Location: Warmwater Aquaculture Research Unit
2021 Annual Report
Objectives
Objective 1. Enhance selection of channel and blue catfish broodstock for economically important traits.
Sub-objective 1.1. Continue selection for increased growth rate and carcass yield in channel catfish, blue catfish and channel catfish x blue catfish hybrids, and establish a selected line of blue catfish to produce improved broodstock.
Sub-objective 1.2. Determine magnitude of genetic variation and evaluate potential for including additional traits in channel and blue catfish selection indices.
Sub-objective 1.3. Characterize structural variation in the channel and blue catfish genomes and examine the potential for this information to improve the accuracy of estimated breeding values.
Objective 2. Improve the efficiency of reproduction for purebred and hybrid catfish.
Sub-objective 2.1. Identify and test reproductive pheromones in channel and blue catfish.
Sub-objective 2.2. Evaluate the formulation of mammalian Luteinizing Hormone Releasing Hormone analog to improve ovulation and hatching success to improve the efficiency of hybrid catfish embryo production.
Sub-objective 2.3. Determine impact of broodfish nutritional strategies on maturation and reproductive performance of channel catfish to maximize hatching success and hybrid catfish fry production.
Objective 3. Increase efficiency of warmwater aquaculture by developing and improving production systems and management practices.
Sub-objective 3.1. Model split-pond ecosystem dynamics to optimize design and performance.
Objective 4. Improve catfish product quality by identifying and managing pre-harvest factors that affect the quality of catfish products.
Sub-objective 4.1. Isolate and identify geosmin-producing species of cyanobacteria from catfish aquaculture ponds and determine the seasonal occurrences of blooms of these noxious cyanobacteria species.
Sub-objective 4.2. Determine the efficacy of using sodium carbonate peroxyhydrate (SCP) in managing undesirable blooms of cyanobacteria in west Mississippi catfish ponds.
Sub-objective 4.3. Determine the effects of pond culture systems on fillet flavor and texture of hybrid catfish.
Approach
In order to enhance selection of channel and blue catfish broodstock for economically important traits we will continue selection for increased growth rate and carcass yield in channel catfish, blue catfish, and channel x blue catfish hybrids, and establish a selected line of blue catfish to produce improved broodstock; determine the magnitude of genetic variation and evaluate potential for including additional traits in channel and blue catfish selection indices; and characterize structural variation in the channel and blue catfish genomes and examine its potential to improve the accuracy of estimated breeding values. In order to improve catfish reproductive efficiency, we will identify reproductive pheromones of channel and blue catfish; evaluate the formulation of mammalian Luteinizing Hormone Releasing Hormone analog to improve ovulation and hatching success to improve the efficiency of hybrid catfish embryo production; and determine the impact of broodfish nutritional strategies on maturation and reproductive performance of channel catfish to maximize hatching success and hybrid catfish fry production. In order to increase the efficiency of warmwater aquaculture by developing and improving production systems and management practices, we will model split-pond ecosystem dynamics to optimize system design and performance. In order to improve catfish product quality by identifying and managing pre-harvest factors that affect the quality of catfish products, we will isolate and identify geosmin-producing species of cyanobacteria from catfish aquaculture ponds and determine the seasonal occurrences and blooms of these noxious cyanobacteria species; determine the efficacy of using sodium carbonate peroxyhydrate (SCP) in managing undesirable blooms of cyanobacteria in west Mississippi catfish ponds; and determine the effects of pond culture system on fillet flavor and texture of hybrid catfish.
Progress Report
Due to pandemic restrictions and the maximized telework posture, we prioritized the genomic selection of channel and blue catfish. The 2019 year class Delta Select catfish were harvested and measured for growth rate and carcass yield, fillet color and body composition. The 2 year old broodstock were ranked using a selection index and spawned naturally in earthen ponds. High-throughput SNP genotypes were obtained from these fish – though not in time for the spawning season, the genotypes will be utilized to produce a genomic selection index as these fish are spawned in spring/summer 2022.
Snails are an intermediate host to parasitic worms that can degrade catfish health and filet quality. The Warmwater Aquaculture Research Unit began on-farm research to characterize snail ecology in catfish ponds and to develop strategies for the reduction or eradication of the snails. This research was complemented by the identification of selected natural compounds that can kill snails in laboratory culture, and future research will determine whether these compounds will effectively kill snails in ponds while safe for fish and beneficial organisms.
Accomplishments
1. Industry utilization of spawning aid. ARS researchers in Stoneville, Mississippi, developed a new spawning aid that has been well received by the catfish industry. More than half of U.S. catfish production is in the production of a hybrid between the channel catfish females and blue catfish males, and hybrid production depends on induced ovulation in females. In past years producers utilized a carp pituitary extract or a synthetic peptide based on a mammalian reproductive hormone. Scientists at the Warmwater Aquaculture Research Unit in Stoneville, Mississippi, developed a synthetic peptide based on the chicken and catfish gonadotropin hormone releasing hormone (GnRH II), and helped producers test it on farms during the 2020 spawning season. The success of the new GnRH II on farms led to its use in 2021 by all 8 producers that supply the U.S. catfish industry with hybrid catfish fingerlings, and 6 of the 8 producers used GnRH II exclusively for hybrid production.
Review Publications
Gao, G., Magadan, S., Waldbieser, G.C., Youngblood, R., Wheeler, P., Scheffler, B.E., Thorgaard, G., Palti, Y. 2021. A long reads-based De novo assembly of the genome of the Arlee homozygous line reveals structural genome variance in rainbow trout. Genes, Genomes, and Genomics. https://doi.org/10.1093/g3journal/jkab052.
Li, M., Wise, D., Kumar, G., Bosworth, B.G., Mischke, C., Aarattuthodiyil, S., Rutland, B., Lucas, P. 2020. Effects of long-term restricted feeding followed by full feeding on growth, processing yield, fillet proximate composition, and economics of market-size hybrid catfish, ¿ Ictalurus punctatus × ¿ Ictalurus furcatus. Journal of the World Aquaculture Society. 51(4):931-943. https://doi.org/10.1111/jwas.12727.
Perrin, M.T., Pawlak, R., Allen, L.H., Hampel, D. 2019. Total water-soluble choline concentration does not differ in milk from vegan, vegetarian, and non-vegetarian lactating women. Journal of Nutrition. 150(3):512-517. https://doi.org/10.1093/jn/nxz257.
Green, B.W., Rawles, S.D., Schrader, K., Mcentire, M.E., Abernathy, J.W., Ray, C.L., Gaylord, T.G., Lange, M.D., Webster, C.D. 2021. Impact of dietary phytase on tilapia performance and biofloc water quality. Aquaculture. 541:1-11. https://doi.org/10.1016/j.aquaculture.2021.736845.
Lopez-Porras, A., Griffin, M.J., Armwood, A.R., Camus, A.C., Waldbieser, G.C., Ware, C., Richardson, B., Greenway, T.E., Rosser, G., Aarattuthodiyil, S., Wise, D.J. 2021. Genetic variability Of Edwardsiella piscicida isolates from Mississippi catfish aquaculture with an assessment of virulence in channel and channel × blue hybrid catfish. Journal of Fish Diseases. 44(11):1725-1751. https://doi.org/10.1111/jfd.13491.
