The effect of crude protein (CP) concentration in starter diet (259 or 216 g CP and 11.7 MJ ME/kg, fed from 0 to 21 d of age) on postnatal growth pattern (from hatching to 70 d of age) was analysed in Japanese quail lines divergently selected for high (HG) and low (LG) relative gain of body weight (BW) between 11 and 28 d of age, and constant BW at 49 d of age. 2. Males and females of both lines fed on the low CP diet showed a transient BW retardation between 7 and 28 d of age, and 7 and 35 d of age, respectively, when compared with their counterparts receiving the standard CP diet. 3. Although the negative effect of low CP concentration on growth rate was observed in both lines, a lower tolerance of young HG vs. LG quail to the reduction of CP level in food was evident from their (i) stronger BW retardation at 14 d of age (16 vs. 7%), (ii) more delayed onset of compensatory growth (21 vs. 7 d of age) and (iii) greater prolongation of the acceleration growth phase (3 vs. 1 d of age) following insufficient dietary CP. 4. The line differences in early growth rate were accompanied by significant differences in food intake. The LG line consumed more food than the HG line on both CP diets and consumption was not influenced by food quality. In contrast, HG quail reduced food intake with the decrease of dietary CP concentration. On both CP diets, this was associated with a higher body fatness of LG vs. HG quail. 5. The protein-deficient food could thus represent an important factor contributing to the selection advantage of developmentally accelerated genotypes during the selection for high BW in young age categories.
摘要
分析了起始日粮中粗蛋白（CP）浓度（259或216 g CP和11.7 MJ ME/kg，从0至21日龄饲喂）对日本鹌鹑品系产后生长模式（从孵化至70日龄）的影响，这些品系在11至28日龄期间按体重（BW）相对增重高（HG）和低（LG）进行了不同方向的选择，且在49日龄时体重恒定。2. 与接受标准CP日粮的对应鹌鹑相比，两个品系中饲喂低CP日粮的雄性和雌性鹌鹑分别在7至28日龄和7至35日龄时出现了短暂的体重增长迟缓。3. 尽管在两个品系中均观察到低CP浓度对生长速率有负面影响，但从以下方面明显看出，幼年HG鹌鹑比LG鹌鹑对食物中CP水平降低的耐受性更低：（i）14日龄时体重增长迟缓更严重（16%对7%），（ii）补偿性生长开始延迟更多（21日龄对7日龄），以及（iii）日粮CP不足后加速生长阶段延长更多（3日龄对1日龄）。4. 早期生长速率的品系差异伴随着采食量的显著差异。在两种CP日粮下，LG品系的采食量均高于HG品系，且采食量不受食物质量影响。相反，HG鹌鹑随日粮CP浓度降低而减少采食量。在两种CP日粮下，这与LG鹌鹑比HG鹌鹑体脂更高有关。5. 因此，蛋白质缺乏的食物可能是在幼年高体重选择过程中有助于发育加速基因型选择优势的一个重要因素。
