Bdellovibrio and Like Organisms Enhanced Growth and Survival of Penaeus monodon and Altered Bacterial Community Structures in Its Rearing Water

Abstract

bIn this study, a 96-h laboratory reduction test was conducted with strain BDHSH06 (GenBank accession no. EF011103) as the test strain for Bdellovibrio and like organisms (BALOs) and 20 susceptible marine bacterial strains forming microcosms as the targets. The results showed that BDHSH06 reduced the levels of approximately 50% of prey bacterial strains within 96 h in the seawater microcosms. An 85-day black tiger shrimp (Penaeus monodon) rearing experiment was performed. The shrimp survival rate, body length, and weight in the test tanks were 48.1% ؎ 1.2%, 99.8 ؎ 10.0 mm, and 6.36 ؎ 1.50 g, respectively, which were values significantly (P < 0.05) higher than those for the control, viz., 31.0% ؎ 2.1%, 86.0 ؎ 11.1 mm, and 4.21 ؎ 1.56 g, respectively. With the addition of BDHSH06, total bacterial and Vibrio numbers were significantly reduced (P < 0.05) by 1.3 to 4.5 log CFU · ml ؊1 and CFU · g ؊1 in both water and shrimp intestines, respectively, compared to those in the control. The effect of BDHSH06 on bacterial community structures in the rearing water was also examined using PCR amplification of the 16S rRNA gene and denaturing gradient gel electrophoresis (DGGE). The DGGE profiles of rearing water samples from the control and test tanks revealed that the amounts of 44% of the bacterial species were reduced when BDHSH06 was added to the rearing water over the 85-day rearing period, and among these, approximately 57.1% were nonculturable. The results of this study demonstrated that BDHSH06 can be used as a biocontrol/probiotic agent in P. monodon culture.

Halobacteriovorax, an underestimated predator on bacteria: potential impact relative to viruses on bacterial mortality

“…The fact that the experimental results concerned native predators in NWs adds relevance to the findings. Other investigators using different experimental models have also reported a reduction of prey bacteria by Halobacteriovorax and the potential of the predators to affect the mortality of susceptible bacterial populations in aquatic systems (Richards et al, 2012;Li et al, 2014;Wen et al, 2014). Richards et al (2012) used several strains of V. parahaemolyticus and a strain of V. vulnificus as amendments to a natural seawater sample and observed a decline in their numbers along with an increase in Halobacteriovorax as we observed in the experiments described in this report.…”

“…The fact that Halobacteriovorax are also abundant in the surface microlayer (Williams, 1987) suggests that they prey on the large numbers of bacteria present. Although high concentrations of prey were used in this study, it should be noted that BALOs are typically capable of reducing prey concentrations via population dynamics similar to those shown in Figures 2 and 3 at prey concentrations as low as of 1 × 10 4 ml -1 , albeit over a longer time period (Ahmed, 2007;Richards et al, 2012;Li et al, 2014;Wen et al, 2014).…”

Bacterial predation in a marine host-associated microbiome

“…One group of Bdellovibrionales, the marine Halobacteriovorax, are broadly distributed in marine waters across temperature, salinity and pH gradients (Pineiro et al, 2007). Halobacteriovorax predation represents a regulatory mechanism that can alter the structure of bacterial communities (Li et al, 2014).…”

Effects of Bdellovibrio and Like Organisms on Survival and Growth Performance of Juvenile Turbot, Scophthalmus maximus

“…Considering these factors, the use of probiotics or beneficial bacteria to control pathogens is increasingly viewed as an alternative to antibiotics and vaccines (Balcazar et al ; Kim et al ; Mirbakhsh et al ; Chen et al ). The use of probiotics in aquaculture has originated in human and animals since 1989 (Fuller ) and became popular thereafter (Wang et al ; Selvin and Ninawe ; Villamil et al ; Khanitta and Tipparat ; Wu et al ; Daga' et al ; Pérez‐Sánchez et al ; Li et al ).…”