Effect Of Major Ions In Water On Survival And Growth, Shrimp Taste, Metabolic Enzymes Of Litopenaeus Vannamei

The salinity and Ca²⁺, Mg²⁺, K⁺in water play an important role on survival andgrowth of Litopenaeus vannamei, especially in inland freshwater aquaculture, andhow to deploy the salinity and the contents of major inos in water has become animportant part in the process of Litopenaeus vannamei farming. The effects of salinityand major ions on Litopenaeus vannamei were studied emphasis in the experiment.Each factor and the interaction of the factors to the Litopenaeus vannamei wereresearched inorder to find the law of the affect and the best salinity and ions adding inwater. The experiment contains three tests and two years to inspect, and the resultswere as follows:1. Effect of salinity, Ca²⁺, Mg²⁺in water on survival and growth, shrimp taste,metabolic enzymes of Litopenaeus vannamei. The experiment designed using theTaguchi method with three factors (Ca²⁺, Mg²⁺and salinity), each with7levels （L49）was run for60days to analyze the independent role of Ca²⁺, Mg²⁺and salinity on thesurvival, growth and flavor of Litopenaeus vannamei. The results showed that Ca²⁺,Mg²⁺and salinity in water significantly affected the survival rate and flavor aminoacids of Litopenaeus vannamei; Ca²⁺, Mg²⁺significantly affected the growth. And themaximum impact factor of survival rate was Mg²⁺, the growth was Ca²⁺, the flavoramino acids was the salinity. The highest survival rate were observed at Ca²⁺of 100mg/L and400mg/L, Mg²⁺of1200mg/L and the salinity of10; The growth did notsignificantly change at Ca²⁺of≥200mg/L and Mg²⁺of≥300mg/L, the fastestlength and weight gains were found at Ca²⁺of100mg/L, Mg²⁺of150mg/L andthe salinity of10-20; The concentration of flavor amino acids was high as Ca²⁺, Mg²⁺and salinity increased, and the highest contents of flavor amino acids in shrimpmuscle were presented at Ca²⁺of400mg/L, Mg²⁺of750mg/L with the salinity of35and20; Low salt, low calcium, low magnesium in water significantly reduced thegrowth and survival of shrimp; The metabolic enzymes results showed that Ca²⁺,Mg²⁺and salinity significantly affected the digestive enzymes（P<0.05）, and theprotease which most closely associated with absorption of Litopenaeus vannamei, thesalinity significantly affected the pepsin, maximum activity at the salinity of10, theCa²⁺and salinity significantly affected the tgryptase, maximum activity at Ca²⁺of200mg/L, salinity of20; Ca²⁺, Mg²⁺and salinity significantly affected the ATPenzymes （P<0.05）, and Ca²⁺, Mg²⁺and salinity significantly affected theNa+-K⁺-ATPase, maximum activity at Ca²⁺of300mg/L，Mg²⁺of500mg/L，salinity of30, Ca²⁺and Mg²⁺significantly affected the Mg²⁺-ATPase, maximum activity at Ca²⁺of200mg/L，Mg²⁺of500mg/L; Ca²⁺significantly affected the Ca²⁺-ATPase,maximum activity at Ca²⁺of200and300mg/L; Ca²⁺, Mg²⁺and salinity significantlyaffected the immune enzymes（P<0.05）, and Ca²⁺, Mg²⁺and salinity significantlyaffected the ACP, maximum activity at Ca²⁺of100mg/L，Mg²⁺of150mg/L，salinityof30; Mg²⁺significantly affected the AKP, maximum activity at Mg²⁺of150mg/L;Ca²⁺and salinity significantly affected the SOD, maximum activity at Ca²⁺of100mg/L，salinity of35.2. The interaction effect of salinity, Ca²⁺, Mg²⁺in water on survival and growth,shrimp taste, metabolic enzymes of Litopenaeus vannamei. Take L8（27） orthogonalexperimental design to investigate the three factors Ca²⁺, Mg²⁺and salinity in water,and two levels of each factor are based.In order to analysis the interaction role of Ca²⁺,Mg²⁺and salinity in water to the survival,growth and shrimp taste of Litopenaeusvannamei. The interaction between Ca²⁺and Mg²⁺significantly affected the survivalrate and daily weight gain, the interaction between Ca²⁺and salinity significantlyaffected the survival rate, but the interaction between Mg²⁺and salinity did notsignificantly affected the test indicator, the interaction of Ca²⁺, Mg²⁺, and salinity also had some impact on metabolic enzymes of Litopenaeus vannamei.3. Effect of K⁺and the interaction of major ions on survival, growth and ATPenzymes specific activity of Litopenaeus vannamei. Take L16（215） orthogonalexperimental design to investigate the four factors salinity, Ca²⁺, Mg²⁺, K⁺in water,and two levels of each factor were based. In order to analysis the role of K⁺and theinteraction of salinity, Ca²⁺, Mg²⁺, K⁺in water to the survival, growth and ATPenzymes specific activity of Litopenaeus vannamei, the survival rate, daily lengthgain, daily weight gain and ATP enzymes specific activity were compared during the5weeks cycle. Results showed that K⁺significantly affected the survival rate, lengthand weight gain, ATP enzymes specific activity in Litopenaeus vannamei（P<0.05）.The highest survival rate at k+of150mg/L, but the fastest growth rate andoptimal ATP enzymes activity at k+of50mg/L. And the results showed the interactionof salinity, Ca²⁺, Mg²⁺, K⁺in water also significantly affected the survival rate, lengthand weight gain, ATP enzymes specific activity in Litopenaeus vannamei（P<0.05）.The best combination of survival rate in the experiment was at salinity of15, K⁺of150mg/L, Ca²⁺of100mg/L, Mg²⁺of300mg/L, the best combination ofgrowth rate was at salinity of15, K⁺of50mg/L, Ca²⁺of100mg/L, Mg²⁺of100mg/L,the best combination of Na+-K⁺-ATPase, Mg²⁺-ATPase, Ca²⁺-ATPase specific activityin Litopenaeus vannamei was at salinity of5, K⁺of50mg/L, Ca²⁺of100mg/L, Mg²⁺of100mg/L.