Document Type

Internship Report

Publication Date

Spring 2016

Abstract

Larval fish are sensitive to pathogenic bacteria which can be transmitted through live feeds, such as rotifers (Brachionus plicatilis). This paper reviews the methods of disinfection of live feeds that have been developed in the literature, and describes the testing of a few methods experimentally. The experiments conducted analyzed the effect of rinsing, peroxide, and the product Sanocare SURE for the effect on the bacterial load and composition of rotifers. The rotifers received these treatments in a “harvester” as part of a potential industry protocol, and bacterial samples were sent off site for analysis. This study also found a concentration of peroxide at which the rotifers did not regurgitate, as well as its lethal level. The study found no difference between total bacteria load for varying peroxide concentrations. The peroxide treatments pooled together and Sanocare SURE were found to have a weakly significant effect on the total bacterial load of rotifers (p=.058, p=.059 respectively). Rinsing had an apparent trend of decreasing the bacterial load over time. The analysis of composition showed three predominant bacteriums: Pseudoalteromonas sp, Listonella anguillarum (or Vibrio anguillarum), and Marinomonas sp. The control was combined with the rinsing samples and compared against the peroxide group and Sanocare SURE group, and the effect on composition of bacteria by the groups was found to be highly significant (<.001). In a subset analysis, peroxide was found to be significantly effective at reducing Pseudoalteromonas sp. (p=.057) Rinsing eliminated L.anguillarum in both samples. The results of the study recommend further experimentation to confirm the efficacy of rinsing, peroxide, and Sanocare SURE, but suggest that low levels of peroxide may be as effective as SURE at reducing bacterial load, and do not cause regurgitation. The study also suggests rinsing may be more effective over longer time periods, and further research should determine the maximum efficacy.

Comments

Department: MES

MPS Track: AQU

Location: Golden Eagle Sablefish

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