Biochemical changes of Litopenaeus vannamei and Fenneropenaeus indicus in the different stages of WSSV infection

Objective:To find out the difference in the proximate composition and fatty acid profile of both the species of shrimp Litopenaeus vannamei(L.vannamei)and Fenneropenaeus indicus(F.indicus)infected with different stages of white spot syndrome virus(WSSV).Methods:Standard methods were followed by estimating the proximate composition and fatty acid analysis.Each fish specimens were beheaded,eviscerated and filleted manually.The tissue samples were oven dried at 67°C for 24 h.Then the samples were grounded finely with pestle and mortar.The saponified samples were cooled at room temperature for 25 min.They were acidified and methylated by adding 2 mL 54%6 mol/L HCL in 46%aqueous methanol and incubated at 80°C for 10 min in water bath.Following the base wash step,the fatty acid methyl esters were cleaned in anhydrous sodium sulphate and then transferred into gas chromatograph sample vial for analysis.Fatty acid methyl esters were separated by gas chromatograph.Results:The proximate composition was higher in the both control tissue than the three(low,moderate,severe)infected ones.For L.vannamei and F.indicus,the carbohydrates are 5.07%and 6.18%,and the proteins are 25.01%and 22.17%,respectively.Lipid level recorded was little higher in the shrimps maintained and showed severe sign of WSSV infection than the control and the fatty acid profile result revealed that saturated fatty acids and monounsaturated fatty acid was in higher[48.72%(Severe)&16.87%(low)]L.vannamei.In the polyunsaturated fatty acid,F.indicus was 40.47%(low).Conclusions:Our study showed that the healthy shrimps are nutritionally rich than the WSSV affected shrimps.

Assessment of antimicrobial activity of c-type lysozyme from Indian shrimp Fenneropenaeus indicus

Objective:To assess the multitudinal antimicrobial effects of recombinant lysozyme fromFenneropenaeus indicus(rFi-Lyz)in comparison with commercially available recombinant hen egg white lysozyme(rHEWL).Methods:Antimicrobial activity of the recombinant rFi-Lyz using several Gram positive,Gram negative bacteria and fungi in comparison with rHEWL has been evaluated.rFi-Lyz was expressed and purified using Ni2+affinity chromatography.The effect of rFi-Lyz in the growth of yeast Candida krusei,plant molds Rhizoctonia solani and Fusarium solani was assessed by well diffusion assay in petri plates with potato dextrose agar.Results:rFi-Lyz exhibited high inhibitory activity on Gram positive bacteria such as Staphylococcus aureus and Bacillus subtilis.Among various Gram negative bacteria testedKlebsiella pneumoniae exhibited the highest inhibition followed by Pseudomonas aeruginosa and Shigella dysenteriae.rFi-Lyz also exhibited significant inhibition on two marine pathogens Aeromonas veronii and Vibrio alginolyticus.Among the various fungal strains tested,rFi-Lyz inhibited the growth of budding yeast Candida krusei significantly.Further the growth of two other plants fungus Rhizoctonia solani and Fusarium oxysporum were retarded by rFi-Lyz in the plate inhibition assay.Conclusions:rFi-Lyz exhibits a broad spectrum of antimicrobial activity like a natural antibiotic on various pathogenic bacteria and fungal strains.