Effects Of Environmental Factor On Growth And Blood Biochemical Indexes Of Plectropomus Leopardus

To evaluate the effects of environmental stress on the growth,serum biochemical parameters of Plectropomus leopardus,experiments were perefromed under different environmental stresses inclding medium density,catching stress,crowding stress,ransportation stress and intensity of illumination.A 56-day experiment was performed at three stocking densities of low density(9.34kg/m~3,Group L),medium density(19.23 kg/m~3,Group M)and high density(37.22 kg/m~3,Group H)to evaluate the effects of stocking density on the growth,serum biochemical parameters of Plectropomus leopardus.Each density was replicated in three tanks.Fish were sampled after 56-day culture.Results showed that the final body weight,percent weight gain and specific growth rate in Group H were significantly lower than those in Group M and Group L,while no significant difference were observed between Group M and Group L.No significant difference was observed on feed conversion ratio,feeding rate,instantaneous growth rate and thermal-unit growth coefficient among three groups.Significant difference were observed on superoxide dismutase activity,which was the highest in Group H while the lowest in Group M.The total antioxidant capacity in Group H was significantly lower than that in Group M and L.Malondialdehyde level Group H was significantly higher than that in Group M and L.No significant difference was observed on Malondialdehyde between Group M and L.The lactic dehydrogenase activity increased with the augment of stocking density,and statistical difference was observed among three groups.The alanine aminotransferase and aspartate aminotransferase level in Group H were statistically higher than those in Group M and L,while lysozyme was significantly lower than that in Group M and L.No statistical difference was observed on plasma GLUcose,cholesterol,C-reactive protein,total protein,and lactic acid among three groups.The effects of catching stress on Plectropomus leopardus were studied by the blood physiological and biochemical parameters.Blood of experimental groups and the control groups was sampled at 4h,8h,12h,24h,72h,168h after catching stress for 40 mins.The results showed that parameters like Leukocytes,Optical density value of NBT positive cells,Hemoglobin level,activity of alanine aminotransferase(ALT),activity of aspartate aminotransferase(AST),malondialdehyde(MDA),total antioxidant capacity(T-AOC)and total superoxide dismutase T-SOD show a significant difference in different time atter the catching stress.Fishing stress test showed that acute stress will damage the Physiological tissues of Plectropomus leopardus,causing fish body immune resistance a deep decrease and metabolic process disordered.Therefore,to reduce the negative impact of catching stress and protet the welfare of fish,they should try to shorten the acute fishing time stress in production management.In order to evaluate the influence of cute crowding stress(2 h,105.56 g/L)on the health of Plectropomus leopardus,the P.Leopardus was recovered to the normal density(28.15 g/L)and was sampled at 4 h,8 h,12 h,24 h,72 h,168 h after the stress to test the blood parameters of the P.leopardus.Results showed thatAcute crowding stress can lead to the T-SOD,GLU,LD,LDH,TP,LZM of Plectropomus leopardus significantly increase,the MDA significantly decrease,while the T-Cho,ALT,CRP shows no obvious change.To study the effect of different modes of transport time on the biochemical indicators of Plectropomus leopardus,the transport time was 0h(control group),0.5h,1.5h,3h.After each transport transportation 0h,24h,72h,120h sampling.The results show that in both group0.5h and group 1.5h,the GHO,TP,Alb,LD,LDH and MDA in blood shows a significant difference,while the GLU have no difference;it has a significant difference on GLU,Alb,LD,LDH,TP,CHO and MDA in the blood of Plectropomus leopardusin the 3h group.We can find similar results throngh the control experiment of transportion experiment in spite there are minute numerical differences.In order to evaluate the influence of intensity of illumination(0lx,20lx,1000lx,2000lx and 300lx)on the health of Plectropomus leopardus,and was sampled at 1d,4d and 8d.Results showed that in both 1000lx group and 2000lx group,the T-AOC,MDA,LDH,CAT and LD shows a significant difference.Activity of alanine aminotransferase(ALT),aminotransferase(AST),malondialdehyde(MDA),total antioxidant capacity(T-AOC)and total superoxide dismutase T-SOD show a significant difference in different time atter the catching stress.