Oral administration of bacterocin, albusin B, improved fatty acid oxidation
Date Issued
2011
Date
2011
Author(s)
Hsieh, Ya-Hui
Abstract
Albusin B (bacteriocin), a 32 kDa protein, is isolated from Ruminococcus albus 7 and mass-produced by the Saccharomyces cerevisiae expression system. In previous study, we found that broilers supplemented with albusin B had a better intestinal absorption of protein and carbohydrate, and thus caused greater growth performance. The first objective of this study was to elucidate the effect of albusin B on lipid metabolism of healthy mice. Twenty-four of BALB/c male mice at age of 6 weeks were randomly assigned into 3 groups: normal saline (control), yeast ( 0.125μg /g BW ) , yeast with albusin B ( albusin B, 0.125μg /g BW ) with daily oral administration for 14 days exhibited until sampling. Compared with the control, mice with albusin B treatment decreased body weight, lowered plasma triglyceride and free fatty acids, but increased plasms total cholesterol and high density lipoproteins (P <0.05). In the intestinal morphology, mice oral administrated with albusin B displayed higher villus lenght in the ileum than those of the other two groups (P <0.05). Mice with yeast alone or administrated with yeast + albusin B had a higher mRNA expression of fatty acid binding proteins and acyl-CoA oxidase（ACO） in the ileum, heart and liver than those of control mice (P <0.05). Compared with the control mice, yeast only and albusin B treatments caused a decreased mRNA expression of hepatic acetyl-CoA carboylase (ACC) and n fatty acid synthase (FAS) in the heart and liver (P <0.05). Moreover, albusin B administration also suppressed mRNA level of diacylglycerol acyltransferase, responsible for triglyceride synthesis in the ileum and liver (P <0.05). Mice albusin B treatment also exhibited better ATP production and antioxidant capability in the heart and liver of mice (P <0.05). To sum up, these results demonstrated that albusin B treatment increased the intestinal lipid absorption, while it enhanced lipid oxidation but decreased the lipid synthesis in liver and heart, and therefore may accoumt for the decresed BW of mice orally doesd with albusin B.
The second objective of this study was to elucidate the role of albusin B on lipid metabolism of cardiomyocytes（H9c2） and intestinal cell（Caco2） under oxidative stress. Hydrogen peroxide was applied to induce oxidative stress. The results showed that H9c2 and Caco2 with albusin B treatment had higher cell viability, and increased uptake and oxidation of fatty acid and ATP production when compared to the control (P <0.05). Consistent results were also observed in both of cell lines under oxidative stress. The mRNA expressions of ACO and antioxidative enzymes were upregulated and ATP production was increased by albusin B. The beneficial effect thus may improve cell survival rate.
Taken together, under healthy condition, albusin B treatment promotes the lipid oxidation and ATP production but reduces the lipid synthesis and therefore cause body weight loss in mice. Under oxidative stress, treatment of albusin B increases energy metabolism and improves antioxidative system, and therefore improves the cell viability. This study demonstrated beneficial effect of albusin B on lipid metabolism and body weight. More comprehensive studies, however, required to elucidate the mechanism.
Subjects
albusin B
fatty acid metabolism
ATP production
mice
cardiomyocytes
colon carcinoma cell line
Type
thesis
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