Table 2.

Studies of the prebiotic effects of DKGM in vitro and in vivo

Test			Substance	Subject	Prebiotic effect	Reference
In vitro			DP 10–70	Single microculture	Enhanced all Lactobacillus and Bifidobacterium strains examined	Al-Ghazzewi et al., 2007
					Reduced Propionibacterium	Al-Ghazzewi and Tester, 2010
			Molecular weight 1000–6000 Da	Microculture with human faeces	Selective stimulation of beneficial gut microbiota and a favourable SCFA profile	Connolly et al., 2010
			Containing less than 10% by weight degree of DP 3	Single microculture	Enhanced lactic acid bacteria	Al-Ghazzewi and Tester, 2012
			Molecular weight 1000–6000 Da	Co-microculture	Reduced Staphylococcus aureus and Salmonella typhimurium	Al-Ghazzewi et al., 2012
			2000 u, 5000 u, 10000 u	Single microculture	Enhanced the proliferation of Lactobacillus acidophilus	Wang et al., 2015
			DP 2–6	Single microculture	Enhanced four different lactic acid bacteria	Wang et al., 2016b
				Co-microculture	Lactobacillus plantarum was the dominant strain in the co-culture with Enterococcus	Guo et al., 2017
				Microculture with human faeces	Improved the composition of fermentation broth and the prebiotic effect can be enhanced by γ-irradiation	Li et al., 2017
In vivo				Mice	Enhanced anaerobes and Lactobacillus; reduced Clostridium perfringens and Escherichia coli	Elamir et al., 2008
				Female patients suffering from vaginal infection	Decreased the clue cells and yeast-like fungi	Tester et al., 2012
				Female patients suffering from acne vulgaris	Improved skin health	Bateni et al., 2013
			Molecular weight <10 000 Da and >10 000 Da	Patients suffering IBD	Improve the patients’ life style	Suwannaporn et al., 2013
			DP 2–10	Mice	Enhanced Bifidobacterium and Lactobacillus	Qin et al., 2014
			DP 2–10 ≥85%, DP 2–6 ≥50%	Ulcerative colitis mice	Decreased the ulcer areas and rates of the colon	Feng et al., 2015
			DP 2–4	Mice	Improved the gut environment; enhanced the probiotics	Wan et al., 2015
			DP 2–4	Rat	Improved the intestinal environment; regular intestinal flora	Wang et al., 2016a
			DP 2–10 ≥85%, DP 2–6≥50%	Ulcerative colitis rat	Improved the gut environment; improved the gut microbiota structure; anti-inflammatory	Liu et al., 2016
			DP 2–10 ≥85%	Ulcerative colitis rat	Improved the gut environment; improved the gut microbiota structure	Liu et al., 2017

DP: degree of polymerization; IBD: inflammatory bowel disease; SCFA: short chain fatty acid