## 4 Discussion
The subjects had a daily intake of 330 g of yogurt for 8 weeks. The result was confirmed that the probiotic yogurt caused a decrease in LDL-C/HDL-C ratio and significantly increased HDL-C levels. Oxidative stress is an imbalance in the cells between the system of reactive oxygen species (or free radicals); production and accumulation lead to the damage of cellular structures such as lipids, proteins, and nucleic acids [35]. Therefore, the harmful effects can respond with dyslipidemia. The lipid peroxidation is one of the possible outcomes of aberrant free radicals, of which MDA is the primary marker. In the current study, the MDA level was significantly decreased to 68.42% in the probiotic group, from 0.19 \(\pm\) 0.07 mg/dL at the baseline to 0.06 \(\pm\) 0.01 mg/dL at the endpoint. These findings agree with the results of a previous study that reported decreased MDA levels in the serum and liver of hyperlipidemic rats following _L. casei_ supplementation [36]. Moreover, the ability of an antioxidant defense system is based on main enzymatic components, including CAT, GPx, and SOD. For the probiotic group, the levels of CAT and GPx were significantly increased to 8.07 and 31.75% at Day 30 compared to Day 0. However, the level of SOD was an insignificant difference after the endpoint compared to the baseline of the study period. Similarly, within a clinical trial, [PERSON] et al. [37] reported that probiotic yogurt decreased oxidative stress in healthy women within a clinical trial. That is, intake of the probiotic yogurt for six weeks significantly increased CAT activity compared to the normal yogurt. [PERSON] et al. [26] found that the supplement containing probiotic _L. casei_ (4 \(\times\) 10\({}^{8}\) CFU) and prebiotic Inulin (400 mg) might be an advantageous influence on the antioxidant properties of healthy human plasma after 7 weeks. Briefly, the symbiotic could be a significant increase in CAT activity; however, the activity of SOD and GPx was an insignificant increase compared to a control group. The result was slightly dissimilar because of the difference in probiotic bacterial strain. These results could show that VFJ with probiotic bacteria affected oxidative stress. Several mechanisms explained the probiotics affecting antioxidant activity and reduced damages caused by oxidation. The probiotics have their antioxidant enzymatic system, especially SOD. Furthermore, the probiotic strain was able to provoke the system of antioxidant in the host and increased the antioxidant enzymatic activity. As a result, they can prevent or decrease the seriousness of intestinal pathology caused by reactive oxygen species [38]. Moreover, the metabolites of antioxidant activity were produced by probiotics. For example, butyrate, as SCFA, was generated by the fermentation of microbiota in the small intestine and/or a final section of the small intestine led to induce antioxidative enzymes [39]. [PERSON] et al. [38] reported that the probiotics _Lactobacillus_ and _Bifidobacterium_ were able to produce lactic acid, acetic acid, and propionic acid, resulting in a lower intestinal pH, maintaining a balance of the gut microbiota. The probiotics can also regulate the growth of harmful bacteria, which may contribute to reduced oxidative stress. BAs or bile salts are synthesized from cholesterol in the liver and, subsequently, become conjugated to glycine or taurine, which increases their solubility [40; 41]. Approximately 200-600 mg of BA is produced daily in the human liver and excreted in feces [40]. The alteration in the BA level of the probiotic group was significant increased by 19.40%. Thus, based on the marked increase in BAs within the probiotic group of the current study, it could be inferred that the BSH activity of _L. paracasei_ reduced the TC, LDL-C, TG, and TG/HDL-C ratio, resulting in increased fecal BAs [33; 42]. The BAs that are lost in the feces are then regenerated from cholesterol, via de novo synthesis, in the liver to maintain a constant BA pool [40; 41], thus, reducing serum cholesterol levels [33].