Elliott K E C, Lindsey L L, Fatemi S A, Gerard P D, Peebles E D
USDA-ARS, Poultry Research Unit, Mississippi State, MS 39762, USA.
Department of Poultry Science, Mississippi State University, Mississippi State, MS 39762, USA.
Poult Sci. 2025 Apr;104(4):104991. doi: 10.1016/j.psj.2025.104991. Epub 2025 Mar 6.
The effects of a reduction in incubation temperature, made to accommodate higher levels of embryonic heat production, on the post hatch body temperature and somatic characteristics of Ross 708 broilers were determined. Incubation temperature treatments (TRT) were a standard (STRT, 37.5 °C) and a lower (LTRT, 35.6°C) TRT provided between 12 and 21 d of incubation (DOI). All eggs were incubated at 37.5 °C between 0 and 12 DOI. Temperature transponders implanted in the air cell of each egg at 12 DOI were extracted and inserted subcutaneously into the neck of the corresponding hatchling to record chick body temperature (CBT) through 21 d of grow out (DOG). After placement, multiple CBT and litter temperature (LT) readings were recorded daily between 1 and 21 DOG, and BW was determined at placement (0 DOG), and BW, body length (BL), and BW to length ratio (BWTLR) were determined on 7, 14, and 21 DOG. Thirteen daily mean CBT readings in the STRT were significantly higher than those in the LTRT between 1 and 21 DOG. Nevertheless, there was no significant correlation between LT and CBT, and when hatch time (HT) and BW were accounted for, embryo temperature (ET) and CBT were not significantly correlated. At 0 and 7 DOG, no significant differences in BW were observed between the STRT and LTRT within either sex; however, BW was greatest in males belonging to the STRT at 14 (x̄ = 483.1 g) and 21 (x̄ = 1,033.8 g) DOG. Across DOG and sex, BL was significantly longer in the STRT than in the LTRT, and at 14 and 21 DOG, BWTLR was greater in the STRT than in the LTRT. The LTRT subsequently lowered CBT and negatively affected chick BW, BL, and BWTLR. In conclusion, CBT is not directly associated with ET, but the reductions in CBT and various performance variables in Ross 708 broilers in response to the LTRT is a result of its adverse effects on chick HT and BW.
为适应胚胎更高的产热水平而降低孵化温度，对罗斯708肉鸡出壳后的体温和身体特征的影响进行了测定。孵化温度处理（TRT）包括一个标准处理（STRT，37.5°C）和一个较低处理（LTRT，35.6°C），在孵化的第12至21天（DOI）进行设置。所有种蛋在孵化的第0至12天均在37.5°C下孵化。在第12天DOI时，将植入每个种蛋气室的温度应答器取出，并皮下插入相应雏鸡的颈部，以记录雏鸡出壳后21天（DOG）的体温（CBT）。放置后，在出壳后1至21天每天记录多次CBT和垫料温度（LT）读数，并在放置时（0 DOG）测定体重（BW），在第7、14和21天DOG时测定BW、体长（BL）和体重体长比（BWTLR）。在出壳后1至21天，STRT组的13次每日平均CBT读数显著高于LTRT组。然而，LT与CBT之间没有显著相关性，并且在考虑孵化时间（HT）和BW后，胚胎温度（ET）与CBT之间也没有显著相关性。在0和7天DOG时，无论雌雄，STRT组和LTRT组之间的BW均未观察到显著差异；然而，在14天（x̄ = 483.1 g）和21天（x̄ = 1,033.8 g）DOG时，STRT组雄性的BW最大。在整个DOG期间和不同性别中，STRT组的BL显著长于LTRT组，并且在14和21天DOG时，STRT组的BWTLR大于LTRT组。LTRT随后降低了CBT，并对雏鸡的BW、BL和BWTLR产生了负面影响。总之，CBT与ET没有直接关联，但LTRT导致罗斯708肉鸡的CBT和各种性能变量降低是其对雏鸡HT和BW产生不利影响的结果。
