Feeding a reduced protein diet with a near ideal amino acid profile improves amino acid efficiency and nitrogen utilization for milk production in sows
作者：Sai Zhang,* Mu Qiao,† and Nathalie L. Trottier*,3
*Department of Animal Science, Michigan State University, East Lansing, MI 48824; and†Hubei KeyLaboratory of Animal Embryo Engineering and Molecular Breeding, Institute of Animal Husbandry and Veterinary Medicine, Hubei Academy of Agricultural Sciences, Wuhan 430064, China
来源：J. Anim. Sci. 2019.XX:XX-XX ；doi: 10.1093/jas/skz220
翻译：肠动力研究院 梁琦
【摘要】在美国，繁殖群体每年会产生11.8×106吨的新鲜粪便，因此在全球范围内泌乳母猪对日粮中氮利用效率的微小变化会对氮排泄产生重大影响。基于此，在接近最大生物潜力条件下，测定个体对必需氨基酸（EAA）的生物效率可准确预测机体对每种EAA的需求。本文旨在探究喂食含有接近理想氨基酸（NIAA）的低蛋白日粮对母猪产奶的氮和EAA生物利用效率的影响。54头泌乳经产约克夏母猪（2胎以上）随机分配成3个处理组，1）CON组：喂食含有18.74%蛋白的日粮，n=18；2）OPT组：饲喂含有13.78%蛋白的日粮，n=19；3）OPTLEU组：喂食含有14.25%蛋白的日粮（OPT+亮氨酸），n=17。同时保证三种日粮的能量水平相同，其中OPT和OPTLEU组日粮中含有等浓度的结晶氨基酸（CAA）以满足母猪对限制性AA的需求；将结晶亮氨酸（Leu）加入到OPTLEU中以含有与CON相同的标准回肠消化率（SID）的Leu浓度。母猪在哺乳期第1天和第21天称重，仔猪在哺乳期第1、4、8、14、18和21天称重。在泌乳的第4-8天（早期）和第14-18天（高峰期）之间测定48或72小时的氮保留量。结果显示，喂食三种不同日粮的母猪的体重（BW）变化和平均日采食量（ADFI）无显著差异（P>0.05）。哺乳早期的猪群生长速率（LGR）在各组之间没有差异。在哺乳高峰期，OPT组母猪的LGR高于CON（P <0.05），而OPTLEU组母猪的LGR高于OPT（P <0.05）。在泌乳早期和高峰期，与CON组相比，OPT（P <0.01）和OPTLEU组（P <0.05）母猪的总氮保留率和乳汁氮利用效率均较高。除此外，与CON组相比，OPT和OPTLEU组母猪的N，Arg，His，Ile，Leu，Phe和Trp的整体生物学效率更高（P <0.05），而Lys，Met，Thr和Val的生物学效率没有差异。同样，Leu在OPTLEU和CON之间没有显著差异。与OPT相比，OPTLEU组母猪对Leu利用率较低（P <0.01），Met则倾向于更低（P = 0.10）。研究结果表明，饲喂含有接近理想氨基酸的低蛋白日粮（低Leu浓度）可维持母猪的整体泌乳性能并提高其对N，Arg，His，Ile，Leu，Phe + Tyr和Trp的利用效率，最大化母猪对Ile，Leu，Lys，Met + Cys，Phe + Tyr，Thr，Trp和Val的利用效率。此外，添加Leu并未降低母猪对N和EAA利用效率。本研究为Ile（65.4），Leu（75.1），Lys（63.2），Met + Cys（78.2），Phe + Tyr（69.5），Thr（71.0），Trp（70.1）和Val（57.0）提供了修订的、全新的最大生物效率值（MBEV）。这些MBEV可以更准确地预测哺乳期母猪对AA的需求。
【关键词】效率，哺乳母猪，亮氨酸，低蛋白日粮，氮保留
以下是相关图表
表1：试验日粮的组成成分和营养成分（以饲喂为基础）
表2：分析和计算试验日粮中的N，总EAA和游离EAA的浓度（基于饲喂）
表3：超过21天的哺乳期，饲喂对照（CON; 18.74％CP），最佳（OPT; 13.78％CP）或最佳+亮氨酸（OPTLEU; 14.25％CP）日粮的母猪的泌乳性能
表4：选择用于N平衡分析和饲喂对照（CON; 18.74％CP），最佳（OPT; 13.78％CP）或最佳+亮氨酸（OPTLEU; 14.25％CP）日粮的母猪早期和泌乳高峰期的生产性能和奶水的营养成分和产量
表5：选择用于N平衡研究和饲喂对照（CON; 18.74％CP），最佳（OPT; 13.78％CP）或最佳+亮氨酸（OPTLEU; 14.25％CP）日粮的母猪早期和泌乳高峰期的乳汁中氮利用率
表6：饲喂对照（CON; 18.74％CP），最佳（OPT; 13.78％CP）或最佳+亮氨酸（OPTLEU; 14.25％CP）日粮的母猪的哺乳期（哺乳期早期）的第4-8天以及哺乳期第14-18天（泌乳高峰期）的真实日粮AA利用效率（基于蛋白质N保留量估算）
总结
饲喂含有接近理想氨基酸的低蛋白日粮（低Leu浓度）可维持母猪的整体泌乳性能并提高其对N，Arg，His，Ile，Leu，Phe + Tyr和Trp的利用率，同时最大化母猪对Ile，Leu，Lys，Met + Cys，Phe + Tyr，Thr，Trp和Val的利用效率。此外，添加Leu并未降低母猪对N和EAA利用效率。
Abstract
Fifty-four lactating multiparous Yorkshire sows were used to test the hypothesis that feeding a reduced protein diet with a near ideal AA (NIAA) profile increases the biological utilization efficiency of N and essential AA (EAA) for milk production in part as a result of reduced dietary Leu concentration. Sows were fed 1 of 3 isocaloric diets containing the following concentration of CP (% as-fed, analyzed): 18.74 (Control: CON), 13.78 (Optimal: OPT), and 14.25 (Optimal + Leu: OPTLEU). The OPT and OPTLEU diets contained the same concentration of crystalline AA (CAA) to
meet requirements of the limiting AA. Crystalline Leu was added to OPTLEU to contain the same SID Leu concentration as that of CON. Sows were weighed on days 1 and 21 of lactation and piglets on days 1, 4, 8, 14, 18, and 21 of lactation. Nitrogen retention was measured for 48 or 72 h between days 4 and 8 (early) and days 14 and 18 (peak) of lactation. Sow BW change and ADFI did not differ between diets. Litter growth rate (LGR) during early lactation did not differ between diets. At peak lactation, LGR was higher in sows fed OPT compared with CON (P < 0.05) and lower in sows fed OPTLEU compared with OPT (P < 0.05). In early and peak lactation, total N retention, and milk N output efficiency were greater in OPT (P < 0.01) and OPTLEU (P < 0.05) than CON. Compared with CON, overall biological efficiency of N, Arg, His, Ile, Leu, Phe, and Trp were greater (P < 0.05), whereas those of Lys, Met, Thr, and Val did not differ in sows fed OPT and OPTLEU, except for Leu which did not differ between OPTLEU and CON. Compared with OPT, only Leu and Met efficiency were lower (P < 0.01) and tended to be lower (P = 0.10), respectively, in sows fed OPTLEU. Reducing CP with a NIAA profile to attain the minimum Leu requirement maintained overall lactation performance, improved utilization efficiency of N, Arg, His, Ile, Leu, Phe + Tyr, and Trp for milk production, and maximized efficiency of Ile, Leu, Lys, Met + Cys, Phe + Tyr, Thr, Trp, and Val. Addition of Leu did not reduce N and EAA utilization efficiency. This study provides revised and novel maximum biological efficiency value (MBEV) for Ile (65.4), Leu (75.1), Lys (63.2), Met + Cys (78.2), Phe + Tyr (69.5), Thr (71.0), Trp (70.1), and Val (57.0). These MBEV can be used to more accurately predict the requirement for those AA during lactation.
Keywords：efficiency, lactating sows, leucine, low protein diet, nitrogen retention
Conclusion
Reducing CP with a NIAA profile to attain the minimum Leu requirement maintained overall lactation performance, improved utilization efficiency of N, Arg, His, Ile, Leu, Phe + Tyr, and Trp for milk production, and maximized efficiency of Ile, Leu, Lys, Met + Cys, Phe + Tyr, Thr, Trp, and Val. Addition of Leu did not reduce N and EAA utilization efficiency.
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