Relative Abundance and Species Composition of Gram‐Negative, Aerobic Bacteria Associated with the Gut of Juvenile White Shrimp Litopenaeus vannamei Reared in Oligotrophic Well Water and Eutrophic Pond Water

Abstract

Gut bacteria may contribute significantly to the growth and survival of cultured shrimp, although little is known about factors that affect bacterial community structure in shrimp guts. The objective of this study was to determine the abundance and species composition of gut bacteria in juvenile white shrimp Litopenaeus vannamei reared in two different environments. Eight 120‐L tanks were stocked at a density of 8 shrimphank. Two treatments were tested for 10 d and consisted of tanks receiving flow‐through water from one of two sources: 1) well water pumped from a sea‐water aquifer (Well treatment), and 2) pond water pumped from an intensive shrimp pond (Pond treatment). Shrimp mid‐ and hindguts were excised on days 1, 3, 6, and 10 for enumeration of gram‐negative, aerobic bacteria by quantifying colony‐forming units (CFU) using standard microbiological plating techniques. Identification of bacterial isolates was made using the Biologa® GN Microplate system. Bacterial numbers were significantly greater (P > 0.05) in Well shrimp than in Pond shrimp on days 1 and 3. Following day 3, a decrease in bacterial numbers occurred in the Well shrimp, and no significant differences between treatments were observed on days 6 or 10. Guts from Well shrimp were dominated by Vibrio and Aero‐monas, and these two genera accounted for 80–851 of the bacteria on each sampling day. Guts from Pond shrimp exhibited a greater bacterial diversity and were dominated by Vibrio, Aeromonas, and Pseudomonas. Flavobacterium were identified in the guts of Pond shrimp on days 3 and 10, but were not identified in any of the Well shrimp. A greater understanding of gut bacteria‐shrimp interactions could lead to increased production and profitability for shrimp farmers through the development of more cost‐effective feeds and novel disease control strategies.

Quantitative role of shrimp fecal bacteria in organic matter fluxes in a recirculating shrimp aquaculture system

“…However, bacterial abundances in the gut and feces of P. vannamei were of the same order of magnitude as in Moss et al (2000); they estimated 2 Â 10 10 CFU g À1 gut tissue in P. vannamei. Comparisons of our direct bacterial counts in shrimp feces with published values are difficult because previous studies used culture-based methods.…”

Probiotic Applications in Crustaceans

“…However, the current knowledge on the intestinal microbiota of crustaceans is still very limited and the majority of studies conducted so far have used conventional culture based microbiological methods, therefore providing incomplete information (Dempsey et al 1989;Harris 1993;Moss et al 2000;Oxley et al 2002). Only a limited number of studies have used molecular methods to describe the microbiota of shrimps (Li P. et al 2007;Johnson et al 2008;Castex 2009;Liu et al 2011a) or other crustaceans (Battison et al 2008;Daniels et al 2010).…”

“…It is accepted that crustaceans have a less developed GI microbiota than fish and that the microbiota would be predominately transient in the foregut and the hindgut regions. Bacterial concentration and composition are thus likely to be influenced by a variety of parameters, such as the culture system, temperature, bacterial communities of the culture medium, feeding, moulting, intestinal transit and defecation (Moss et al 2000). Also while most research has focused on bacteria that are able to attach to intestinal mucus, transient bacteria have also been demonstrated to exert beneficial effects in crustaceans (Castex et al 2008;2009;2010).…”

Vibrio fortis sp. nov. and Vibrio hepatarius sp. nov., isolated from aquatic animals and the marine environment

“…Vibrios also belong to the normal microflora of the shrimp Litopenaeus vannamei (Vandenberghe et al, 1999). Moss et al (2000) reported that Vibrio and Aeromonas species comprised up to 85 % [about 10 9 c.f.u. (g gut tissue)…”