Critser D J, Miller P S, Lewis A J
Department of Animal Science, University of Nebraska, Lincoln 68583-0908, USA.
J Anim Sci. 1995 Nov;73(11):3376-83. doi: 10.2527/1995.73113376x.
An experiment using 120 crossbred pigs (60 barrows and 60 gilts) was conducted to determine the effect of dietary protein concentration on the compensatory response in growth after a period of feed restriction. Thirty pigs were allowed ad libitum (AL) access to one of five corn-soybean meal diets (13.1 to 18.4% CP) from approximately 42 to 102 kg BW. Thirty additional pigs were restricted (R) to a maintenance amount of a 14.4% CP diet for 21 d, after which they were allotted to one of the five diets and allowed ad libitum access to feed until they reached 102 kg. Restricted pigs had lower ADFI, ADG, and ADG/ADFI (P < .05) than did AL pigs. During the postrestriction period, R pigs had higher ADFI and ADG (P < .001) and tended to be more efficient (P < .08) than AL pigs. Average backfat thickness was not different (P > .8) between AL and R pigs. Lean percentage (5% fat) was not affected (P > .5) by feeding regimen but increased linearly (P < .1) as protein level increased. Organ weights (expressed as a percentage of empty BW.75) were similar in AL and R pigs. However, kidney and stomach weights differed among protein levels (P < .01), as did liver weight (P < .06), with a linear increase (P < .02) in both kidney and liver weights to dietary protein level. Barrows had higher ADFI and ADG and greater average backfat thickness (P < .02) than gilts. Barrows had smaller LMA, a lower percentage of lean (P < .001), and higher average backfat (P < .005) than gilts. Liver weight was heavier (P < .02) and small intestine weight tended to be heavier (P < .07) for barrows than for gilts. Kidney, spleen, and lungs were heavier (P < .05) in gilts than in barrows. Livers from barrows tended to contain more protein (P < .06) and less fat (P < .05) than livers from gilts. These results indicate that a compensatory growth response occurred during relimentation, and that the effects of dietary protein concentration on growth rate and carcass measurements were similar in both AL and R pigs.
采用120头杂交猪（60头公猪和60头母猪）进行了一项试验，以确定日粮蛋白质浓度对限饲一段时间后生长补偿反应的影响。从体重约42 kg至102 kg期间，30头猪随意采食（AL）5种玉米-豆粕型日粮（粗蛋白含量13.1%至18.4%）中的一种。另外30头猪限饲（R）于粗蛋白含量14.4%的日粮维持量21天，之后将它们分配到5种日粮中的一种，并随意采食直至体重达到102 kg。限饲猪的平均日采食量（ADFI）、平均日增重（ADG）和ADG/ADFI均低于随意采食猪（P<0.05）。在限饲期后的阶段，限饲猪的ADFI和ADG较高（P<0.001），且效率倾向于高于随意采食猪（P<0.08）。随意采食猪和限饲猪的平均背膘厚度无差异（P>0.8）。瘦肉率（5%脂肪）不受饲喂方式影响（P>0.5），但随蛋白质水平升高呈线性增加（P<0.1）。随意采食猪和限饲猪的器官重量（以空腹体重的75%表示）相似。然而，肾脏和胃的重量在蛋白质水平间存在差异（P<0.01），肝脏重量也有差异（P<0.06），肾脏和肝脏重量均随日粮蛋白质水平呈线性增加（P<0.02）。公猪的ADFI和ADG较高，平均背膘厚度也更大（P<0.02）。公猪的瘦肉率较低（P<0.001），平均背膘较厚（P<0.005），且瘦肉量（LMA）较小。公猪的肝脏较重（P<0.02），小肠重量倾向于比母猪重（P<0.07）。母猪的肾脏、脾脏和肺比公猪重（P<0.05）。公猪肝脏中的蛋白质含量倾向于比母猪肝脏多（P<0.06），脂肪含量比母猪肝脏少（P<0.05）。这些结果表明，再饲喂期间发生了补偿性生长反应，日粮蛋白质浓度对生长速度和胴体指标的影响在随意采食猪和限饲猪中相似。
