Obesity and estrogen reduction are known to affect the gut microbiota and gut microbial-derived metabolites in some species, but limited information is available in dogs. The aim of this study was to determine the effects of dietary macronutrient profile on apparent total tract macronutrient digestibility, fecal microbiota, and fecal metabolites of adult female dogs after spay surgery. Twenty-eight adult intact female beagles (age: 3.02 ± 0.71 yr, BW: 10.28 ± 0.77 kg; BCS: 4.98 ± 0.57) were used. After a 5-wk baseline phase (week 0), 24 dogs were spayed and randomly allotted to one of three experimental diets (n = 8 per group): 1) control (CO) containing moderate protein and fiber (COSP), 2) high-protein, high-fiber (HPHF), or 3) high-protein, high-fiber plus omega-3 and medium-chain fatty acids (HPHFO). Four dogs were sham-operated and fed CO (COSH). All dogs were fed to maintain BW for 12 wk after spay and then allowed to consume twice that amount for 12 wk. Fecal samples were collected at weeks 0, 12, and 24 for digestibility, microbiota, and metabolite analysis. All data were analyzed using repeated measures and linear mixed models procedure of SAS 9.4, with results reported as a change from baseline. Apparent organic matter and energy digestibilities had greater decreases in HPHF and HPHFO than COSH and COSP. Increases in fecal acetate, total short-chain fatty acids, and secondary bile acids were greater and decreases in primary bile acids were greater in HPHF and HPHFO. Principal coordinates analysis of weighted UniFrac distances revealed that HPHF and HPHFO clustered together and separated from COSH and COSP at weeks 12 and 24, with relative abundances of Faecalibacterium, Romboutsia, and Fusobacterium increasing to a greater extent and Catenibacterium, Bifidobacterium, Prevotella 9, Eubacterium, and Megamonas decreasing to a greater extent in HPHF or HPHFO. Our results suggest that high-protein, high-fiber diets alter nutrient and energy digestibilities, fecal metabolite concentrations, and fecal gut microbiota, but spay surgery had minor effects. Future research is needed to investigate how food intake, nutrient profile, and changes in hormone production influence gut microbiota and metabolites of dogs individually and how this knowledge may be used to manage spayed pets.

中文翻译：

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日粮宏量营养素分布对绝育手术后母犬全肠道宏量营养素表观消化率和粪便微生物群、发酵代谢物和胆汁酸的影响

众所周知，肥胖和雌激素减少会影响某些物种的肠道微生物群和肠道微生物衍生代谢物，但在狗身上可获得的信息有限。本研究的目的是确定日粮常量营养素分布对绝育手术后成年雌性犬的表观总肠道常量营养素消化率、粪便微生物群和粪便代谢物的影响。使用了 28 只成年完整雌性小猎犬（年龄：3.02 ± 0.71 岁，体重：10.28 ± 0.77 kg；BCS：4.98 ± 0.57）。在 5 周的基线阶段（第 0 周）后，24 只狗被绝育并随机分配到三种实验饮食中的一种（每组 n = 8）：1）含有中等蛋白质和纤维（COSP）的对照（CO），2）高蛋白、高纤维 (HPHF)，或 3) 高蛋白、高纤维加上 omega-3 和中链脂肪酸 (HPHFO)。四只狗进行了假手术并喂食CO（COSH）。绝育后，所有狗都被喂食以维持体重 12 周，然后在 12 周内允许摄入两倍的体重。在第 0、12 和 24 周收集粪便样本，用于消化率、微生物群和代谢物分析。使用 SAS 9.4 的重复测量和线性混合模型程序分析所有数据，结果报告为相对于基线的变化。HPHF 和 HPHFO 的表观有机质和能量消化率比 COSH 和 COSP 下降幅度更大。在 HPHF 和 HPHFO 中，粪便乙酸盐、总短链脂肪酸和次级胆汁酸的增加幅度更大，而初级胆汁酸的减少幅度更大。加权 UniFrac 距离的主坐标分析表明，HPHF 和 HPHFO 在第 12 周和第 24 周聚集在一起并与 COSH 和 COSP 分离，在 HPHF 或 HPHFO 中，粪杆菌、朗布氏菌和梭杆菌的相对丰度增加幅度较大，而链状杆菌、双歧杆菌、普雷沃氏菌 9、真杆菌和巨单胞菌的相对丰度下降幅度较大。我们的研究结果表明，高蛋白、高纤维饮食会改变营养和能量的消化率、粪便代谢物浓度和粪便肠道微生物群，但绝育手术的影响较小。未来的研究需要调查食物摄入、营养成分和激素产生的变化如何影响狗的肠道微生物群和代谢物，以及这些知识如何用于管理绝育宠物。在 HPHF 或 HPHFO 中，巨单胞菌的减少程度更大。我们的研究结果表明，高蛋白、高纤维饮食会改变营养和能量的消化率、粪便代谢物浓度和粪便肠道微生物群，但绝育手术的影响较小。未来的研究需要调查食物摄入、营养成分和激素产生的变化如何影响狗的肠道微生物群和代谢物，以及这些知识如何用于管理绝育宠物。在 HPHF 或 HPHFO 中，巨单胞菌的减少程度更大。我们的研究结果表明，高蛋白、高纤维饮食会改变营养和能量的消化率、粪便代谢物浓度和粪便肠道微生物群，但绝育手术的影响较小。未来的研究需要调查食物摄入、营养成分和激素产生的变化如何影响狗的肠道微生物群和代谢物，以及这些知识如何用于管理绝育宠物。