日糧脂肪來源和飼喂時(shí)間對(duì)育肥豬生長(zhǎng)性能、胴體組成和脂肪品質(zhì)的影響

畜牧編輯

　　日糧脂肪來源和飼喂時(shí)間對(duì)育肥豬生長(zhǎng)性能、胴體組成和脂肪品質(zhì)的影響

　　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

　　本試驗(yàn)旨在評(píng)估日糧脂肪來源和飼喂時(shí)間對(duì)育肥豬生長(zhǎng)性能、胴體組成和脂肪品質(zhì)的影響。

　　選用160頭豬（PIC 327 × 1050;初始重45.6 kg）進(jìn)行84天的試驗(yàn)。每個(gè)處理8欄，每欄2頭豬。試驗(yàn)共10個(gè)處理，其中不添加脂肪的玉米-豆粕基礎(chǔ)日糧為對(duì)照組，以脂肪來源（4%動(dòng)物油，4%大豆油，2%動(dòng)物油與2%大豆油組成的混合油）和飼喂時(shí)間（0-42天、42-84天、0-84天）組成的3 × 3雙因素設(shè)計(jì)構(gòu)成9個(gè)試驗(yàn)處理。在未進(jìn)行處理組日糧添加時(shí)，均飼喂基礎(chǔ)日糧。第0天，每欄標(biāo)記1頭豬，收集第0、41和81天的背部、腹部和頜部組織樣品用于脂肪酸分析。試驗(yàn)結(jié)束時(shí)，屠宰所有豬只評(píng)估其胴體品質(zhì)，收集背部、腹部和頜部脂肪樣品用于分析。

　　整體來看（0-84天），飼喂不同脂肪來源的豬生長(zhǎng)性能和胴體特征無明顯差異；然而，與未添加脂肪日糧相比，整個(gè)階段飼喂脂肪日糧的豬飼料利用率明顯提高（P = 0.036）。與僅在1個(gè)階段飼喂脂肪日糧的豬相比，整個(gè)階段飼喂脂肪日糧的豬平均日增重和飼料利用率增加(P < 0.05)，并且最末體重較大(P =0.006)。與未添加脂肪的日糧相比，整個(gè)階段飼喂脂肪日糧的豬背膘厚明顯增加 (P = 0.032)，無脂瘦肉率有降低的趨勢(shì)(P= 0.079)。與對(duì)照組相比，添加脂肪的日糧能夠明顯提高碘價(jià)(P < 0.05)。隨著大豆油飼喂時(shí)間的增加，所有脂肪樣品中單不飽和脂肪酸含量降低，多不飽和脂肪酸含量增加，而通過添加動(dòng)物油這些值保持相對(duì)不變（時(shí)間× 脂肪來源交互作用，P < 0.05）。本研究發(fā)現(xiàn)飼喂時(shí)間和脂肪來源對(duì)脂肪酸組成和頜部脂肪碘價(jià)不存在交互作用，而對(duì)腹部脂肪和背膘產(chǎn)生交互作用，這可能表明頜部脂肪周轉(zhuǎn)率較長(zhǎng)。

　　結(jié)論，日糧中額外添加脂肪可以提高平均日增重和飼料利用率；然而，大豆油飼喂時(shí)間過長(zhǎng)，無論單獨(dú)飼喂還是與動(dòng)物油混合飼喂，都對(duì)不同脂肪組織的脂肪酸組成和碘價(jià)造成負(fù)面影響。

　　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.

　　翻譯：杜環(huán)利 豬營(yíng)養(yǎng)國(guó)際論壇CSIS