Fatty acids of plant origin in diets fed to domestic cats accumulate in renal cytoplasmic lipid droplets and are pre-oxidative.

背景：未发表的证据：家养猫科动物，甚至是幼龄动物，在其肾脏中有大量来源不明或原因不明的细胞质脂肪滴。和人类一样，狗和野猫基本上没有这种异位沉积，尤其是在肾脏中。在相对年轻的动物身上发现这样的结果是非常不寻常的。我认为家猫天生就容易受到这种异位脂质的影响，因为a)它们是专性食肉动物，b)不习惯在饮食中不经意地摄入植物性脂肪。后者表明，与食用野生或天然饮食的猫相比，食用商业饮食的猫更容易发现这种肾脂质。PI的初步证据证实了这一点。自英国一半以上的同伴动物只吃主人每天给他们什么,作为湿宠物食品罐头或袋等,或颗粒状干燥食品和品牌忠诚度,个人偏好往往意味着美联储同样的产品是专门为长时间(月年),这是义不容辞的宠物食品制造商生产营养均衡,完整的产品符合所有我们的狗或猫的营养需求,但对于猫,不含任何植物油。迄今为止，研究人员在n=10只猫/狗/野猫身上结合使用脂质组学技术（薄层色谱、GC-MS、ESI-MS/MS），发现家猫的脂滴含有高浓度的饱和脂肪酸，这种脂肪酸通常存在于植物中，如C12:0（月桂酸；椰子油）、C14:0（肉豆蔻酸；棕榈油）和C16:0（棕榈酸；棕榈核油），而在狗或野猫身上不存在。因此，这些植物油的可能来源是商业饮食，这些便宜的油通常取代高质量，更昂贵的脂肪，如omega-3 FA （n3系列）。因此，家猫很可能把这些脂肪当作毒素，通过肝脏和肾脏排出体外。然而，猫早就失去了排毒的能力，因为它们从来没有出现在祖先的饮食中。猫的肝脏和肾脏缺乏许多去饱和酶和cyp450酶（初步RNAseq未发表的数据[n=3只猫对n=3只狗]）。因此，这些脂肪在肝脏和肾脏中的积累可能是促氧化的，随着时间的推移逐渐引发慢性间质纤维化/坏死（CIN）。CIN是老年家猫健康状况不佳的主要非传染性、非癌性原因。因此，该项目将研究以下研究问题：需要解决的研究问题：1)进一步表征猫肾细胞质脂滴的脂质组；2)确定主要脂肪酸的来源，如饮食类型；3)将其与其他专性食肉动物（如雪貂）的特征进行比较和对比

Background unpublished evidence: Domestic felines, even young animals, have a preponderance of cytoplasmic fatty droplets of unknown origin or cause in their kidneys. Dogs and wildcats are largely free from such ectopic deposits, as are humans, particularly in their kidneys. Such a finding in relatively young animals is highly unusual. I propose that domestic cats are inherently susceptible to such ectopic lipid because a) they are obligate carnivores and b) unused to inadvertently consuming fats of plant origin in their diets. The latter implies that such renal lipids are found to a greater extent in cats consuming commercial diet as oppose to a wild or natural diet. Preliminary evidence by the PI confirms this to be the case. Since more than half of companion animals in the UK only eat what their owners give them on a daily basis, as either wet pet foods such as tins or pouches, or pelleted dry food and brand loyalty and personal preference often means the same product is fed exclusively for long periods of time (months to years), it is incumbent upon pet food manufacturers to produce a nutritionally-balanced, 'complete' product that meets all the nutritional requirements of our dogs or cats, but for cats, without any oils of plant origin. To date, using a combination of lipidomic techniques (thin-layer chromatography, GC-MS, ESI-MS/MS) in n=10 cats/dogs/wildcats the investigators and found that lipid droplets in domestic cats contain a high concentration of saturated fatty acids that are often found in plants such as C12:0 (lauric acid; coconut oils), C14:0 (myristic acid; palm oils) and C16:0 (palmitic acid; palm kernel oil), that were not present in dogs or wildcats. The likely source of these plant oils, therefore, is commercial diets where these cheaper oils often replace higher quality, more expensive fats such as omega-3 FA (n3 series). Hence, domestic cat likely treats these fats as toxins, to be excreted via the liver and the kidney. However, cats have long lost the capability to de-toxify many toxins, since they were never present in ancestral diet. Cats lack many desaturases and cyp450 enzymes in liver and kidney (prelim RNAseq unpublished data [n=3 cats vs n=3 dogs]). Thus, accumulation of such fats in liver and kidney is likely to be pro-oxidative, gradually initiating a condition of chronic interstitial fibrosis/necrosis (CIN) over time. CIN is the predominant non-infectious, non-cancerous cause of poor health in older domestic cats. This project will therefore investigate the following research questions:Research questions to be addressed: 1) further characterise the lipidome of renal cytoplasmic lipid droplets in cats2) identify the source of the predominant fatty acids e.g. types of diet 3) compare and contrast the profile with other obligate carnivores such as ferret