Journal of Veterinary and Applied Sciences

Abstract
Broiler production in humid tropical environments is challenged by heat stress and daily fluctuations in ambient temperature, relative humidity and temperature-humidity index (THI), which disrupt physiological stability. This study evaluated the effects of chrono-nutrition (timed feeding) on thermoregulation, respiratory responses and oxidative stress status of broiler chickens raised under humid tropical environmental condition. A total of 100 Arbor Acre broilers were used for the study. They were randomly assigned to four feeding regimens: Ad libitum (Control), Morning (06.00 – 08.00 h), Afternoon (12.00 – 14.00 h), and Evening feeding (17.00 – 19.00 h) groups. Environmental parameters (ambient temperature, relative humidity and THI) were monitored to capture diurnal variation. Rectal temperature, respiratory rate, serum levels of malondialdehyde (MDA) and antioxidant enzymes (superoxide dismutase [SOD] and catalase [CAT]) were measured at days 14 (baseline), 28 and 42 of the feeding experiment. Results showed that Evening-fed birds had significantly lower (p < 0.05) mean rectal temperatures at days 28, 35 and 42, and lower respiratory rates at days 35 and 42, indicating improved thermoregulation under peak environmental load. Morning- and Afternoon-fed groups also showed moderate lower rectal temperatures and respiratory rates, when compared with the Control. Time-restricted feeding significantly reduced (p < 0.05) MDA levels at day 28, with the greatest decline in Evening-fed birds. Serum SOD activity was higher in Morning-fed birds at day 14, and CAT activity was higher in time-restricted feeding groups at day 28 (p < 0.05). The reduction in MDA at 28 days highlights improved oxidative stability during peak growth, making evening feeding a simple, cost-effective strategy to enhance poultry welfare and productivity. Feeding time produced stage-specific differences in feed intake, with Afternoon-fed birds showing lower intake than controls at days 21 and 28, whereas Morning- and Evening-fed birds showed higher (p < 0.05) intake at selected periods. Initial live-weight did not differ significantly among groups, but by day 42, Afternoon-fed birds had significantly lower (p < 0.05) live-weight than all other groups. Weight gain was significantly lower (p < 0.05) in Afternoon-fed birds at days 28 and 42 compared with the Control group. It was concluded that aligning feeding time with cooler periods led to significantly less thermal and oxidative stress, and greater weight gain per feed consumed in the broilers chickens.

Keywords: Chrono-nutrition (timed feeding); Circadian entrainment; Heat load; Redox homeostasis; Temporal feeding strategy; Weight gain.

How to cite this article:
Egbuniwe IC and Felix ES (2026). Effects of chrono-nutritional feeding (timed feeding) strategies on thermoregulation, respiratory rate and oxidative stress status of broiler chickens raised under humid tropical conditions. Journal of Veterinary and Applied Sciences, 16(2): 1648 – 1669.

*Correspondence: E-mail: ifeanyi.egbuniwe@gmail.com Phone: +2348065308980