Enhancing Seafood Quality and Safety by Reducing Reliance on Antibiotics: Applying a Novel Antibody in Tilapia

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Virginia Tech

Disease outbreaks have overwhelmed the aquaculture industry as a whole and have been catastrophic for many single operations. To minimize disease outbreaks, efforts are underway to enhance animal health and disease resistance to pathogens without the use of antibiotics.

The overall purpose of this study was to explore a potential prophylactic, a novel antibody diet, for the bacterial pathogen, Aeromonas hydrophila, in tilapia.

The tilapia were on an anti-interleukin-10 antibody diet as a neutralization of interleukin-10 (IL-10), an anti-inflammatory cytokine. The anti-inflammatory function of IL-10 has been shown to allow persistence of gastrointestinal pathogens. Tilapia were fed the novel diet and were challenged via bath immersion or oral gavage with A. hydrophila. Four trials of challenge studies were conducted. Clinical signs of the disease and survival were monitored post-challenge of the bacteria. Out of the 4 trials, one bath immersion trial showed significantly lower survival in the group fed the novel antibody diet (p=0.044) compared to the control fed group, after challenged with A. hydrophila. The other trials tested showed no significant differences in survival between diets. Among the survival percentages collected as a whole, it cannot be determined from in vivo results whether this anti-IL-10 diet is effective in preventing mortality from A. hydrophila in tilapia. Therefore, an in vitro study using an enzyme-linked immunosorbent assay (ELISA) was used to determine the neutralization capability of anti-IL-10 on IL-10 using tilapia splenocytes. Interferon-γ, a pro-inflammatory cytokine, was quantified in order to find a trend in expression of IL-10 in vitro in various tilapia cell treatments. The protocol for the ELISA study is under development being that the use of this antibody is novel and has never before been done in fish.

Aeromonas hydrophila, tilapia, bath immersion, oral gavage, antibody