Collaborative Research: The role of maternal iron transfer in the development of heme stores and aerobic diving capacity in grey seal pups

合作研究：母体铁转移在灰海豹幼崽血红素储备和有氧潜水能力发展中的作用

• 批准号: 2133825
• 负责人: Greg Breed
• 金额: $ 4.64万
• 依托单位: University of Alaska Fairbanks Campus
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-09-01 至 2026-08-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2133825&HistoricalAwards=false
• 关键词: Collaborative; Research; role; maternal; iron

A fundamental question in animal ecology is when and why physiology limits how animals behave, how often they reproduce, and how likely they are to survive. Marine mammals are particularly suited for these studies because their ability to forage underwater is constrained by the size of their tissue heme and O2 stores, and pups are born with very low hemoglobin (Hb) and myoglobin (Mb) levels that can limit breathold ability. Iron is an essential micronutrient for the biosynthesis of Hb and Mb, and maternal iron status and milk iron content strongly influences early development of heme stores in many species. This project will study grey seals (Halichoerus grypus) at Sable Island, Nova Scotia to determine how maternal and offspring dietary iron dynamics impact heme maturation and subsequent foraging activities. The team will first determine maternal diet, iron stores, milk iron content and milk transfer rates. Then, researchers will provide supplemental iron to half of the study animals to determine if iron intake limits pup physiological development. Finally, the impact of heme stores on the diving behavior and movement patterns of weaned pups will be evaluated. Understanding the interplay between iron intake, physiological development and foraging behavior, may reveal how ongoing changes in grey seal diet and ecosystem structure could influence pup survival and population trajectories. This work will provide training opportunities to graduate and undergraduate students at HSI and Alaska Native serving institutions and provide outreach through a diverse suite of activities in Texas, Alaska, Canada, and Massachusetts. This study will elucidate the underlying ecological and cellular mechanisms that facilitate or constrain the ontogeny of heme and O2 stores in grey seal pups (12 pups/year/3yrs). Bulk and compound specific stable isotope analysis will be used to identify maternal diet and iron intake, while milk iron and milk transfer rates will be quantified using hydrogen isotope dynamics to determine pup iron intake. The pup’s ability to utilize milk iron will be assessed by measuring the expression of iron transporters (Divalent metal transporter 1, Ferroportin) and serum hepcidin, transferrin, and ferritin concentrations. Age-related changes in blood and muscle heme stores, iron-containing enzymes, and endocrine factors known to regulate heme protein synthesis (i.e., Erythropoietin, Hypoxia-inducible-factor-1) will be measured. Providing half the study pups with supplemental iron at the start and end of the lactation period will reveal if maternal iron transfer rates are a significant influence on pup physiological development. At the end of the post-weaning fast, pups will be outfitted with a satellite-linked dive recorder to monitor foraging patterns and locations. Behavioral comparisons between iron-supplemented and control groups will reveal whether maternal effects as mediated through micronutrient limitations influence pup foraging capacity, or if behavioral plasticity can compensate for phenotypic constraints. Studies integrating across multiple physiological and behavioral scales in juvenile marine mammals remain rare, yet understanding these linkages becomes increasingly important as climate change and human activities are causing significant shifts in the functioning of marine ecosystems across the globe.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

动物生态学中的一个基本问题是生理学何时以及为什么限制动物的行为，它们繁殖的频率以及它们生存的可能性。海洋哺乳动物特别适合这些研究，因为它们在水下觅食的能力受到其组织血红素和O2储存量的限制，而幼崽出生时血红蛋白（Hb）和肌红蛋白（Mb）水平非常低，这可能会限制呼吸能力。 铁是血红蛋白和肌红蛋白生物合成所必需的微量营养素，母体铁状况和乳汁铁含量强烈影响许多物种血红素储存的早期发育。本项目将研究灰海豹（Halichoerus grypus）在Sable岛，新斯科舍省，以确定如何母亲和后代的饮食铁动态影响血红素成熟和随后的觅食活动。研究小组将首先确定母亲的饮食、铁的储存、牛奶铁含量和牛奶转移率。然后，研究人员将为一半的研究动物提供补充铁，以确定铁摄入量是否会限制幼犬的生理发育。最后，血红素储存对断奶幼鼠的潜水行为和运动模式的影响将被评估。了解铁摄入量，生理发育和觅食行为之间的相互作用，可以揭示灰海豹饮食和生态系统结构的持续变化如何影响幼崽的生存和种群轨迹。 这项工作将为HSI和阿拉斯加土著服务机构的研究生和本科生提供培训机会，并通过在德克萨斯州，阿拉斯加州，加拿大和马萨诸塞州的各种活动提供外展服务。本研究将阐明潜在的生态和细胞机制，促进或限制个体发育的血红素和O2存储在灰海豹幼崽（12幼崽/年/3岁）。将使用批量和化合物特定稳定同位素分析来确定母体饮食和铁摄入量，而乳铁和乳转移率将使用氢同位素动力学来量化，以确定幼崽铁摄入量。将通过测量铁转运蛋白（二价金属转运蛋白1，膜铁转运蛋白）的表达和血清铁调素、转铁蛋白和铁蛋白浓度来评估幼犬利用乳铁的能力。血液和肌肉血红素储存、含铁酶和已知调节血红素蛋白合成的内分泌因子（即，将测量促红细胞生成素、缺氧诱导因子-1）。在哺乳期开始和结束时为一半的研究幼仔提供补充铁，将揭示母体铁转移率是否对幼仔生理发育有显著影响。在断奶后禁食结束时，幼崽将配备一个与卫星相连的潜水记录器，以监测觅食模式和位置。铁补充组和对照组之间的行为比较将揭示是否通过微量营养素的限制介导的母体效应影响幼崽觅食能力，或者如果行为可塑性可以补偿表型的限制。综合多种生理和行为尺度的幼年海洋哺乳动物研究仍然很少见，但了解这些联系变得越来越重要，因为气候变化和人类活动正在导致地球仪海洋生态系统功能的重大变化。该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估来支持。