Gill B P
Meat and Livestock Commission, PO Box 44, Winterhill House, Snowdon Drive, Milton Keynes, UK, MK6 1AX.
J Anim Sci. 2006 Jul;84(7):1926-34. doi: 10.2527/jas.2005-203.
The relationships among BW, backfat depth, and body physical and chemical composition were evaluated in response to dietary protein and DE balance in breeding gilts from 30 kg of BW to weaning of the first litter. Large White (sire) x Landrace (dam) F1 hybrid (White; n = 75) and Landrace (sire) x (Meishan x Large White; dam) (Meishan; n = 19) hybrid gilts were received at 30 kg of BW. Five gilts were taken as the initial slaughter group at 30 kg of BW, and the remaining gilts were fed diets differing in total lysine to DE ratio, high (H) vs. low (L), from 30 kg of BW to mating (rearing), and during gestation and lactation, allowing factorial investigation of dietary treatment effects and interactions during rearing, gestation, and lactation. Gilts were slaughtered at approximately 50 and 90 kg of BW, and at mating, farrowing, and weaning. Gilts fed L diets during rearing were lighter at mating (117.9 vs. 133.6 kg of BW, P = 0.035) due to a reduction in gain (592 vs. 720 g/d, P = 0.002) and a restriction in protein accretion (83 vs. 117 g/d, P = 0.001). During rearing, lipid accretion did not differ between L- and H-fed gilts (208 vs. 198 g/d, P = 0.60), but the ratio of lipid to protein accretion was about 1.5-fold greater in L-fed gilts, where lipid mass expressed as a percentage of BW was increased at mating (26.0 vs. 21.9%, P = 0.005). Effects of L diets on lipid accretion during rearing were transient; no residual effects on body lipid mass (P > 0.17) were found at farrowing or weaning. Overall, Meishan hybrids carried greater lipid mass (P < 0.001) than White hybrid gilts. Whereas the rate of body lipid and protein accretion and body lipid and protein mass can be nutritionally influenced and can vary according to growth stage, reproductive status, and genotype, this study established that body protein mass expressed as a proportion of the lipid free empty BW remains inflexible. A value for this measure of 0.188 +/- 0.0052 was found in White and Meishan hybrid gilts ranging from 28 to 203 kg of BW and 3 to 36 mm backfat depth, covering growth, pregnancy, and lactation, and offered diets differing in protein and energy balance. Body protein mass can be predicted as approximately 0.2 of the lipid free empty BW once body lipid mass is estimated accurately from physical measurements, such as backfat depth (P2, mm) and BW (kg), by regression using lipid (kg) = - 8.14 (SE, 1.302) + 0.167 (SE, 0.010) BW + 0.883 (SE, 0.065) P2 (residual SD = 3.51; R2 = 0.912).
本研究评估了体重（BW）、背膘厚度与身体物理和化学成分之间的关系，这些关系受配种小母猪从30 kg体重到第一胎断奶期间日粮蛋白质和消化能平衡的影响。大白猪（父本）×长白猪（母本）F1杂种猪（白色；n = 75）和长白猪（父本）×（梅山猪×大白猪；母本）（梅山猪；n = 19）杂种小母猪在体重30 kg时入栏。5头小母猪在体重30 kg时作为初始屠宰组，其余小母猪从体重30 kg到配种（饲养期）、妊娠期和哺乳期，饲喂总赖氨酸与消化能比值不同的日粮，高（H）组和低（L）组，以便对饲养期、妊娠期和哺乳期日粮处理效果及相互作用进行析因研究。小母猪在体重约50 kg和90 kg时，以及在配种、产仔和断奶时屠宰。饲养期饲喂L组日粮的小母猪配种时体重较轻（117.9 vs. 133.6 kg体重，P = 0.035），这是由于增重减少（592 vs. 720 g/d，P = 0.002）和蛋白质沉积受限（83 vs. 117 g/d，P = 0.001）。饲养期，饲喂L组和H组日粮的小母猪脂肪沉积无差异（208 vs. 198 g/d，P = 0.60），但饲喂L组日粮的小母猪脂肪与蛋白质沉积比值约高1.5倍，其中脂肪质量占体重的百分比在配种时增加（26.0 vs. 21.9%，P = 0.005）。饲养期L组日粮对脂肪沉积的影响是短暂的；产仔或断奶时未发现对体脂质量有残留影响（P > 0.17）。总体而言，梅山杂种猪比白色杂种小母猪的脂肪质量更高（P < 0.001）。虽然体脂和蛋白质沉积速率以及体脂和蛋白质质量可受营养影响，并可因生长阶段、繁殖状态和基因型而异，但本研究确定，以无脂空体重比例表示的体蛋白质量保持不变。在体重28至203 kg、背膘厚度3至36 mm的白色和梅山杂种小母猪中，涵盖生长、妊娠和哺乳期，并提供蛋白质和能量平衡不同的日粮，该指标值为0.188±0.0052。一旦通过物理测量（如背膘厚度（P2，mm）和体重（kg））准确估计体脂质量，体蛋白质量可预测为无脂空体重的约0.2，通过回归方程脂肪（kg） = - 8.14（标准误，1.302） + 0.167（标准误，0.010）体重 + 0.883（标准误，0.065）P2（残差标准差 = 3.51；R2 = 0.912）计算得出。
