| In this paper, the apparent digestibility of 8 commonly feed ingredients for Eriocheir sinensis was studied, and the effect on growth performance, amino acid composition of serum and muscle, conventional composition of body, nonspecific immunity and microstructure of gut was elucidated. On this basis, the effect of vegetable protein sources : soybean meal, rapeseed meal, cottonseed meal and peanut meal, commonly used in Eriocheir sinensis feed at different ratio(15%～60%) on growth performance, conventional composition of body, amino acid composition of muscle, activities of digestive enzyme in hepatopancreas, nonspecific immunity and microstructure of gut was further studied. The results could provide more basic information for artificial formulated feed development of Eriocheir sinensis, and enhance the source of plant protein ratio in the feed, to provide guidance to optimize feed formulations. The application of the research fingdings can not only alleviate our coungtry's nervous condition of animal protein source, but also help to promoting sustainable and high efficiency development of aquaculture industry.Experiment one was designed eight kinds of feed, which made by 70%basic feed+30%protein materials(blood by 85%+15%), feeding Eriocheir sinensis (weight: 5.61±0.19 g) for 60 days in interior circulation system. Feed coefficient and survival rate (63.3%～75.0%) had not significant difference in different groups, but the average weight gain rate (83.2%～96.3%) of Eriocheir sinensis in peanut meal, blood meal and bone meal group was significantly higher than other test groups, and corn gulten meal group was the lowest(P<0.05). The apparent digestion rate for Eriocheir sinensis in animal protein source, such as fish meal, blood meal and bone meal group gained higher digestibility (73.0%～88.0%), but some plant sources (such as corn gulten meal and rapeseed meal: 50.8%～55.7%) were significantly lower. Amino acid composition show that methionine and lysine in plant protein sources of feed were relatively low(0.40%,0.59%),and amino acid balance was less effective. The amino acid levels could reflect the state of absorption from feed(fish meal:817.96 mg/L, corn gulten meal:333.23 mg/L). The effect on conventional components of Eriocheir sinensis from different protein sources in body, muscle, and amino acid composition in muscle was not significantly affected(P>0.05). It was found from nonspecific immune parameters of Eriocheir sinensis that transaminase (GPT:177.8 U/100mL, GOT:214.7 U/100mL) was higher in group of corn gluten meal, but the other enzymes activity were lower. The microstructure of gut showed some folds in peanut meal, soybean meal, bone meal and corn gluten meal group were the most near or similar to the control group, and there were long and thin micro-villous structure in all groups, but not as good as the control group on the number of rich. In short, the different protein sources of dietary have an impact on function of digestion and physiology, leading to the differences in crab growth.Experiment two further studied effects on growth and physiological function of Eriocheir sinensis from different groups, which contained 4 kinds of vegetable protein sources, soybean meal, peanut meal, rapeseed meal and cottonseed meal, with different ratio(15%～60%) in feed. It was designed 10 kinds of feed conteined crude protein about 34%, feeding Eriocheir sinensis (weight: 6.69±0.03 g) for 60 days in interior circulation system. It was showed that survival rate of Eriocheir sinensis among all groups was 50.0%～70.0%, which had no statistical significant difference; but with the proportion of soybean meal, peanut meal, rapeseed meal and cottonseed meal increasing(15%～60%) in feed, weight gain rate(79.4%～125.2%) of Eriocheir sinensis showed the trend of slow growth. Conventional composition and amino acid composition in muscle of Eriocheir sinensis had no significant difference among the diet groups. From impact of different vegetable protein sources with different ratio on non-specific immune activity found superoxide dismutase(174.5±13.6～215.6±22.8 U/mL), alkaline phosphatase (2.16±0.32～4.53±0.71 U/mg) and acid phosphatase (1.53±0.35～2.45±0.52 U/mg) had the trend of declining with ratio of vegetable protein source in feed improving, but the activity of alanine aminotransferase (120.8±10.8～ 179.2±16.8 U/100mL) and aspartate aminotransferase (67.7±15.6～124.8±17.9 U/100mL)were increasing. The results of the digestive enzymes found the activity of protein proteinase(0.40±0.06～0.82±0.06 U/mgprot) was lower in plant protein sources, but the activity of amylase(1.04±0.08～1.22±0.12 U/mgprot) was higher, which illustrating a clear adaptation to feed nutrients. Intestinal SEM results showed that apparent intestinal symptoms in the vegetable protein source with high level groups(60%) were found, secretion increasing, the microvilli structure was fuzzy, reduction of quantity and so on. Therefore, more vegetable protein sources were used in feed would change the function of physiology and gut microstructure, which have an impact on the growth of crab health. |
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