Potter L M, McCarthy J P
Poult Sci. 1985 Oct;64(10):1941-9. doi: 10.3382/ps.0641941.
Two series of three consecutive 4-week experiments with a total of 1,370 Large White turkeys between 8 and 20 weeks of age were conducted to determine the effects of varying levels of dietary fat and protein on body weight gain and feed efficiency. Diets containing 0, 5, and 10% added fat and 18, 20, 22, and 24% protein in a 3 X 4 factorial were each fed to a total of three pens of males and three pens of females. At the end of each 4-week period, the turkeys were rerandomized to form 12 new equivalent groups, and similar diets with 2% less protein were fed. As part of this study, two fats, varying in fatty acid composition, were also compared but found not to affect significantly body weight gain or feed efficiency. Interaction effects of fat and protein on body weight gain, feed consumption, or feed efficiency were not significant. Body weight gain increased .5, .6, and 1.1%, feed consumption decreased 1.1, 1.0, and .9%, and feed efficiency increased 1.7, 1.8, and 2.2% for each 1% added fat during the 8 to 12-, 12 to 16-, and 16 to 20-week periods, respectively. The greater-than-expected increase in feed efficiency from added fat to diets of older turkeys is postulated to be due to stimulated feed consumption and body weight gain rather than to an extra caloric content of fat per se.
进行了两系列连续四周的实验，共有1370只8至20周龄的大白火鸡参与，以确定不同水平的膳食脂肪和蛋白质对体重增加和饲料效率的影响。采用3×4析因设计，含有0%、5%和10%添加脂肪以及18%、20%、22%和24%蛋白质的日粮分别饲喂给总共三组雄性和三组雌性火鸡。在每个4周周期结束时，将火鸡重新随机分组，形成12个新的等效组，并饲喂蛋白质含量低2%的类似日粮。作为本研究的一部分，还比较了两种脂肪酸组成不同的脂肪，但发现它们对体重增加或饲料效率没有显著影响。脂肪和蛋白质对体重增加、采食量或饲料效率的交互作用不显著。在8至12周、12至16周和16至20周期间，每添加1%的脂肪，体重增加分别提高0.5%、0.6%和1.1%，采食量分别降低1.1%、1.0%和0.9%，饲料效率分别提高1.7%、1.8%和2.2%。推测老龄火鸡日粮中添加脂肪使饲料效率增加幅度高于预期，是由于采食量和体重增加受到刺激，而非脂肪本身额外的热量含量所致。
