| Penaeus monodon,commonly known as black tiger shrimp,has the characteristics of large size,strong adaptability and delicious meat.It is one of the largest cultivation shrimp species in the world,and also an important species in China’s farm.In recent years,the global production of fish meal has not increased,but the demand is increasing.The contradiction between supply and demand leads to the rising price of fish meal,which leads to the rising cost of shrimp feed.The increase of feed cost has become an important factor in the increase of shrimp breeding cost.At the same time,the relative shortage of fish meal also restricts the sustainable development of shrimp feed production.Therefore,the study of fish meal substitution in shrimp feed has become a hot spot.One way is to find new and efficient fish meal substitutes through the study of fish meal substitutes to reduce the amount of fish meal added in shrimp feed.another way to solve the problem effectively is to breed a new shrimp variety(strain)adapted to plant protein instead of some fish meal--low fish meal level feed through the method of family selection.In this paper,we first carried out a study on the substitution of concentrated dephenolization cottonseed protein for fish meal in the feed of Penaeus monodon,and explored the feasibility of reducing the fish meal content from 30% to 20% and below.It was found that the fish meal content in the feed from 30% to 20% could fully meet the growth of Penaeus monodon when the protein content in the feed was sufficient.At the same time,soybean meal and soybean protein isolate were selected as the source of mixed plant protein to replace fish meal to carry out the family breeding experiment.The growth and related parameters of different families of Penaeus monodon fed with normal fish meal level(feed fish meal content 30%)and low fish meal level feed(feed fish meal content 20%)were compared and studied.The growth and related parameters of different families of Penaeus monodon fed with normal fish meal level(feed fish meal content 30%)and low fish meal level feed(feed fish meal content 20%)were compared and studied.Two families with high survival rate,one family with fast growth rate and high feed utilization rate,and three families with non-specific immune function of serum,and two families with high non-specific immunity of hepatopancreas were screened out under low fish meal level feed.1.In the study on the replacement of fish meal with concentrated dephenolization cottonseed protein,In order to determine the appropriate proportion of concentrated dephenolization cottonseed protein instead of fish meal in the formula feed of Penaeus monodon.the growth experiment of Penaeus monodon(0.81 ±0.00g)was conducted for 8 weeks to study the effects of partial substitution of fish meal with concentrated dephenolization cottonseed protein in feed on growth performance,muscle composition,feed utilization,digestive enzymes and antioxidant capacity of hepatopancreas and intestinal properties of Penaeus monodon.According to the nutrient requirement of Penaeus monodon,four isoenergetic feeds and control feed(fish meal content 30%)were designed.Concentrated dephenolization cottonseed protein content in the feed was5%,10%,15%,20% respectively,which replaced16.67%,33.33%,50% and 66.67%fish meal,respectively.The test results show that:When the total protein content of shrimp feed was sufficient,the growth of shrimp was not significantly affected by using concentrated dephenolization cottonseed protein to replace fish meal.This indicated that it was feasible to use concentrated dephenolization cottonseed protein to replace fish meal partly.Among them,the experimental group(fish meal content 20%)using 10% concentrated dephenolization cottonseed protein instead of fish meal had the best growth and feed utilization effect.the experimental group using 10% concentrated dephenolization cottonseed protein to replace fish meal(fish meal content was 20%)had the best growth and feed utilization effect,and its weight gain rate,specific growth rate,survival rate,apparent digestibility of feed dry matter and feed conversion ratio were 234.50 ±15.90%,2.15±0.09%,68.89±2.94%,62.69 ±0.65% and 2.14 ±0.04% respectively.respectively.The weight gain rate,specific growth rate,survival rate and apparent digestibility of feed dry matter were not significantly different from those of the control group(P >0.05),while the feed conversion ratio was significantly lower than that of the control group(P < 0.05).In view of the experimental group using 10% concentrated dephenolization cottonseed protein to replace fish meal had the best growth,The results showed that the potential could be further exploited and the proportion of concentrated dephenolization cottonseed protein replacing fish meal could be increased,which needs further study in the future.The activity of trypsinase,lipase and amylase was affected by the substitution level of fish meal.The activity of trypsinase was the highest in the experimental group using5% concentrated dephenolization cottonseed protein replace fish meal,which was significantly higher than that in the control group(P < 0.05);the activity of lipase was the highest in the experimental group using 15% concentrated dephenolization cottonseed protein replace fish meal,which was significantly higher than that in the control group(P < 0.05);Amylase activity was highest in the test group using 20% concentrated dephenolization cottonseed protein replace fish meal.,which was significantly higher than that of the control group and the test group of using 5% concentrated dephenolization cottonseed protein replace fish meal(P < 0.05).The T-AOC was affected by the substitution level of fish meal.The T-AOC value of the test group of using 5% concentrated dephenolization cottonseed protein replace fish meal was the highest,which was significantly higher than that of the test group of using 20% concentrated dephenolization cottonseed protein replace meal(P < 0.05),but was no significant difference compared the control group(P > 0.05).SOD activity and MDA content was unaffected by the substitution level of fish meal feed fish meal level had no significant effect on crude protein,crude fat and ash content in muscle of Penaeus monodon,but had significant effect on water content(P < 0.05).The intestinal fold height,width and number of folds were affected by the level of fish meal substitution.The intestinal traits of shrimp fed 10% concentrated dephenolization cottonseed protein group(fish meal content was 20%)were excellent.The height,width and number of folds were 46.72 ±1.94 um,35.76 ±1.23 um and 23.33±0.88,respectively.The height of folds was significantly higher than that of control group(P < 0.05);the width of folds was not significantly different from that of control group(P < 0.05),the number of folds was significantly higher than that of control group and other experimental feed groups(P < 0.05).2.In the study of substituting fish meal with soybean meal and soybean protein isolate as mixed vegetable protein sources,nine families of Penaeus monodon(0.76±0.00g)were tested for 60 days to study the changes of growth performance,feed utilization and related parameters of different families of Penaeus monodon under normal fish meal level and low fish meal level.According to the nutritional needs of Penaeus monodon,According to the nutritional needs of Penaeus monodon,two kinds of isoenergetic feedstuffs were designed,one was normal fish meal level feed(fish meal content was 30%)and the other was low fish meal level feed(fish meal content was20%).Each family was fed two kinds of feeds,three parallel feeds were set up under each feed,30 shrimps were fed in parallel.The experimental shrimps were fed in fiberglass barrel(500L)three times a day,and were fed by the regular apparent satiety method.The results show that:At the same fish meal level,the growth performance and feed utilization of different Penaeus monodon families were different,and there were significant differences among individual families(P < 0.05).There was no significant difference in specific growth rate,survival rate,feed conversation ratio and apparent digestibility of feed dry matter between two fish meal levels in the same Penaeus monodon family(P > 0.05).Two-way ANOVA analysis of feed and family showed that there was no significant interaction between feed fish meal level and Penaeus monodon family(P >0.05).Family factors played a dominant role in growth performance and feed utilization(P < 0.05).Families No.5 and No.9 had high survival rate under low fish meal level feed(feed fish meal level was 20%);Families No.2 had fast growth rate and high feed utilization under low fish meal level feed(feed fish meal level was 20%).The activities of lysozyme,acid phosphatase and SOD in families No.2,No.3 and No.7 fed with 20% fish meal level feed were higher than the average values of all families,respectively.Compared with 30% fish meal diet group,the activity of acid phosphatase in Family No.2 increased significantly(P < 0.05),while the activity of lysozyme and SOD did not change significantly(P > 0.05).There were no significant changes in lysozyme,acid phosphatase and SOD activity in Family No.3(P > 0.05).Family No.7 lysozyme and acid phosphatase did not change significantly(P > 0.05),but SOD activity increased significantly(P < 0.05).Therefore,families No.2,No.3 and No.7 could be considered as families with high serum non-specific immunity at low fish meal level(feed fish meal level was 20%).The ACP,AKP and SOD activities of families No.7 and No.8 were higher than those of all families fed 20% fish meal level feed;Compared with 30% fish meal level feed group,AKP and SOD in family No.7 did not change significantly(P > 0.05),but ACP activity increased significantly(P > 0.05).ACP and AKP activity in family No.8increased significantly(P < 0.05)and SOD activity did not change significantly(P >0.05).Therefore,family No.7 and No.8 could be considered as a family with high nonspecific immunity of hepatopancreas at low fish meal level(feed fish meal level was20%). |
PDF Full Text Request