Effect of dietary protein and genetic line of Litopenaeus vannamei on its hepatopancreatic microbiota

Host genetics and diet can exert an influence on microbiota and, therefore, on feeding efficiency. This study evaluated the effect of genetic line (fast-growth and high-resistance) in Pacific white shrimp (Litopenaeus vannamei) on the hepatopancreatic microbiota and its association with the feeding efficiency in shrimp fed with diets containing different protein sources. Shrimp (2.08 +/- 0.06 g) from each genetic line were fed for 36 days with two dietary treatments (animal and vegetable protein). Each of the four groups was sampled, and the hepatopancreatic metagenome was amplified using specific primers for the variable V4 region of the 16S rRNA gene. The PCR product was sequenced on the MiSeq platform. Nineteen bacterial phyla were detected, of which Proteobacteria was the most abundant (51.0 - 72.5 %), Bacteroidetes (3.6 - 23.3 %), Firmicutes (4.2 - 13.7 %), Actinobacteria (1.9 -12.1 %), and Planctomycetes (1.3 - 9.5 %). Diet was the most influential factor in the taxonomic composition of the microbiota, while genetic line was not a strong influential factor. The results suggest that the taxonomic profile of the bacteria colonizing shrimp hepatopancreas was determined by the diet consumed, similar to what occurs in the intestine. Shrimp in the fast-growth line had greater feeding efficiency regardless of the diet supplied. Finally, the results suggest that Proteobacteria influenced (p < 0.05) the feeding efficiency of shrimp fed with a vegetable diet. Nevertheless, further studies are required to explore how shrimp genetic line-diet interaction influences microbiota for probiotic development and functional food formulation for farmed shrimp according to the genetic line.