Department of Nutritional Sciences, University of Toronto, Toronto, Ontario, Canada.
Translational Medicine Program, The Hospital for Sick Children, Toronto, Ontario, Canada.
J Nutr. 2021 Apr 8;151(4):840-847. doi: 10.1093/jn/nxaa383.
Bovine milk-based protein modulars are currently available to nutrient-enrich enteral feedings; however, they have limitations for use in very-low-birth-weight infants.
Our objectives were to develop a human milk-based protein (HMP) concentrate and to conduct a preclinical assessment of the HMP concentrate in weanling rats.
An HMP concentrate was produced from donor milk using pressure-driven membrane filtration processes and high hydrostatic pressure processing. Protein and lactoferrin concentrations and lysozyme activity were determined by Kjeldahl, HPLC, and turbidimetric assay, respectively. Male Sprague Dawley rats 24 d old (n = 30) were randomly assigned to 1 of 3 isocaloric AIN-93G diets for 4 wk containing 100% casein (control) or with 50% of the casein replaced with the HMP concentrate (treatment) or a bovine whey protein isolate (treatment). Body weight, food intake, fat mass, plasma amino acid profiles, and organ weights were measured. Data were analyzed using linear regression models.
Raw donor milk contained (mean ± SD) 101 ± 6 g protein/kg and 5 ± 1 g lactoferrin/kg of milk solids. Postprocessing, protein and lactoferrin concentrations were 589 ± 3 g/kg and 29 ± 10 g/kg, respectively. Lysozyme activity was initially 209 ± 4 U/kg and increased to 959 ± 39 U/kg in the HMP concentrate. There were no statistically significant differences in body weight, food intake, fat mass, or plasma amino acid profiles between rats fed diets containing the HMP concentrate and the control diet. Full cecum weights were higher in rats fed the HMP concentrate than in those fed control diets (mean difference: 5.59 g; 95% CI: 4.50, 6.68 g; P < 0.0001), likely reflecting the concentration of human milk oligosaccharides. No differences were found for other organ weights.
The HMP concentrate retained important bioactive proteins and supported normal rat growth in the preclinical assessment.
目前可通过添加基于牛乳的蛋白质模块来强化肠内营养制剂，但这些模块在极低出生体重儿中的应用存在局限性。
本研究旨在开发一种人乳来源的蛋白质浓缩物（HMP），并对其在断奶大鼠中的预临床评估进行研究。
采用压力驱动膜过滤和高静压处理工艺，从捐赠人乳中制备 HMP 浓缩物。采用凯氏定氮法、高效液相色谱法和比浊法分别测定蛋白质、乳铁蛋白浓度和溶菌酶活性。24 日龄雄性 Sprague Dawley 大鼠（n=30）随机分为 3 组，每组 10 只，分别给予含 100%酪蛋白（对照组）、50%酪蛋白被 HMP 浓缩物替代（实验组）或牛乳分离乳清蛋白替代（实验组）的等热量 AIN-93G 饮食，共 4 周。测定体重、食物摄入量、体脂量、血浆氨基酸谱和器官重量。采用线性回归模型分析数据。
原始捐赠人乳中含有（均值±标准差）101±6g/kg 蛋白质和 5±1g/kg 乳固体中的乳铁蛋白。加工后，蛋白质和乳铁蛋白浓度分别为 589±3g/kg 和 29±10g/kg，溶菌酶活性初始值为 209±4U/kg，在 HMP 浓缩物中增加至 959±39U/kg。与对照组相比，给予 HMP 浓缩物的大鼠体重、食物摄入量、体脂量或血浆氨基酸谱无统计学差异。给予 HMP 浓缩物的大鼠空肠全重高于对照组（平均差异：5.59g；95%置信区间：4.50，6.68g；P<0.0001），这可能反映了人乳寡糖的浓度。其他器官重量无差异。
在预临床评估中，HMP 浓缩物保留了重要的生物活性蛋白，并支持大鼠的正常生长。
