Brian G. Bosworth

Comparison of Production, Meat Yield, and Meat Quality Traits of NWAC103 Line Channel Catfish, Norris Line Channel Catfish, and Female Channel Catfish × Male Blue Catfish F1 Hybrids

Abstract NWAC103 line channel catfish Ictalurus punctatus, Norris line channel catfish, and Norris line female channel catfish × Dycus Farm line male blue catfish I. furcatus F1 hybrids were compared for production, meat yield, and meat quality traits. Juvenile fish from each genetic group were stocked at 12,000 fish/ha into three, 0.04-ha ponds per genetic group. Fish were fed once daily to satiation from June through October, and fed on days when afternoon water temperatures were above 17°C from November through December. Fish were harvested, weighed, and counted in January, and 150 fish per genetic group (50 fish per pond) were processed and measured for meat and body component yield. Instrumental and sensory panel evaluations of quality were measured on fresh, frozen-thawed, and baked fillets. Stocking weight, harvest weight, and net production (kg/ha) were highest for the NWAC103 line channel catfish, intermediate for the hybrid, and lowest for the Norris line channel catfish. Growth at unit size (a)...

Comparison of the Channel Catfish, Ictalurus punctatus (NWAC103 Strain) and the Channel × Blue Catfish, I. punctatus × I.furcatus, F1 Hybrid for Growth, Feed Efficiency, Processing Yield, and Body Composition

Abstract A pond trial was conducted to compare growth, feed efficiency, survival, processing yield, and body composition of the NWAC103 strain of channel catfish, Ictalurus punctatus and the F1 channel X blue catfish hybrid (CB hybrid), I. punctatus X I. furcatus. Each genotype was stocked into five 0.4-ha earthen ponds at a rate of 14,820 fish/ha. Initial weights were 24.9 and 31.8 g/fish for the NWAC103 strain of channel catfish and the CB hybrid, respectively. Fish were fed a commercial, 28% protein diet once daily to satiation for 160 days. Compared to NWAC103 channel catfish, the CB hybrid consumed more diet, gained more weight, converted diet more efficiently, and had higher net production, survival, carcass yield, nugget yield, visceral fat, fillet moisture and protein, and a lower level of fillet fat. There were no differences in fillet yield and fillet ash concentration between the channel X blue catfish hybrid and the channel catfish. These results suggest that the CB hybrid possesses superior production traits compared with the NWAC103 channel catfish. However, problems of producing a large number of hybrid fingerlings in a cost-effective manner remain to be resolved before the hybrid catfish can be commercially farmed.

Effects of bovine growth hormone (Posilac®) on growth performance, body composition, and IGFBPS in two strains of channel catfish

The effects of recombinant bovine growth hormone (rbGH; Posilac®) on growth rate, feed efficiency, body composition, and insulin-like growth factor binding proteins (IGFBPs) were investigated in Norris and NWAC103 strains of channel catfish. Three hundred and twenty fish from each strain were assigned randomly to four treatments with four replicates each. The treatments were (1) Sham-injected control (needle puncture per 3 weeks); (2) Low (30 μg g−1 BW per 3 weeks, Posilac®); (3) Medium (60 μg g−1 BW per 3 weeks, Posilac®); and (4) High (120 μg g−1 BW per 3 weeks, Posilac®). Fish were reared in 76-l tanks supplied with 26.0 °C flow-through well water for 9 weeks. Fish were fed a 36% CP commercial diet twice each day to apparent satiation. Feed consumption increased (P<0.05) 15% with rbGH treatment in the Norris strain while no significant increase in feed consumption was observed in rbGH-treated NWAC103 catfish. Compared to sham controls, all treatments (Low, Medium, and High) increased final weights (P<0.05) (168±13.2 vs. 144±10.0 g) (average weight of the three treatments), but no overall improvement in feed conversion ratio (FCR) was observed in NWAC103 fish. In the Norris strain, the High treatment increased (P<0.05) final weight (135±6.2 vs. 106±8.7 g) but no improvement in FCR was observed when compared to sham controls. rbGH treatments increased (P<0.05) total length in both strains, but no difference in condition factor (CF), hepatosomatic index (HSI), or body composition was observed. On day 63, levels of a 45-kDa IGFBP (catfish-IGFBP-3) were similar between treated and untreated fish in both strains. Results of this study indicate the Low treatment was as effective in promoting growth as the High treatment in the NWAC103 strain. Results of the body composition analysis suggest that the increase in weight gain was not due to an increase in fat deposition. The observed increase in length suggests rbGH enhances linear growth in channel catfish. Similar levels of cf-IGFBP-3 between treated and untreated fish may reflect “steady state” levels of cf-IGFBP-3 in growing fish. Identifying other endogenous growth factor(s) responsible for the observed increase in growth rate will be crucial in our understanding of improving growth in cultured channel catfish.

Aquaculture genomics, genetics and breeding in the United States: current status, challenges, and priorities for future research

Advancing the production efficiency and profitability of aquaculture is dependent upon the ability to utilize a diverse array of genetic resources. The ultimate goals of aquaculture genomics, genetics and breeding research are to enhance aquaculture production efficiency, sustainability, product quality, and profitability in support of the commercial sector and for the benefit of consumers. In order to achieve these goals, it is important to understand the genomic structure and organization of aquaculture species, and their genomic and phenomic variations, as well as the genetic basis of traits and their interrelationships. In addition, it is also important to understand the mechanisms of regulation and evolutionary conservation at the levels of genome, transcriptome, proteome, epigenome, and systems biology. With genomic information and information between the genomes and phenomes, technologies for marker/causal mutation-assisted selection, genome selection, and genome editing can be developed for applications in aquaculture. A set of genomic tools and resources must be made available including reference genome sequences and their annotations (including coding and non-coding regulatory elements), genome-wide polymorphic markers, efficient genotyping platforms, high-density and high-resolution linkage maps, and transcriptome resources including non-coding transcripts. Genomic and genetic control of important performance and production traits, such as disease resistance, feed conversion efficiency, growth rate, processing yield, behaviour, reproductive characteristics, and tolerance to environmental stressors like low dissolved oxygen, high or low water temperature and salinity, must be understood. QTL need to be identified, validated across strains, lines and populations, and their mechanisms of control understood. Causal gene(s) need to be identified. Genetic and epigenetic regulation of important aquaculture traits need to be determined, and technologies for marker-assisted selection, causal gene/mutation-assisted selection, genome selection, and genome editing using CRISPR and other technologies must be developed, demonstrated with applicability, and application to aquaculture industries. Major progress has been made in aquaculture genomics for dozens of fish and shellfish species including the development of genetic linkage maps, physical maps, microarrays, single nucleotide polymorphism (SNP) arrays, transcriptome databases and various stages of genome reference sequences. This paper provides a general review of the current status, challenges and future research needs of aquaculture genomics, genetics, and breeding, with a focus on major aquaculture species in the United States: catfish, rainbow trout, Atlantic salmon, tilapia, striped bass, oysters, and shrimp. While the overall research priorities and the practical goals are similar across various aquaculture species, the current status in each species should dictate the next priority areas within the species. This paper is an output of the USDA Workshop for Aquaculture Genomics, Genetics, and Breeding held in late March 2016 in Auburn, Alabama, with participants from all parts of the United States.Advancing the production efficiency and profitability of aquaculture is dependent upon the ability to utilize a diverse array of genetic resources. The ultimate goals of aquaculture genomics, genetics and breeding research are to enhance aquaculture production efficiency, sustainability, product quality, and profitability in support of the commercial sector and for the benefit of consumers. In order to achieve these goals, it is important to understand the genomic structure and organization of aquaculture species, and their genomic and phenomic variations, as well as the genetic basis of traits and their interrelationships. In addition, it is also important to understand the mechanisms of regulation and evolutionary conservation at the levels of genome, transcriptome, proteome, epigenome, and systems biology. With genomic information and information between the genomes and phenomes, technologies for marker/causal mutation-assisted selection, genome selection, and genome editing can be developed for applications in aquaculture. A set of genomic tools and resources must be made available including reference genome sequences and their annotations (including coding and non-coding regulatory elements), genome-wide polymorphic markers, efficient genotyping platforms, high-density and high-resolution linkage maps, and transcriptome resources including non-coding transcripts. Genomic and genetic control of important performance and production traits, such as disease resistance, feed conversion efficiency, growth rate, processing yield, behaviour, reproductive characteristics, and tolerance to environmental stressors like low dissolved oxygen, high or low water temperature and salinity, must be understood. QTL need to be identified, validated across strains, lines and populations, and their mechanisms of control understood. Causal gene(s) need to be identified. Genetic and epigenetic regulation of important aquaculture traits need to be determined, and technologies for marker-assisted selection, causal gene/mutation-assisted selection, genome selection, and genome editing using CRISPR and other technologies must be developed, demonstrated with applicability, and application to aquaculture industries.Major progress has been made in aquaculture genomics for dozens of fish and shellfish species including the development of genetic linkage maps, physical maps, microarrays, single nucleotide polymorphism (SNP) arrays, transcriptome databases and various stages of genome reference sequences. This paper provides a general review of the current status, challenges and future research needs of aquaculture genomics, genetics, and breeding, with a focus on major aquaculture species in the United States: catfish, rainbow trout, Atlantic salmon, tilapia, striped bass, oysters, and shrimp. While the overall research priorities and the practical goals are similar across various aquaculture species, the current status in each species should dictate the next priority areas within the species. This paper is an output of the USDA Workshop for Aquaculture Genomics, Genetics, and Breeding held in late March 2016 in Auburn, Alabama, with participants from all parts of the United States.

Effects of Dietary Protein Concentration on Production Characteristics of Pond-Raised Channel Catfish Fed Once Daily or Once Every other Day to Satiation

Abstract We evaluated the effects of dietary protein and feeding regime on the production characteristics, processing yield, and body composition of channel catfish Ictalurus punctatus. Stocker-size fish with an average weight of 93 g/fish were stocked into twenty-four 0.4-ha ponds at a rate of 11,115 fish/ha. Fish were fed once daily or every other day (EOD) to apparent satiation with three commercial diets containing 28, 32, or 35% protein in a 2 × 3 factorial arrangement for 110 d. Compared with daily feeding, EOD feeding resulted in lower average net production, feed consumption, weight gain per fish, and feed conversion ratio and produced fewer marketable fish. The EOD ponds required less aeration than ponds with fish fed daily. Fish fed EOD had lower visceral fat and fillet fat, carcass yield, and fillet yield compared with fish fed daily. Dietary protein levels had no effect on net production, aeration time, processing yield, fillet composition, and feed consumption and weight gain per fish. Howeve...

SNP discovery in wild and domesticated populations of blue catfish, Ictalurus furcatus, using genotyping-by-sequencing and subsequent SNP validation

Blue catfish, Ictalurus furcatus, are valued in the United States as a trophy fishery for their capacity to reach large sizes, sometimes exceeding 45 kg. Additionally, blue catfish × channel catfish (I. punctatus) hybrid food fish production has recently increased the demand for blue catfish broodstock. However, there has been little study of the genetic impacts and interaction of farmed, introduced and stocked populations of blue catfish. We utilized genotyping‐by‐sequencing (GBS) to capture and genotype SNP markers on 190 individuals from five wild and domesticated populations (Mississippi River, Missouri, D&B, Rio Grande and Texas). Stringent filtering of SNP‐calling parameters resulted in 4275 SNP loci represented across all five populations. Population genetics and structure analyses revealed potential shared ancestry and admixture between populations. We utilized the Sequenom MassARRAY to validate two multiplex panels of SNPs selected from the GBS data. Selection criteria included SNPs shared between populations, SNPs specific to populations, number of reads per individual and number of individuals genotyped by GBS. Putative SNPs were validated in the discovery population and in two additional populations not used in the GBS analysis. A total of 64 SNPs were genotyped successfully in 191 individuals from nine populations. Our results should guide the development of highly informative, flexible genotyping multiplexes for blue catfish from the larger GBS SNP set as well as provide an example of a rapid, low‐cost approach to generate and genotype informative marker loci in aquatic species with minimal previous genetic information.

Effects of dietary protein concentration and L-carnitine on growth, processing yield, and body composition of channel catfish × blue catfish F1 hybrids

Abstract A study was conducted in earthen ponds to evaluate effects of dietary protein concentration and l-carnitine supplementation on feed consumption, weight gain, feed conversion ratio (FCR), processing yield, and body composition of hybrid catfish (female channel catfish Ictalurus punctatus × male blue catfish I. furcatus). Hybrid catfish fingerlings with a mean initial weight of 66 g/fish were stocked into twenty 0.04-ha earthen ponds at a density of 17,290 fish/ha. Five ponds were randomly allotted to each dietary treatment in a complete randomized design. Fish were fed one of three practical diets containing 28, 32, or 36% crude protein without l-carnitine and a 28% protein diet containing l-carnitine at 500 mg/kg once daily to apparent satiation for a 151-d growing season. Dietary protein levels ranging from 28% to 36% did not affect feed consumption, weight gain, or FCR of catfish hybrids fed to apparent satiation. Fish fed the 36% protein diet had a higher fillet yield than fish fed the 28% pro...

Endocrine Responses of Fast- and Slow-Growing Families of Channel Catfish

Abstract Sixty-eight families of USDA303 channel catfish Ictalurus punctatus were evaluated for growth performance for 30 d. The fastest- and slowest-growing catfish families were further evaluated to examine the hypothesis that genes or gene products associated with the growth regulatory and stress axes can be used to describe differences in growth performance. Research examined mRNA levels of genes involved in the growth hormone–insulin-like growth factor (GH–IGF) network in fast- (family A) and slow-growing (family H) USDA303 catfish. Fish (59.0 ± 2.4 g) were fed for 7 weeks, weighed, and had tissues for RNA extraction. The remaining fish were subjected to an acute 10-min dewatering stress. Insulin-like growth factor-II mRNA was higher in the muscle of fast-growing fish, while the levels of IGF-I receptor (IGF-IR) and IGF-II receptor (IGF-II) were similar. Muscle IGF-IIR mRNA was two-fold higher than muscle IGF-IR mRNA. There were no differences in liver and muscle IGF-I and GH receptor mRNA or pituita...

A translog demand model for inherited traits in aquacultured catfish

Abstract Manipulation of physical traits of catfish body form has the potential to change the relative quantities of different final product forms. Some of these forms will have higher value to consumers, resulting in higher profits for producers. Advances in genetic research will allow more effective manipulation of physical traits of aquacultured catfish in orderto increase relative quantities of desirable product forms. To identify which product forms hold the most potential value to consumers, we use the indirect Translog demand system to estimate welfare effects from substitution among various forms of fresh catfish.

New Data on Henneguya pellis (Myxozoa: Myxobolidae), a Parasite of Blue Catfish Ictalurus furcatus

Abstract The original description of Henneguya pellis, a myxozoan parasitizing blue catfish Ictalurus furcatus, is supplemented with new data on histopathology, spore morphology, and 18S small subunit (SSU) ribosomal DNA (rDNA) sequence. Plasmodia presented as both internal and external, raised, cyst-like lesions on the body wall of the peritoneal cavity and on the skin. The cysts contained numerous elongate, lanceolate myxospores, flattened parallel to the suture line. The spore body was 14.8 ± 1.1 µm (range 13.0–17.1) long and 4.8 ± 0.8 µm (range 4.0–7.4) wide in frontal view. The caudal appendages were 77.7 ± 8.8 (range 57.4–96.4) in length. There were 2 pyriform polar capsules, unequal in length, with the longer capsule measuring 7.2 ± 0.6 µm (range 6.2–8.4) in length and the shorter capsule measuring 6.5 ± 0.5 µm (range 5.5–8.0). The polar capsules were not significantly different in width, measuring 1.7 ± 0.2 µm (range 1.4–1.9). There were 8 turns in the polar filament coil. The total length of the spore was 92.5 ± 9.2 µm (range 73.3–113.5). Spore morphology and site of development are similar to that of Henneguya sutherlandi from channel catfish; however, 18S rDNA sequence data support previous findings that identify H. pellis and H. sutherlandi as 2 distinct species.