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不同衛生條件下豬只的生長性能受到蛋白攝入量和氨基酸添加量的影響 Y. van der Meer, A. Lammers, A. J. M.Jansman, M. M. J. A. Rijnen, W. H. Hendriks and W. J. J. Gerrits 越來越多的證據表明當豬只所處的衛生環境變差，某些氨基酸的需要量就會增加。然而，與生長性能下降相關氨基酸需要量的增加程度還未知曉。為了探明二者之間的關系，我們選取612頭公豬（每圈9頭）分別置于低衛生水平（LSC）條件下和高衛生水平（HSC）條件下進行飼養，日糧分為兩大類：正常蛋白水平（NP）組（保育、生長和育肥各階段日糧蛋白質水平分別為17%、15%和15%）和低蛋白水平（LP）組（相較NP組，各階段日糧中蛋白質水平降低20%），兩種蛋白水平的日糧組內又分為不補充氨基酸的基礎日糧（AA-B）和補充氨基酸的日糧（AA-S）。補充氨基酸的日糧組相較基礎氨基酸日糧組內含的表觀回腸可消化的Met、Thr和Trp與Lys之比均提高20%。目標出欄重為110k時育肥期結束，然后進行屠宰。在教槽、保育和育肥階段分別收集血清并檢測結合珠蛋白的濃度（LSC組為0.92g/L；HSC組為0.78 g/L ）和針對鑰孔蟲戚血蘭素的抗體效價（LSC組為3.53；HSC組為3.08）。屠宰時LSC組的胸膜炎得分（LSC組為0.51；HSC組為0.20）相較HSC組更高(P ≤ 0.01)，表明動物所處的衛生狀況影響了健康水平。HSC組的平均日增重和飼料轉化率相比LSC組要高（P ≤ 0.01）。如果飼養在低衛生水平下AA-S組豬只的白細胞數目（WBC）相比AA-B組要高一些，但如果飼喂在高衛生水平條件下則不然（衛生條件與氨基酸交互作用，P=0.04）正常蛋白水平日糧組內豬只的白細胞數目相較低蛋白水平日糧組要少（P = 0.02）。 飼喂AA-S日糧的豬只血液中血小板數目比飼喂AA-B日糧的要高（P ≤ 0.01）。對于低衛生水平條件下飼養的豬只，日糧中Met、Thr和Trp與Lys的比例下降20%引起飼料轉化率降低的程度要高于飼養在高衛生水平條件下的豬只（交互作用，P = 0.03），表明不同的衛生條件下豬只對這些氨基酸的需求量不同。本試驗是在實際生產環境下進行的，結果表明動物對氨基酸需要量是與其所處的衛生環境條件有關的。日糧中補充某些特殊的氨基酸可改善生長性能，尤其是對于生長在衛生條件較差環境下的動物。日糧中蛋白水平的提高和補充Met、 Thr和Trp均可改變動物的免疫機能，進而可以影響動物對臨床及亞臨床疾病的抵抗能力。 Performance of pigs kept under different sanitary conditions affected by protein intake and amino acid supplementation Y. van der Meer, A. Lammers, A. J. M.Jansman, M. M. J. A. Rijnen, W. H. Hendriks and W. J. J. Gerrits There is growing evidence that requirements for particular AA increase when pigs are kept under low sanitary conditions.The extent to which reduction in growth performance is related to these increased requirements is unclear. To evaluate this relationship, an experiment (2 × 2 × 2 factorial arrangement) was performed with 612 male pigs (9 per pen) kept under low sanitary conditions (LSC) or high sanitary conditions (HSC) and offered ad libitum access to either a normal CP concentration diet (NP; 17, 15,and 15% CP for the starter, grower, and finisher phase, respectively) or a low CP concentration diet (LP; 20% CP reduced relative to NP for each phase), each of which containing a basal AA profile (AA-B) or a supplemented AA profile (AA-S). The supplemented diet type contained 20% more Met, Thr, and Trp relative to Lys on an apparent ileal digestible basis compared with the basal diet type. Pigs were followed for a complete fattening period and slaughtered at a targeted pen weight of 110 kg. Haptoglobin concentrations in serum (0.92 g/L for LSC and 0.78 g/L for HSC) and IgG antibody titers against keyhole limpet hemocyanin (3.53 for LSC and 3.08 for HSC) collected in the starter, grower, and finisher phases and pleuritis scores at slaughter (0.51 for LSC and 0.20 for HSC) were greater for LSC pigs compared with HSC pigs (P ≤ 0.01), illustrating that sanitary conditions affected health conditions. The ADG and G:F were greater for HSC pigs compared with LSC pigs (P≤ 0.01). The number of white blood cells (WBC) was higher in (AA-S)–fed pigs compared with (AA-B)–fed pigs when kept at LSC but not at HSC[SS (sanitary conditions) × AA interaction, P = 0.04]. Pigs fed NP had a lower number of WBC compared with pigs fed LP (P = 0.02). The number of platelets in pigs fed AA-S diets was higher compared with pigs fed AA-B diets (P ≤ 0.01). A 20% reduction in dietary supplementation of Met, Thr, and Trp relative to Lys decreased G:F more in LSC pigs than in HSC pigs (interaction, P = 0.03), illustrating that dietary requirements for these AA differ depending on sanitary conditions. This study, performed under practical conditions, shows that AA requirements are dependent on sanitary conditions. Furthermore, supplementation of diets with particular AA may improve performance, especially under poor hygienic conditions. Dietary protein concentrationas well as Met, Thr, and Trp supplementation can modify immune status, which may influence resistance to subclinical and clinical diseases。 作者：李光燃 來源：豬營養國際論壇CSIS 
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