Evaluation of an AQUAVAC-ESC® Booster on Production of Food-size Channel Catfish Ictalurus punctatus in Earthern Ponds

Abstract

The effect of administering a more economically feasible dose of AQUAVAC-ESC® to channel catfish (Ictalurus punctatus) fingerlings for protection against enteric septicemia of catfish (ESC) was evaluated. The study consisted of three laboratory components and a field study. In the first laboratory study, fish were vaccinated by immersion at 24 C at 2.44 x 10^4, 3.48 x 10^5, or 3.16 x 10^6 CFU/mL for 4 or 8 hrs. Serum samples were later collected and evaluated for agglutinating antibody titers against Edwardsiella ictaluri, the causative agent of ESC. Mean antibody titers were significantly higher in fish vaccinated at 3.48 x 10^5 CFU/mL than in fish vaccinated at 2.44 x 10^4 CFU/mL. In addition, antibody titers were significantly higher in fish vaccinated at 3.16 x 10^6 CFU/mL than in fish vaccinated at the lower doses. The main effect of time, however, was not found to be significant, nor was a dose*time interaction observed. In the second laboratory study, fingerlings were stocked into aquaria, vaccinated by immersion at 18 C at 1.0 x 10^4, 1.0 x 10^5, or 1.0 x 10^6 CFU/mL for 4 h, and later challenged with E. ictaluri. No significant differences in antibody titers were observed among treatments. In the third laboratory study, fingerlings were stocked into aquaria, vaccinated by immersion at 25 C at 0, 1.95 x 10^4, 3.80 x 10^5, or 1.95 x 10^6 CFU/mL for 4 h, and later challenged with E. ictaluri. Significant differences were observed between control fish and fish vaccinated at the highest dose and between fish vaccinated at the highest dose and fish vaccinated at the lowest dose. In the field study, treatment groups consisted of fish (1) non-vaccinated as fry and non-vaccinated as fingerlings, (2) vaccinated as fry at 10-d post-hatch and non-vaccinated as fingerlings, (3) non-vaccinated as fry and vaccinated as fingerlings, and (4) vaccinated as fry at 10-d post-hatch and vaccinated as fingerlings. Fish were vaccinated by immersion at 18 C for 4 h at a concentration 1:10 dilution rate of the manufacturer’s recommended dose rate. The main effect of vaccination at the fry stage on survival was found to be significant. However, the main effect of vaccination at the fingerling stage on survival was not found to be significant, nor was a fry*fingerling interaction observed. The main effects of vaccination at the fry stage and vaccination at the fingerling stage on FCR values, average weights, or net production figures were not found to be significant, nor were any fry*fingerling interactions observed.