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Litopenaeus shrimp (Litopenaeus vannamei) shrimp species per unit of production in the three farmed shrimp worldwide. N-acetyl-beta-D-glucosaminidase (N-Acetyl-β-D-glucosaminidase, referred NAGase EC.3.2.1.52) shrimp molting development and nutrition metabolism plays an important role. Therefore, the study of Litopenaeus vannamei enzymatic changes in the prevalence of the process, to explore the NAGase vigor regulation of environmental contaminants, feed additives, aquaculture commonly used drugs, and shrimp vivo acute toxicity test to carry out, explore heavy metal ions Litopenaeus vannamei NAGase vitality, will be conducive to the development of the shrimp farming industry, environmental pollution monitoring water for shrimp farming more fully, the the intuitive scientific basis, at home and abroad to fill in this research gap. In this paper, Litopenaeus shrimp shell membrane and visceral mentioned NAGase object, expand the following study. (1) analysis of health and suffering from red body disease in Litopenaeus tracking expedition differences of the shrimp shell membrane and visceral NAGase the vitality and nature. Measured health of the shrimp shell membrane NAGase the vitality to 34.80 U / mg, and the vitality of visceral NAGase 35.34 U / mg; suffering from red body disease of shrimp shell membrane NAGase activity was 38.32 U / mg, visceral NAGase activity was 20.02 U / mg. The results show that: the the NAGase vitality of the two sources of shrimp, basic enzymatic properties, etc. differences. Vannamei red body disease after suffering from shell membrane with the viscera the NAGase the catalytic reaction kinetic constants K m and V m values ??were higher activation energy, but the optimum temperature lower, pH stability, and thermal stability is poor. Shrimp sick before and after the shell membrane and visceral sources NAGase on the outside of each influencing factor (Hg 2 Zn 2 Cu 2 cd 2 the pb 2 , Al 3 and other heavy metal ion contaminants: ethanol, formaldehyde, phenol, methanol, dioxane, DMF, DMSO and other organic contamination; urea, NBS, SDS, and other commonly used chemical modification and denaturant) sensitivity also changed. (2) disinfect commonly used drugs in aquaculture water, sodium hypochlorite, TCCA quaternary ammonium salt Litopenaeus the vitality of the the shrimp shell membrane and the visceral sources NAGase have varying degrees of impact. Meanwhile, sodium hypochlorite, trichloroisocyanuric acid to the inhibition of the two sources of the enzyme for the irreversible process. Penicillin potassium, streptomycin, gentamicin, kanamycin neomycin, etc. essentially no effect on the shell membrane and visceral sources NAGas vitality; farming used orally, topical antimicrobial agents ciprofloxacin hydrochloride on two sources enzyme activation, norfloxacin and sulfamethoxazole azole different degrees of inhibition of enzyme activity. Sulfamethoxazole azole of shell membrane NAGase performance of mixed-type reversible inhibition, the NAGase performance visceral sources for noncompetitive inhibition; norfloxacin mixed irreversible inhibition of visceral origin NAGase. Examine several breeding commonly used vitamin on the the visceral the NAGase vitality of the impact, which VB 12 , niacin, riboflavin, enzyme activity is basically no effect; while VB the 1 VB 6 , ascorbic acid, such as the inhibition of enzyme activity in varying degrees, to further study the inhibition kinetics of VB 6 , the non-enzyme inhibition competitive reversible inhibition. (3) Litopenaeus vannamei breeding experiments to study the heavy metal ion impact on prawn NAGase activity sampled at different times and study Cu 2 Zn 2 , Cd 2 , Pb 2 , Hg 2 heavy metal ions such as shrimp shell membrane and visceral the NAGase vitality of Litopenaeus. The results showed that low concentrations of heavy metal ions in Litopenaeus shrimp shell membrane and visceral NAGase vitality within a short period of time did not significantly affect after 48 hours with the treatment time, the two sources of heavy metal ions NAGase activity decreased gradually significant inhibition dose-response relationship.
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