Doctoral Dissertation Improvement: The Effects of Maternal Condition on Lactational Investment and Infant Outcome in Rhesus Macaques

拟议的项目将解决两个重要问题：(1)通过牛奶成分、产奶量和哺乳行为衡量，产妇的生理和社会状况如何影响哺乳投资？以及(2)哺乳投资的差异如何影响婴儿的结局？目前，人们对影响母体对非人类灵长类动物投资的主要形式的因素知之甚少，即为哺乳调动母体储备。几项研究表明，一些牛奶成分，特别是脂肪，在个体之间存在很大的差异，但个体差异的来源和大小尚未得到解释。这项拟议的研究将评估加州国家灵长类研究中心(CNPRC)饲养的75只圈养恒河猴的母亲年龄、健康和哺乳之间的关系。对健康状况良好或不佳的年轻和壮年母亲的牛奶质量、哺乳行为和婴儿结局进行比较，将表明母亲如何根据自己的生理状况操纵投资。这些数据将提供有关产妇护理行为和生理投入如何影响婴儿生长和活动的系统信息。这项研究将探索以前没有被研究过的哺乳的基本方面，并增进我们对选择如何塑造母亲生殖策略的理解。这项研究的数据将为影响人类母亲及其婴儿健康的关键全球问题提供信息。美国和世界各地的母乳喂养率明显低于最佳水平，这对婴儿的发育和健康造成了长期有害的影响。在受控研究条件下，了解恒河猴母亲在哺乳期如何受到健康和发育的限制的进展，将为人类母亲面临的类似挑战提供洞察，并为当前的全球健康问题提供重要信息。这项研究将为从进化论角度和机制解释工作的研究人员提供一个合作框架。此外，一旦更好地了解产妇状况和牛奶成分，就可以在自然生态条件下对人群进行有针对性的研究，促进未来研究项目的国际合作。

The proposed project will address two important questions: (1) How does maternal physiological and social condition affect lactational investment as measured by milk composition, milk yield, and nursing behavior? and (2) How do differences in lactational investment affect infant outcomes? Currently little is known about the factors that influence the primary form of maternal investment in non-human primates, the mobilization of maternal bodily reserves for lactation. Several studies demonstrate that some milk constituents, particularly fat, have high inter-individual variation, but the source and magnitude of individual differences have not been explained. The proposed study will assess the relationship between maternal age, health and lactation in 75 captive rhesus macaques housed at the California National Primate Research Center (CNPRC). Comparisons of milk quality, nursing behavior, and infant outcome in young and prime age mothers in good or poor health will indicate how mothers manipulate investment in relation to their own physiological condition. These data will provide systematic information about how maternal nursing behavior and physiological investment affect infant growth and activity. This study will explore fundamental aspects of lactation that have previously not been investigated, and advance our understanding of how selection has shaped maternal reproductive strategies.The data from this study will inform a critical global issue affecting the health of human mothers and their infants. Breastfeeding rates in the US and throughout the world are significantly below optimum, contributing to long-term deleterious developmental and health consequences for the infant. Advances in understanding how rhesus mothers are constrained by health and growth during lactation under controlled research conditions will provide insight into similar challenges for human mothers and provide vital information for current global health concerns. This study will provide a framework for collaboration with researchers working from evolutionary perspectives and mechanistic explanations. Additionally, once a better understanding of maternal condition and milk composition is achieved, targeted studies can be implemented with populations under natural ecological conditions, facilitating international collaboration on future research projects.