不同卫生条件下猪只的生长性能受到蛋白摄入量和氨基酸添加量的影响

畜牧编辑

　　2016. J. Anim. Sci. 94(11):4704-4719

　　不同卫生条件下猪只的生长性能受到蛋白摄入量和氨基酸添加量的影响
　　Y. van der Meer, A. Lammers, A. J. M.Jansman, M. M. J. A. Rijnen, W. H. Hendriks and W. J. J. Gerrits

　　越来越多的证据表明当猪只所处的卫生环境变差，某些氨基酸的需要量就会增加。然而，与生长性能下降相关氨基酸需要量的增加程度还未知晓。为了探明二者之间的关系，我们选取612头公猪（每圈9头）分别置于低卫生水平（LSC）条件下和高卫生水平（HSC）条件下进行饲养，日粮分为两大类：正常蛋白水平（NP）组（保育、生长和育肥各阶段日粮蛋白质水平分别为17%、15%和15%）和低蛋白水平（LP）组（相较NP组，各阶段日粮中蛋白质水平降低20%），两种蛋白水平的日粮组内又分为不补充氨基酸的基础日粮（AA-B）和补充氨基酸的日粮（AA-S）。补充氨基酸的日粮组相较基础氨基酸日粮组内含的表观回肠可消化的Met、Thr和Trp与Lys之比均提高20%。目标出栏重为110k时育肥期结束，然后进行屠宰。在教槽、保育和育肥阶段分别收集血清并检测结合珠蛋白的浓度（LSC组为0.92g/L；HSC组为0.78 g/L ）和针对钥孔虫戚血兰素的抗体效价（LSC组为3.53；HSC组为3.08）。屠宰时LSC组的胸膜炎得分（LSC组为0.51；HSC组为0.20）相较HSC组更高(P ≤ 0.01)，表明动物所处的卫生状况影响了健康水平。HSC组的平均日增重和饲料转化率相比LSC组要高（P ≤ 0.01）。如果饲养在低卫生水平下AA-S组猪只的白细胞数目（WBC）相比AA-B组要高一些，但如果饲喂在高卫生水平条件下则不然（卫生条件与氨基酸交互作用，P=0.04）正常蛋白水平日粮组内猪只的白细胞数目相较低蛋白水平日粮组要少（P = 0.02）。

　　饲喂AA-S日粮的猪只血液中血小板数目比饲喂AA-B日粮的要高（P ≤ 0.01）。对于低卫生水平条件下饲养的猪只，日粮中Met、Thr和Trp与Lys的比例下降20%引起饲料转化率降低的程度要高于饲养在高卫生水平条件下的猪只（交互作用，P = 0.03），表明不同的卫生条件下猪只对这些氨基酸的需求量不同。本试验是在实际生产环境下进行的，结果表明动物对氨基酸需要量是与其所处的卫生环境条件有关的。日粮中补充某些特殊的氨基酸可改善生长性能，尤其是对于生长在卫生条件较差环境下的动物。日粮中蛋白水平的提高和补充Met、 Thr和Trp均可改变动物的免疫机能，进而可以影响动物对临床及亚临床疾病的抵抗能力。

　　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
来源：猪营养国际论坛CSIS

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