Effects of sex, family, and size grading on feed conversion ratio, growth, visceral fat, and weight loss in Delta Select channel catfish

Authors: Bosworth, Brian; YAMAMOTO, FERNANDO - Mississippi State University; Chisolm, Dakoda; Patterson Jr, Michael; Ott, Brian

Submitted to: Journal of the World Aquaculture Society
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/24/2025
Publication Date: 3/4/2025
Citation: Bosworth, B.G., Yamamoto, F., Chisolm, D.O., Patterson Jr, M., Ott, B.D. 2025. Effects of sex, family, and size grading on feed conversion ratio, growth, visceral fat, and weight loss in Delta Select channel catfish. Journal of the World Aquaculture Society. 56(2)e70011. https://doi.org/10.1111/jwas.70011.
DOI: https://doi.org/10.1111/jwas.70011

Interpretive Summary: The mission of the Warmwater Aquaculture Research Unit (WARU), USDA-ARS is to develop genetically improved catfish lines for release to U.S. catfish producers. The Delta Select channel catfish line has been improved for growth rate and meat yield, and WARU researchers are evaluating feed conversion efficiency (FCE) as a trait for improvement through selection. FCE, the weight gained by a fish relative to weight of feed consumed, has a large impact on profitability of catfish farming and improving FCE would benefit catfish farmers. Unfortunately measuring feed consumption of individual fish is difficult and hinders selection for improved FCE. However, weight loss during feed deprivation and lipid accumulation during periods of feeding are correlated with feed conversion efficiency in several fish species and could be used as an indirect selection criteria to improve of FCE in catfish. Relationships among weight loss during feed deprivation, fat accumulation during periods of feeding, and FCE were measured in Delta Select catfish. In addition, the effects fish gender, family and size grading on FCE of juvenile Delta Select catfish were determined. There was not a strong relationship between weight loss and FCE in catfish, but visceral fat was highly correlated with FCE in female catfish. We report male catfish have better FCE and lower fat levels than female catfish, and that large fish from a family had better FCE than smaller fish from the same family. Results suggest gender has an impact on FCE which may be related to differences in fat metabolism between genders. This information provides insights into factors affecting FCE in channel catfish and may be useful in developing breeding programs or management strategies to improve FCE in catfish.

Technical Abstract: Feed conversion efficiency is an important determinant of profitability in catfish production and understanding factors affecting feed conversion efficiency at a physiological level could lead to improvement of FCR at production scale. Effect of sex, family and size grading within family on juvenile channel catfish (Ictalurus punctatus) growth, feed consumption, feed conversion, visceral fat accumulation, and weight loss during feed deprivation was determined. In Trial 1, fingerlings from 5 channel catfish families were graded by weight into small, large and random mixed-size groups, fed for 8 weeks, subjected to 2 weeks of feed deprivation, and then euthanized to determine sex. Family had a significant effect on fish growth, feed consumption, feed conversion efficiency, and percent weight loss during feed deprivation. Large fish had faster growth, better feed conversion efficiency, and lower percent weight gain than small fish from the same family. Mixed-sized fish were generally intermediate for all measured traits. In Trial 2, all-male, all-female and mixed-sex groups of channel catfish fingerlings were fed for 8 weeks, subjected to 2 weeks of feed deprivation, and then euthanized to confirm sex and weigh visceral fat. Males had a higher percent weight gain, better feed conversion, and less visceral fat than females; mixed-sex fish were generally intermediate between all-male and all-female groups. Feed conversion efficiency was positively correlated with visceral fat percentage in the all-female treatment (i.e. fatter fish had poor feed conversion), but not in the all-male treatment. Feed conversion and weight loss during feed deprivation were generally not correlated in either trial. This is the first report that male channel catfish convert feed more efficiently than females. Future studies should investigate the relationship between fat and feed conversion in channel catfish.