This study aimed to investigate the efficacy of probiotic supplementation in mitigating stress and improving performance, carcass yield, carcass quality parameters, sensory acceptability, microbiological quality and economic profitability of broilers reared at different stocking densities. Two hundred and forty chicks were divided into four groups; two groups were reared at a low stocking density (LSD, 10 bird/m2), including one group that was provided with Protexin® probiotic (Enterococcus faecium) supplemented in water (LSDP). Similarly, the other two groups were reared at a high stocking density (HSD, 15 bird/m2), including one group that was provided with the same probiotic supplementation (HSDP). Throughout the growing cycle, bird performance was monitored. At the end of the growing cycle, stress indicators were measured in blood. Besides, carcass and giblet weights, dressing yield, carcass quality parameters, sensory acceptability, microbiological quality and economic profitability were assessed. As a result, HSD mostly impaired broiler performance, increased stress indicators, reduced carcass yields, carcass quality parameters and sensory acceptability, while boosted profitability and slightly lowered microbiological quality. On the other hand, probiotic supplementation reversed the negative effects of HSD. As probiotic supplementation boosted broiler performance, reduced blood stress indicators, increased carcass and giblet yields, carcass quality parameters and sensory scores, besides, it improved the microbiological status of broiler meat in terms of fecal coliforms and E. coli MPN. To conclude, rearing broilers at high stocking density induced stress, compromised performance and reduced carcass quality. These negative impacts could be successfully faced by using probiotic supplementation in drinking water.

Objective: The purpose of this work was to investigate the combination of early-age acclimation and linseed dietary inclusion in enriching polyunsaturated fatty acids (PUFAs) in broilers meat as a strategy to mitigate heat stress. Materials and Methods: A total of 400 broiler chicks were assigned to four experimental groups with four duplicates (25 animals each): C: control (basal diet), AC: early-age acclimated (basal diet), Cl: fed 5% ground linseed, and Acl: early-age acclimated and fed 5% ground linseed. The lipid and fatty acid contents of different parts (breast, thigh, liver, subcutaneous, and abdominal fat) of broilers were determined. Results: Low levels of lipids and unsaturated fatty acids have been found in the meat of accli¬mated broilers. Higher levels of linolenic acids were noted in Cl thigh meat compared to C (6% vs. 2.68%, respectively). The results showed that oleic and linoleic acids constitute a large part of the PUFAs of different meats. The most elevated levels of monounsaturated fatty acids were recorded in the breast meat of AcL animals. The highest content of omega-3 was recorded in the liver of AcL animals compared to that of C (14.98% vs. 7.8%, respectively). Conclusion: We suggest that the combination of treatments during hot conditions has led to the reversion of the environment-affected variables to accepted values, and yields better ther¬moresistance, PUFA-enriched meat, and safeguard animal health which conferred to birds better solutions to reduce fatigue and hypoxic activities, which induces a considerable consumption of oxygen. [J Adv Vet Anim Res 2021; 8(2.000): 237-245]