Location: Aquatic Animal Health Research
Title: Efficacy of a commercial water conditioner on transportation-, temperature-, and bacterial challenge stress responses of Ictalurus punctatus fingerlingsAuthor
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TUTTLE, J. - Auburn University |
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BRUCE, T. - Auburn University |
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ROY, L. - Auburn University |
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ABDELRAHMAN, H. - Auburn University |
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Garcia, Julio |
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KELLY, A. - Auburn University |
Submitted to: Aquaculture
Publication Type: Abstract Only Publication Acceptance Date: 12/10/2024 Publication Date: 3/6/2025 Citation: Tuttle, J.T., Bruce, T.J., Roy, L.A., Abdelrahman, H.A., Garcia, J.C., Kelly, A.M. 2024. Efficacy of a commercial water conditioner on transportation-, temperature-, and bacterial challenge stress responses of Ictalurus punctatus fingerlings [ABSTRACT]. Aquaculture 2025, New Orleans, Louisiana. March 6-10, 2025. Interpretive Summary: Catfish [channel (Ictalurus punctatus) and hybrid catfish (' I. punctatus × ' I. furcatus)] are the most produced domestic aquaculture finfish species. While grow-out occurs nationwide, Mississippi hatcheries produce most food-fish fingerlings. This necessitates transporting large numbers of fingerlings long distances. Additionally, due to inefficiencies and complications in pond-stock turnover, producers receive new fingerlings at inopportune times and suboptimal pond conditions. The objectives of this study were to determine the physiological, immune, and stress responses of I. punctatus fingerlings to transportation, temperature, and bacterial challenge stressors when individuals were transported in conditioner-treated water compared to untreated water. First, 720 Marion strain I. punctatus fingerlings (8.45±2.72g) were split evenly and transported approximately 255 km in 18°C oxygenated water from Greensboro, AL to Auburn, AL at a density of 0.45 kg/L. One group was exposed to a commercial water conditioner (V…) and the second group was not (NV…). After 2 hours and 48 minutes of travel, the two containers were each split into 4 different groups. One group was stocked at 18°C (-.CFN), second was stocked at 27°C (-.HFN), third was exposed to a lethal concentration (1.27x107 CFU/mL) of Flavobacterium covae (ALG-00-530) at 18°C (-.CFC), and fourth was exposed to a lethal dose of the same F. covae isolate at 27°C (-.HFC). These 8 groups consisted of 6 tanks (2 for sampling, 4 for survival monitoring) randomly distributed among 4 sets of 12 flow-through tanks housed in a secure system. Blood, mucus, gills, kidney, and spleen sampling from 3 individuals from each treatment occurred before and after transport, as well as 2, 6, 24, and 48 hours post stocking. Survival (Figure 1), blood cortisol, glucose, and lactose concentrations, mucus lysozyme activity, gill histology, and kidney, spleen, and gill immune gene expression were analyzed. Survival probability of all treatments exposed to F. covae was different from treatments naïve to the pathogen (P < 0.001), and the VCFC treatment was different from all other treatments, except NVHFC (P = 0.179). No distinguishable trends over time occurred in any treatment regarding blood cortisol, glucose, lactose concentrations, or mucus lysozyme activity. These findings provide valuable insight into fingerling transportation and stocking challenges, as well as progress towards a viable stress management strategy in the commercial catfish industry. Technical Abstract: Catfish [channel (Ictalurus punctatus) and hybrid catfish (' I. punctatus × ' I. furcatus)] are the most produced domestic aquaculture finfish species. While grow-out occurs nationwide, Mississippi hatcheries produce most food-fish fingerlings. This necessitates transporting large numbers of fingerlings long distances. Additionally, due to inefficiencies and complications in pond-stock turnover, producers receive new fingerlings at inopportune times and suboptimal pond conditions. The objectives of this study were to determine the physiological, immune, and stress responses of I. punctatus fingerlings to transportation, temperature, and bacterial challenge stressors when individuals were transported in conditioner-treated water compared to untreated water. First, 720 Marion strain I. punctatus fingerlings (8.45±2.72g) were split evenly and transported approximately 255 km in 18°C oxygenated water from Greensboro, AL to Auburn, AL at a density of 0.45 kg/L. One group was exposed to a commercial water conditioner (V…) and the second group was not (NV…). After 2 hours and 48 minutes of travel, the two containers were each split into 4 different groups. One group was stocked at 18°C (-.CFN), second was stocked at 27°C (-.HFN), third was exposed to a lethal concentration (1.27x107 CFU/mL) of Flavobacterium covae (ALG-00-530) at 18°C (-.CFC), and fourth was exposed to a lethal dose of the same F. covae isolate at 27°C (-.HFC). These 8 groups consisted of 6 tanks (2 for sampling, 4 for survival monitoring) randomly distributed among 4 sets of 12 flow-through tanks housed in a secure system. Blood, mucus, gills, kidney, and spleen sampling from 3 individuals from each treatment occurred before and after transport, as well as 2, 6, 24, and 48 hours post stocking. Survival (Figure 1), blood cortisol, glucose, and lactose concentrations, mucus lysozyme activity, gill histology, and kidney, spleen, and gill immune gene expression were analyzed. Survival probability of all treatments exposed to F. covae was different from treatments naïve to the pathogen (P < 0.001), and the VCFC treatment was different from all other treatments, except NVHFC (P = 0.179). No distinguishable trends over time occurred in any treatment regarding blood cortisol, glucose, lactose concentrations, or mucus lysozyme activity. These findings provide valuable insight into fingerling transportation and stocking challenges, as well as progress towards a viable stress management strategy in the commercial catfish industry. |