Burke W H, Marks H L
Growth. 1982 Winter;46(4):283-95.
Plasma growth hormone and prolactin levels were measured in two lines of commercial broiler chickens (lines 2 and 4) and two nonselected randombred broiler lines (lines 1 and 3). The body weights of the 4 lines differed by only a few grams at day of age but by 1 week of age the selected lines were 60-80 g heavier than the unselected lines. At 8 weeks body weights of the selected lines exceeded 2000 g while the unselected lines were approximately half this. At all bleeding times between 1 and 8 weeks of age GH levels of both nonselected lines were significantly higher than those of both selected lines. GH levels of the two selected lines did not differ from each other, nor in general did GH levels of the unselected lines differ from each other. In both experiments GH levels of the unselected lines increased between 1 and 3 weeks then dropped week by week. In contrast, GH levels of the selected lines were rather stable from 1 to 3 weeks and gradually declined thereafter. Prolactin levels of the unselected lines tended to exceed those of the selected lines, but the differences only achieved significance at 2-3 weeks of age. GH levels at various ages were found to be significantly correlated to relative growth at different time periods. These significant correlations were generally positive and occurred most often in the selected broiler lines. Overall analysis of variance showed a significant relationship between GH levels and growth in Expt. 2, but not in Expt. 1.
在两个商业肉鸡品系（品系2和品系4）以及两个非选择随机繁殖肉鸡品系（品系1和品系3）中测量了血浆生长激素和催乳素水平。这4个品系在日龄时体重仅相差几克，但到1周龄时，选择品系比未选择品系重60 - 80克。8周龄时，选择品系的体重超过2000克，而未选择品系约为其一半。在1至8周龄之间的所有采血时间，两个未选择品系的生长激素水平均显著高于两个选择品系。两个选择品系的生长激素水平彼此无差异，未选择品系的生长激素水平总体上也彼此无差异。在两个实验中，未选择品系的生长激素水平在1至3周之间升高，然后逐周下降。相比之下，选择品系的生长激素水平在1至3周相当稳定，此后逐渐下降。未选择品系的催乳素水平往往超过选择品系，但差异仅在2至3周龄时达到显著水平。发现不同年龄的生长激素水平与不同时间段的相对生长显著相关。这些显著相关性通常为正，且最常出现在选择的肉鸡品系中。总体方差分析表明，在实验2中生长激素水平与生长之间存在显著关系，但在实验1中不存在。
