Shields R G, Mahan D C, Graham P L
J Anim Sci. 1983 Jul;57(1):43-54. doi: 10.2527/jas1983.57143x.
An experiment using 81 crossbred swine was conducted to evaluate quantitative and percentage chemical compositional changes of swine from 1.5 kg (birth) to 145 kg body weight. Groups of eight pigs were sacrificed at 1.5, 6.4 and 18 kg, and then at 18 kg increments to 145 kg. Body composition was determined by grinding the entire body, minus digesta, partitioning the carcass from other body components and chemically analyzing each subsample. Results indicated that weight of the carcass increased linearly with live weight, while the total weight of the other body components increased quadratically. Percentage fat in the empty body (ingesta-free) increased rapidly from birth to weaning (6.4 kg), plateaued until 36 kg and then increased, while water percentage declined dramatically from 1.5 to 6.4 kg, but then declined more gradually to 145 kg. Percentage protein increased from birth to 18 kg, plateaued and declined after 54 kg. When expressed on a fat-free basis, the percentage water decreased in a curvilinear manner with increasing animal weight while protein increased curvilinearly inverse to the change in water. Constancy of composition ("chemical maturity") between protein and water in the fat-free body was not attained by 145 kg. When expressed on an absolute empty body basis, water, protein and fat weight increased curvilinearly with increasing empty body weight; the rate of fat deposition increased faster during the latter growth stages while water and protein had declining deposition rates. Logarithmic and quadratic equations relating body composition to animal weight had similar R2 and lower coefficients of variation than linear or semilog functions. Gilts contained more water and less fat than barrows at similar slaughter weights, but sex differences were not apparent when expressed on a fat-free basis. The growth and fattening process was reflected in several carcass measurements. Backfat thickness, longissimus muscle area and body length increased as pig weight increased.
进行了一项使用81头杂交猪的实验，以评估猪从1.5千克（出生时）到145千克体重期间化学成分的定量和百分比变化。每组8头猪在体重为1.5、6.4和18千克时屠宰，然后以18千克的增量直至145千克时屠宰。通过研磨整个身体（减去消化道内容物）、将胴体与其他身体成分分开并对每个子样本进行化学分析来确定身体组成。结果表明，胴体重量随活体重呈线性增加，而其他身体成分的总重量呈二次方增加。空腹体（无消化道内容物）中的脂肪百分比从出生到断奶（6.4千克）迅速增加，在36千克之前保持平稳，然后增加，而水分百分比从1.5千克到6.4千克急剧下降，但随后到145千克时下降更为缓慢。蛋白质百分比从出生到18千克增加，在54千克后保持平稳并下降。以无脂肪为基础表示时，水分百分比随动物体重增加呈曲线下降，而蛋白质呈曲线增加，与水分变化相反。在145千克时，无脂肪体中蛋白质和水分之间的组成恒定性（“化学成熟度”）尚未达到。以绝对空腹体为基础表示时，水分、蛋白质和脂肪重量随空腹体重增加呈曲线增加；在生长后期脂肪沉积速率增加得更快，而水分和蛋白质的沉积速率下降。将身体组成与动物体重相关的对数和二次方程具有相似的R²，并且变异系数比线性或半对数函数更低。在相似的屠宰体重下，小母猪比阉公猪含有更多的水分和更少的脂肪，但以无脂肪为基础表示时性别差异不明显。生长和育肥过程反映在几个胴体测量指标上。随着猪体重增加，背膘厚度、背最长肌面积和体长增加。
