White shrimp Litopenaeus vannamei that have received carrageenan show protective immunity after salinity stress

Abstract

Green synthesized silver nanoparticles from Nigella sativa essential oil were used to study the inhibitory activity against pathogenic Vibrio harveyi and Vibrio parahaemolyticus isolated from aquatic environments. Essential oil of Nigella sativa based silver nanoparticle synthesis (EONs-AgNPs) was observed using UV-visible spectroscopy, FTIR and the morphological characteristics of the NPs were analyzed by scanning electron microscope (SEM). In the present study, increasing concentrations of EONs-AgNPs (30 μg/ml) effectively reduced the number of colonies of V. harveyi and V. parahaemolyticus. Among the two bacterial strains, EONs-AgNPs exhibited greater antibacterial activity against V. harveyi than V. parahaemolyticus. Similarly, the antibiofilm activity of EONs-AgNPs was also clearly observed under light and CLSM studies. EONs-AgNPs showed better inhibition of biofilm formation of V. harveyi followed by V. parahaemolyticus at 80 μg/ml after 24 h. The present study thus recommends that green synthesized silver nanoparticles of EONs-AgNPs could be used as an effective, safe and low cost control measures against pathogenic microbes of aquaculture importance.白蝦浸泡在含鹿角菜膠0及200 mg/l的千分之35海水中，3小時後，移到千分之25海水，6-96小時後檢測其透明球、顆粒球（包括半顆粒球）、總血球數、酚氧化酵素活性、超氧離子、超氧歧化酵素活性、血淋巴球蛋白質濃度。白蝦以沒有浸泡鹿角菜膠及受到鹽度變化為對照組。結果顯示浸泡含200 mg/l鹿角菜膠的白蝦在鹽度緊迫後的6-12小時，其透明球、半顆粒球、總血球數、酚氧化酵素活性、超氧離子、超氧歧化酵素活性、血淋巴球蛋白質濃度明顯高於對照組。結果也顯示，浸泡含200 mg/l鹿角菜膠的白蝦，其免疫因子在鹽度緊迫後24、24、24、48、12、48及12小時即回到背景值，而對照組白蝦其免疫因子則到96小時才回復。顯示白蝦浸泡在含鹿角菜膠海水，受到鹽度緊迫時，免疫因子較早恢復，證實免疫保護。