Joseph Olusegun Ayo

Ameliorative effects of vitamin C on short-term sensorimotor and cognitive changes induced by acute chlorpyrifos exposure in Wistar rats

Human and experimental animal studies have shown long- and short-term neurological sequelae following acute organophosphate (OP) exposure. Although the main molecular mechanism of OP neurotoxiicty involves acetylcholinesterase (AChE) inhibition, studies have also implicated the induction of oxidative stress. The present study was therefore aimed at evaluating the effect of acute chlorpyrifos (CPF) exposure on short-term sensorimotor and cognitive changes in Wistar rats, the role of brain lipoperoxidative changes and the effect of pretreatment with vitamin C. Twenty-eight rats divided into four groups of seven rats in each group served as subjects for this study. Rats in group I were given soya oil (2 ml/kg) while those in group II were dosed vitamin C (100 mg/kg). Group III were administered CPF only (42.5 mg/kg ∼50% of LD50), while group IV were pretreated with vitamin C (100 mg/kg) and then exposed to CPF (42.5 mg/kg), 30 min later. The regimens were administered once orally and the animals were examined for clinical signs, death and subjected to periodic neurobehavioral evaluation for motor strength, coordinated gait, neuromuscular coordination, learning and memory. At the end of 8 weeks of evaluation, the rats were sacrificed and the brain tissue evaluated for AChE activity and malonaldehyde (MDA) concentration, as an index of lipoperoxidative changes. The rats administered with CPF showed deficits in motor strength, coordinated gaits, neuromuscular coordination, learning and memory, slight decrease in AChE activity and an increase in brain MDA concentration. Pretreatment with vitamin C improved the neurobehavioral deficits and AChE activity, and caused a significant reduction in MDA concentration. In conclusion, the study has demonstrated that acute CPF exposure in Wistar rats caused short-term impairment in sensorimotor and cognitive functions partly due to brain lipoperoxidative changes, which were ameliorated by pretreatment with vitamin C.

Effects of heat stress on some blood parameters and egg production of Shika Brown layer chickens transported by road

The effects of vitamins C and E on layer chickens transported by road for 6 h during the hot dry season were investigated. Two experimental groups consisting of thirty Shika Brown layers were separately administered vitamins C and E orally just before transportation, while another 30 layers, which were only given sterile water, served as control. Blood samples analyzed before and after transportation in the control layers showed a decrease (p<0.05) in total white blood cell, (p<0.01) lymphocyte and monocyte values, and a significant (p<0.05) and (p<0.001) increase in the values of eosinophils and heterophils post-transportation, respectively. In the experimental groups, post-transportation values of total white blood cells, eosinophils and monocytes were not different (p>0.05) from those obtained before transportation. Heterophil/lymphocyte values were highest in the control group. The result showed that transportation was stressful for the control layers. Post-transportation egg production was not significantly (p>0.05) different in the vitamin E treated group, but values recorded for the vitamin C and control groups were significantly (p<0.05) and (p<0.001) reduced compared to pre-transportation. In conclusion, vitamins C and E administration ameliorated the adverse effect of road transportation stress during the hot dry season.

Effects of Heat Stress on the Well-Being, Fertility, and Hatchability of Chickens in the Northern Guinea Savannah Zone of Nigeria: A Review

The paper examines heat stress and its adverse effects as a hindrance to profitable poultry production in the tropics, with emphasis on the Northern Guinea Savannah zone of Nigeria. It elucidates the general negative effects of heat stress on physiological parameters of domestic chickens, and the specific impact of the stress on reproduction in the tropics. The deleterious effects are expressed in poor poultry well-being and reproductive performance. It is concluded that measures aimed at alleviating heat stress in domestic chickens must be adopted in order to enhance reproductive and, consequently, efficiency of modern poultry production in the tropics.

Effect of Yeast Probiotic on Growth, Antioxidant Enzyme Activities and Malondialdehyde Concentration of Broiler Chickens.

The aim of the study was to determine the effect of yeast probiotic on body weight, and the activities of anti-oxidant enzymes: superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx), and malondialdehyde (MDA) concentration of broiler chickens. The experiment was carried out on hybrid Hubbard broiler chickens (n = 200). Two-hundred day-old chicks were randomly selected and distributed into four groups of 50 day-old chicks each: Control, C, and treatment groups comprising T1, T2 and T3 administered with 0.25 mL, 0.5 mL and 1.0 mL yeast probiotic, respectively. Chicks were fed a commercial starter diet for the first 28 days of age, followed by pelleted finisher diet from 29 to 42 days. Chickens in T1 had a significantly (p < 0.01) higher body weight at 4th week of age when compared with the control. SOD activity in all treatment groups was not significantly (p > 0.05) different when compared with the control. GPx activity was significantly (p < 0.01) higher in T1, when compared with the control. GPx activity in T2 was higher (p < 0.01) when compared with the control. There was no significant (p > 0.05) difference in MDA level in all the treatment groups. In conclusion, administering yeast probiotic supplement increased body weight and enhanced serum anti-oxidant enzyme activities of broiler chickens.

Vitamin E protects Wistar rats from chlorpyrifos-induced increase in erythrocyte osmotic fragility

The aim of the present study was to evaluate the effect of chronic chlorpyrifos (CPF) exposure on erythrocyte osmotic fragility, the role of lipid peroxidation and the ameliorative effect of vitamin E on the erythrocyte fragility. Twenty young adult male Wistar rats divided into four groups of five animals each served as subjects for this study. Groups I (control) and II were exposed to soya oil (2 ml/kg) and vitamin E (75 mg/kg), respectively. Rats in group III were exposed to CPF (10.6 mg/kg 1/8th of the previously determined LD50 of 85 mg/kg over a period of 48 h), while those in group IV were pretreated with vitamin E (75 mg/kg) and then exposed to CPF, 30 min later. The regimens were administered orally by gavage once daily for a period of 17 weeks. Blood samples collected at the end of the test period were analyzed for erythrocyte osmotic fragility, while the washed erythrocytes were used to evaluate malondialdehyde (MDA) concentration, as an index of lipid peroxidation. The study showed that repeated CPF exposure caused increased erythrocyte fragility and MDA concentration. Pretreatment with vitamin E ameliorated CPF-induced increase in erythrocyte fragility and lipoperoxidative changes in Wistar rats.

Ameliorative effect of vitamin C on chronic chlorpyrifos-induced erythrocyte osmotic fragility in Wistar rats.

Chronic exposure to chlorpyrifos (CPF) has been shown to cause increased lipoperoxidative changes in the erythrocyte membranes. The relationship between chronic CPF-induced lipoperoxidative changes and erythrocyte fragility has not been elucidated. The aim of the present study is to evaluate the role of lipoperoxidation on CPF-induced erythrocyte fragility and the ameliorative effect of vitamin C. Twenty animals divided at random into four groups of five animals each served as subject for this study. Rats in group I served as the control group and were given only soya oil at a dose of 2 mL/kg body weight (b.w.). Rats in group II were dosed with vitamin C (100 mg/kg b.w.) and then supplemented with soya oil (2 mL/kg b.w.), while those in group III were administered with CPF only at a dose of 10.6 mg/kg b.w. (∼one-eighth of the previously determined median lethal dose [LD50]). Rats in group IV were pretreated with 100 mg/kg b.w. of vitamin C, and then dosed with CPF at a dose of 10.6 mg/kg b.w., 30 min later. The different treatment regimens were orally administered daily for a period of 17 weeks. Blood collected from the animals at the end of the test period were analyzed for erythrocyte osmotic fragility and malonaldehyde (MDA) concentration as an index of lipid peroxidation. The study showed that CPF caused significant increase in erythrocyte fragility and MDA concentration, which were ameliorated by pretreatment with vitamin C. In conclusion, the study showed that CPF-evoked erythrocyte fragility due to increased lipoperoxidative changes was ameliorated by pretreatment with vitamin C.

Hemotoxicity Induced by Chronic Chlorpyrifos Exposure in Wistar Rats: Mitigating Effect of Vitamin C

The study evaluated the ameliorative effect of vitamin C on chronic chlorpyrifos-induced hematological alterations in Wistar rats. Twenty adult male rats divided into 4 groups of 5 animals each were exposed to the following regimens: group I (S/oil) was administered soya oil (2 mL/kg b.w.), while group II (VC) was given vitamin C (100 mg/kg b.w.); group III was dosed with CPF (10.6 mg/kg b.w.); group IV was pretreated with vitamin C (100 mg/kg) and then exposed to CPF (10.6 mg/kg b.w.), 30 minutes later. The regimens were administered by oral gavage once daily for a period of 17 weeks. Blood samples collected at the end of the study revealed reduction in the levels of pack cell volume, hemoglobin, red blood cells, leukocytes (attributed to neutropenia, lymphopenia, and monocytopenia), and platelets in the CPF group, which were ameliorated in the vitamin C- pretreated group. The elevated values of malonaldehyde, mean corpuscular volume, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, and neutrophil/lymphocyte ratio in the CPF group were restored in those pretreated with vitamin C. The study has shown that chronic CPF-induced adversity on hematological parameters of Wistar rats was mitigated by pretreatment with vitamin C.

Erythrocyte osmotic fragility of pigs administered ascorbic acid and transported by road for short-term duration during the harmattan season

The experiment was carried out with the aim of investigating the effect of an antioxidant ascorbic acid on erythrocyte osmotic fragility of pigs transported by road for 4 h during the harmattan season. 16 pigs administered with ascorbic acid at the dose of 250 mg/kg per os and individually served as experimental animals and 13 others administered orally with sterile water were used as control animals. The animals were then transported for 4 h at a speed of 40 - 50 km/h covering a distance of 140 km. Blood samples for erythrocyte osmotic fragility determination which was done using standard procedure, were taken early in the morning a day before transportation, immediately after and a week after transportation. Erythrocyte osmotic fragility decreased significantly (P < 0.05) at NaCl concentration of 0.85, 0.80 and 0.70% in both experimental and control pigs following road transportation and the difference in the post-transportation values was higher (P < 0.05) in experimental compared to control pigs. The results indicated that ascorbic acid protected the integrity of the erythrocyte membrane in experimental pigs administered ascorbic acid following road transportation as demonstrated by lower percentage haemolysis immediately after road transportation and thus may alleviate the risk of increase in haemolysis due to road transportation stress in pigs during the harmattan season.

Seasonal, sex and live weight variations in feed and water consumptions of adult captive African Giant rats (Cricetomys gambianus, Waterhouse-1840) kept individually in cages.

Adult African Giant rats (Cricetomys gambianus, Waterhouse) (AGRs) (n = 231) of both sexes (117 bucks, 114 does) were live-trapped in the wild in Zaria, Nigeria. Live weight (LW), daily feed consumption (FC) and water consumption (WC) of the AGRs were measured during the cold-dry (CDS), hot-dry (HDS) and rainy (RS) seasons for 2 years with the aim of determining seasonal, sex and LW variations. Feed consumption was significantly different (p < 0.001) between all the seasons, with the lowest mean value recorded during the HDS, while the highest was obtained during the RS. Water consumption was also lowest (p < 0.001) during the HDS but did not differ significantly (p > 0.05) between the CDS and RS. Both feed and water consumptions were higher (p < 0.01) in the males (bucks) than the females (does) during the CDS and HDS, but the sex difference was not significant (p > 0.05) during the RS. Feed consumption correlated positively (p < 0.0001) with WC and relative humidity, but negatively (p < 0.0001) with LW, ambient temperature and heat index. In conclusion, both feed and water consumptions in AGRs decrease with increased seasonal heat and adult LW and are lower in does than in bucks during the dry seasons (CDS and HDS). Intervention may be indicated during the HDS to improve feed and water consumptions for optimal performance of the AGRs.

The organophosphate, chlorpyrifos, oxidative stress and the role of some antioxidants: A review

The present paper reviews the current state of our knowledge of the role of oxidative stress in the mechanism underlying chlorpyrifos poisoning, and the role of some antioxidants in ameliorating adverse effect of pesticides. In order to understand better the nature of oxidative stress, the principle of free radical generation, the body’s normal defense system including antioxidants are discussed. The adverse health effects of the organophosphate, chlorpyrifos and their ability to induce oxidative stress through the generation of free radicals and alteration in body antioxidant status were also discussed. Some antioxidant molecules that have been proven to mitigate against chlorpyrifos induced toxicity were also enumerated. It is concluded that the generation of reactive oxygen species induces oxidative damages and disturbances of the antioxidant body defence systems, which are implicated in the mechanisms of toxicity in most pesticides, including chlorpyrifos were inhibited by some of the antioxidants. It is recommended that further research be geared towards identifying more agents that may ameliorate chlorpyrifos and other organophosphates of adverse effects.