The Study Of Effect Of Dietary Protein Sources And Anti-nutritional Factors On Physiology And Chemistry In The Chinese Mitten-handed Crab, Eriocheir Sinensis

In this paper, the apparent digestibility of crude protein and amino acids of 11 feed ingredients for Eriocheir sinensis was studied, and the effect of gossypol and soybean saponin on growth performance, nonspecific immunity, microstructure and ultrastructure of hepatopancreas, digestive enzyme of hepatopancreas was elucidated. The results could provide more basic information for artificial formulated feed development and reference data for reasonable use of cotton seed meal and soybean meal. It would promote the development and extensive use of plant protein sources and boost the persistent and high efficiency development of aquaculture industry.1. Apparent digestibility of protein sources for E. sinensisThe result of apparent digestibility of crude protein and amino acids in protein sources for E. sinensis shows that the apparent digestibility of the fish meal and blood meal were highest whereas the rapeseed meal and corn gluten meal were lowest comparing with others. As the result, blood meal is good protein source. The reason of low digestibility on rapeseed meal is the anti-nutritional factors in it and we should remove it before use. The lack of lysine and low coherency of corn gluten meal cause low digestibility. The apparent digestibility of crude protein and amino acids in animal sources is higher than that in plant sources except soybean meal and squid organ meal. The apparent digestibility of lipid in protein sources is high (70% -90% except rapeseed meal), which suggests that E. sinensis can make good use of lipid. And it's consistent with most of fishes.2. Effect of gossypol and soybean saponin on growth performance of E. sinensisIn order to investigate the anti-nutritional function of dietary gossypol and soybean saponin, seven experimental diets which included control, 0.025% gossypol, 0.05% gossypol, 0.1% gossypol, 0.1% soybean saponin, 0.3% soybean saponin, 1.0% soybean saponin were formulated and fed to E. sinensis for 60 days.The result showed that food intake of E. sinensis decreased when the gossypol concentration was higher than 0.025% or the soybean saponin concentration was higher than 0.1% maybe because of their bad appetite. As the concentration of gossypol enhanced (0.025%-0.1% gossypol, 0.1%-1.0% soybean saponin), feed coefficient ascended while protein coefficient descended. At the same time, growth and survival rate were decreased when the concentrations of dietary gossypol and soybean saponin were increased, which maybe caused by low utilization of feed and protein.3. Effect of gossypol and soybean saponin on digestive enzyme activity in hepatopancreas of E. sinensisThe result showed that, the trypsin-like enzyme in hepatopancreas of E. sinensis was inhibited after feeding the diet containing gossypol and soybean saponin. It may caused by the histological structure breakage in hepatopancreas. When the gossypol concentration was 0.025%-0.1%, the soybean saponin concentration was 0.1%-1.0%, the effect on amylase activity and cellulase activity was not obvious . The decline of lipid enzyme activity after feeding the feed containing soybean saponin suggested the lipid enzyme could be inhibited by dietary soybean saponin.4. Effect of gossypols and soybean saponin on nonspecific immunity of E. sinensisAfter dietary gossypol supplementation, superoxide dismutase (SOD) activity in hepatopancreas and haemolymph of E. sinensis increased. However, with dietary soybean saponin increasing, SOD activity in hepatapancreas and haemolymph and gills increased and then decreased. This suggested that the production of superoxide anion increased when the organism was in the condition of stress, which stimulated the increase of SOD activity. If the production of superoxide anion exceeded the ability of elminating anion of organism, SOD activity decreased. Acid Phosphatase (ALP) activity in hepatopancreas was decreased while alkaline Phosphatase (ACP) activity in hepatopancreas was increased by dietary soybean saponin, and ACP activity in hepatopancreas and haemolymph was increased by dietary gossypol, which indicated that the relative tissues were damaged.5. Effect of gossypols and soybean saponin on the microstructure and ultrastructure of hepatopancreas in E. sinensisAfter fed with the feed containing 0.1% gossypol for 60 days, the microstructure of hepatopancreas showed disorganization of some cells, and the pieces of cells appeared in lumen. After fed with diet containing 1.0% soybean saponin for 60 days, the number of vacuoles increased and their volumes augmented. And the ultrastructure of hepatopancreas showed that cell organells of hepatopancreas were damged by dietary gossypol and soybean saponin, which included invagination of nuclear membrane, extravasation of nuclear matter; mitochondria cristaes partly disintegrated, and then fully disintegrated; intimate membrane became disorganized; and the lysosomes increased.