Sulfur amino acid requirements and metabolism in cats

猫的硫氨基酸需求和代谢

• 批准号: RGPIN-2019-04685
• 负责人: Shoveller, Anna
• 金额: $ 3.28万
• 依托单位: University of Guelph
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2021
• 资助国家: 加拿大
• 起止时间: 2021-01-01 至 2022-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=737787
• 关键词: Sulfur; amino; acid; requirements; metabolism

Close to 40% of the Canadian population owns a cat (8.8 million in 2016) and there has been growth in Canadian cat food sales. Cats are obligate carnivores and animal proteins are used in large amounts to manufacture cat food. The availability and price of animal proteins may become constrained in the future as the human population increases and developing countries demand more animal-based proteins. While we have sufficient data to precisely feed many mono-gastric agricultural animals, our current knowledge of the indispensable amino acid (AA) requirements and broader effects of provision of AA on cats is woefully lacking. In general, outcomes of either growth or nitrogen balance have been used to measure AA requirements in growing cats, but no estimates in adult cats exist. Much less invasive carbon oxidation techniques, and more specially, the indicator AA oxidation (IAAO) technique have been used to empirically estimate AA requirements in many mammals. My laboratory estimated phenylalanine turnover in cats and these data suggest that orally dosing a tracer is a valid approach and small, frequent meals support a pseudo isotopic steady state. We have also validated behavioural acclimation to space restriction required to conduct respiratory gas collection and quantification in cats and applied these to measure energy metabolism and the net energy of different foods consumed by cats. Finally, I have applied the IAAO to estimate AA requirements and protein quality in pigs and dogs. My long term goals are to determine the requirement for the indispensable AA requirements of adult cats and understand how other dietary factors, such as dietary vitamins, may alter these. These data will lead to significant optimization in the delivery of protein to cats and reduce over supply of protein and AA in feline diets. The short-medium term goals of my program are to: 1. Measure the phenylalanine requirements when tyrosine is provided in excess to adult neutered male and female cats using the direct AA oxidation technique (Study 1)  2. Measure the methionine requirement when minimal cyst(e)ine is provided in adult castrated male and spayed female cats using the IAAO (Study 2) 2. Measure the methionine requirement when cysteine is provided in excess in adult castrated male and spayed female cats using the IAAO (Study 3)  3. Understand how the ratio of dietary methionine to cysteine alter transmethylation, remethylation and transsulfuration and contribute to the control synthesis of taurine and felinine in adult castrated male and spayed female cats using labeled methionine and cysteine tracers (Study 4) SIGNIFICANCE: The proposed studies will provide fundamental knowledge of sulfur AA requirements and how other nutrients affect sulfur AA requirements in domestic cats. When applied to cat food development, this knowledge will lead to more precise AA delivery, reduce excess provision of dietary protein, and support the health and well-being of cats.

近40%的加拿大人口拥有一只猫（2016年为880万），加拿大猫粮销售量也有所增长。猫是专性食肉动物，动物蛋白被大量用于制造猫粮。随着人口的增加和发展中国家对动物蛋白的需求增加，动物蛋白的供应和价格在未来可能会受到限制。虽然我们有足够的数据来精确地喂养许多单胃农业动物，但我们目前对不可或缺的氨基酸（AA）需求和AA对猫的更广泛影响的了解非常缺乏。一般来说，生长或氮平衡的结果已被用来衡量AA的需求在成长中的猫，但没有估计成年猫存在。侵入性小得多的碳氧化技术，更具体地说，指示剂AA氧化（IAAO）技术已被用于经验估计AA的需求在许多哺乳动物。我的实验室估计了猫的苯丙氨酸周转率，这些数据表明，口服示踪剂是一种有效的方法，少量频繁的进餐支持假同位素稳态。我们还验证了对猫进行呼吸气体收集和定量所需的空间限制的行为适应，并将其应用于测量猫消耗的不同食物的能量代谢和净能量。最后，我应用IAAO来估计猪和狗的AA需求量和蛋白质质量。我的长期目标是确定成年猫不可或缺的AA需求，并了解其他饮食因素，如饮食维生素，可能会改变这些。这些数据将导致猫蛋白质递送的显著优化，并减少猫饮食中蛋白质和AA的过度供应。我的计划的中短期目标是：1。使用直接AA氧化技术（研究1）2，测量当向成年去势雄性和雌性猫提供过量酪氨酸时的苯丙氨酸需求量。使用IAAO（研究2）2，在成年去势雄猫和去势雌猫中提供最低限度胱氨酸时，测量蛋氨酸需求量。使用IAAO（研究3）3，在成年去势雄猫和去势雌猫中过量提供半胱氨酸时，测量蛋氨酸需求量。了解饮食中蛋氨酸与半胱氨酸的比例如何改变转甲基化、再甲基化和转硫作用，并有助于使用标记的蛋氨酸和半胱氨酸示踪剂控制成年去势雄猫和去势雌猫中牛磺酸和猫氨酸的合成（研究4）意义：拟议的研究将提供关于硫AA需求的基础知识，以及其他营养素如何影响家猫中硫AA需求。当应用于猫粮开发时，这些知识将导致更精确的AA输送，减少膳食蛋白质的过量供应，并支持猫的健康和福祉。