Veum T L, Ledoux D R, Shannon M C, Raboy V
Department of Animal Sciences, University of Missouri, Columbia, MO 65211, USA.
J Anim Sci. 2009 Aug;87(8):2625-34. doi: 10.2527/jas.2008-1604. Epub 2009 Apr 9.
Fifty crossbred barrows with an average initial age of 31 d and BW of 9.94 kg were used in a 28-d experiment to evaluate the effect of a low-phytic acid (LPA) barley mutant (M) M955, a near-isogenic progeny of the normal barley (NB) cultivar Harrington with about 90% less phytate than NB, to increase the utilization of Fe, Zn, and Cu compared with diets containing NB. The response criteria were growth performance, hematocrit volume, metacarpal bone characteristics, and the apparent absorption, retention, and excretion of Zn and Cu. The 2 barley cultivars (NB and M955) and the 5 trace mineral (TM) treatment concentrations of Fe and Zn (0, 25, 50, 75, and 100% of the requirement as FeSO(4) and ZnSO(4)) and Cu (0, 40, 80, 120, and 160% of the requirement as CuSO(4)) made 10 treatments in a factorial arrangement. Available P was equalized at 0.33% in all diets by adding monosodium phosphate to the basal diet containing NB, and all diets contained 0.65% Ca. Diets were adequate in all other nutrients. Barley and soybean meal were the only sources of phytate in the practical diets that also contained spray-dried whey. The barrows were fed the diets to appetite in meal form twice daily in individual metabolism crates. There were no barley cultivar x TM treatment interactions, and there were no differences between the NB and M955 barley cultivars for any of the response criteria measured. However, for the TM treatments, there were linear increases (P < or = 0.05) in ADFI, ADG, hematocrit volume, metacarpal bone breaking strength and ash weight, and the apparent absorption, retention, and excretion (mg/d) of Zn and Cu. In conclusion, the LPA barley had no effect on the response criteria in this experiment, apparently because of the small increase in the availability of the endogenous trace minerals in the practical diets containing M955 compared with NB. However, increasing the supplementation of Fe and Zn from 0 to 100% (160% for Cu) of the requirement resulted in linear increases in growth performance, hematocrit volume, metacarpal bone strength and ash weight, and the apparent absorption, retention, and excretion of Zn and Cu. Therefore, these results indicate that the inorganic trace mineral supplementation of practical diets for young pigs should not be less than the National Research Council requirements for swine.
选用50头平均初始年龄为31天、体重9.94千克的杂交公猪，进行为期28天的试验，以评估低植酸（LPA）大麦突变体（M）M955（正常大麦（NB）品种哈林顿的近等基因后代，植酸含量比NB低约90%）对提高铁、锌和铜利用率的效果，与含NB的日粮进行比较。反应标准为生长性能、血细胞比容、掌骨特征以及锌和铜的表观吸收、保留和排泄。2个大麦品种（NB和M955）以及铁和锌的5种微量矿物质（TM）处理浓度（分别为硫酸亚铁和硫酸锌需求量的0、25、50、75和100%）和铜的处理浓度（分别为硫酸铜需求量的0、40、80、120和160%），按析因设计形成10种处理。通过向含NB的基础日粮中添加磷酸二氢钠，使所有日粮中的有效磷均为0.33%，所有日粮中钙含量均为0.65%。所有其他营养素在日粮中均充足。在实际日粮中，大麦和豆粕是植酸的唯一来源，日粮中还含有喷雾干燥乳清。公猪在个体代谢栏中，每天分两次以粉料形式自由采食日粮。不存在大麦品种×TM处理的交互作用，对于所测定的任何反应标准，NB和M955大麦品种之间均无差异。然而，对于TM处理，平均日采食量（ADFI）、平均日增重（ADG）、血细胞比容、掌骨断裂强度和灰分重量以及锌和铜的表观吸收、保留和排泄（毫克/天）均呈线性增加（P≤0.05）。总之，在本试验中，LPA大麦对反应标准无影响，显然是因为与含NB的日粮相比，含M955的实际日粮中内源性微量矿物质有效性的增加幅度较小。然而，将铁和锌的添加量从需求量的0提高到100%（铜为160%），导致生长性能、血细胞比容、掌骨强度和灰分重量以及锌和铜的表观吸收、保留和排泄呈线性增加。因此，这些结果表明，仔猪实际日粮中无机微量矿物质的添加量不应低于美国国家研究委员会对猪的需求量。
