Effect of heat stress on oxidative stress, lipid peroxidation and some stress parameters in broilers

1. This study was conducted to determine the effects of heat stress on fearfulness, leucocyte components, oxidative stress and lipid peroxidation in two commercial broiler strains, Cobb (C) and Ross (R). 2. At 36 and 37 d of age birds were exposed to 38 +/- 1 degree C for 3 h. Rectal temperatures, duration of tonic immobility (TI), haematocrit values, proportions of leucocyte components (heterophil, lymphocyte, basophil, eosinophil, monocyte), malondialdehyde (MDA) concentrations and antioxidant enzyme activities (CAT, SOD, GPx) of all the birds were determined, before and after heat treatment. 3. Rectal temperatures increased and haematocrit values decreased in birds exposed to heat stress. Heat stress caused a significant increase in heterophil/lymphocyte and in basophil ratios. 4. Exposing birds to heat stress increased duration of TI, suggesting heat-stressed birds tended to be more fearful. 5. Heat stress resulted in a significant Genotype x Treatment interaction for MDA concentration. CAT, SOD and GPx activities; MDA concentrations in heat-stressed R strain birds were greater than in heat-stressed C strain birds.     

Differences in lipid peroxidation and Cu,Zn-superoxide dismutase in the hippocampal CA1 region between adult and aged dogs

Reactive oxygen species have been long associated with oxidative stress relevant to many pathological damages. In brain, 4-hydroxy-2E-nonenal (HNE), a major cytotoxic end product of lipid peroxidation, is produced. In contrast, superoxide dismutase (SOD), one of the major antioxidant enzymes, protects neurons from oxidative stress. The aim of this study is to observe differences in the distribution of HNE and Cu,Zn-superoxide dismutase (SOD1) in the hippocampal CA1 region of adult (2-3 years of age) and aged (10-12 years of age) dogs. The HNE immunoreactivity and protein level in the CA1 region were significantly high in the aged dogs compared to those in the adult dogs. SOD1 immunoreactivity and its protein level were also higher in the aged dogs than those in the adult dogs. However, there were not significant differences in NeuN (a neuron-specific soluble nuclear antigen) immunoreactivity in CA1 neurons between the adult and aged dogs. These differences may be associated with oxidative stress in aged dogs compared to that in adult dogs.     

Treadmill exercise prevents diabetes-induced increases in lipid peroxidation and decreases in Cu,Zn-superoxide dismutase levels in the hippocampus of Zucker diabetic fatty rats

In the present study, we investigated the effects of treadmill exercise on lipid peroxidation and Cu,Zn-superoxide dismutase (SOD1) levels in the hippocampus of Zucker diabetic fatty (ZDF) rats and lean control rats (ZLC) during the onset of diabetes. At 7 weeks of age, ZLC and ZDF rats were either placed on a stationary treadmill or made to run for 1 h/day for 5 consecutive days at 16~22 m/min for 5 weeks. At 12 weeks of age, the ZDF rats had significantly higher blood glucose levels and body weight than the ZLC rats. In addition, malondialdehyde (MDA) levels in the hippocampus of the ZDF rats were significantly higher than those of the ZLC rats whereas SOD1 levels in the hippocampus of the ZDF rats were moderately decreased. Notably, treadmill exercise prevented the increase of blood glucose levels in ZDF rats. In addition, treadmill exercise significantly ameliorated changes in MDA and SOD1 levels in the hippocampus although SOD activity was not altered. These findings suggest that diabetes increases lipid peroxidation and decreases SOD1 levels, and treadmill exercise can mitigate diabetes-induced oxidative damage in the hippocampus.     

Effects of a blend of essential oils and overcrowding stress on the growth performance,meat quality and heat shock protein gene expression of broilers

Overcrowding stress is common in the poultry industry. Chickens exposed to long-term stressful situations are characterised by welfare impairment and immunosuppression.

1. The present study evaluated the effects of a blend of essential oils (EOB; cinnamaldehyde and thymol) and stocking density on the performance, gut microflora, meat quality and physiological stress markers of broilers.

2. One-day-old Ross 308 male broiler chickens (n = 360) were allocated to 4 experimental groups from d 22 to 42. Each treatment had 6 replicates of 15 chicks. Two groups were subjected to a high stocking density (HSD) of 20 birds/m² and the other two groups were kept at a low stocking density (LSD) of 10 birds/m².

3. The results of this study indicate that overcrowding stress decreased growth performance parameters, blood immunoglobulin (Ig)G and heterophil:lymphocyte (H:L) ratio but increased IgA and IgM levels. HSD reduced water-loss rate and pH decline at 45 min post mortem in the breast muscle.

4. Essential oils supplementation elevated H:L ratio but decreased breast meat redness and pH₂₄.

5. Significant interactions between EOB and stocking density were observed for corticosterone (CS) level and mRNA levels of heat shock protein 70 (HSP70) in brain and heart. Although HSD increased CS and HSP70 when compared to LSD, the effects of the former were inconsistent with EOB supplemented diets.

6. In conclusion, dietary EOB supplementation could improve some of the biomarkers associated with overcrowding stress in broiler chickens.