Department of Biomedical Sciences, College of Veterinary Medicine, Oregon State University, Corvallis, Oregon, United States of America.
Pet Nutrition Center, Hill's Pet Nutrition, Topeka, Kansas, United States of America.
PLoS One. 2020 Jul 2;15(7):e0235480. doi: 10.1371/journal.pone.0235480. eCollection 2020.
A cross-over study within a split-plot design was performed using healthy (n = 10) and CKD cats [IRIS Stage 1 and 2; n = 10]. Cats were fed dry Prescription Diet® k/d® Feline with chicken, during a pre-trial period and then randomly assigned to two fiber treatments for 4 weeks each. Treatment foods were formulated similar to pre-trial food, with the exception that they contained 0.500% betaine, 0.586% oat beta glucan, and either 0.407% short chain fructooligosaccharides (scFOS) fiber or 3.44% apple pomace. Both foods had similar crude fiber percent (2.0 and 2.1% for scFOS and apple pomace, respectively) whereas soluble fiber was 0.8 and 1.6%, respectively.
Plasma metabolites separated cats based on health status. At baseline, cats with CKD had significantly higher circulating concentrations of creatinine, urea, and some microbial and host tryptophan metabolites including several indole sulfates and kynurenate. Healthy cats had higher concentrations of the antioxidant α-tocopherol after consuming apple pomace; alternatively, they had higher concentrations of inflammatory sphingolipid metabolites after consuming scFOS, but not after consuming apple pomace. The CKD cats had higher concentrations of the more oxidized glutathione metabolites after consuming apple pomace compared with scFOS, as well as higher concentrations of inflammatory sphingolipid metabolites after consuming apple pomace, but not scFOS. After consuming scFOS, CKD cats had lower concentrations of the phenolic uremic toxins guaiacol sulfate and 4-vinylphenol sulfate compared with after consuming apple pomace. At baseline, there were five significant microbiota OTU differences in CKD cats compared with healthy cats. Overall, the OTUs in CKD cats were more resistant to change after feeding either fiber source. Counts of an unclassified genus in the family S24-7 in the order Bacteroidales (OTU 100296), were lower in CKD cats compared with healthy cats at baseline (P = 0.001), but increased after consumption of food containing scFOS (P = 0.006). Linear regression analysis showed that this genus had significant negative correlations with several microbial uremic toxins. None of the baseline differences in OTUs between healthy and CKD cats changed after CKD cats consumed food containing apple pomace.
Health status impacts the influence of dietary fermentable fibers on the feline plasma metabolome and fecal microbiome. A more readily fermented fiber such as scFOS is preferable to apple pomace as a fiber source for cats with CKD.
采用交叉设计的析因设计，对健康猫（n=10）和慢性肾脏病猫（IRIS 分期 1 和 2；n=10）进行了研究。在预试验期间，猫均喂食干处方饮食®k/d®鸡肉配方猫粮，然后随机分为两组，每组分别喂食 4 周的两种纤维处理。处理食物的配方与预试验食物相似，不同之处在于它们含有 0.500%甜菜碱、0.586%燕麦 β 葡聚糖和 0.407%短链果聚糖（scFOS）纤维或 3.44%苹果渣。两种食物的粗纤维百分比相似（scFOS 和苹果渣分别为 2.0%和 2.1%），而可溶性纤维分别为 0.8%和 1.6%。
血浆代谢物根据健康状况将猫分开。在基线时，CKD 猫的循环肌酐、尿素和一些微生物和宿主色氨酸代谢物浓度显著升高，包括几种吲哚硫酸盐和犬尿氨酸。健康猫在食用苹果渣后体内α-生育酚浓度升高；相反，在食用 scFOS 后，它们体内的炎症鞘脂代谢物浓度升高，但在食用苹果渣后则不然。与食用 scFOS 相比，CKD 猫在食用苹果渣后体内更氧化的谷胱甘肽代谢物浓度更高，且食用苹果渣后体内的炎症鞘脂代谢物浓度更高，但食用 scFOS 后则不然。在食用 scFOS 后，CKD 猫体内的酚类尿毒症毒素愈创木酚硫酸盐和 4-乙烯基苯酚硫酸盐的浓度低于食用苹果渣后。在基线时，与健康猫相比，CKD 猫的粪便中有 5 个显著的微生物 OTU 差异。总体而言，在喂养任何纤维来源后，CKD 猫的 OTU 更不易发生变化。拟杆菌目 S24-7 科未分类属的一个 OTU100296 的数量在 CKD 猫中低于健康猫（P=0.001），但在食用含有 scFOS 的食物后增加（P=0.006）。线性回归分析表明，该属与几种微生物尿毒症毒素呈显著负相关。CKD 猫食用含苹果渣的食物后，健康猫和 CKD 猫之间的粪便微生物 OTU 基线差异没有改变。
健康状况影响可发酵纤维对猫血浆代谢组和粪便微生物组的影响。对于 CKD 猫，像 scFOS 这样更易发酵的纤维作为纤维来源优于苹果渣。
