ARI Volume 2 Number 1.pdf - Zoo-unn.org

Animal Research International (2005) 2(1): 246 – 251 246EFFECT of Dermestes maculatus INFESTATION ON SOME NUTRITIONALCOMPOSITION OF SMOKED AFRICAN CATFISH, Clarias gariepinusBURCHELL, 18221 UGWU, Lawrence Linus Chukwuma, 2 NWAMBA, Helen Ogochukwu and 2 KANNO, LindaUchenna1 Department of Animal Production and Fisheries Management, Ebonyi State University, Abakaliki, Nigeria2 Department of Applied Biology, Enugu State University of Science and Technology, Enugu, Enugu State,NigeriaCorresponding author: Dr. UGWU, L. L. C., Department of Animal Production and FisheriesManagement, Ebonyi State University, P.M.B.053, Abakaliki, Ebonyi State. NigeriaABSTRACTStudies on pest infestation of some nutritional composition of smoked-dried Clariasgariepinus were carried out, to assess the effect of exposing preserved fish products todifferent levels of infestation by Dermestes maculatus and the resultant effect on pH, crudeprotein (CP), free fatty acid (FFA) and tissue contents. Graded levels (5, 10 and 15) of larvaland adult D. maculatus were used to infest pieces of C. gariepinus placed in 7 groups of 3bottles per group. The experiment lasted 8 weeks (56days). There were consistent decreasesin the pH and CP as well as the tissue contents of fish with storage time, although the CPcontent o f the samples with the larval pests did not differ significantly from those withoutlarval pests (P > 0.05). Fish samples exposed to adult pests showed significant variation (P 0.05). The longer the storage periods of the infested smoked fish the morethe tissue was degraded.Keywords: Dermestes maculatus, Clarias gariepinus infestationINTRODUCTIONThe African catfish, genus Clarias has very highcommercial value in Nigeria owing to its flavourand taste. The good quality coupled with its abilityto feed on virtually anything makes the fish ahighly recommended species for aquaculturedevelopment in Nigeria (Reed et al., 1967; Bard etal., 1976; Olatunde, 1983).The phenomenon of fish preservation isenunciated by the simple principle of making fishunfavourable for the growth of spoilageorganisms. In Nigeria, fish drying is the mostadopted technique since it is within the socioeconomiclevels of artisanal fishermen contributingover 90% of domestic fish supply (Mabawonkuand Ajayi, 1982). Many materials subjecting fish todifferent preservation techniques notably:traditional smoking, traditional solar drying, ovenand Ife solar drying have been carried out (Afolabiet al., 1984). Analyses of the preserved fishshowed the occurrence of a high proportion ofpredominantly unsaturated fatty acids in oven andIfe solar-dried fish compared to the traditionallysmoke-dried fish. In spite of the shortcoming,there is an insatiable market for dried fish productsin the country.An estimated 95% of the total artisanalfish landings are smoked or sun-dried; theproblem of large scale infestation often results inmore than 50% losses due to inadequatepackaging and storage (Moses, 1983). The need tofurther investigate the extent and rate of damageof the nutritional quality of dried fish productsbecomes imminent. Studies on the action of D.maculatus as a pest of dried fish and meat inNigeria and Zambia have been carried out (Osuji,1975; Proctor, 1977). Although much work hasbeen done on the prevalence and rate ofdegradation of this pest to host species, little hasbeen done on the effect of pest infestation onnutritional quality of Clarias gariepinus. Theobjective of this study therefore was to determinethe effect of varying levels of pest infestation onthe crude protein, free fatty acid, pH and tissuedegradation of smoked C. gariepinus.MATERIALS AND METHODSFish Collection and Preservation: Twenty-one(21) live specimens (450 ± 2.30g) of Africancatfish, C. gariepinus (Burchell, 1822) were boughtfrom Artisan market, Enugu, Nigeria. The PracticalManual for the Culture o f the African Catfish,