Comparison of Carcass Characteristics, Meat Quality, and Blood Parameters of Slow and Fast Grown Female Broiler Chickens Raised in Organic or Conventional Production System.

The objective of the study was to compare the carcass characteristics, meat quality, and blood parameters of slow and fast grown female broiler chickens fed in organic or conventional production system. The two genotypes tested were medium slow-growing chickens (SG, Hubbard Red JA) and commercial fast-growing chickens (FG, Ross 308). Both genotypes (each represented by 400 chickens) were divided into two sub-groups fed either organic (O) or conventional (C) systems. Chickens of each genotype and system were raised in a semi environmentally controlled poultry house until 21 d of age and were assigned to 5 pens of 40 chickens each. Then, O system chickens were transferred into an open-side poultry house with an outdoor run. At 81 d of age, 10 female chickens from each genotype and from each production system (n = 40) were randomly chosen to provide material for analysis, and were weighed and brought to the slaughterhouse to assess carcass characteristics and meat quality. The blood parameters were determined by using 5 female chickens from each genotype and from each production system (n = 20). FG had the higher live weight, along with carcass, breast, and thigh-drumstick weights compared to SG (p<0.05). FG had the higher breast yield, whereas SG had the higher thigh-drumstick yield (p<0.05). The O system resulted in a higher amount of abdominal fat (p<0.05). In addition, the O system values were higher for dry matter, crude ash, crude protein, and pH(15) values in breast meat, and for crude ash, crude protein, and pH(15) values in drumstick meat (p<0.05). In addition, total saturated fatty acids, total mono-unsaturated fatty acids, and total omega 3 were significantly higher in the O system than in the C system. Thus, the O system showed a positive advantage compared to the C system regarding female chicken meat quality, primarily within the ash, protein, and total omega 3 fatty acid profiles. In conclusion, the present study indicated that the main factor affecting the carcass characteristics of female chickens was genotype, whereas the organic system contributed to enhanced meat quality. These findings provide a better understanding of the relative roles of genotype and production systems in female broiler characteristics, and might aid producers in designing their facilities to optimize yield and quality while maintaining acceptable animal welfare standards.

The effects of moderately oxidised dietary oil with or without vitamin E supplementation on performance, nutrient digestibility, some blood traits, lipid peroxidation and antioxidant defence of male broilers.

BACKGROUND: The experiment was conducted to determine the effects of dietary supplementation of oxidised oil with or without vitamin E on performance, nutrient digestibility, some blood traits, lipid peroxidation and antioxidant defence system of male broilers. RESULTS: The supplementation of oxidised oil with or without vitamin E to the grower diets did not significantly affect performance, the pH and viscosity values of excreta and nutrient digestibilities in male broilers. Oxidised oil supplementation slightly increased plasma triglyceride and cholesterol concentrations but did not alter plasma glucose concentration. Although malondialdehyde (MDA) and nitric oxide concentrations tended to be higher in the oxidised oil group, these increases were not significant. Birds fed the diet containing oxidised oil had significantly lower superoxide dismutase (SOD) activity. However, no differences were observed in glutathione peroxidase (GSH-Px) activity and uric acid concentrations of broilers fed oxidised oil as compared to the control group. Dietary vitamin E supplementation decreased MDA concentration whereas increasing SOD activity, suggesting that vitamin E supplementation reduced susceptibility to lipid peroxidation. CONCLUSION: The results showed that a milder oxidative stress occurred by supplementation of moderately oxidised oil to the diet of broilers and vitamin E supplementation had been helpful in alleviating lipid peroxidation.

The influence of marginal zinc deficient diet on post-vaccination immune response against hepatitis B in rats.

AIM: To evaluate in vitro T lymphocyte proliferation and specific antibody response to hepatitis B vaccination in two groups of rats fed with normal and marginal zinc content. METHODS: Twenty-two Wistar-Albino rats were randomly assigned into two groups and were fed with constant diet. Zinc was suplemented 10mg/kg dry weight in group I (marginal zinc content) (n=14) and 30mg/kg dry weight in group II (n=8). Hepatitis B vaccine (Engerix B, 4mug) was administered intramuscularly after 8 weeks on feeding and a booster dose was applied 4 weeks after the first injection. Rats were killed 3 weeks after the second injection. Peripheral blood mononuclear cells were stimulated in vitro by PHA (2.5mug/ml) and hepatitis B surface antigen (2.5, 5, 10mug/ml). Proliferation was evaluated by ELISA (celltiter-96 aqueous one solution cell proliferation assay). Serum zinc, anti-HBs titer and zinc per dry liver weight were also measured. Two groups were compared with respect to antigen specific antibody and lymphocyte proliferation responses. Proliferation response to HbsAg were expressed as net percent increase (pci) in lymphocyte proliferation from the baseline activity. RESULTS: Rats' mean body weight and weight gain per month were similar. Median serum zinc was 39 (23-75) and 76(64-115)mug/dl of groups I and II rats, respectively (p<0.05), while there was no difference in liver zinc content between the two groups (37mug/g dry weight versus 32mug/g dry weight). Median anti-HBs levels of groups I and II were 741 (0-10,000)IU/l, 5791 (558-10,000)IU/l, respectively (p<0.05). In lymphocyte proliferation assays, mean net pci with HbsAg of 5 and 10mug/ml were 9.4% and 11.3% in group I rats; while they were 25.3% and 26.1% in group II rats (p<0.01 and p<0.01, respectively). CONCLUSION: In vitro cell-mediated immune response and in vivo specific antibody response to hepatitis B vaccine was decreased in rats fed a diet with marginal zinc content. These observations have shown that marginal Zn deficiency might influence the efficacy of hepatitis B vaccination in humans.