EFFECTS OF FEEDING ZILPATEROL HYDROCHLORIDE ON GROWTH PERFORMANCE, FILLET YIELD, AND BODY COMPOSITION OF RAINBOW TROUT, NILE TILAPIA, AND CHANNEL CATFISH

Brian C. Peterson1, Brian C. Small2, Wendy M. Sealey3, Brian G. Bosworth4, Menghe H. Li4, and Richard G. Endris6
 
1National Cold Water Marine Aquaculture Center, USDA-ARS, Franklin, ME 04634
 
2Hagerman Fish Culture Experiment Station, Department of Fish and Wildlife Sciences, University of Idaho, Moscow, ID 83844
 
3U.S. Fish & Wildlife Service, Bozeman Fish Technology Center, Bozeman, MT 59715
 
4Warmwater Aquaculture Research Unit, USDA-ARS, Stoneville, MS 38776
 
5Thad Cochran National Warmwater Aquaculture Center, Mississippi State University, Stoneville, MS 38776
 
6Endris Consulting, Inc., Bridgewater, NJ 08807

Zilpaterol hydrochloride (ZH) is a potent β-adrenergic agonist (BAA) that has been used in feedlot cattle to increase average daily gain, feed efficiency, yield of trimmed cuts, and dress out percent.  While positive effects of ZH have been observed in cattle, there have been no reports of this product being tested in fish.  Three separate studies were conducted in rainbow trout (528.0 g), Nile tilapia (423.0 g), and channel catfish (245.2 g) to evaluate the effects ZH on growth performance, survival, dress out percent, and fillet composition.  The three species of fish were fed ZH at 0, 1, 5, and 10 ppm for approximately 30 days.  Results showed that weight gain was significantly reduced in catfish fed ZH at 1 ppm while weight gain was not significantly affected by ZH treatment in rainbow trout and tilapia.  Feed conversion ratio, food intake, and survival were similar among treatments in all species of fish.  Dress out percent was similar among all treatments for both rainbow trout and channel catfish while dress out percent was lower in tilapia fed the 5 ppm diet.  Fillet proximate composition and visceral fat percent were not significantly affected by ZH treatment in any of the three species of fish.  There was no qualitative behavior differences observed among treatments for any of the species tested.  The observed lack of differences in growth performance and condition traits suggests there is no benefit to feeding rainbow trout, Nile tilapia, or channel catfish ZH.  Dose of ZH, number of days on feed, and age of fish may play important roles in how fish respond to BAAs.  Further research is needed to fully evaluate their efficacy for use in aquaculture.