De la Llata M, Dritz S S, Tokach M D, Goodband R D, Nelssen J L, Loughin T M
Department of Animal Sciences, Kansas State University, Manhattan 66506-0201, USA.
J Anim Sci. 2001 Oct;79(10):2643-50. doi: 10.2527/2001.79102643x.
We conducted two experiments to evaluate the effects of added choice white grease on performance and carcass merit of barrows and gilts reared under commercial conditions. Pigs were housed either 20 (Exp. 1) or 25 (Exp. 2) per pen and were provided 0.67 m2 of pen space per pig. Diets were based on corn and soybean meal and fed in a meal form. The proportion of soybean meal was increased in diets with added fat to maintain the same calorie:lysine ratio in all diets within a weight phase. In Exp. 1, 480 pigs were fed diets with 0, 2, 4, or 6% fat. Total lysine contents of the control diets were 1.21, 0.88, and 0.66% during the weight phases 36 to 59, 59 to 93, and 93 to 120 kg, respectively. Gain:feed was increased linearly (P < 0.01) due to fat addition in all weight intervals and over the total experiment. The effect of added fat on ADG was not consistent among the weight phases; a linear (P < 0.01) improvement was found from 36 to 59 kg, but no effect was found during the heavier weight phases. Over the total experiment, however, ADG was improved (P < 0.01) linearly. Carcass traits were not affected by treatment. Experiment 2 used 900 pigs to evaluate possible carryover effects on performance and carcass merit from feeding 6% fat. The experiment was divided into four phases: 25 to 45, 45 to 70, 70 to 90, and 90 to 115 kg; lysine contents of the control diets fed in each phase were 1.23, 1.05, 0.81, and 0.63%, respectively. The six treatments consisted of no added fat throughout the experiment or 6% added fat fed from 25 to 45 kg, 25 to 70 kg, 25 to 90 kg, 25 to 115 kg, or 45 to 70 and 90 to 115 kg. Carryover effects for ADG and G:F (P < 0.07) were found for the 90- to 115-kg interval and for ADFI and ME intake (P < 0.05) for the 45- to 70- and 70-to 90-kg intervals. When fat was added in the previous weight interval, ADG and G:F were improved and ADFI and ME intake were decreased in the subsequent weight interval. Pigs fed fat from 25 to 115 kg had more (P < 0.05) backfat and lower (P < 0.05) carcass leanness than pigs on the other treatments. These data suggest that fat can be added or removed from diets of growing-finishing pigs without any detrimental carryover effects. In fact, the positive carryover effect on ADG and G:F from 95 to 115 kg suggests that feeding fat from 25 to 95 kg will maximize performance over the total growing-finishing period but minimize any detrimental effects of added fat on carcass leanness.
我们进行了两项试验，以评估在商业条件下饲养的公猪和母猪日粮中添加精选白油脂对其生产性能和胴体品质的影响。试验中每栏饲养20头猪（试验1）或25头猪（试验2），每头猪占有0.67平方米的栏舍空间。日粮以玉米和豆粕为基础，制成粉料饲喂。在添加脂肪的日粮中增加豆粕比例，以确保在同一体重阶段内所有日粮的能量:赖氨酸比值相同。在试验1中，480头猪分别饲喂含0%、2%、4%或6%脂肪的日粮。在体重36至59千克、59至93千克和93至120千克阶段，对照日粮的总赖氨酸含量分别为1.21%、0.88%和0.66%。在所有体重区间及整个试验期内，添加脂肪均使料重比呈线性增加（P<0.01）。添加脂肪对平均日增重（ADG）的影响在各体重阶段并不一致；在36至59千克阶段呈线性改善（P<0.01），但在体重较大阶段无显著影响。不过，在整个试验期内，ADG呈线性提高（P<0.01）。胴体性状不受处理影响。试验2选用900头猪，评估饲喂6%脂肪对生产性能和胴体品质的潜在残留效应。试验分为四个阶段：25至45千克、45至70千克、70至90千克和90至115千克；各阶段对照日粮的赖氨酸含量分别为1.23%、1.05%、0.81%和0.63%。六种处理分别为：整个试验期不添加脂肪；25至45千克、25至70千克、25至90千克、25至115千克添加6%脂肪；45至70千克和90至115千克添加6%脂肪。在90至115千克阶段发现ADG和料重比（G:F）有残留效应（P<0.07），在45至70千克和70至90千克阶段发现采食量（ADFI）和代谢能摄入量有残留效应（P<0.05）。在前一体重阶段添加脂肪后，后续体重阶段的ADG和G:F提高，ADFI和代谢能摄入量降低。与其他处理相比，25至115千克全程添加脂肪的猪背膘更厚（P<0.05），胴体瘦肉率更低（P<0.05）。这些数据表明，生长育肥猪日粮中可以添加或去除脂肪，而不会产生任何有害的残留效应。事实上，95至115千克阶段对ADG和G:F的正向残留效应表明，25至95千克阶段饲喂脂肪可使整个生长育肥期的生产性能最大化，同时将添加脂肪对胴体瘦肉率的有害影响降至最低。
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