Effects Of Salinity And PH Stress On Energy Metabolism And Gonad Development Of Eriocheir Sinensis

This paper aimed to study the effects of salinity and pH on energy metabolism and sexual gonad development of Eriocheir sinensis. To discuss the roll of environmental conditions in the gonadal development of Eriocheir sinensis and to discuss the energy metabolism mechanisms, which can offere help in practice for the Eriocheir sinensis culture of health.The results are as follows:Part one:effect of salinity on energy metabolism and gonad development1. Salinity had remarkable effect on growth of the crab. Assimilation rate, apparent digestibility coefficient, feed conversion efficiency and energy conversion efficiency of crab lowered as the salinity rose(P<0.05). The dividing point of salinity was 8.5. Assimilation rate and feed conversion efficiency were remarkably lower than 4.5 when salinity was at 10.5, and assimilation rate and feed conversion efficiency were remarkably lower than 2.5-8.5 when salinity was at 12.5 (P<0.05)2. On respect of energy allocation, growth energy of crab lowered with the increase of salinity. Group of salinity 2.5 was significantly higher than the groups of salinity 10.5 and 12.5 while there was no difference in feeding energy (P>0.05)3. Hepatopancreas index under a salinity between 10.5 and 12.5 was remarkably lower than that under a salinity of 2.5. Gonad index displayed distribution curve and reached its maximum at a salinity of 8.5. Salinity could promote consumption of more nutrient and development of gonad.4. AKP activity of hepatopancreas tissue declined as salinity increased, while AKP activity of ovary and muscle displayed distribution curve and reached its maximum at a salinity of 8.5.5. It can be inferred form above:salinity stress effect on growth of Chinese mitten crab is achieved through consumption of nutrient, and salinity can prohibit growth and promote gonad, especially at a salinity of above 8.5.Part two:effect of pH on energy metabolism and gonad development1. Effect of pH stress on crab mainly concentrated on growth, assimilation and conversion efficiency. Feed conversion efficiency and energy conversion efficiency in groups of higher pH were higher than that in groups of lower pH (P<0.05).2. Growth energy got higher and metabolizable energy lowered when pH rose. There was significant difference between group of pH 7.5 and pH 9.0 (P<0.05)3. Effect of pH stress on gonad and hepatopancreas index was not remarkable (P>0.05)4. AKP activity of muscle and hepatopancreas in group 9.0 was significantly higher than those of the other groups. It can be deduced that effect of pH stress on crab mainly focused on nonspecific immunity other than consumption of nutriment.5. The optimum pH for growth of Chinese mitten crab was 8.5 at which growth energy ratio and hepatopancreas tissue index was high. And pH higher than 8.5 goes against survival.In a word, Compared with pH stress, salinity stress can promote gonad development of Chinese mitten crab. Effect of pH is not significant.