Microbiota intestinal de camarões Litopenaeus vannamei e Farfantepenaeus brasiliensis em ambientes de cultivo e natural

Abstract

The present work analyzed the intestinal microbial community in four different environments (green water, BFT, clear water and natural), and verified the association and occurrence of two viruses (WSSV and IMNV) in the marine shrimp species Litopenaeus vannamei and Farfantepenaeus brasiliensis. Microbiological and molecular methods were used to isolate and identify the microbial strains. In green water, L. vannamei showed higher microbial counts for intestine contents, with dominance by lipolytic, BHC and amylolytic groups. as well as the presence of fungi. The genus Vibrio was present in all functional groups analyzed. Non-pathogenic as well as potentially pathogenic species in shrimp farming were found. The highest growths were associated with the animals infected by the IMNV (6.76 x 102 to 1.14 x 105 copies of IMNV.μg-1 RNA). When considering BFT and clear water systems, the intestinal microbial profile of L. vannamei showed higher microbial counts for BFT. Fungal growth was observed in water, tissue and intestinal contents for both culture systems. Significant differences between environments were found for the groups of amylolytic, lipolytic and Bacillus bacteria. All shrimp in clear water were positive to IMNV. Finally, in natural environment F. brasiliensispresented higher microbial counts for cellulolytic and BHC bacteria. The presence of fungi was higher in the gut than in the water. From 45 shrimp analyzed, 21 were positive for the IMNV with a mean viral load of 7.65 x 103 copies / μg RNA RT-qPCR. This was the first record of IMNV for this species in the Pacoti River, Ceará. In conclusion, Vibrio was the most prevalent genus among functional groups and environments studied. The intestinal microbial composition in terms of diversity seems to be similar among all environments; however, it is different in terms of proportions. In addition to that, IMNV was present in all environments. The results obtained here will help to achieve ideal conditions of farming, through the knowledge of the microbial community from the environment and shrimp gut under artificial and natural conditions.