IOSR Journal of Agriculture and Veterinary Science (IOSR-JAVS) e-ISSN: 2319-2380, p-ISSN: 2319-2372. Volume 9, Issue 8 Ver. I (Aug. 2016), PP 26-33 www.iosrjournals.org DOI: 10.9790/2380-0908012633 www.iosrjournals.org 26 | Page Effects of Dietary Fumonisin B1 on Haematology and Growth Performance of the Clariid FishHeterobranchus longifilis Adeyemo, Bolade Thomas 1 , 2 ٭ ; Tiamiyu, Lateef Oloyede 2,3 ; Ayuba, Victoria Ogeh 2 ; Cheikyula, Joseph Orkuma 2 1. Department of Veterinary Pathology, Faculty of Veterinary Medicine,University of Abuja, PMB 117 Abuja, Nigeria. 2. Department of Fisheries and Aquaculture, College of Forestry and Fisheries,University of Agriculture Makurdi, PMB 2373 Makurdi, Nigeria. 3. Department of Aquaculture and Fisheries, Faculty of Agriculture, Universityof Ilorin, PMB 1515 Ilorin, Nigeria. Abstract: Mycotoxins are secondary metabolites produced by fungi. There are evidence that mycotoxins cause pathologies including growth reduction in aquatic species. Experiments were carried out to determine the effects of fumonisin B1 (FB1) on haematology and growth performance of Heterobranchuslongifilis catfish. Fifteen 1,000 L capacity tanks divided into five groups made of three replicates each were stocked with 30 juvenile fish and fed diets amended with varying concentrations of FB1 (0.0 mg FB1/kg; 10.0 mg FB1/kg; 20.0 mg FB1/kg; 40.0 mg FB1/kg and 80.0 mg FB1/kg). At time points 7; 14; 28 and 56 days of feeding, the fish were randomly sampled from each tank, weighed, length measured and bled for haematology. Results obtained shows that except for the haemoglobin concentration of fish fed diet containing 40 mg FB1/kg, there were no significant difference (P > 0.05) in the erythrocytes count, haemoglobin concentration and haematocrit at 7 days of feeding. At 14 days of feeding, the erythrocytes counts of fish fed the control diet, was not significantly different (P > 0.05) from those fed diets containing 10.0 and 20.0 mg FB1/kg but was significantly different from that of fish fed 40.0 and 80.0 mg FB1/kg. Also, the erythrocytes counts and haemoglobin concentration of fish fed diet containing 40 mg FB1/kg do not differ significantly compared with those of fish fed diets containing 80 mg FB1/kg. ANOVA reveals significant difference (P < 0.05) in the haematocrit of fish fed the control diet compared with fish fed diets containing FB1; Turkey post hoc shows the haematocrit of fish fed diet containing 10.0 and 20.0 mg FB1/kg do not differ significantly (P > 0.05) but however, significantly (P< 0.05) differ from those of fish fed diets containing amounts ≥ 40.0 mg FB1/kg. Dietary FB1 caused leucocytopeania that was dependent on the concentration of the FB1 in the diet as on the duration of feeding on the diets. Growth performance indices were significantly affected by the presence of FB1 in the diets. In conclusion, this study showed diets containing fumonisin B1 levels ≤ 20 mg FB1/kg produced the least pathology in j uvenile Heterobranchuslongifilis catfish. Keywords: Fumonisin B1, Heterobranchuslongifilis, Growth performance, Haematology, Catfish. I. Introduction Fumonisins are metabolites produced by species of the filamentous fungus Fusarium ( Fusarium verticiloides and F. proliferatum) (Gelderblom et al, 1998). About 28 homologues of the Fumonisins have been described (Bezuidenhou et al, 1988), of these fumonisin B1 (FB1) is reported to be the most common and most toxic (Voss et al, 2011). Whereas the Fumonisins have been reported to be present in several agricultural commodities (Binder et al, 2007; Walter and Marasas, 2001), animal and human health problems associated to the fumonisins are almost exclusively related to the consumption of maize and or products made from maize (Voss et al., 2007). The chemical structure of the fumonisins has been reported to be similar to that of the sphingolipids (sphinganine and sphingosine); biochemically, the fumonisins competitively, inhibits the enzyme Ceramide synthase thereby causing a disruption of the de novo biosynthesis of Ceramide and Sphingolipids metabolism resulting in the promotion of the accumulation of Sphinganine and to a lesser extent, Sphingosine in tissues, blood and urine (Hascheck, 2006; Riley and Voss, 2006; Tardieus et al, 2006). The accumulation of Sphinganine in tissues have been reported to induce a pro-apoptotic, cytotoxic and growth inhibitory effects (Rauber et al, 2012; Voss et al, 2007), which elicits immunotoxicity, hepatotoxicity, nephrotoxicity and carcinogenicity in exposed animals (Theumer et al, 2002; Voss et al, 2002). Two notable diseases/syndromes have been reported in animals fed FB1 contaminated feeds; Equine leucoencephalomalacia (Marasas et al, 1998) and Porcine pulmonary edema (Harrison et al, 1990). In fishes, the role of fumonisins as toxic agents remains unclear as conflicting reports concerning the effects of FB1 abound in scientific literature. For example, whereas Brown et al (1992), reported that the dietary exposure of Channel