Effects of methanolic macroalgae extracts from Caulerpa sertularioides and Ulva lactuca on Litopenaeus vannamei survival in the presence of Vibrio bacteria

Macroalgae are potentially excellent sources of highly bioactive secondary metabolites that are useful for the development of new functional ingredients. This study was conducted to determine whether methanolic extracts from Caulerpa sertularioides and Ulva lactuca macroalgae might be possible alternatives for the prevention of shrimp vibriosis, which is caused by Vibrio parahaemolyticus and Vibrio alginolyticus. Macroalgae extracts prepared with methanol as the solvent were evaluated for antibacterial activity with the microplate method. The extracts' effects on the mortality of juvenile Litopenaeus vannamei were evaluated at doses of 150 and 300 mg L-1. Two independent assays for V. parahaemolyticus and V. alginolyticus were performed. The methanolic extract of C sertularioides exhibited activity against V. parahaemolyticus and V alginolyticus, and it had minimal inhibitory concentrations of <1000 and < 1500 mu g mL(-1), respectively. L. vannamei mortality in the presence of both The methanolic extract of C. sertularioides exhibited activity against V parahaemolyticus and V alginolyticus, and it had minimal inhibitory concentrations of <1000 and <1500 mu g mL(-1), respectively. and V. alginolyticus bacteria significantly decreased after treatment with 300 mg L-1 C. sertularioides methanolic extract. (C) 2016 Elsevier Ltd. All rights reserved.