Effects of probiotics combination on breeding of Litopenaeus vannamei under zero-water exchange condition

Abstract:

In order to explore breeding technology with the application of probiotics combinations for Penaeus vannamei under zero-water exchange conditions, four probiotic bacteria with different ecological functions were formulated to two combinations (i.e., PBE and PEN), which were applied in the breeding experiment from nauplius larval phase V (N5) to postlarvae phase V (PL5). Each experimental group contained six parallels and the control group was set at the same time. Culturing water was not exchanged throughout the experiment, and probiotics combinations were continuously applied to the water in the PBE and PBN groups. The larval metamorphosis rate, total culturable bacterial count (TBC) and total presumptive Vibrio bacteria (TPVB) in larva and water were counted at the phases of zoea Ⅲ (ZⅢ), mysis Ⅲ (MⅢ) and PL5. At the end of the experiment, the survival rate of postlarvae in each experimental group was determined, and the microbial communities from postlarvae were sequenced using an Illumina platform. The results showed that there was no disease outbreak in each group, and that probiotics combinations significantly decreased (P<0.05) relative abundances of TPVB in postlarvae and culturing water in the groups of PBE and PBN compared to that in the control group, and significantly increased (P<0.05) the larval metamorphosis rate (15%) and survival rate (15%) at the phases of ZⅢ and PL5, respectively. There was no striking difference of microbial diversities and structures of the core populations in the microbial communities from postlarvae in the three groups, and every microbial community was dominated by Rhodobacteriaceae with the relative abundance ranging from 40% to 86%. Taking together, probiotics combinations can effectively inhibit the overabundance of Vibrio in rearing-water and postlarvae and improve the survival rate of postlarvae, thereby achieving healthy breeding of P. vannamei under zero-water exchange conditions.