OBJECTIVETo evaluate the effect of probiotics (bifidobacterium breve and lactobacillus acidophilus) on serum lipid, serum insulin and insulin resistance in high-fat diet (HFD)-induced obese rats.

METHODSFifty male Sprague-Dawley rats were randomly assigned to a control (n=10) and a high fat diet groups (n=40) and were fed with standard diet and HFD respectively. Four weeks later, thirty-six HFD-induced obese rats were randomly administered with normal saline (NS), bifidobacterium breve and lactobacillus acidophilus daily (n=12 each). Four weeks later, body lengths, body weights and abdomen circumference of rats were measured, blood lipid, glucose and insulin levels were measured, and Lee's index and insulin resistance index were calculated.

RESULTSBody weight, abdomen circumference, Lee's index, fasting glucose, triglyceride (TG), total cholesterol (TC), low density lipoprotein (LDL) in the NS-treated HFD group were significantly higher than the control group (P<0.05). The bifidobacterium breve and lactobacillus acidophilus-treated groups had significantly lower levels of body weight, abdomen circumference, Lee's index, fasting glucose, TC, TG and LDL than the NS-treated HFD group (P<0.05), but the levels of the parameters in the bifidobacterium breve and lactobacillus acidophilus-treated groups were significantly higher than the control group (P<0.05). High density lipoprotein (HDL) and insulin sensitivity index in the NS-treated HFD group were significantly lower than the control group (P<0.05). Bifidobacterium breve and lactobacillus acidophilus treatment dramatically increased HDL levels and insulin sensitivity index compared with the NS-treated HFD group (P<0.05), although the levels of the two parameters did not reach to the levels of the control group. There were significant differences in the levels of fasting insulin, insulin resistance index and insulin secretion index between the bifidobacterium breve and lactobacillus acidophilus groups (P<0.05).

CONCLUSIONSLactobacillus acidophilus and bifidobacterium breve can decrease serum levels of lipid and glucose and improve insulin resistance in obese rats. Bifidobacterium breve seems to be more effective on attenuating insulin resistance than lactobacillus acidophilus.