Table 5.

Related reports on the role of microorganisms in yak milk and products.

Disease	Strain	Experiment content	Experimental conclusion	Reference
Anti-fatigue	Lactobacillus fermentum HFY03 in fermented yak milk	Seventy-five ICR mice (6 weeks old) were divided into five groups: LF-HFY03 low-dose group (1.0 × 108 CFU/kg), high-dose group (1.0 × 109 CFU/kg), vitamin C group given 100 mg/kg vitamin C, running group and control group given 0.2 mL saline for oour weeks	Mice with prolonged swimming failure reduced urea nitrogen and lactate, increased fatty acid and liver glycogen, and reduced serum alanine aminotransferase, creatine kinase, and aspartate aminotransferase levels	(Zhang et al., 2021)
Type 2 Diabetes Mellitus	Paenibacillus bovis sp. nov. BD3526 in yak milk	Sixteen GK rats (18 weeks) were divided into two groups: BD3526 group rats were gavaged with 2 mL 50 mg/ml lyophilized BD3526 metabolite daily and control rats were gavaged with 2 mL 50 mg/ml skim milk powder daily for 4 weeks	Paenibacillus bovis sp. nov. BD3526 metabolite can improve diabetes by regulating intestinal flora through mucus enrichment and enhancing intestinal barrier function by stimulating intestinal epithelial cells to increase OCLN expression	(Qiao et al., 2020)
	Lactobacillus plantarum SHY130 in yak yogurt	Twenty-four male C57BL/6J mice (4 weeks old) were divided into three groups and treated with 1010 CFU kg−1 L of Lactobacillus plantarum SHY130 (SHY130) for 10 weeks in the diabetic group, and equal amounts of saline were administered by oral gavage daily in the normal control and diabetic groups	Lactobacillus plantarum SHY130 inhibits the proliferation of β and α cells in the pancreas of T2DM mice and increases the expression of short-chain fatty acid receptors GPR43 and GPR41 in the colon	(Wang et al., 2022)
Obesity	Lactobacillus plantarum HFY01 in fermented yak milk	60 C57BL/6 mice were randomly divided into 6 groups (normal group, model group, l-carnitine group, soymilk group, Lactobacillus plantarum HFY01 fermented soymilk group and Lactobacillus bulgaricus fermented soymilk group) for 12 weeks	Lactobacillus plantarum HFY01 significantly reduced body fat percentage and liver index, increased LDL cholesterol, triglycerides, alkaline phosphatase and transglutamic acid aminotransferase, and decreased HDL cholesterol in obese mice	(Li et al., 2020)
Hypercholesterolemia	Lactobacillus casei YBJ02 in yak yogurt	50 mice were divided into 5 groups: normal group, low concentration LC-YBJ02 treatment group, medium concentration LC-YBJ02 treatment group, high concentration LC-YBJ02 treatment and high fat model group	Different concentrations of LC-YBJ02 have inhibitory effects on elevated blood lipids in mice, especially high concentrations of LC-YBJ02 can reduce the content of cholesterol, triglycerides and low-density lipoprotein, and also effectively reduce the level of cholesterol in fecal excretion	(Qian et al., 2019)
	Lactobacillus plantarum LP3 in traditional yak fermented milk	Thirty male Sprague-Dawley rats (5 weeks old, weighing 120–130 g) were divided into normal diet, high-fat diet and high-fat diet + Lactobacillus plantarum LP3	The serum levels of total cholesterol, triglycerides and LDL cholesterol as well as the atherosclerotic index were reduced in the high-fat diet rats with Lactobacillus plantarum LP3	(Ding et al., 2020)
Alcoholic Liver Injury	Lactobacillus plantarum HFY05 in yak yogurt	Sixty male mice (6 weeks old) were divided into 6 groups: LP-HFY05-L and LP-HFY05-H groups were given 108 and 109 CFU/kg of LP-HFY05 per day, respectively; the LDSB group received 109 CFU/kg of LDSB per day; and the silymarin group received 100 mg/kg of silymarin per day for 8 weeks	The liver index of liver-injured mice and the levels of IL-6, IL-12, TNF-α and interferon-γ in the serum of mice were reduced, and pathological observations further indicated that Lactobacillus plantarum HFY05 reduced alcohol damage to hepatocytes	(Yi et al., 2019)
Constipation	Lactobacillus fermentum Lee in yak yogurt	120 mice were divided into six groups (20 mice in each group): regular and control groups were fed standard diet for 9 d; LF-Lee high-dose group (1x109 CFU/mL), low-dose group (1x108 CFU/mL) and Lactobacillus bulgaricus group (1x109 CFU/mL) were given 2 mL orally; mice in the drug-treated group were given 100 mg/kg dose of bixadil in water for 9 d	Increased gastrointestinal transit rate; increased levels of motilin, gastrin, endothelin, acetylcholinesterase, substance P, and vasoactive intestinal peptide, suggesting that Lactobacillus fermentum Lee has a beneficial effect on constipation	(Qian et al., 2015)
Cancer	Lactic acid bacteria Lan4 in yak milk	Hela (human cervical cancer cells) and HEK293 (human embryonic kidney) cells were used to perform anti-cancer activity assays. Cancer cell lines supplemented with 10 % heat inactivated (30 min, 56 °C) fetal bovine serum and 1 % penicillin–streptomycin mixture were grown in RPMI medium at 37 °C, 5 % CO2 and 95 % relative humidity for the experiments	Lactic acid bacteria Lan4 exhibited significant anticancer activity and induced maximal apoptosis in Hela cells and was not toxic to non-cancerous HEK293 cells	(Kaur et al., 2017)
	Lactobacillus casei SB27 in yak milk	The human colon cancer cell line HT-29 was cultured in RPMI-1640 medium containing 10 % fetal bovine serum, and the cells were placed in 25 cm2 flasks at 37 °C in an incubator with 95 % air and 5 % CO2 humidified atmosphere	Extracellular polysaccharide produced by Lactobacillus casei SB27 significantly inhibits the proliferation of HT-29 colon cancer cells and increases the expression of genes such as B-lymphoma-2-related promoter, B-cell lymphoma/leukemia-2-related X protein, cysteinase-3 and cysteinase-8	(Di et al., 2017)
	Kluyveromyces marxianus PCH397 in yak milk	Human colorectal adenocarcinoma cells (SW480) were thawed and maintained in Leibovitz's/L5 medium supplemented with fetal bovine serum and antibiotics and grown at 95 % relative humidity, CO2-free, and 37 °C	Cell-free supernatant of Kluyveromyces marxianus PCH397 exhibits cytotoxic effects on SW480 colon cancer cells and induces cell cycle phase arrest after 24 h of treatment, suggesting that Saccharomyces marcescens PCH397 has potential preventive and palliative effects against colon cancer	(Nag et al., 2022)