Asian Fisheries Society

Role of Gut Probionts in Enhancing Growth and Disease Resistance in Rainbow Trout (Oncorhynchus mykiss, Walbaum) Fingerlings


Seven out of 34 isolates were selected as putative probionts. These were mixed with an equal volume of a lipid oralizer and incorporated into compounded feed pellets to achieve a dose of 5 x 107 bacterial cells•g-1 of fish food and fed to Rainbow trout Oncorhynchus mykiss fingerlings (average weight 23.69 g) for a period of 25 days. Superior growth (SGR) ranging between 0.32 to 0.57 (P<0.05) as compared to 0.05 of the control group was obtained in fingerlings maintained on the probiotic incorporated diets. A comparatively lower growth of 0.12 was obtained in group F5 but this was still higher than that of the animals maintained on a feed devoid of probiotics. Feed efficiencies ranging between 0.36 for group F5 to 1.03 for group F7 (P< 0.05) as compared to 0.08 of the control group were obtained in animals fed the probiotic feeds.

A challenge of these probiotic fed rainbow trout with intra-peritoneal injections of an inoculum contain-ing x 106 cells•ml-1 of A. Salmonicida (strain PR 107) recorded high survival rates ranging between 38% in group F5 to 78% in group F7 as compared to 20% survival in the animals fed the control diet devoid of any probiotic up to 14 days after challenge. The results of the present study clearly demonstrate the beneficial effects of orally administered probionts in enhancing growth of culture organisms as well as in increasing their resistance to diseases.

Publication Date : 2006-06-01

Volume : 19

Issue : 1

Page : 1-13

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Date 2006/06/01
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