Institute of Animal Science, Agricultural Research Organization, the Volcani Center, Bet Dagan 50250, Israel.
Poult Sci. 2013 Apr;92(4):882-9. doi: 10.3382/ps.2012-02568.
The significance and importance of the preincubation and incubation temperatures for broiler chickens has been elucidated by altering normal incubation conditions to study the effects on embryo development. Furthermore, only recently has convincing evidence that temperature could influence the sex ratio of avian offspring become available. The objective of this study was to elucidate the effects of temperature before or during (or both) the sex determination period of incubation on hatchability, apparent sex ratio, growth and development posthatching, and secondary sexual phenotypic characteristics. Two experiments were conducted in winter and summer using Cobb 500 fertile eggs that had been stored for 4 and 9 d, respectively. Four treatments of 180 eggs each were applied: control, preheating (Pre) 30.2°C for 12 h before incubation, heating (38.1°C) the embryos between embryonic d 0 (E0) and E5 (M) of incubation, and a combination of both (Pre+M). All 3 thermal treatments increased early embryonic deaths, but improved hatchability in both experiments. The point of 50% hatchability was achieved more rapidly in the treated eggs. The BW of males and females at 35 d of age in both experiments was numerically or significantly greater in the broilers that had been exposed to thermal treatments, which was coincident with a similar trend for increased relative breast muscle weight. Secondary sexual characteristics (comb, wattles, testes in males) were also affected by thermal treatments, being heavier in most cases, which may be attributed to the finding that the 3 thermal treatments resulted in numerically or significantly increased plasma testosterone concentration in both sexes and experiments. Differences in the level of significance between the experiments probably related to the length of storage period and the season in which each experiment took place. It was concluded that thermal treatments preincubation or during the sex determination period of incubation had, in general, a positive effect on hatchability, growth performance, and secondary sexual characteristics of broiler males and females, probably caused by the increase of plasma testosterone concentration in both sexes.
种鸡孵化前和孵化期间温度的重要性已经通过改变正常孵化条件来研究对胚胎发育的影响得到了阐明。此外，直到最近才有令人信服的证据表明，温度可以影响禽类后代的性别比例。本研究的目的是阐明孵化期间（或两者）性别决定期之前或期间的温度对孵化率、表观性别比例、孵化后生长和发育以及次级性表型特征的影响。本研究在冬季和夏季进行了两次试验，使用分别储存了 4 天和 9 天的科布 500 枚种蛋。应用了 4 种处理，每个处理 180 枚蛋：对照组、孵化前预加热（Pre）30.2°C 12 小时、孵化期间胚胎（E0）至 E5 期间加热（38.1°C）（M）以及两者的组合（Pre+M）。所有 3 种热处理都增加了早期胚胎死亡，但在两次试验中都提高了孵化率。处理组的种蛋达到 50%孵化率的时间更快。在两次试验中，35 日龄雄性和雌性的 BW 均在暴露于热处理的肉鸡中数值上或显著增加，这与增加相对胸肌重量的趋势一致。次级性特征（鸡冠、肉垂、睾丸）也受到热处理的影响，在大多数情况下更重，这可能归因于 3 种热处理导致雄性和雌性的血浆睾酮浓度数值上或显著增加的发现。两次试验之间的显著水平差异可能与储存期的长短以及进行每个试验的季节有关。总之，孵化前或孵化期间性别决定期的热处理通常对肉鸡雄性和雌性的孵化率、生长性能和次级性特征有积极影响，这可能是由于两性血浆睾酮浓度的增加。
