Individual and synergistic effect of highly diluted bioactive compounds and probiotic actinomycetes on the growth and survival of juvenile shrimp Penaeus vannamei

Abstract

The objective of this study was to evaluate two Streptomyces spp. probiotic strains (RL8 and N7) and four highly-diluted bioactive compounds (HDBC) in the growth, survival, and modulation of the microbial content in culture water and hepatopancreas of juvenile white shrimp Penaeus vannamei. An experimental design was applied with five treatments in triplicate, including T1: (RL8+N7); T2: [(ViP-7C+ViA-7C) + (PhA-7C+SiT-7C)]; T3: [(ViP-7C+ViA-7C) + (PhA-7C+SiT-7C) + (N7)]; T4: [(ViP-7C+ViA-7C) + (PhA-7C+SiT-7C) + (RL8)] and T5 as the control without actinobacteria or HDBC. T2 showed significant differences (P < 0.5) in height increase compared to the other treated and control groups. The organisms in T2, T3, and T4 recorded higher weight gain compared to T1 and T5. A survival rate from 94.13 ± 2.12 to 99.01 ± 2.45% was obtained with a significant difference (P < 0.05) between T1, T2, and T3, concerning the untreated control (T5). A significant decrease in Vibrio spp. the content was observed in water and shrimp in T1 and T2 concerning the control. The heterotrophic bacterial count in hepatopancreas increased with all treatments compared to T5. Our results suggest a positive synergy between the HDBC mixture [(ViP-7C+ViA-7C) + (PhA-7C+SiT-7C)] and N7 Streptomyces sp. strain, whose probiotic action has been previously demonstrated by improving culture conditions for P. vannamei juveniles in terms of growth, survival, and reduction of potentially pathogenic bacteria.