L. fermentum CECT5716 reduced weight gain and fat tissue accumulation and improved glucose tolerance test and plasma biochemical profile
Body weight was recorded in all experimental groups twice a week during the 11-weeks treatment period. As expected, the intake of HFD resulted in a higher mouse body weight gain in the untreated control group when compared to control group receiving the standard diet (Figure 1A). The daily administration of L. fermentum to HFD-fed mice significantly reduced weight gain from day 53 onwards, even though food intake was similar in the two groups throughout the experimental period (Figure 1A). Thus, the treatment was able to significantly decrease energy efficiency in comparison with untreated HFD-fed mice, consequently reducing both epididymal and abdominal fat deposits (Figure 1A). The probiotic also had a positive impact on glucose homeostasis as evidenced when glucose tolerance test was performed. Mice fed HFD showed significantly higher glucose level peaks than those fed control diet; however, L. fermentum treatment significantly reduced plasma glucose levels in comparison with HFD control group from 60 min onwards, which resulted in a significant reduction in the area under the curve (AUC) (Figure 1B). Moreover, the histological sections of epididymal fat tissue from untreated HFD-fed mice showed hypertrophy when compared with control diet-fed mice, which was significantly ameliorated after treatment with L. fermentum (Figure 1C).
The plasma biochemical determinations evidenced the obesity-induced alterations in glycemic and lipid profiles. Thus, control HFD-fed mice showed a significant increase of fasted glucose levels compared to non-obese mice, which were significantly reduced by L. fermentum , obtaining similar values to those of the control diet group (Figure 2A). Furthermore, and although no differences were observed among groups when plasma insulin levels were analyzed, an improvement on insulin sensitivity was showed after L. fermentum administration, as evidenced by the reduced HOMA-IR index value compared to control HFD-fed mice (Figure 2A). Similarly, control HFD-fed mice displayed hypercholesterolemia in comparison with control diet-fed mice, with higher levels of both low-density lipoprotein (LDL)-cholesterol and high-density lipoprotein (HDL)-cholesterol (data not shown), which resulted in increased LDL/HDL ratio. This ratio was significantly reduced by L. fermentum administration to obese mice. In addition, probiotic-treated mice showed reduced plasma triglycerides levels, which were also increased in control HFD-fed mice compared to control diet mice (Figure 2B).