日粮脂肪来源和饲喂时间对育肥猪生长性能、胴体组成和脂肪品质的影响

畜牧编辑

　　日粮脂肪来源和饲喂时间对育肥猪生长性能、胴体组成和脂肪品质的影响

　　E.W. Stephenson, M. A. Vaughn, D. D. Burnett, C.B. Paulk, M. D. Tokach, S. S. Dritz, J. M. DeRouchey, R.D. Goodband , J. C. Woodworth 和 J. M. Gonzalez

　　本试验旨在评估日粮脂肪来源和饲喂时间对育肥猪生长性能、胴体组成和脂肪品质的影响。

　　选用160头猪（PIC 327 × 1050;初始重45.6 kg）进行84天的试验。每个处理8栏，每栏2头猪。试验共10个处理，其中不添加脂肪的玉米-豆粕基础日粮为对照组，以脂肪来源（4%动物油，4%大豆油，2%动物油与2%大豆油组成的混合油）和饲喂时间（0-42天、42-84天、0-84天）组成的3 × 3双因素设计构成9个试验处理。在未进行处理组日粮添加时，均饲喂基础日粮。第0天，每栏标记1头猪，收集第0、41和81天的背部、腹部和颌部组织样品用于脂肪酸分析。试验结束时，屠宰所有猪只评估其胴体品质，收集背部、腹部和颌部脂肪样品用于分析。

　　整体来看（0-84天），饲喂不同脂肪来源的猪生长性能和胴体特征无明显差异；然而，与未添加脂肪日粮相比，整个阶段饲喂脂肪日粮的猪饲料利用率明显提高（P = 0.036）。与仅在1个阶段饲喂脂肪日粮的猪相比，整个阶段饲喂脂肪日粮的猪平均日增重和饲料利用率增加(P < 0.05)，并且最末体重较大(P =0.006)。与未添加脂肪的日粮相比，整个阶段饲喂脂肪日粮的猪背膘厚明显增加 (P = 0.032)，无脂瘦肉率有降低的趋势(P= 0.079)。与对照组相比，添加脂肪的日粮能够明显提高碘价(P < 0.05)。随着大豆油饲喂时间的增加，所有脂肪样品中单不饱和脂肪酸含量降低，多不饱和脂肪酸含量增加，而通过添加动物油这些值保持相对不变（时间× 脂肪来源交互作用，P < 0.05）。本研究发现饲喂时间和脂肪来源对脂肪酸组成和颌部脂肪碘价不存在交互作用，而对腹部脂肪和背膘产生交互作用，这可能表明颌部脂肪周转率较长。

　　结论，日粮中额外添加脂肪可以提高平均日增重和饲料利用率；然而，大豆油饲喂时间过长，无论单独饲喂还是与动物油混合饲喂，都对不同脂肪组织的脂肪酸组成和碘价造成负面影响。

　　Influence of dietary fat source and feeding duration on finishing pig growth performance, carcass composition, and fat quality

　　E. W. Stephenson, M. A. Vaughn, D. D. Burnett, C. B. Paulk, M. D. Tokach, S. S. Dritz, J. M. DeRouchey, R. D. Goodband , J. C. Woodworth and J. M. Gonzalez

　　Atotal of 160 finishing pigs (PIC 327 × 1050; initially 45.6 kg) were used in an 84-d experiment to evaluate the effects of dietary fat source and feeding duration on growth performance, carcass characteristics, and carcass fatquality. There were 2 pigs per pen with 8 pens per treatment. The 10 dietary treatments were a corn–soybean meal control diet with no added fat and a 3 × 3 factorial with main effects of fat source (4% tallow, 4% soybean oil, or a blend of 2% tallow and 2% soybean oil) and feeding duration (d 0 to 42, 42 to84, or 0 to 84). The control corn–soybean meal diet was fed in place of added fat diets when needed for duration treatment purposes. On d 0, 1 pig was identified in each pen and fat biopsy samples of the back, belly, and jowl were collected on d 0, 41, and 81 for fatty acid analysis. At the conclusion of the study, all pigs were harvested, carcass characteristics were determined, and back, belly, and jowl fat samples were collected for analysis. Overall (d 0 to 84), there were no differences among pigs fed the different fat sources for growth and carcass characteristics; however, pigs fed diets with added fat for the entire study had improved (P = 0.036) G:F compared with pigs fed the control diet without added fat. Pigs fed supplemental fat throughout the entire study also had improved (P < 0.05) ADG and G:F as well as heavier d-84 BW (P = 0.006) compared with pigs fed additional fat during only 1 period. Adding fat for the entire study increased (P =0.032) backfat and tended to reduce (P= 0.079) the fat free lean index compared with pigs fed the control diet without added fat. Added fat also increased (P < 0.05) the iodine value (IV) when compared with pigs fed the control diet. Increasing the feeding duration of soybean oil lowered MUFA and increased PUFA concentrations for all fat depots, whereas these values remained relatively unchanged by the addition of tallow (duration × fat source interactions, P <0.05). Our study failed to show any feeding period × fat source interactions (P <0.05) in fatty acid composition or IV for jowl fat, whereas this interaction occurred for belly fat and backfat, which would indicate a longer turnover rate for jowl fat. In conclusion, feeding additional fat improved ADG and G:F; however, feeding soybean oil for an increased duration, either alone or incombination with tallow, negatively affected the fatty acid composition and IV of different fat depots.

　　翻译：杜环利 猪营养国际论坛CSIS