1. The study was designed to assess the impact of stocking density (6 and 13 birds/m² equivalent to 12·6 or 27·2 kg/m², respectively) on growth performance, meat quality, behaviour, and indicators of physiological and oxidative stress as measures of bird welfare. 2. The higher stocking density negatively affected final body weight and feed intake but not cumulative feed conversion rate. Muscle colour traits, pH₂₄, cooking loss and shear values were not affected. Birds reared at the lower density showed higher intramuscular fat, liver weight, liver NADP-isocitrate and NADP-malate dehydrogenase activity. 3. Higher stocking density was associated with decreased locomotor activity and increased physiological (H:L ratio and bursa weight) and oxidative (glutathione concentrations and reduced:oxidised glutathione ratios) stress indicators. 4. The results show that stocking density did not significantly affect broiler meat quality characteristics but higher density decreased growth performance, increased physiological and oxidative stress levels and decreased locomotor activity.

The present study was conducted to describe the effects of quercetin dietary supplementation, at levels of 0.5 and 1 g/kg of feed, on growth performa

Body weight; yield of the major carcass component parts of breast, leg, thigh, drumstick, breast meat, thigh meat, and drumstick meat; feed consumption; feed conversion; and mortality of male broiler chickens from two commercial strains were measured from hatching to 154 d of age. As no differences were observed between the two strains, for any of the traits measured, the statistical analysis was made using pooled data. Growth curves for BW, breast weight, and leg weight were calculated. The Richards function was chosen to fit the data. The type of the curves predicted was typically sigmoid. Asymptotic weights for BW, breast weight, and leg weight were estimated at 6,870.2, 1,744.2, and 851.5 g, respectively. Age at point of inflection, at which maximum growth rate is attained, was predicted at 44.4, 47, and 49.1 d, respectively. The percentage of breast and breast meat increased with age, whereas percentages of leg, thigh, and drumstick remained roughly constant. Weekly feed conversion was determined, and polynomial functions were applied to relate feed consumption and feed conversion to the age of the birds. Cumulative mortality increased with age, especially beyond 70 d of age, rising to 50% by the end of the experiment. Mortality was related to high incidence of leg weakness observed in the same period. The results of the current study provide information on the growth potential of contemporary, genetically improved broiler chickens by means of a mathematical model.

Agro-industrial by-products (AIBPs) that are not intended for human consumption can be used as alternatives to conventional feedstuffs in animal nutrition to produce animal products without competing for land or triggering the food-feed competition, thus leading to environmental, social, and economic sustainability. These by-products are also known to contain several bioactive compounds and have a potential to become nutraceuticals that can promote the health and well-being of poultry. The potentials of some AIBPs (e.g., fruit juice industry leftovers, oilseed industrial by-products, distillers’ grain by-products, vinification by-products, olive oil industry by-products, pomegranate by-products, tomato processing by-products) and their derivative products as functional feeds for poultry, but also potential limitations of utilizing AIBPs in poultry nutrition are elaborated in the present review. The possible mechanisms through which AIBPs may improve the health status and productivity of poultry are also discussed. We suggest that nutrient variability across countries should be stabilized and potential hazards such as mycotoxins and pesticides should be eliminated, and the potential hazards present in AIBPs (e.g., mycotoxins) should be better controlled through appropriate legislation and proper application of control measures. Modern processing methods, new types/classifications, and proper developmental strategies foster the utilization of AIBPs in animal nutrition. This review focuses on the AIBPs as feeds, not only for their nutritional value but also for their contribution to sustainable practices.

An experiment was conducted to examine the effects of supplementing broiler feed with hesperidin or naringin, on growth performance, carcass characteristics, breast meat quality and the oxidative stability of breast and thigh meat. Two hundred and forty 1-day-old Ross 308 broiler chickens were randomly assigned to 6 groups. One of the groups served as a control (C) and was given commercial basal diets, whereas the other five groups were given the same diets further supplemented with naringin at 0.75 g/kg (N1), naringin at 1.5 g/kg (N2), hesperidin at 0.75 g/kg (E1), hesperidin at 1.5 g/kg (E2) and a-tocopheryl acetate at 0.2 g/kg (E). At 42 days of age, 10 chickens per treatment group were slaughtered for meat quality and oxidative stability assessment. No significant differences were observed among groups in final body weight, carcass weight and internal organs weights (P>0.05) apart from liver that decreased linearly with increased levels of naringin (P-linear<0.05). Regarding the breast meat quality parameters, only redness (a*) value was higher in E1 and N1 group compared to VE group (P0.05). Measurement of lipid oxidation values showed that after hesperidin and naringin dietary supplementation, malondialdehyde values decreased in tissue samples in a dose depended manner (P-linear<0.05). In conclusion, hesperidin and naringin, positively influence meat antioxidative properties without negative implications on growth performance and meat quality characteristics in poultry, thus appearing as important additives for both the consumer and the industry.