Primary Studies On The Feeding And Metabolic Physiology Of Southern-China-cultured Stichopus Japonicus

This paper describes the growth,digestive physiology of stichopus japonicus cultured in southern China basis ofthe culture environment and breeding process models in the southern area by indoor experiments. The results areas follows:1Feeding rate, absorption efficiency and energy budget of Southern-China-cultured stichopus japonicus fedwith three different sediments (from sea area, shrimp-culture pond and artificial sediments) were studied. TheResults demonstrated that there was no significant difference in the feeding rate among3types of sediments(P>0.05) when S. japonicus acclimatized in southern China was with26.11±1.5g weight under temperature of17±1℃. Assimilation efficiency(AEO)and specific growth rate(SGR)in sea area group is the lowest in those threegroups.the highest proportion of12.35±3.53％intake energy for growth were found at shrimp-culture pondgroup, significant higher than other two groups It was found that, shrimp-culture pond will accelerate S.japonicus growth.2This study explored the influence of different diets on growth and energy budget in Southern-China-cultured Stichopus japonicus. S. japonicus with the body weight of20±2.25g were fed with Sargassum thunbergiiKuntze, laminaria japonica, undaria pinnatifida,and diatom. The results showed that The feeding rate(FR) of S.japonicus fed with diet of laminaria japonica were lower then others.The FR, the specific growth rate(SGR) ofthe S.thunbergii Kuntze group is highest, there is no significant difference in L. japonica group. Regressionanalysis showed that the proportions of tovarious components of energy budget were significantly affected bydiets. The highest proportion of6.84％intake energy for growth were found at S.thunbergii Kuntze group,there isno significant difference in proportion of energy intake for growth.L. japonica group(6.21％)and diatomgroup6.12％）, those three groups were significantly higher than with the undaria pinnatifida group(5.11％).Itwas found that, L. japonica is an alternative food source for S. japonicus.3Oxygen consumption rate(OCR) and ammonia excretion rate(AER) of Southern-China-cultured stichopusjaponicus, were determined with the body weight of20±2.25g at gradual changes and rapid fluctuating oftemperatures and salinity in laboratory.The results showed that the oxygen consumption and nitrogen excretion ofS. japonicus increased at first, and then decreased with the increase of temperature, OCR attains maximum of thetemperature was15℃.The OCR and AER first decrease then increase while the salinity increased,they all, theyare all reached minimized simultaneously by30‰.4Southern-China-cultured Stichopus japonicus were examed for tolerability in differentenvironmental conditions(15、20、25℃)×(20、35、30‰)by gradual changes and rapid fluctuatingof temperatures and salinity. The results showed that the median lethal temperature (LT50) ofS.juveniles by gradual changes of temperatures is higher than rapid fluctuating with good tolerance.Mortality rate were positively correlated to the acclimated temperature,but negatively correlated tothe acclimated salinity. The salinity tolerance of S.juveniles can tolerance to a lower limit salinity when salinity gradient. At higher salinity, The median lethal salinity (LS50) in gradual changes ofsalinity higher than gradual changes of salinity were1.9~3.4‰.