FEEDING THE REPARTITIONING AGENT, RACTOPAMINE, TO CHANNEL CATFISH (ICTALURUS-PUNCTATUS) INCREASES WEIGHT-GAIN AND REDUCES FAT DEPOSITION

Channel catfish (average initial weight, 156 g) were fed to satiety with a high performance diet (36% crude protein, 3.2 kcal digestible energy/g) containing 0, 20, or 100 ppm of ractopamine in flowing-water raceways for 4 weeks. The fish fed 20 ppm of ractopamine pined 17% more weight (P < 0.05) and had 24% less muscle fat (P < 0.05) and 18% less mesenteric fat (P < 0.05) than those fed the control diet (0 ppm ractopamine). There was no difference in weight pin or body fat between fish fed 20 and 100 ppm of ractopamine/kg of diet. Moisture content of muscle increased as fat decreased. Protein percentage of wet muscle was not different among treatments; however, on a moisture-free basis there was a higher (P < 0.05) percentage of protein in muscle of the ractopamine-fed fish. These results indicate that channel catfish fed a high-performance diet to appetite at optimum. growth temperature show increased weight gain and reduced fat deposition with dietary supplement tation of ractopamine.