Subchronic Exposure to Fenthion Induces Hematological Changes in Liver Tissue of African Catfish Clarias gariepinus.

In this study, African Catfish (also known as Sharptooth Catfish) Clarias gariepinus were exposed to sublethal concentrations of fenthion of 2.0, 4.0, and 8.0 mg/L for 21 d and allowed to recover for 7 d to investigate the potential for hematological changes. Whole blood was sampled on days 1, 7, 14, and 21 postexposure and after a 7-d recovery period. During exposure, fenthion caused a reduction in red blood cell counts, hemoglobin concentration, and packed cell volume. There was an increase in white blood cell counts but no significant difference in mean corpuscular hemoglobin concentration, mean corpuscular volume, and mean corpuscular hemoglobin. Both increases and decreases were observed in white blood cell differentials. After the 7-d recovery period, both increases and decreases were observed in the hematological parameters. These results reveal that sublethal concentrations of fenthion can cause hematological alterations in African Catfish and that the substance should be used with caution. Received October 20, 2015; accepted May 4, 2016.

Oxidative stress and biochemical responses in the tissues of African catfish Clarias gariepinus juvenile following exposure to primextra herbicide.

Primextra is a commercial herbicide formulation generally used in agriculture for weed control. The present study was designed to investigate the oxidative stress biomarkers and biochemical responses in the tissues of Clarias gariepinus juvenile exposed to primextra. Fish were exposed to 0.24 and 0.47 mgL(-1) corresponding to 1/20 and 1/10th of 96 h LC50 of the herbicide. The liver and muscle tissues were sampled on day 1, 5, 10 and 15 and results showed concentration and time dependent significant increase (p < 0.05) in the values of lipid peroxidation, glutathione peroxidase, catalase and alkaline phosphatase in both tissues. A marked significant increase (p < 0.05) was observed in the values of aspartate aminotransferase, alanine aminotransferase and glucose in the liver while a mixed trend in their values were observed in the muscle. The values of superoxide dismutase and protein in both tissues were comparable to the control except on day 15 in the liver where the values significantly declined. The condition factor was not directly affected but values of hepatosomatic index were significantly reduced. The present findings revealed that primextra induced toxic stress even at sublethal concentrations resulting in alterations of the studied parameters which were more evident in the fish liver than in the muscle tissue.

Assessment of biometrics and stress indicators of the adult Village Weaver birds (Ploceus cucullatus) during breeding and post-breeding seasons in Jos, Nigeria.

In this era of climate change, some biological conservationists' concerns are based on seasonal studies that highlight how wild birds' physiological fitness are interconnected with the immediate environment to avoid population decline. We investigated how seasonal biometrics correlated to stress parameters of the adult Village Weavers (Ploceus cucullatus) during breeding and post-breeding seasons of the Weaver birds in Amurum Forest Reserve. Specifically, we explored the following objectives: (i) the seasonal number of birds captured; (ii) whether seasonal baseline corticosterone (CORT), packed cell volume (PCV), and heterophil to lymphocytes ratio (H:L) were sex-dependent; (iii) whether H:L ratio varied with baseline (CORT); (iv) whether phenotypic condition (post-breeding moult) and brood patch varied with baseline (CORT) and H:L ratio; and (v) how body biometrics co-varied birds' seasonal baseline (CORT), (PCV) and (H:L) ratio. Trapping of birds (May-November) coincided with breeding and post-breeding seasons. The birds (n = 53 males, 39 females) were ringed, morphologically assessed (body mass, wing length, moult, brood patch) and blood collected from their brachial vein was used to assess CORT, PCV and H:L ratio. Although our results indicated more male birds trapped during breeding, the multiple analyses of variance (MANOVA) indicated that the seasonal temperature of the trapping sites correlated (P < 0.05) significantly to baseline (CORT). The general linear mixed model analyses (GLMMs) indicated that the baseline (CORT) also correlated significantly to H:L ratio of the male and female birds. However, PCV correlated significantly to body size of the birds (wing length) and not body mass. Haematological parameters such as the baseline CORT and the H:L ratio as indicators of stress in wild birds. Hence, there is the possibility that the Village Weaver birds suffered from seasonally induced stress under the constrained effect of environmental temperature. Hence, future studies should investigate whether the effect observed is also attributable to other passerine species.

Effects of grapefruit (Citrus paradisi MACF) (Rutaceae) peel oil against developmental stages of Aedes aegypti (Diptera: Culicidae).

Laboratory bioassay of the essential oil extracted from the grapefruit (Citrus paradisi) peel by steam distillation was carried out against the developmental stages of the yellow fever vector Aedes aegypti to evaluate its toxicity, and ovicidal and larvicidal potency. Volatile oil components isolated and characterized by coupled gas chromatography/mass spectrometry included varying levels of monoterpene aldehydes, alcohols, and esters. Test results of the essential oil showed that egg hatching was completely inhibited at 400 ppm, while further development of 1st to 2nd larval stage was inhibited at 100 ppm. Regression analysis results also indicated that the peel essential oil significantly (p<0.01) reduced the viability of the test eggs and inhibited the development of 1st larval stage to 2nd larval instar. The LC50 and LC90 values obtained for 2nd instars (180.460, 334.629 ppm, respectively); and for 4th instars (210.937, 349.489 ppm, respectively) after 24-hour exposure were time but not dose dependent, as each LC value was a product of an inverse relationship between the oil concentration and exposure time. The results indicated that the peel oil could be a potent persistent larvicide.

Toxicity and genotoxic evaluations in African catfish Clarias gariepinus (Burchell 1822) exposed to Act Force Gold®, Butaforce®, and Atraforce®.

Act Force Gold®, Butaforce®, and Atraforce® are among the most commonly used pesticides in Nigeria. The lethal concentrations and the respective toxic units for the three pesticides were determined. The genotoxic effects of the three pesticides were investigated in the red blood cells of Clarias gariepinus using micronucleus (MN) assay. The 96 h LC50 was 4.75, 4.84, and 54.74 mg L-1 for Act Force Gold®, Butaforce®, and Atraforce®, respectively. The toxic units in ascending order of toxicity were 1.83, 20.66, and 21.05 for Act Force Gold®, Butaforce®, and Atraforce® respectively. The estimated safe levels based on NAS/NAE varied from 4.75 × 10-1-4.75 × 10-5 in Act Force Gold® through 4.64 × 10-1-4.85 × 10-5 in Butaforce® to 5.74-5.74 × 10-5 in Atraforce®. Fish specimens were exposed to the pesticides and sampling was done at regular intervals at days 1, 7, 14, and 21 and after another 7-day recovery period. The results obtained indicated concentration- and duration-dependent increase in % MN formation with maximum values of 3.40 ± 0.25 for Act Force Gold® on day 14 and 3.05 ± 0.36 and 2.35 ± 0.14 for Butaforce® and Atraforce® respectively on day 7 of exposure. The 7-day recovery period could not reverse the trend as the % MN values obtained were significantly different from the control. The results further support the use of MN assay in assessing the toxicity of aquatic pollutants and can be used in the monitoring of aquatic ecosystems.

HEXANE EXTRACT OF Dacryodes edulis FRUITS POSSESSES ANTI-DIABETIC AND HYPOLIPIDAEMIC POTENTIALS IN ALLOXAN DIABETES OF RATS.

BACKGROUND: The fruit extract of Dacryodes edulis (D. edulis), the African pear or plum, a tree indigenous to the humid tropics has been used for managing wounds, skin diseases, sickle cell anaemia, dysentery and fever in some African nations. In South Eastern Nigeria, 'herbal doctors' include its marshed fruit in decoctions administered to diabetic patients. However no scientific substantiation of their claim and use exist in literature. Hence, the need to evaluate the antidiabetic and hypolipidaemic activity of hexane extracts of D. edulis fruit in alloxanised animal model. MATERIALS AND METHODS: Sub-toxic doses between 400 and 1600mg/kg were orally administered sub-chronically to alloxan-induced diabetic rats for 15 days and compared to glibenclamide (2.5mg/kg). The glycaemia levels, body weights, lipid profile, blood urea, creatinine and liver enzyme levels were measured. Basic histology of the pancreatic tissue was also performed to examine the effects on the pancreas as possible mechanistic lead. RESULTS: Oral acute dosing of D. edulis hexane extract decreased blood glucose levels, while sub-chronic treatment of the extract down-regulated significantly hyperglycaemia, total cholesterol, triglycerides, LDL-C, ALT and ALP levels. However, the HDL-C levels increased significantly. Histopathological examination of the pancreatic tissues after sub-chronic treatment showed that glibenclamide and the highest dose of the extract 1600mg/kg restored the afore-damaged pancreatic ß-cell architecture. CONCLUSION: Our findings portend that D. edulis hexane fruit extract possesses hypoglycaemic and hypolipidaemic activities as well as restoration of the pancreatic architecture without any obvious untoward hepatic damages, suggesting that its use in the management of the diabetes may be valid. List of Non-standard abbreviations:D. edulis = dacryode edulis, DEnH = Dacryodes edulis n-hexane fruit extract, B.wt. = Body weight, Per os = Oral administration, NC = normal control, DC =Diabetic control, SC = Standard control, LDL-C = low density lipoprotein cholesterol, HDL-C = High density lipoprotein cholesterol, TG = Triglyceride, TC = Total cholesterol.