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Probiotics and their use in Commercially Important Aquaculture Species in the Northeastern United States

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dc.contributor.author Myer, Jacqueline
dc.date.accessioned 2019-02-28T15:00:58Z
dc.date.available 2019-02-28T15:00:58Z
dc.identifier.uri http://hdl.handle.net/20.500.12090/384
dc.description.abstract Probiotics have shown to be beneficial to aquatic farming in aspects such as growth and development. This study, using three commercial aquaculture species, intends to ascertain if certain strains of Bacillus and Shewanella bacteria could possibly be used in aquaculture to improve finfish growth and survival, and be classified as true probiotics. Trials run at the DSU ARDF dose Nile tilapia (Oreochromis niloticus), rainbow trout (Oncorhynchus mykiss) and hybrid striped bass (Morone chrysops x M. saxatilis) with three probiotics Bacillus spp. (Iso 5 and Iso 11) and Shewanella spp. (Iso 12). Mortality was observed in three finfish trials over a 56-day trial or until one tank in the trial attained 10% survival. Ammonia, nitrite and nitrate were monitored throughout the trial. Feed conversion ratios, specific growth rates, weight gains and mortality were assessed at the end of the study. During the Nile tilapia experiment control tanks lost a total of 42 of 75 fish. ISO 12 (60/75), ISO 5 (56/75), and ISO 11 (58/75), treated tanks had statistically higher survival rates then the control tanks. Significant differences were also seen in survival during the hybrid striped bass experiment between the control tanks (16/30), ISO 12 (24/30) and ISO 11 (30/30). No significant differences were seen in survival for the rainbow trout experiment, but no treatment lost more than 10 finfish during the entirety of the experiment. Significant differences were observed for nitrite concentrations among tanks with probiotic treatments in the hybrid striped bass as well as with the rainbow trout experiment. ISO 5 treated tanks had a significantly lower concentration (0.107 ± 0.027 mg/l) of nitrite when compared to control tanks (0.231 ± 0.027 mg/l) during the rainbow trout experiment. Tanks treated with ISO 12 were significantly higher in nitrite concentration (0.038 ± 0.002 mg/l) than tanks treated with ISO 5 (0.030 ± 0.002 mg/l), and significantly higher than those treated with ISO 11 (0.029 ± 0.002 mg/l) during the hybrid striped bass experiment. The difference in ISO 5 and ISO 12 nitrite concentrations could be attributed to the ability of Bacillus spp. bacteria to metabolize ammonia into nitrate and nitrite, jumpstarting the nitrogen cycle. ISO 12 treated tanks very high nitrite concentration in comparison, might also be due to Shewanella spp. ability to denitrify nitrate into nitrite. If the experiment had lasted longer, perhaps an eventual decrease in nitrite would have been seen as the nitrite was converted into ammonium, a benign gaseous output. All three tested bacteria have the potential to be probiotics and used in aquaculture. Higher survival of finfish in the probiotic treatment tanks and the control tanks suggest that all three probiotics have the ability to increase survival in warm water (24 ºC) conditions, though no significant results were observed for cooler water (19 ºC). ISO 5, Bacillus cereus, and ISO 12, Shewanella spp., were both shown to have an effect on the concentrations of nitrite, but ISO 5 decreased the nitrite concentration while ISO 12 increased the concentrations when compared to ISO 5 and ISO 11, not the control. Further testing is required for ISO 12 to see if it could possibly lower the nitrite over a longer time period. Further testing is required for all three probiotic strains, and different systems as well as temperatures and salinities should be used to better understand the functions of these bacteria.
dc.title Probiotics and their use in Commercially Important Aquaculture Species in the Northeastern United States
dc.date.updated 2019-02-13T20:02:12Z
dc.language.rfc3066 en


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