Robbins K R, Ballew J E
Growth. 1984 Spring;48(1):44-58.
A series of serial slaughter experiments was conducted with three strains of chickens of greatly different rates of body growth through 49 days of age. During the first week of life, the body weight of the rapidly growing strain increased from hatching at a rate twice that observed in either the medium or slowly growing strain of chicken. The percentage increase in body weight which occurred during the seventh week of life (i.e., gain from day 42 to day 49 as a percentage of 42-day body weight) was similar for all three strains. Daily gains in crude protein and ash, expressed as percentages of daily carcass weight gain, were similar among strains. However, daily fat gain, expressed as a percentage of daily carcass weight gain, decreased slightly in the slow growing strain during the last two weeks of the study, remained relatively constant in the medium growing strain, but increased linearly and substantially in the rapid growing strain. It is hypothesized that the biological factors which facilitate the very rapid early rate of growth in the rapid growing breed also result in excessive energy consumption as the bird ages and the rate of proportional increase in body weight declines.
对三种生长速度差异极大的鸡进行了一系列连续屠宰实验，实验持续到49日龄。在生命的第一周，快速生长品系的鸡体重从孵化开始的增长速度是中等生长品系或缓慢生长品系鸡的两倍。在生命的第七周（即从第42天到第49天的增重占42日龄体重的百分比），所有三个品系的体重增加百分比相似。以每日胴体增重的百分比表示的粗蛋白和灰分的日增重，各品系之间相似。然而，以每日胴体增重的百分比表示的日脂肪增重，在研究的最后两周，缓慢生长品系略有下降，中等生长品系相对保持恒定，但在快速生长品系中呈线性且大幅增加。据推测，促进快速生长品种早期极快速生长速度的生物学因素，也会导致随着鸡龄增长和体重成比例增加速度下降而出现能量消耗过多的情况。
