Kaempferol and zinc gluconate mitigate neurobehavioral deficits and oxidative stress induced by noise exposure in Wistar rats.

This study investigated the effects of kaempferol and zinc gluconate on neurobehavioural and oxidative stress changes in Wistar rats exposed to noise. Thirty (30) rats were randomly divided into five groups: Groups I and II were administered with deionized water (DW); Group III, kaempferol (K); Group IV, zinc gluconate (Zn); Group V, kaempferol + zinc gluconate. Groups II, III, IV, and V were subjected to noise stress (N) induced by exposing rats to 100 dB (4 h/day) for 15 days, from day 33 to day 48 after starting the drug treatments. Neuromuscular coordination, motor coordination, motor strength, sensorimotor reflex, and learning and memory, were evaluated using standard laboratory methods. Levels of nitric oxide (NO), malondialdehyde (MDA) and activities of glutathione peroxidase (GPx), catalase and superoxide dismutase (SOD) were evaluated in the hippocampus. Exposure of rats to noise, induced significant neurobehavioural deficits and oxidative stress while the combined administration of kaempferol and zinc gluconate significantly (P < 0.05) improved open-field performance, motor coordination, motor strength, sensorimotor reflex, and learning and memory. Co-administration of kaempferol and zinc gluconate ameliorated noise-induced oxidative stress as demonstrated by the significantly increased activities of GPx, catalase, and SOD, and decreased levels of NO and MDA (P < 0.05 and P < 0.01 respectively), compared to the DW + N group. Our results suggest that oxidative stress, evidenced by increased NO and MDA concentration and decreased activities of GPx, catalase and SOD, were involved in the molecular mechanism underlying neurobehavioural impairment in Wistar rats, exposed to noise stress. Single treatment of kaempferol exerted a more potent mitigative effect than zinc gluconate, while their combination produced an improved outcome.

Changes in feed consumption and water intake among broiler chickens subjected to melatonin treatment during the hot-dry season.

The experiment was conducted to evaluate changes in feed consumption and water intake among broiler chickens subjected to melatonin treatment during the hot-dry season. A total of 300 broiler chicks were selected and assigned into three groups, by simple random sampling, comprising 100 chicks each: group I was exposed to natural photoperiod of about 12-h light and 12-h darkness cycle (12D/12L), without melatonin supplementation; group II was kept under 24-h continuous lighting (CL), without melatonin supplementation; and group III was raised under 24-h CL and administered daily with melatonin orally at 0.5 mg/kg (CL + MEL). Live weight (LW), feed consumption, and water intake for each group were obtained at weekly intervals over a period of 8 weeks. On day 42 of age, the LW of 2420 ± 50 g/bird was obtained in group III administered with melatonin (CL + MEL), while LW values recorded in the 12D/12L and CL groups not administered with melatonin were 1470.00 ± 30.00 and 1907.00 ± 38.00 g/bird, respectively. The mean weight gain in CL + MEL (345.00 ± 21.01 g) was significantly (P < 0.05) higher than those of the 12D/12L (244.99 ± 18.67 g) and CL (307.48 ± 18.14 g) groups. Feed consumptions were significantly (P < 0.05) different in all the groups. Group II, raised on CL without melatonin supplementation, had the highest feed consumption value of 25.14 ± 0.51 g/bird from day 14, and attained the peak value of 206.77 ± 7.82 g/bird at day 56. The highest overall amount of water intake was recorded in the melatonin-treated group. In conclusion, melatonin administration to broiler chickens enhanced water intake but decreased feed consumption with increase in LW during the hot-dry season.

Combined effects of retinol, ascorbic acid and α-tocopherol on diurnal variations in rectal temperature of Black Harco pullets subjected to heat stress.

The experiment was performed with the aim of determining the effect of co-administration of antioxidant vitamins, retinol, ascorbic acid and α-tocopherol on rectal temperature (RT) fluctuations in pullets during the hot-dry season in Nigeria. Forty-eight Black Harco pullets, aged 16 weeks and weighing 1.5 ± 0.03 kg were divided by simple random sampling into two groups, consisting of 28 treated and 20 control Black Harco pullets. The RTs of 28 treated and 20 control Black Harco pullets were measured hourly for 3 days, 3 days apart, from 06:00 to 19:00 h (GMT + 1) with a standard clinical thermometer. The treated pullets were administered individually with the vitamins orally in water, while the control pullets were given only water. The lowest hourly RT of 40.9 ± 0.04 °C was obtained in treated pullets at 06:00 h, while the highest value of 41.1 ± 0.01 °C was recorded from 17:00 to 19:00 h (P < 0.001). In control pullets, the RT rose significantly from 41.0 ± 0.03 °C at 06:00 h to the maximum value of 41.6 ± 0.04 °C at 15:00 h (P < 0.001). The pullets co-administered with retinol, ascorbic acid and α-tocopherol had consistently lower RT values than those of control pullets, especially during the hot hours of the day, from 13:00 to 17:00 h. It is concluded that co-administration of retinol, ascorbic acid and α-tocopherol, by preventing a rise in body temperature, ameliorated heat stress, and may enhance productivity of pullets reared under unfavourable, thermal environment conditions.

Melatonin modulates tonic immobility and vigilance behavioural responses of broiler chickens to lighting regimens during the hot-dry season.

Experiments were conducted with the aim of determining the influence of melatonin administration on vigilance and tonic immobility (TI) responses of Marshall broiler chickens. The broiler chickens were reared on different lighting regimens and subjected to heat stress during the hot-dry season. Simple random sampling was used to assign 300 broiler chicks into three groups, comprising 100 broiler chicks each. Group I (12D:12L cycle) was raised under natural photoperiod of 12-h light and 12-h darkness, without melatonin supplementation. Group II (CL) was kept under 24-h continuous lighting, without melatonin administration. Group III (CL+MEL) was raised under 24-h continuous lighting; with melatonin supplementation at 0.5mg/kg per os, via drinking water using a syringe. Beginning from day-old, broiler chickens in group III were individually administered with melatonin once daily for 8weeks at 17:00h. TI was induced by manual restraint, and vigilance elicited at self-righting graded for three days, two weeks apart, in 15 labeled broiler chickens from each of the three groups; at 06:00h, 13:00h and 18:00h, starting from week 4-8. Each broiler chicken was laid on its back in a U-shaped cradle, covered with cloth. Thermal microenvironment parameters of dry bulb temperature (DBT) and relative humidity (RH) were recorded at the experimental site, concurrently during the vigilance and TI tests. Inside the broiler chickens' house, the weekly temperature-humidity index (THI) was lowest at week 4 of the study, with the value of 48.60±0.08°C. At week 4, the relationship between the THI and TI induction attempts was stronger in 12D:12L cycle (r=0.589, P<0.001) than CL (r=0.264, P>0.05) or CL+MEL (r=0.096, P>0.05) broiler chickens. This indicated that the broiler chickens on 12D:12L cycle were more active compared to their melatonin-treated counterparts, apparently due to adverse effects of high DBT and high RH on the broiler chickens during the hot-dry season. The highest numbers of TI induction trial attempts were recorded at 13:00h in 12D:12L cycle and CL groups (2.13±0.34 and 2.15±0.22, respectively), when the broiler chickens were at week 8. The overall mean values of induction trial attempts differed significantly (P<0.0001) between the groups; with the lowest mean values of 1.22±0.4 recorded in CL+MEL broiler chickens. At day 42, the lowest mean TI duration of 101.87±10.24s in the CL group, recorded at 06:00h rose (P<0.001) to 184.07±23.69s at 13:00h. The overall mean duration of TI differed significantly (P<0.0001) again between the groups; with the highest mean duration of 167.82±8.35s, recorded in CL+MEL broiler chickens administered with melatonin. The overall mean vigilance behavioural ranking values of 1.85+0.07 and 1.70+0.08, obtained in 12D:12L cycle and CL broiler chickens, respectively were higher (P<0.0001) than the value of 1.44+0.05 recorded in melatonin-treated broiler chickens. The results indicated that broiler chickens belonging to both 12D:12L cycle and CL groups were more emotional, fearful or anxious, compared to CL+MEL broiler chickens. It was concluded that melatonin administration elicits boldness and confidence by suppressing freezing behaviour in broiler chickens, and it may improve their welfare and productivity.