Hypercholesterolaemic is a major risk factor associated with coronary
heart diseases and it is considered that keeping blood cholesterol at
a desirable level is one of the major preventive strategies for these
diseases. Thus, much attention has been given to the relationship between
diet and blood cholesterol levels.
Fermented dairy products have been recommended as dietary supplements
because of their hypocholesterolaemic effect in humans (Mann, 1977) and
rats (Suzuki et al., 1991). It was reported that buffalo milk yoghurt
or soymilk yoghurt containing bifidobacterium reduced the level of plasma
and liver cholesterol (Abdel Gawad et al., 1998).
Relatively little is yet known regarding the potential role of the health promoting effects
of Gariss and Gariss containing bifidobacteria by reducing
cholesterol. Therefore, the objective of this investigation was to detect
the hypocholesterolaemic effect of Gariss and Gariss containing
bifidobacterium on the levels of plasma and liver lipids of rats.
MATERIALS AND METHODS
Animal Feeding Experiment
Twenty four albino rats with an average weight between 80 and 100 g were
house in cages with wiremesh floors in a room at 23<Â±1Â°C and
60<Â±5% relative humidity. All animals were fed on basal diet for
one week. After this adoption period, the rats were divided randomly into
4 experimental groups of 6, one group received a basal diet (cholesterol-free
diet) throughout the experimental period of 6 weeks and served as a negative
control group. The other three groups were fed on basal diet with cholesterol
added at a level of 0.5% (w/w) (cholesterol-enriched diet) for 1-2 weeks
to create hypercholesterolaemic rats. One of the three groups, which served
as positive control group, was fed only on a cholesterol enriched diet
for the six-week period.
|| Experimental groups of rats and diets
The other 2 groups were fed for five weeks on a cholesterol-enriched
diet supplemented with G and G+Bb-12. The experimental diets given to
the 4 groups are described in Table 1. The rats were
allowed free access to experimental diet and water and their body weights
were monitored, at the end of the 6 weeks experimental period. Blood samples
were collected from the eye vein under diethyl ether anesthesia. The samples
were collected in tubes, with EDTA as an anti-coagulating agent.
The tubes were centrifuged at 3000 rpm for 15 min to obtain the plasma,
which was kept frozen (-23<Â±1Â°C) until analysis.The rats were
sacrificed and the liver, heart, kidney and spleen were excised immediately
and weighed. The liver was washed with ice-cold saline solution (0.9%
w/v, NaCl) and stored at 23<Â±1Â°C until analyzed.
The basal diet consisted of 15% (w/w), casein 10% (w/w), maize oil 10%
(w/w), cellulose 4% (w/w), mineral mix 1% (w/w), vitamin mix 1% and starch
Determination of Plasma Lipid
Total plasma cholesterol, High Density Lipoprotein (HDL) and triglycerides
were determined using the enzymatic colourimetric method according to
Trinder (1969). The VLDL+LDL was calculated as follows:
VLDL+LDL cholesterol = Total cholesterol - HDL cholesterol.
Determination of Cholesterol and Triglycerides in Liver
Cholesterol and triglycerides were extracted from the liver by the
method of Fernandez et al. (1997) and were measured by the method
of Trinder (1969).
Data are presented as means and standard deviations. The significance
differences between groups/treatments were evaluated using general linear
model procedure of Statistical Analysis Systems (SAS) (1990). The biological
examination data was analyzed by Least Significant Difference (LSD) at
p<0.05 (SAS, 1990).
RESULTS AND DISCUSSION
Plasma and Lipids
The effect of the experimental diets on the levels of plasma and liver
lipids in rats are presented in Table 2-4.
The total concentration of plasma cholesterol was significantly reduced
from 135.7 mg/100 mL in the positive control to the a mean value of 87.9
mg/100 mL in both G and G-Bb-12 groups. This decrease corresponds to 35.3
and 35.2% reduction, respectively. In contrast, there was no significant
difference in total cholesterol detected in (G and G-Bb-12) and negative
It was noticed cholesterol-enriched diet (supplemented with G-Bb-12) lowered
total cholesterol with the same efficiency of Gariss. Abdel Gawad
et al. (1998) reported that cholesterol-enrich diet supplemented
with yoghurt containing bifidobacteria were more effective at lowering
||Effect of bifidobobacterial Gariss on liver triglyceride,
total cholesterol and 7 keto-cholesterol in rats fed on cholesterol
||Effect of biofidobacterial Gariss on serum lipid
profile in rats fed on cholesterol enriched diet
||Effect of bifidobobacterial Gariss on body weight
gain and weight f liver, heart and kidney in rats feed on cholesterol
Beena and Prasad (1997) found lower serum cholesterol in rats fed on
yoghurt containing Bifidobacterium bifidum (120 mg/100 mL) compared
to a positive control (172 mg/100 mL) after 30 days. However, Homma (1998)
found that fermented milk containing bifidobactria (109 cfu
g-1) resulted in a decrease in the total cholesterol level
from 300 to 150 mg/100 mL) in human subject. Moreover, Schaarmann et
al. (2001) reported that the consumption of the probiotic yoghurt
made by B. Longum and Lactobacillus acidophilus decreased
total cholesterol in hypercholesterolaemic women from 293 mg/100 mL at
the beginning of experiment to 255 mg/100 mL after 153 days.
As shown in Table 3, there was no significant difference
in the plasma HDL-cholesterol level between the negative control group
and other experimental groups at the end of the 6-week experimental period.
Endo et al. (1999) reported that the addition of the probiotic
to diet had on effect no the HDL-cholesterol level. Our data agree well
with this finding.
Rats fed on (G) and (G+Bb-12) diet significantly lowered plasma VLDL+LDL-cholesterol
than positive control group of rats. The (G+Bb-12) diets were more effective
in lowering plasma VLDL+LDL-cholesterol levels than (G). Beena and Prasad
(1997) found that yoghurt containing B. bifidum markedly lowered
the levels of LDL-cholesterol in rats fed on a cholesterol-enriched diet
(positive control) from 97 mg/100 mL to 22.16 and 15 mg/100 mL, respectively,
in rats fed on yoghurt containing B. bifidum fortified with
skimmed milk, condensed whey or lactose-hydrolysed condensed whey at the
end of the 30 days experimental period. Moreover, Schaamann et al.
(2001) reported that the consumption of probiotic yoghurt made using B.
longum and L. acidophilus reduced the LDL-cholesterol level
in normocholesterolaemic and cholesterolamemic women.
The levels of plasma triglycerides in rats fed on (G) and (G+Bb-12) diets
were significantly lower than that in those fed the cholesterol-enriched
diet (positive control). The reduction in triglyceride levels with the
above mentioned groups was 52.6 and 33.1%, respectively (Table
3). Schaarmann et al. (2001) reported that the consumption
of probiotic yoghurt made with B. longum and L. acidphilus
lowered triglycerides in hypercholesterolaemic women from 114 mg/100 mL
to 91 mg/100 mL after 153 days. The data in Table 4
show that the content of liver cholesterol in the positive control group
(4.94 mg g-1) was significantly higher than in the negative
control group (2.38 mg g-1). In addition, there was a significant
difference between rats fed on the positive control diet and those fed
on (G) and (G+Bb-12) diets. It can be observed that Garris was
effective in lowering the levels of liver cholesterol. These results are
in agreement with those reported by Kheadr et al. (2000) who suggested
that the yoghurt diets supplemented with B. bifidum reduced cholesterol
in rat liver tissues.
The content of liver triglycerides was significantly higher in rats fed
on the positive control diet than those fed the negative control diet
(Table 4). In contrast, the levels of liver triglycerides
in rats fed on the experimental diet groups were significantly lower than
in rats fed on the positive control diet.
The value of body weight gain was significantly higher in rats fed (G)
and (G+Bb-12) than that in rats fed the negative control diet. The body
weight gain in rats fed (G+Bb-12) diet was non-significnatly higher than
that in rat fed the positive control diet (Table 4).
No significant difference in weights of heart or were detected between
rats fed on the (G) and (G+Bb-12) diets and rats fed the two control diets.
There was a significant difference in kidney weight between rats fed the
negative control diet and rats fed other diets. The liver weight in rats
fed the positive control diet was significantly higher than rats fed negative
control diet. There was a significant difference in the liver weight between
rats fed the positive control diet and rats fed the other experimental
This study has demonstrated that the inclusion of Gariss and
Gariss with bifidobacteria in the diet of rats fed a cholesterol-enriched
diet had a marked effect on the level of plasma and liver lipids. Gariss
and Gariss containing bifidobacterium Bb-12 were very effective
in lowering the level of plasma and liver lipids in rats. These hypercholesterolaemic
effects of Gariss and Gariss containing bifidobacterium Bb-12, which have
been demonstrated in the rats in the present study, could make an effective
and economic contribution in treating hyperchloesterolaemic if these effects
could be confirmed in human volunteers.
This review forms part of a research carried out at the Food research
cooperation, Egypt. The authors express their sincere thanks to all staff
and the colleagues for their assistance.