Improved Palatability of Channel Catfish Feeds Containing Romet-30®

Studies were conducted in the laboratory and in ponds to further evaluate the palatability of Romet-30® (5:1, sulfadimethoxine : Ormetoprim) to channel catfish Ictalurus punctatus and to devise methods to improve the palatability of feeds containing this drug. Healthy channel catfish were used in all experiments. Studies conducted in the laboratory indicated that the palatability of diets containing ormetoprim at a rate equivalent to 0.82% Romet-30 to age-0 (10–12g) fish was poor. Additionally, palatability decreased as the level of Romet-30 increased in the feed. In the remaining studies, 1.65% Romet-30 (one-half of the amount originally used in commercial catfish feeds) was used in all experimental feeds. Adjusting the pH of the feed to 7.0 did not improve palatability, nor did the addition of sucrose to the feed. Increasing the level of menhaden fish meal in medicated feeds to 16% appeared to improve palatability. Data from a preference trial conducted in ponds with demand feeders indicated that the palatability of medicated feeds was improved when they contained 8% blood meal or 16% fish meal. Feeding trials conducted in ponds, in which age-1 (0.5–0.7-kg) fish were fed by hand to satiation daily, demonstrated that medicated feeds containing 16% fish meal were consumed as well as nonmedicated control feeds containing 4% fish meal. It is recommended that Romet-30 be used at a rate of 1.65% in catfish feeds and that the feeds contain at least 16% fish meal.