Effect of salinities on digestive enzyme activities of juvenile Litopenaeus vannamei Boone

In this paper,the effect of salinity on digestive enzyme activities of the juvenile Litopenaeus vannamei Boone was studied by means of enzyme analysis.The experiment was made under three levels of salinities equal to 1,15and 30 respectively.The results were as follows:(1)In the hepatopancreas of juvenile Litopenaeus vanname Boone under the salinity equal to 1,the pepsin has the highest activity[29.58μg/(mg.min)],and the activity of tyrsic-like[92.46 μg/(mg.min)] corresponds to the highest[97.60 μg/(mg.min)] under the salinity equal to 15,and in stomach,both tyrosic-like and pepsin have the highest activity.(2)The lipase has the highest activity in hepatopancreas and stomach under the salinity equal to 1,but the differences among various groups are not prominent(P0.05) through the statistical analysis.(3)The activities of amylase are equite contiguous in hepatopancreas,and there is no prominent difference among various groups of salinities(P0.05),and in stomach the juvenile Litopenaeus vannamei Boone’s amylase has the highest activity under the salinity equal to 1,and reaches 109.29 μg/(mg.min),prominently higher than that under the groups of salinities equal to 15 and 30(P0.05).