Milk oligosaccharides (MO) are bioactive compounds in mammalian milk that provide health benefits to neonates beyond essential nutrients. GNU100, a novel animal MO biosimilar, was recently tested in vitro, with results showing beneficial shifts in microbiota and increased short-chain fatty acid (SCFA) production, but other effects of GNU100 were unknown. Three studies were conducted to evaluate the safety, palatability, and gastrointestinal (GI) tolerance of GNU100. In study 1, the mutagenic potential of GNU100 was tested using a bacterial reverse mutation assay and a mammalian cell micronucleus test. In study 2, palatability was assessed by comparing diets containing 0% vs. 1% GNU100 in 20 adult dogs. In study 3, 32 adult dogs were used in a completely randomized design to assess the safety and GI tolerance of GNU100 and explore utility. Following a 2-wk baseline, dogs were assigned to one of four treatments and fed for 26 wk: 0%, 0.5%, 1%, and 1.5% GNU100. On weeks 2, 4, and 26, fresh fecal samples were collected to measure stool quality, immunoglobulin A, and calprotectin, and blood samples were collected to measure serum chemistry, inflammatory markers, and hematology. On weeks 2 and 4, fresh fecal samples were collected to measure metabolites and microbiota. On week 4, total feces were collected to assess apparent total tract macronutrient digestibility. Although revertant numbers were greater compared with the solvent control in tester strain WP2uvrA(pKM101) in the presence of metabolic activation (S9) in the initial experiment, they remained below the threshold for a positive mutagenic response in follow-up confirmatory tests, supporting that GNU100 is not mutagenic. Similarly, no cytotoxicity or chromosome damage was observed in the cell micronucleus test. The palatability test showed that 1% GNU100 was strongly preferred (P < 0.05; 3.6:1 consumption ratio) over the control. In study 3, all dogs were healthy and had no signs of GI intolerance or illness. All diets were well accepted, and food intake, fecal characteristics, metabolite concentrations, and macronutrient digestibilities were not altered. GNU100 modulated fecal microbiota, increasing evenness and Catenibacterium, Megamonas, and Prevotella (SCFA producers) and reducing Collinsella. Overall, the results suggest that GNU100 is palatable and well-tolerated, causes no genotoxicity or adverse effects on health, and beneficially shifts the fecal microbiota, supporting the safety of GNU100 for the inclusion in canine diets.

中文翻译：

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一种新型动物乳寡糖生物仿制药的评价：健康成年犬的常量营养素消化率和胃肠耐受性、粪便代谢物和粪便微生物群以及体外基因毒性测定

乳寡糖 (MO) 是哺乳动物乳汁中的生物活性化合物，可为新生儿提供除必需营养素外的健康益处。GNU100 是一种新型的动物 MO 生物仿制药，最近在体外进行了测试，结果显示微生物群发生了有益的变化并增加了短链脂肪酸 (SCFA) 的产生，但 GNU100 的其他作用尚不清楚。进行了三项研究来评估 GNU100 的安全性、适口性和胃肠道 (GI) 耐受性。在研究 1 中，使用细菌回复突变试验和哺乳动物细胞微核试验测试了 GNU100 的诱变潜力。在研究 2 中，通过比较 20 只成年犬的 0% 和 1% GNU100 的饮食来评估适口性。在研究 3 中，32 只成年犬被用于完全随机设计，以评估 GNU100 的安全性和 GI 耐受性并探索实用性。在 2 周基线后，狗被分配到四种治疗中的一种，并喂食 26 周：0%、0.5%、1% 和 1.5% GNU100。在第 2、4 和 26 周，收集新鲜粪便样本以测量粪便质量、免疫球蛋白 A 和钙卫蛋白，并收集血液样本以测量血清化学、炎症标志物和血液学。在第 2 周和第 4 周，收集新鲜粪便样本以测量代谢物和微生物群。在第 4 周，收集总粪便以评估表观总肠道常量营养素消化率。尽管在初始实验中存在代谢激活 (S9) 的情况下，与测试菌株 WP2uvrA(pKM101) 中的溶剂对照相比，回复体数量更大，但它们在后续验证性测试中仍低于阳性诱变反应的阈值，这支持了这一点GNU100 没有致突变性。同样，在细胞微核试验中也没有观察到细胞毒性或染色体损伤。适口性测试表明 1% 的 GNU100 比对照更受欢迎（P < 0.05；3.6:1 消耗比）。在研究 3 中，所有的狗都很健康，没有胃肠道不耐受或疾病的迹象。所有饮食都被很好地接受，食物摄入量、粪便特征、代谢物浓度和常量营养素消化率没有改变。GNU100 调节粪便微生物群，增加均匀度和链状杆菌、巨单胞菌和普雷沃氏菌（SCFA 生产商）并减少柯林氏菌。总体而言，结果表明 GNU100 适口性和耐受性良好，不会对健康造成遗传毒性或不利影响，并且有益地改变粪便微生物群，支持 GNU100 在犬类饮食中的安全性。细胞微核试验未观察到细胞毒性或染色体损伤。适口性测试表明 1% 的 GNU100 比对照组更受欢迎（P < 0.05；3.6:1 消耗比）。在研究 3 中，所有的狗都很健康，没有胃肠道不耐受或疾病的迹象。所有饮食都被很好地接受，食物摄入量、粪便特征、代谢物浓度和常量营养素消化率没有改变。GNU100 调节粪便微生物群，增加均匀度和链状杆菌、巨单胞菌和普雷沃氏菌（SCFA 生产商）并减少柯林氏菌。总体而言，结果表明 GNU100 适口性和耐受性良好，不会对健康造成遗传毒性或不利影响，并且有益地改变粪便微生物群，支持 GNU100 在犬类饮食中的安全性。细胞微核试验未观察到细胞毒性或染色体损伤。适口性测试表明 1% 的 GNU100 比对照更受欢迎（P < 0.05；3.6:1 消耗比）。在研究 3 中，所有的狗都很健康，没有胃肠道不耐受或疾病的迹象。所有饮食都被很好地接受，食物摄入量、粪便特征、代谢物浓度和常量营养素消化率没有改变。GNU100 调节粪便微生物群，增加均匀度和链状杆菌、巨单胞菌和普雷沃氏菌（SCFA 生产商）并减少柯林氏菌。总体而言，结果表明 GNU100 适口性和耐受性良好，不会对健康造成遗传毒性或不利影响，并且有益地改变粪便微生物群，支持 GNU100 在犬类饮食中的安全性。