Zhang Sai, Marini Juan C, Mavangira Vengai, Claude Andrew, Moore Julie, Mohammad Mahmoud A, Trottier Nathalie L
Department of Animal Science, Michigan State University, East Lansing, 48824, USA.
State Key Laboratory of Swine and Poultry Breeding Industry, Key Laboratory of Animal Nutrition and Feed Science in South China, Ministry of Agriculture and Rural Affairs, Guangdong Provincial Key Laboratory of Animal Breeding and Nutrition, Institute of Animal Science, Guangdong Academy of Agricultural Sciences, Guangzhou, 510640, PR China.
J Anim Sci Biotechnol. 2024 May 7;15(1):65. doi: 10.1186/s40104-024-01020-9.
The study objective was to test the hypothesis that low crude protein (CP) diet with crystalline amino acids (CAA) supplementation improves Lys utilization efficiency for milk production and reduces protein turnover and muscle protein breakdown. Eighteen lactating multiparous Yorkshire sows were allotted to 1 of 2 isocaloric diets (10.80 MJ/kg net energy): control (CON; 19.24% CP) and reduced CP with "optimal" AA profile (OPT; 14.00% CP). Sow body weight and backfat were recorded on d 1 and 21 of lactation and piglets were weighed on d 1, 14, 18, and 21 of lactation. Between d 14 and 18, a subset of 9 sows (CON = 4, OPT = 5) was infused with a mixed solution of 3-[methyl-H]histidine (bolus injection) and [C]bicarbonate (priming dose) first, then a constant 2-h [C]bicarbonate infusion followed by a 6-h primed constant [1-C]lysine infusion. Serial blood and milk sampling were performed to determine plasma and milk Lys enrichment, Lys oxidation rate, whole body protein turnover, and muscle protein breakdown.
Over the 21-d lactation period, compared to CON, sows fed OPT had greater litter growth rate (P < 0.05). Compared to CON, sows fed OPT had greater efficiency of Lys (P < 0.05), Lys mammary flux (P < 0.01) and whole-body protein turnover efficiency (P < 0.05). Compared to CON, sows fed OPT tended to have lower whole body protein breakdown rate (P = 0.069). Muscle protein breakdown rate did not differ between OPT and CON (P = 0.197).
Feeding an improved AA balance diet increased efficiency of Lys and reduced whole-body protein turnover and protein breakdown. These results imply that the lower maternal N retention observed in lactating sows fed improved AA balance diets in previous studies may be a result of greater partitioning of AA towards milk rather than greater body protein breakdown.
本研究的目的是验证以下假设：补充结晶氨基酸（CAA）的低粗蛋白（CP）日粮可提高赖氨酸用于产奶的利用效率，并减少蛋白质周转和肌肉蛋白质分解。将18头经产泌乳约克夏母猪分配至两种等热量日粮（净能10.80 MJ/kg）中的一种：对照组（CON；19.24% CP）和具有“最佳”氨基酸谱的低CP日粮（OPT；14.00% CP）。在泌乳第1天和第21天记录母猪体重和背膘厚度，并在泌乳第1天、第14天、第18天和第21天对仔猪称重。在第14天至第18天期间，先对9头母猪的一个子集（CON = 4头，OPT = 5头）静脉注射3-[甲基-H]组氨酸（大剂量注射）和[C]碳酸氢盐（起始剂量）的混合溶液，然后持续2小时输注[C]碳酸氢盐，随后6小时持续输注[1-C]赖氨酸。进行系列血液和乳汁采样以测定血浆和乳汁中赖氨酸富集量、赖氨酸氧化率、全身蛋白质周转和肌肉蛋白质分解。
在21天的泌乳期内，与CON组相比，饲喂OPT日粮的母猪仔猪生长速度更快（P < 0.05）。与CON组相比，饲喂OPT日粮的母猪赖氨酸利用效率更高（P < 0.05）、赖氨酸乳腺流量更高（P < 0.01）以及全身蛋白质周转效率更高（P < 0.05）。与CON组相比，饲喂OPT日粮的母猪全身蛋白质分解率有降低趋势（P = 0.069）。OPT组和CON组之间的肌肉蛋白质分解率无差异（P = 0.197）。
饲喂氨基酸平衡改善的日粮可提高赖氨酸利用效率，并降低全身蛋白质周转和蛋白质分解。这些结果表明，在之前的研究中，饲喂氨基酸平衡改善日粮的泌乳母猪母体氮保留较低，可能是由于氨基酸更多地分配到乳汁中，而非体蛋白分解增加所致。
