Location: Warmwater Aquaculture Research Unit
Project Number: 6402-31000-009-10
Start Date: Apr 01, 2011
End Date: Jun 01, 2012
We recently demonstrated that matrix encapsulated essential oils (Biomin® P.E.P. MGE) increased weight gain 40% in channel catfish grown for 12 weeks in a tank environment. In addition, fillet fat was decreased and fillet protein was increased in catfish fed essential oils. These results suggest that the addition of Biomin® P.E.P. MGE to catfish diets may improve growth and positively affect fillet composition. The next step in testing this product is to examine its effects on growth performance and fillet composition in commercial ponds. Fifteen one-acre ponds at Delta-Western Research Center, Indianola, MS, will be filled with well water and treated with 20 mg/L KMnO4 as a prophylaxis for Proliferative Gill Disease prior to stocking fish. The ponds will be stocked with 6,000 channel catfish per acre averaging 250-500 pounds/1000 (stocker size). Eight one-acre ponds will serve as controls while seven one-acre ponds will serve as the test group (or vice versa). Fish will be supplied by Delta Western. If the stocked fish are from different source ponds, fish from each source pond will be alternately stocked in control and test ponds. Fish in control ponds will be fed a 32% crude protein commercial floating diet while fish in test ponds will be fed the same 32% crude protein commercial diet supplemented with Biomin® at 200 g/ton. Both diets will be made in 10-15 ton batches on the same day so changes in diet composition during the year resulting from least-cost formulations are similar for both treatments. On day 0, fish will be randomly stocked into 15 ponds. The mean weight of each pond will be based on a sample of 500-600 fish. The fish will be fed once per day to apparent satiation and the amount of feed consumed by fish in each pond will be recorded daily. Temperature and dissolved oxygen (DO) concentration will be measured at two-hour intervals throughout the night. Aeration (provided by one five-hp paddlewheel aerator per pond) will be initiated when the DO drops to 4 mg/L. Aerators will be turned off in the morning when the DO is 4 mg/L and rising. Aerator run times will be recorded for each pond daily. Salt (NaCl) will be added to maintain a chloride concentration of 100 mg/L as a prophylaxis against methemoglobinemia (brown blood). Sick fish will be taken to the National Warmwater Aquaculture Center (NWAC) diagnostic laboratory and only approved treatments will be applied. Where not stated, normal aquaculture practices will be used. At the end of the six-month study, ponds will be harvested by seining and draining the water. The fish will be weighed as a group and then fish (200-300) will be sampled to obtain an average weight. Thirty fish from each pond will be processed to determine headed-gutted yield, fillet yield, and amount of visceral fat. Ten random fillets will be analyzed for body composition (fat, ash, protein, water). At the end of the study, data (weight gain, feed efficiency, survival, fillet composition, and fillet yield) will be subjected to statistical analysis. Differences between treatments will be considered significant at P < 0.05.