The Efficacy of the Red Seaweed (Laurencia Snyderiae) Extract on Growth Performance, Survival and Disease Resistance in White Shrimp

Shrimp aquaculture has expanded rapidly in many countries and this rapid development resulted diseases outbreaks and further considerable utilization of antibiotics. use of natural products as antimicrobial has been reported as a resolution problem. the crude extract of a red seaweed (laurencia snyderiae) collected from the persian gulf was evaluated for shrimp growth performance and to determine in vivo efficacy of this seaweed to prevention of shrimp vibriosis. the ethanol extract of laurencia snyderiae (eels) was not toxic to the artemia instar- i when it was fed to them for enrichment. the white shrimp (litopenaeus vannamei) juveniles fed with these enriched artemia at 0 mg ml-1 (control group), and three treatments of 200 , 400 and 600 mg ml-1 for a 30 days period. results showed an increase in survival rate in treatment groups compared with control group but wasn’t significantly (p<0.05). shrimps that fed with enriched artemia showed a significant in growth parameters comparing to control group (p<0.05). the notably lower mortality was observed when these juvenile shrimps were challenged to vibrio harveyi (after 30 days) in comparison with control. the results indicated that eels has a good potential in growth- promoting and antibacterial activity against v.harveyi in which is useful in shrimp aquaculture.