ABSTRACT Background Optimal incubation temperature and in ovo feeding strategies during incubation are crucial for ideal performance and welfare of chicks. Objective This study investigated the effects of incubation temperature and early in ovo feeding on hatchability, internal organ development, bone mineralisation and blood metabolites in broiler chicks. Methods A total of 1200 eggs from 58‐week‐old Arbor Acre breeders, averaging 62 ± 1 g, were incubated in separate dual‐system automatic incubators (Senjie series DZ 47‐53) at specified temperatures and 60% humidity. A total of 400 eggs were randomly assigned to three incubation temperature treatments, with four replicates per treatment, based on predetermined air temperatures of 36.5°C, 37.0°C and 37.5°C, maintained from embryonic day (ED) 1 until ED 18. On ED 10, eggs were candled, and each temperature group was further divided into three subgroups: the first serving as a control, where eggs were perforated but not injected; the second receiving an in ovo injection of glucose solution (5 mg/mL); and the third receiving an in ovo injection of vitamin‐D3 solution (25 mg/mL). The supplements were administered 0.2 mL at egg level in the air sac. Results Hatchability showed a clear temperature‐dependent response, reaching a maximum of 89.86% in glucose‐injected eggs at 37.5°C and decreasing to 48.33% in vitamin‐D3 injected eggs at 36.5°C ( p < 0. 05). Bone mineral content was influenced by interactions between incubation temperature and feeding, with calcium highest in glucose‐fed chicks incubated at 37.0°C, while phosphorus was highest in control eggs incubated at 36.5°C ( p < 0.05). By Day 21, chicks fed vitamin‐D3 consistently demonstrated lower cholesterol levels, whereas those fed glucose and controls showed higher alkaline phosphatase activity under increased incubation temperatures ( p < 0.05). Conclusion Optimal results were achieved with glucose injection at 37.0°C and 37.5°C, improving hatchability, intestinal development and bone mineralisation, whereas vitamin‐D3 supplementation at lower temperatures negatively impacted hatchability and metabolic balance.
Okai et al. (Thu,) studied this question.