日糧脂肪來源和飼喂時間對育肥豬生長性能、胴體組成和脂肪品質的影響

畜牧編輯

　　日糧脂肪來源和飼喂時間對育肥豬生長性能、胴體組成和脂肪品質的影響

　　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

　　本試驗旨在評估日糧脂肪來源和飼喂時間對育肥豬生長性能、胴體組成和脂肪品質的影響。

　　選用160頭豬（PIC 327 × 1050;初始重45.6 kg）進行84天的試驗。每個處理8欄，每欄2頭豬。試驗共10個處理，其中不添加脂肪的玉米-豆粕基礎日糧為對照組，以脂肪來源（4%動物油，4%大豆油，2%動物油與2%大豆油組成的混合油）和飼喂時間（0-42天、42-84天、0-84天）組成的3 × 3雙因素設計構成9個試驗處理。在未進行處理組日糧添加時，均飼喂基礎日糧。第0天，每欄標記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。試驗結束時，屠宰所有豬只評估其胴體品質，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個階段飼喂脂肪日糧的豬相比，整個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(P= 0.079)。與對照組相比，添加脂肪的日糧能夠明顯提高碘價(P < 0.05)。隨著大豆油飼喂時間的增加，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，而通過添加動物油這些值保持相對不變（時間× 脂肪來源交互作用，P < 0.05）。本研究發現飼喂時間和脂肪來源對脂肪酸組成和頜部脂肪碘價不存在交互作用，而對腹部脂肪和背膘產生交互作用，這可能表明頜部脂肪周轉率較長。

　　結論，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，大豆油飼喂時間過長，無論單獨飼喂還是與動物油混合飼喂，都對不同脂肪組織的脂肪酸組成和碘價造成負面影響。

　　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：杜環利 豬營養國際論壇CSIS