Location: Warmwater Aquaculture Research Unit
Title: Relationships between weight loss during short-term feed deprivation, feed conversion efficiency and growth in Delta Select and Delta Control line channel catfish familiesAuthor
Submitted to: Journal of the World Aquaculture Society
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 4/1/2024 Publication Date: 6/25/2024 Citation: Bosworth, B.G., Chisolm, D.O., Patterson Jr, M., Ott, B.D. 2024. Relationships between weight loss during short-term feed deprivation, feed conversion efficiency and growth in Delta Select and Delta Control line channel catfish families. Journal of the World Aquaculture Society. e13072. https://doi.org/10.1111/jwas.13072. DOI: https://doi.org/10.1111/jwas.13072 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 selected for increased growth rate and meat yield and has been released to the industry. Selection continues for improved growth and meat yield in the Delta Select line, but WARU researchers are evaluating other traits, including feed conversion efficiency as potential targets for selection. Feed conversion efficiency (FCE), the weight gained by a fish relative to weight of feed consumed, the has a large impact on profitability of catfish farming and improving FCE would be very beneficial to catfish farmers. Unfortunately measuring feed consumption of individual fish is difficult making selection for improved FCE problematic. However, weight loss during feed deprivation is correlated with feed conversion efficiency in several fish species and could be used as an indirect measurement to improve of FCE in catfish. Relationships among weight loss during feed deprivation and feed conversion efficiency was measured in families of Delta Select and Delta Control line channel catfish fingerlings to determine if weight loss could be used to predict FCE at the family level. Delta Control line catfish are a unselected population derived from the same base population as the Delta Select line and comparisons of the two lines can be used to measure effects of selection on performance. Percent of body weight loss was measured in families from both lines after three separate 2-week feed deprivation trials and then growth and feed conversion efficiency were measured in the same families in an 8-week feeding trial. Families had consistent differences in weight loss across feed deprivation trials suggesting existence of a long-term physiological differences in response to feed deprivation in catfish. However, there was no relationship between family values for weight loss and FCE. Therefore, selection for weight loss after feed deprivation would not result in improved FCE in channel catfish. The Delta selects grew 50% faster than the Delta Controls but it was because they ate more feed, not because they converted feed better. Technical Abstract: Weight loss during feed deprivation is correlated with feed conversion efficiency in several fish species, suggesting weight loss could be used to indirectly select for improved feed conversion. Trials were conducted to determine relationships among weight loss and feed conversion efficiency with Delta Select and Delta Control line channel catfish fingerlings. Weight loss was measured for 79 Delta Select line families and 20 Delta Control line families in replicate feed deprivation trials. Weight loss was higher for the Delta Controls than the Delta Selects. The 10 Delta Select families with the highest weight loss, 10 Delta Select families with the lowest weight loss, and 10 random Delta Control families were used in a feeding trial. Initial weight, final weight, percent weight gain, and percent feed consumption were not different between Delta Select groups but were higher than the Delta Control. Feed conversion and survival were similar for all groups. Catfish from the feeding trial were used in a third feed deprivation trial. Family means for weight loss were positively correlated across all three feed deprivation trials but were not correlated with feed conversion. The faster growth of Delta Select catfish is primarily due to increased feed consumption, not improved feed efficiency. |