Culture-independent characterization of the bacterial populations associated with cod (Gadus morhua L.) and live feed at an experimental hatchery facility using denaturing gradient gel electrophoresis
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- 作者：Douglas McIntosh ; Baijing Ji ; Benjamin S. Forward ; Velmurugu Puvanendran ; Danny Boyce ; Rachael Ritchie
- 关键词：Probiotics ; Cod ; Larval rearing ; Microbial profiling
- 刊名：Aquaculture
- 出版年：2008
- 出版时间：31 March 2008
- 年：2008
- 卷：275
- 期：1-4
- 页码：42-50
- 全文大小：794 K
文摘
Atlantic Cod (Gadus morhua L.) represents an attractive species for cold water aquaculture. However, like many so called ‘alternative species’ early larval culture remains a challenge to commercial production. Indeed in comparison to other cultured finfish species, there exists limited information concerning the bacterial species associated with cod larviculture. Herein, we have employed PCR amplification of 16S rDNA coupled to Denaturing Gradient Gel Electrophoresis (DGGE) and sequencing of isolated amplicons, to profile the bacterial species associated with cod (both eggs and larvae) and the live feed (rotifer and Artemia) provided to the larvae during the first 50 days of development. A stable core microflora, comprising a total of six bacterial species with a putative Arcobacter sp. as the dominant component, was recorded in the majority of the rotifer samples. In contrast, Artemia showed a highly variable microflora composed of Vibrio spp, Alteromonas spp and Pseudoalteromonas spp. An association between Colwellia spp and cod eggs was demonstrated, although these species rapidly disappeared from the larval microflora which subsequently showed a reproducible (in 6 tanks over 2 years), and well-defined bacterial succession. Vibrio logei, V.fischeri and Listonella anguillarum predominated during the first 3 weeks of feeding but were gradually replaced by Flexibacter aurantiacus, a species of Sulfitobacter, and a putative Mycoplamsa sp. At 50 days post feeding the putative Mycoplasma sp. emerged as the dominant component of the microflora in all tanks. The culture-independent approach employed in this study generated a dynamic description of bacterial colonization of cod larvae and live feed and revealed the existence of previously undescribed bacterial associations with eggs and rotifers which would almost certainly have gone undetected using conventional culture based methods.