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：家猫，甚至是幼年动物，在它们的肾脏中有大量来源或原因不明的细胞质脂肪滴。狗和野猫很大程度上没有这种异位沉积，人类也是如此，特别是在他们的肾脏里。这样的发现在相对年轻的动物身上是非常不寻常的。我认为，家猫天生就容易受到这种异位脂肪的影响，因为a)它们是专职的食肉动物，b)它们不习惯在饮食中不经意地摄入植物性脂肪。后者意味着，与野生或天然饮食相反，食用商业饮食的猫在更大程度上发现了这种肾脏脂质。公安局的初步证据证实了这一点。在英国，超过一半的宠物只吃主人每天给它们的食物，因为要么是罐头或袋子等湿宠物食品，要么是颗粒干粮，品牌忠诚度和个人偏好通常意味着相同的产品会长时间(几个月到几年)单独喂养，因此宠物食品制造商有责任生产出营养平衡的、满足猫狗所有营养需求的产品，但猫不含任何植物油。到目前为止，利用脂组学技术(薄层色谱、GC-MS、ESI-MS/MS)对10只猫/狗/野猫进行了研究，发现家猫的脂滴中含有高浓度的饱和脂肪酸，这些脂肪酸通常在植物中存在，如C12：0(月桂酸；椰子油)、C14：0(肉豆蔻酸；棕榈油)和C16：0(棕榈酸；棕榈仁油)，而这些都是在狗或野猫中没有的。因此，这些植物油的可能来源是商业饮食，在商业饮食中，这些廉价的植物油经常取代更高质量、更昂贵的脂肪，如omega-3 FA(n3系列)。因此，家猫很可能将这些脂肪视为毒素，通过肝脏和肾脏排泄。然而，猫长期以来已经失去了对许多毒素进行解毒的能力，因为它们从未出现在祖先的饮食中。猫在肝脏和肾脏中缺乏许多去饱和酶和CYP450酶(未发表的初步RNAseq数据[n=3猫与n=3狗])。因此，这种脂肪在肝脏和肾脏中的积累很可能是促进氧化的，随着时间的推移逐渐引发慢性间质纤维化/坏死(CIN)的状况。CIN是导致年长家猫健康状况不佳的主要非传染性、非癌症原因。因此，本项目将调查以下研究问题：有待解决的研究问题：1)进一步描述猫科动物肾脏细胞质脂滴的脂体特征2)确定主要脂肪酸的来源，例如饮食类型3)将其与雪貂等其他专性食肉动物进行比较和对比

Background unpublished evidence: Domestic felines, even young animals, have a preponderance of cytoplasmic fatty droplets of unknown origin or cause in their kidneys.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