Adaptive Responses of Industrial Ross 308 Cross Broilers Relative to Rearing, Fattening, and Slaughtering Periods

The global practice’s research in the impact of the technology-related stress on poultry indicates a significant decrease in the poultry industry’s efficiency, requiring science-based approaches to increase the adaptive potential of stressed organisms. The objective of the research study is to investigate the adaptive responses of broiler chickens relative to the periods of rearing, fattening, and slaughtering. The broiler performance and survival rates were the aspects to consider during the observations. The slaughter process for broiler chickens at the age of 38–39 days usually took 2 days. In order to reveal evolution of adaptive responses, the blood was sampled from ten chickens of each group on days 11, 25, 35, and 38 of their life and in the slaughter period to make smears and determine leukogram patterns. Over the slaughter period, the blood samples were collected four times after the fasting, transporting, and stunning phases and prior to being slaughtered. Over the raising period of the experimental broiler chicken batch, 4042 heads of 60 025 chickens died, while the transportation losses comprised 88 heads. The overall survival rate and the feed conversion into products comprised 93.1% and 1.68, respectively. The European Production Efficiency Factor (EPEF) made up 364 units. The basophil count in the blood test for the studied poultry tended to decrease with increasing the age of the birds. The eosinophil ratio in raising chickens remained stable. However, it sharply increased five times in the slaughter period, which is associated with the feed restriction for broilers. The monocyte count shows a pronounced tendency to increase with age, becoming 3.4 times higher at the age of 38 days than the parameter value for 25-day-old chickens. The final fattening stage and the slaughter process in poultry are followed by the stress-induced activation of responses. Therefore, it is advisable to draw attention to these specific periods. Electrical stunning of broilers prior to being slaughtered causes a statistically significant (p = 0.017) decrease in the level of the heterophil-to-lymphocyte ratio by 22.4%.