GENERATIONAL INHERITANCE, GROWTH AND DISEASE RESISTANCE OF MYOSTATIN GENE-EDITED CHANNEL CATFISH Ictalurus punctuatus AND CHANNEL CATFISH × BLUE CATFISH Ictalurus furcatus HYBRIDS

Myostatin (MSTN) is a member of the transforming growth factor β (TGF-β) superfamily and important in the regulation of skeletal muscle growth in all vertebrates. Individuals with mutations in their myostatin-coding region have displayed significantly enhanced muscle growth, as seen in Belgian Blue and Piedmontese cattle. For this reason, myostatin is a potentially and economically important gene in food production. This study measured the effects of gene knockout of the myostatin gene, using CRISPR/Cas9, on growth and disease resistance in P1 channel catfish, Ictalurus punctatus, P1 channel catfish x blue catfish Ictalurus furcatus hybrids and F1 channel catfish.

Four year classes of P1 mutated channel catfish and channel catfish x blue catfish hybrids were produced along with the first F1 generation of mutant channel catfish. Mean body weight was 30%, 10%, and 38% larger in P1 mutants in fry, fingerling and food fish stages respectively when compared to controls (p<0.05). Mean body weight was 63% larger in F1 mutants when compared to controls at 130 days post hatch (p<0.05). Mutants showed significantly increased muscle development. The mutation had a high rate of inheritance in F1 channel catfish.