Rectal temperature and respiration rate as indicators of heat stress in broiler chickens subjected to early-age thermal conditioning and vitamin C supplementation.

One of the major concerns in poultry production presents heat stress (HS) and it is followed by significant economic loss manifested by reduced growth, decreased immune response, increased mortality, etc. The objective of this study was to investigate whether the early-age thermal conditioning (ETC) and vitamin C (Vit.C) treatments, individually and in combination, produce their beneficial effects through increased heat release manifested as a change in respiration rate consequentially leading to a decrease in the chicken's body temperature and thus reduce the harmful effects of HS. A 400 broiler chicks mixed sex male and female were split into four groups. From day 22 through the end of breeding, Group C received Vit.C (2 g/L) diluted in water. On the fifth day of production, group T was exposed to ETC for 24 h at 38 ± 1 °C. Group TC was formed by combining treatments of groups T and C, and group K served as the control. All chicks were exposed to chronic HS in the last two weeks breeding period. On 11 out of 14 days, the highest respiration rate was observed in group TC with a statistically significant difference in comparison with the group in which the lowest values were measured. The lowest rectal temperature in the morning was measured in group TC on all 14 days. During the evening measurements, the average rectal temperature was the lowest in group TC on 13 out of 14 testing days. The ETC and Vit.C reflected to increase in respiration rate resulting in more heat being released to the environment, achieving lower body temperature in broiler chickens and the best results are seen when these methods are combined. [ABSTRACT FROM AUTHOR]