Relationships between weight loss during short‐term feed deprivation, feed conversion efficiency, and growth in Delta Select and Delta Control line channel catfish families

Weight loss during feed deprivation is correlated with feed conversion efficiency (FCR) 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 FCR 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 Delta Controls than 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 similar among Delta Select groups but higher than the Delta Control's. Feed conversion and survival were similar for all groups. Fish from the feeding trial were used in a third feed deprivation trial. Family means for weight loss were positively correlated across three feed deprivation trials but not correlated with feed conversion indicating selection for weight‐loss would not improve feed conversion. The faster growth of Delta Select catfish is as a result of increased feed consumption.