|Goudie, Cheryl - UNIVERSITY OF MEMPHIS|
|Simco, Bill - UNIVERSITY OF MEMPHIS|
Submitted to: Catfish Farmers of America Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: December 20, 2005
Publication Date: February 24, 2006
Citation: Davis Jr, K.B., Goudie, C.A., Simco, B.A. 2006. Growth and body composition of channel catfish with unique sex genotypes. Catfish Farmers of America Book of Abstracts. p. 9. Technical Abstract: Sexual dimorphic growth in channel catfish results in male fish which are about 15% heavier than females when the fish are marketed at about 700 grams. Channel catfish have a XX:XY sex genotypic model system of sex determination and until the present study the influence of sex genotype could not be distinguished from sex phenotype. Unlike many other species, channel catfish cannot be hormonally masculinized. Treatment during the phenocritical period with androgens or estrogens results in an all female population with a 1:1 XX:XY sex genotypic sex ratio. By selective backcrosses, male fish with a YY sex genotype can be produced and these fish produce only male fish with a XY sex genotype when mated with a normal XX female. Several families of all male fish were produced by mating normal females with YY male fish. Some of each family were hormonally feminized and the growth rate and body composition of sibling genotypic XY, phenotypic males and females were compared. The general pattern for body size and composition was higher for males for body weight, standard length and condition factor, and higher for females for liposomatic index and dress-out percentage. Statistical differences between the phenotypic sexes were not as consistent as observed in previous studies with normal males and females. However, when the magnitude of the sex differences are considered an advantage of about 10% in favor of males remains. Since catfish culture is now typically equal numbers of male and females grown together there would be about a 5% gain realized from monosex male culture.