16 June 2010 The use of hematological techniques in fish culture is growing in importance for toxicological research, environmental monitoring and fish health conditions (Mulcany 1975). Sampath et al. (1993) reported the possibility that the blood will reveal conditions within the body of a fish long before there is any outward manifestation of disease. In the present study, supplementation of DCM in the diets had no effect on the blood profile. This suggests that the health status of the fish was not affected by DCM supplementation. Fish feeds constitute over 60 percent of the operating cost of aquaculture (Nwanna 2002). The estimated economics of production indicated that supplementation of DCM in the diets reduced the cost of the diets. Increase in growth performance, resulting from DCM supplementation in the diets, led to reduction in the incidence of cost (IC) and increased profit index. However, profits can be maximized by replacing corn with 25 percent of DCM. In conclusion, both growth and economic data suggest that DCM can replace up to 75 percent of corn in the diets of African catfish. However, for maximization of growth and profit, we recommend replacement of yellow corn with 25 percent DCM for the production of African catfish. Judging from the current price of corn in Nigeria, by replacement of yellow corn with 25 percent DCM, about US$250 would be spared for every ton of corn used in diet preparation. Notes 1Dept. of Fisheries & Wildlife, Fed. Univ. of Technology, PMB 704 Akure-Nigeria References Adegbola, A.A and T.A. Omole. 1973. A simple technique for preparing discarded cocoa-bean meal for use in livestock feed. Nigeria. Agriculltural Journal 10:72-81. AOAC (Association of Official Analytical Chemists). 1990. Official Methods of Analysis. 15th ed. AOAC Inc. Arlington, Virginia, USA. Castell, J.D and K. Tiews, editors. 1980. Report of the EIFAC, IUNS and ICES Working Group on Standardization of Methodology in Fish Nutrition Research EIPAC/T36, EIFAC/FAO, P:24. Duncan, D.B. 1955. Multiple F-test. Biometrics 11:1-42. Fagbenro, O.A, M.A.K Smith and A.I. Amoo. 2000. Acha (Digitaria exilis Stapf) meal compared with corn and sorghum meals as a dietary carbohydrate source for Nile tilapia (Oreochromis niloticus L.) Israeli Journal of Aquaculture 52:3-10. Hanley, F. 1991. Effects of feeding supplementary diets containing varying levels of lipid on growth, food conversion and body composition of Nile tilapia, Oreochromis niloticus (L). Aquaculture 93:323-334. Mulcany, M.F. 1975. Fish blood changes associated with disease: A hematological study of pike lymphoma and salmon ulcerative dermal necrosis. Pages 925-944 In W.E Ribelin and C.M. Migaki, editors. The Pathology of Fishes. University of Wisconsin, Madison, Wisconsin USA. Nwanna L.C. 2002. Performance of hybrid clariid catfish fingerlings (male Heterobranchus Bidorsalis x female Clarias gariepinus) fed poultry layer waste diets in glass tanks. Journal of Applied Aquaculture 12:99-106. Nwanna, L.C, O.A. Fagbenro and O.L. Kehinde. 2003. Effect of substitution of acha for corn on the growth and economic performance of Oreochromics niloticus. Journal of Food Agriculture and Environment 1(3 and 4):100-103. Nwanna, L.O. Fagbenro and S. Olanipekun. 2004. Evaluation of tamarind (Tamarindus indica) seed meal as a dietary carbohydrate for the production of Nile tilapia Oreochromis niloticus (L). Animal Research International 1:164-168 Nwanna, L.C and F.J. Schwarz. 2007. Effect of supplemental phytase on growth, phosphorus digestibility and bone mineralization of common carp (Cyprinus carpio L). Aquaculture Research 38:1037-1044 Nwanna, L.C, A. Adejuigbe, O.A. Fashae, B.V. Oludapo, F.S. Dansu and M.A.K. Smith. 2008. Potentials of some underutilized forest products as energy sources in fish diets. Pages 223-228 In J.C. Onyekwelu, V.A.J. Adekunle and D. O. Oke, editors. Research for development in forestry, forest products and natural resources management. Proceedings of the First National Conference of the Forest and Forest Products Society. Federal University of Technology Akure-Nigeria. 16-18 April 2008. Purseglove, J.W. 1985. Tropical Crops. Pages 300-313 In Monocotyledon, Second editon. Macmlliam Publishers, New York, New York USA Sampath, K.S, I. Velamnial, J. Kennedy and R. James. 1993. Haematological changes and their recovery in Oreochromis niloticus L as a function of exposure period and sub lethal levels of Ekalus Acta. Hydrobiologia 35:73-83. Svobodova, Z, B. Vykusova, H. Modra, J. Jarkovsky and M. Smutna. 2006. Haematological and biochemical profile of harvestsize carp during harvest and post-harvest storage. Aquaculture Research 37:959-965 Tacon, A. G. J. 1990. Standard Methods for the Nutrition and Feeding of Farmed Fish and Shrimp. Argent Laboratories Press, Washington, District of Columbia USA. Vincke, M. 1969. Compte-render d’ áctivite annee 1969. Division d Rcherches Piscicoles, Tananarive, Madagascar. Viola, S. and Y. Arieli. 1983. Nutritional studies with tilapia hybrids. 2. The effects oil supplements to practical diets for intensive aquaculture. Israeli Journal of Aquaculture 35:44-52. Many of the books reviewed in World Aquaculture are available at a discount to WAS members at www.was.org. Save money today by ordering through the Society.
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