Acute Toxicity and Histopathological Changes in Gill and Liver of Catfish (Clarias Gariepinus) Juvenile Exposed to 2, 4-D Amine (Herbex D Sl®)

The acute toxicity and histopathological changes in the gill and liver of Clarias gariepinus juvenile exposed to Herbex-D SL ®, a herbicide containing 720g/l of 2, 4-D amine were investigated. In a static renewal bioassay, the fish were exposed to 0.00, 1.40, 1.44, 1.48 and 1.52mg/l of 2, 4-D amine. The 96 hours lethal concentration (LC50) of 2, 4-D amine to juvenile of Clarias gariepinus was 2g/l. The fish exposed to 2, 4-D amine showed toxicological signs of erratic swimming, loss of reflexes and lethargy. Histopathological changes in the gill architecture were characterized by lifting of epithelia layer, vacuolization, inter-lamella hyperplasia and mild desquamation of the epithelia lining. There was an evidence of advancing phase of hepatic necrosis in the liver of fish exposed to 2, 4-D amine. 2, 4-D amine is highly toxic and its use in or near aquatic environment should be monitored. Key words: 2,4- D amine (Herbex D SL®), Clarias gariepinus, Acute toxicity, Histopathology

AMINO ACID PROFILE AND POLYCYCLIC AROMATIC HYDROCARBONS (PAHS) OF SMOKED FARMED CLARIAS GARIEPINUS (BURCHELL, 1822) RAISED UNDER DIFFERENT CULTURE SYSTEMS IN IBADAN, NIGERIA

Fish food quality and safety is critical to consumers due to its public health implication. To exploit huge export opportunities for smoked farmed catfish, there is need for strict adherence to international quality and safety standards. This paper examined amino acid profile and polycyclic aromatic hydrocarbons (PAHs) of smoked farmed catfish Clarias gariepinus raised under different culture systems with a view to determining its quality and safety. Six farms with the two most common fish culture systems (3 concrete tanks (CTs) and 3 earthen ponds (EPs) were purposively selected based on frequency of harvest and yield. Fish samples (500±10g) obtained from these farms after 4 months of culture were processed, smoked, packaged and stored for 36 weeks. Amino acid profile in farmed fresh and smoked C. gariepinus was determined at 12, 24 and 36 weeks of storage and polycyclic aromatic hydrocarbons (PAH) was determined at 0 and 16 weeks of storage. These were compared with traditional smoked wild catfish obtained from local fish processor (LFP). The amino acids with highest concentrations (mg/g) found in this study were leucine (22.16 - 31.61 and 13.89 – 29.64), lysine (16.31 – 20.19 and 9.86 – 18.08), arginine (15.16 – 12.29 and 8.97 - 15.86), valine (15.96 – 21.35 and 9.68 - 19.36 ) and asparagine (19.66 – 21.61 and 12.36 mg/g – 20.71mg/g) for fresh and smoked catfish respectively. Levels of other amino acids ranged from 1.5mg/g to 9.98mg/g in smoked fish and 2.95mg/g to 12.21mg/g in fresh fish. The mean total poly aromatic hydrocarbons in smoked catfish at 16 weeks of storage were 0.039±0.004µg/kg, 0.034±0.005 µg/kg and 0.053±0.005 µg/kg for EP, CT and LFP, respectively. Therefore smoked farmed catfish raised under different culture systems still contain essential amino acids and Benzo(a)pyrene which is a carcinogen was not at detectable level in the samples

Chemical analysis and nutritional assessment of fluted pumpkin (Telfairiaoccidentalis Hook F.) seed residue fed to African catfish (Clariasgariepinus) at graded inclusion levels

The chemical analysis and nutritional assessment of fluted pumpkin seed residue fed to African catfish (Clariasgariepinus) at graded inclusion levels was carried out in order to evaluate its effect on the growth performance and nutrient utilization of the catfish. Five diets containing 0, 15, 30, 45 and 60% inclusion levels of fluted pumpkin seed residue (FPSR) as partial replacement for groundnut cake were prepared and fed to the fishes for eight weeks. Each treatment had three replicates with 15 fish per replicate (mean initial weight 140.87 ± 8.77g) in 30-litre plastic tanks and fish fed at 3% of body weight twice daily. Fish on control diet showed the best growth and nutrient utilization while diets with defatted fluted pumpkin seeds cake produced weight reduction in the fish with the least reduction on diet 2 (15% inclusion) and greatest on diet 4 (45% inclusion). The specific growth rate, feed conversion ratios and protein intake of the control fish were significantly (p<0.05) higher than those on FPSR-containing diets. Histopathological reports showed some damage to the liver of fish in higher FPSR-containing rations, torn gill tissues and changes of intestinal structure. Haematological parameters like haemoglobin, erythrocyte, sedimentation rate and biochemical parameters were within the ranges for healthy fish though reduced from pre-treatment values

An assessment of the risk of Bt-cowpea to non-target organisms in West Africa

Cowpea (Vigna unguiculata Walp.) is the most economically important legume crop in arid regions of sub-Saharan Africa. Cowpea is grown primarily by subsistence farmers who consume the leaves, pods and grain on farm or sell grain in local markets. Processed cowpea foods such as akara (a deep-fat fried fritter) are popular in the rapidly expanding urban areas. Demand far exceeds production due, in part, to a variety of insect pests including, in particular, the lepidopteran legume pod borer (LPB) Maruca vitrata. Genetically engineered Bt-cowpea, based on cry1Ab (Event 709) and cry2Ab transgenes, is being developed for use in sub-Saharan Africa to address losses from the LBP. Before environmental release of transgenic cowpeas, the Bt Cry proteins they express need to be assessed for potential effects on non-target organisms, particularly arthropods. Presented here is an assessment of the potential effects of those Cry proteins expressed in cowpea for control of LPB. Based on the history of safe use of Bt proteins, as well as the fauna associated with cultivated and wild cowpea in sub-Saharan Africa results indicate negligible effects on non-target organisms

Toxic stress of lead on Clarias gariepinus (African catfish) fingerlings

The toxic stress of lead on fish was tested employing a 96-hour bioassay test. The experimental fish used were Clarias gariepinus fingerlings. Lead in the form of lead chloride was used to prepare the stock solution. The concentrations of lead used for the experiment were 0, 1.8, 3.2, and 5.6, and10.0mg/l. The lethal concentration (LC50) was estimated using the logarithmic method and was found to be 0.6, 0.58 and 0.62mg/l for replicates1, 2 and 3 respectively

Assessment of toxicological impact of light crude oil on Clarias gariepinus (Burchell, 1822) fingerlings

Oil spillage is of critical concern in Nigeria because of the problems of pollution and associated disturbances .It is therefore necessary to study the effects of oil pollution on fish using Clarias gariepinus, a widely cultured fish species in the tropics. A short –term (96-hour), static bioassay was carried out to determine the toxicity of crude oil (Qua Iboe light) on C .gariepinus fingerlings. The bioassay involved five treatments viz: 0, 25, 50, 75 and 100µL/L The water and fish samples were analyzed for total hydrocarbon content (THC) and heavy metals at the end of the experiment. There were significant differences (