Location: Aquatic Animal Health Research
2021 Annual Report
Accomplishments
1. Bioeconomics of Flavobacterium columnare vaccine in pond trials with channel catfish. Flavobacterium columnare is a well-known fish pathogen that has been studied for over 100 years but, columnaris disease remains poorly controlled in farmed catfish. Outside of therapeutants (chemicals and antibiotics), the disease remains relatively unchanged in the U.S. catfish industry. Attempts to improve the management of this disease have led to the development of a live-attenuated genetic group 2 F. columnare vaccine (hereafter 17-23). ARS in Auburn, Alabama, and Auburn University scientists investigated the efficacy of the 17-23 vaccine delivered by immersion to catfish fingerlings that were grown to food size in earthen ponds. Data were collected from the two treatments (vaccinated vs non-vaccinated) to evaluate impacts on survival, growth, feed conversion, antibody development, and economic benefit. There were no obvious natural outbreaks of columnaris disease observed during the trial and no difference in survival of vaccinated versus control fish. The vaccinated fish had significantly elevated antibodies at 4 weeks post-vaccination but not at 12 weeks. However, vaccinated fish were significantly larger at harvest (0.78 ± 0.07 lbs) than control fish (0.64 ± 0.04 lbs), and the feed conversion ratio (FCR) of vaccinated fish (1.35) was significantly better than control fish (2.13). Partial budget analysis demonstrated use of 17-23 vaccinated fingerlings resulted in a net benefit of US $600 per acre. The vaccine showed economic benefit to producers, but the results should be further substantiated under both research and commercial settings.
2. Selectively breeding Nile tilapia for disease resistance does not negatively impact harvest weight. Fish growth is of high economic importance for farmers; therefore, the relationship between growth and other traits that affect performance is paramount. ARS scientists in Auburn, Alabama, in collaboration with industry stakeholders have demonstrated that resistance to Streptococcus (S.) iniae and S. agalactiae is heritable and improved lines of tilapia have been produced that are more resistant to disease. However, the impact of selective breeding for disease resistance on the harvest weight of tilapia was unknown. Data from eight generations of selective breeding including survival following S. iniae/S. agalactiae infection and harvest weight was analyzed. The results demonstrated there were no significant relationships, favorable or unfavorable, between harvest weight and survival to both Streptococcus species. This means that selectively breeding for disease resistance will not negatively impact harvest weight of the fish. Thus, multi-trait selection is recommended to balance growth and disease resistance. The goal of this research is to provide fish farmers with a robust stock of tilapia that are resistant to disease and exhibit fast growth to improve the profitability of tilapia aquaculture.
3. Bioactive and potent recombinant toxins (PirA and PirB) were produced from Vibrio parahaemolyticus. Acute hepatopancreatic necrosis disease (AHPND), caused by emerging strains of V. parahaemolyticus (pirA/pirB plasmid positive isolates), in shrimp aquaculture is of concern not only in Asia but also in Central and North America. Toxins produced by the plasmid of V. parahaemolyticus, residing in shrimp, are the culprit of AHPND. The two secreted proteins from the V. parahaemolyticus culture were subsequently identified and found to be similar with known binary insecticidal toxins, Photorhabdus insect related proteins A and B (PirA and PirB). In this study, recombinant PirA and PirB (rPirA and rPirB) were produced in Escherichia coli and the intra- and inter-molecular interaction between rPirA and rPirB was analyzed. The relative toxicity of rPirA and rPirB was also assessed in shrimp. Results demonstrated bioactive and potent recombinant PirA and PirB were produced. Use of recombinant proteins rPirA and rPirB will enable toxin testing independent of the bacterium. These recombinant proteins may also aid the search for antitoxin strategies against AHPND.
Review Publications
Lafrentz, B.R., Lafrentz, S.A., Beck, B.H., Arias, C. 2020. Draft genome sequences of Cetobacterium somerae 2G large and two novel Cetobacterium isolates from intestines of channel catfish (Ictalurus punctatus). Microbiology Resource Announcements. 9:e01006-20. https://doi.org/10.1128/MRA.01006-20.
Lafrentz, B.R., Lozano, C.A., Shoemaker, C.A., Garcia, J.C., Ospina-Arango, J.F., Rye, M. 2020. Genetic (co)variation between harvest weight and resistance to both Streptococcus iniae and S. agalactiae capsular type Ib in Nile tilapia (Oreochromis niloticus). Aquaculture. 529:735726. https://doi.org/10.1016/j.aquaculture.2020.735726.
Shahin, K., Pirezan, F., Rogge, M., Lafrentz, B.R., Shrestha, R.P., Hildebrand, M., Lu, F., Hogenesch, H., Soto, E. 2020. Development of IglC and GroEL recombinant vaccines for francisellosis in Nile tilapia, Oreochromis niloticus. Fish and Shellfish Immunology. 105:341-349. https://doi.org/10.1016/j.fsi.2020.07.045.
Xu, D., Zhang, D., Shoemaker, C.A., Beck, B.H. 2020. Dose effects of a DNA vaccine encoding the immobilization antigen on the immune response of channel catfish against Ichthyophthirius multifiliis. Fish and Shellfish Immunology. 106: 1031-1041. https://doi.org/10.1016/j.fsi.2020.07.063.
Heckman, T.I., Griffin, M.J., Camus, A.C., Lafrentz, B.R., Morick, D., Smirnov, R., Ofek, T., Soto, E. 2020. Multilocus sequence analysis of diverse Streptococcus iniae isolates indicates an underlying genetic basis for phenotypic heterogeneity. Diseases of Aquatic Organisms. 141:53-69. https://doi.org/10.3354/dao03521.
Lange, M.D., Abernathy, J.W., Shoemaker, C.A., Zhang, D., Kirby, A., Peatman, E., Beck, B.H. 2020. Proteome analysis of virulent Aeromonas hydrophila reveals the upregulation of iron acquisition systems in the presence of a xenosiderophore. FEMS Microbiology Letters. 367(20):1-8. https://doi.org/10.1093/femsle/fnaa169.
Alamdari, N.E., Aksoy, B., Aksoy, M., Beck, B.H., Jiang, Z. 2021. A novel paper-based and pH-sensitive intelligent detector in meat and seafood packaging. Food Control. 224. https://doi.org/10.1016/j.talanta.2020.121913.
Demaar, T.W., Lafrentz, B.R., Garner, M.G. 2021. Three cases of acute bacterial sepsis in pygmy hippopotamus (Choeropsis Liberiensis) calves siblings. Journal of Zoo and Wildlife Medicine. 52(2): 755-762. https://doi.org/10.1638/2020-0097.
Zhang, D., Bader, T.J., Lange, M.D., Shoemaker, C.A., Beck, B.H. 2021. Toxicity of recombinant PirA and PirB derived from Vibrio parahaemolyticus in shrimp. Microbial Pathogenesis. 155:104886. https://doi.org/10.1016/j.micpath.2021.104886.
Barger, P., Liles, M., Newton, J., Beck, B.H. 2021. Differential production and secretion of potentially toxigenic extracellular proteins from hypervirulent Aeromonas hydrophila under biofilm and planktonic culture. BMC Microbiology. 21:8. https://doi.org/10.1186/s12866-020-02065-2.
He, Z., Mattison, C.P., Zhang, D., Grimm, C. 2021. Vicilin and legumin storage proteins are abundant in water and alkali soluble protein fractions of glandless cottonseed. Scientific Reports. 11. Article 9209. https://doi.org/10.1038/s41598-021-88527-7.
Malecki, J.K., Roy, L., Arias, C.R., Lange, M.D., Beck, B.H., Truong, N., Hanson, T.R. 2021. Bioeconomics of Flavobacterium columnare vaccine pond trials with channel catfish Ictalurus punctatus. North American Journal of Aquaculture. 83: 207-217. https://doi.org/10.1002/naaq.10191.
Lewis, M.R., Silliman, K.E., Beck, B.H., Sammons, S.M., Peatman, E.J. 2021. Failure of phenotypic markers to accurately identify black bass species and associated hybrids in Mobile River Basin, Alabama. North American Journal of Fisheries Management. 41(5):1591-1601. https://doi.org/10.1002/nafm.10673.
