significantly reduced the specific growth rate,protein efficiency,feed coefficient,and the feeding rate(P<0.05).The survival rate of the experimental group were not significantly different(P>0.05).The addition of fermented mulberry leaves in feedstuff could significantly reduce the crude fat content and the ratio of liver to body,the ratio of viscera to mesenteric index(P<0.05).High levels of fermented mulberry leaves significantly reduced serum AST and ALT activity as well as TC and TG levels(P<0.05).With the increase of the level of fermented mulberry leaves,the serum glucose content was significantly decreased(P<0.05).It can be seen that the high level of fermentation of mulberry leaves is not conducive to the growth of hybrid snakehead,but can improve its metabolic function(lipid metabolism and glucose metabolism).3.In order to evaluate the effect of a compound protein source(composed of fermented cottonseed meal + fermented rapeseed meal + fermented silkworm pupa + fermented mulberry leaf + crystal amino acid)in feedstuff.Five kinds of isonitrogenous and isocaloric(CP42,GE18 MJ / Kg)test feed were formulated that fed with hybrid snakehead(Average weight 22 g)for 8 weeks.When replace 48% fish meal the ratio of body weight,specific growth rate,protein efficiencyand feed coefficient performance the worst among the groups(P<0.05),and the ratio of body to body,fat ratio and crude fat in treatment group were significantly lower than in the control group(P<0.05).Lipase activity increased significantly at 24% group and as the level rises to an upward trend(P<0.05),but the activity of intestinal protease was opposite,36% and 48% were significantly lower than those in the control group(P<0.05).When at 24% substitution level,the activity of ALT and CAT in the liver was significantly higher than the control group,and the activity of SOD was significantly lower than the control group(P<0.05).The serum metabolic index of CHO decreased significantly with the substitution level(P<0.05).The results showed that the complex protein source could effectively replace 12% fishmeal protein.Although the higher level substitution could reduce the growth performance,the edible ratio of the cultured fish and the liver function could be improved,lipid metabolism would be regulated.In conclusion,it is feasible and effective to replace the appropriate amount of fish meal in hybrid snakehead diet.