Effect of kazunoko lipid on the concentrationsof plasma glucose and lipids and liver lipids inmice

National Food Research InstituteTomoyuki Higuchi, Nobuya Shirai and Hiramitsu Suzuki

INTRODUCTION
Kazunoko, which is Japanesetraditional food, is a salted
herring roe food product.
Kazunoko lipid contains lots of n3 polyunsaturated fatty acids,
such as eicosapentaenoic (EPA)
and docosahexaenoic acids(DHA). EPA and DHA havesuppressing-effects on themorbidity of coronary arterydisease, hypertension, andhyperlipidemia. However,Fig. 1 Kazunoko (salted herring roe food product)
Kazunoko lipid enrichedcholesterol. It has been thought that dietary cholesterol increases a risk of coronary
heart disease. Aim to this study is to clarify the effect of kazunoko lipid on totalcholesterol, triacylglycerol and phospholipid levels in plasma and liver and plasma
glucose level of male Crj:CD-1 mice.

Table 1 Proximate compositions ofKazunoko (g/100g)
Moisture
Protein
Lipid
Ash
Carbohydrate

80.3
16.1
2.7
0.4
0.5

Table 2 Lipid classes of Kazunoko
lipid (g/100g)
Total lipid
CholesterolTriacylglycerol
Phospholipid

2.99
0.26
0.53
2.14

Kazunoko
immersed in 5 volume of distilled water for 10 hours
Desalted Kazunoko
extracted in 5 volume of 1/1(v/v) hexane-ethanol
Homogenate
filtrated through filter paper
Filtrate
remove the hexane-ethanol
Kazunoko lipid sample
Fig. 2Extraction of Kazunoko lipid

Animal: male Crj:CD-1(ICR) mice
Age: 5 months old
Trial term: 12 weeks
Table 4 Composition of experimental diets
Dietary group
LardCorn starch
CaseinGranulated sugar
Cellulose powder
Mineral mixture
Vitamin mixtureL-Methionine
Lard
Kazunoko lipid

47.8
20155420.2
6―1%Kazunoko

3%Kazunoko

6%Kazunoko

47.8
20155420.251

47.8
20155420.2
33

47.8
20
15
5420.2―

6Table 5 Main fatty acids composition of experimental diet (%)
Dietary group

14:0
16:0
18:0
16:1n-7
18:1n-9
18:1n-7
18:2n-6
20:4n-6
20:5n-3
22:6n-3

Lard
2.1
26.1
13.4
3.0
41.8
2.9
8.6
―――

3%
1% Kazunoko
Kazunoko
2.1
2.3
25.7
26.6
12.2
9.53.2
3.9
38.8
31.6
3.2
3.8
7.8
5.8
0.2
0.5
1.7
5.5
2.8
8.4

6%Kazunoko
2.8
29.1
2.5
5.6
13.9
5.0
1.0
1.1
14.7
21.6

Table 6 Cholesterol level of experimental diets (mg/100g diet)
Dietary group1%
3%
6%
Lard Kazunoko Kazunoko Kazunoko
Cholesterol
971
219
432

Lard

1% Kazunoko lipid

3% kazunoko lipid

6% Kazunoko lipid

a300

aa aa

mg/dl

200b bab b

100ab bab b0
GLT-chol

TGPLFig. 3 Concentrations of plasma glucose, total cholesterol, triacylglycerol andphospholipid in mice. Values are means ± SEM, n =10-11. Means without acommon letter differ, P < 0.05. GL, glucose; T-chol, total cholesterol; TG,triacylglycerol; PL, phospholipid.

63% kazunoko lipid

6% Kazunoko lipid

3bb

4
ab

32abµg/ml

6ng/mlng/ml

1% Kazunoko lipid

851Lard42ac bca12

a000Insulin

LeptinAdiponectin

Fig. 4 Levels of plasma insulin, leptin and adiponectin in mice.
Values are means ± SEM, n =10-11. Means without a common letterdiffer, P < 0.05.

Lard

1% Kazunoko lipid

3% kazunoko lipid

6% Kazunoko lipidb60a50a40mg/ga30ababb20
100T-chol

TGPLFig. 5 Levels of liver glucose, total cholesterol, triacylglycerol and phospho-lipid inmice. Values are means ± SEM, n =10-11. Means without a common letter differ, P <0.05. T-chol, total cholesterol; TG, triacylglycerol; PL, phospholipid

40c30%a aba aab20Lard

1% Kazunoko lipid

3% kazunoko lipid

6% Kazunoko lipidbaaccab10bbbbaabcd0

16:0

18:1n-9

18:2n-6

20:4n-6

20:5n-3

22:6n-3

Fig. 6 Percentages of main fatty acids in plasma of mice. Values aremeans ± SEM, n =10-11. Means without a common letter differ, P <0.05.

50

ab

40%30baLard

1% Kazunoko lipid

3% kazunoko lipid

6% Kazunoko lipid

caabc

20acbbc
a10caba b

20:4n-6

20:5n-3

016:0

18:1n-9

18:2n-6cbbbaa

22:6n-3

Fig. 7 Percentages of main fatty acids in liver of mice. Values aremeans ± SEM, n =10-11. Means without a common letter differ, P <0.05.

Conclusion
Plasma cholesterol levels of 3% and 6% Kazunoko lipid diet groups weresignificantly lower than those of lard and 1% Kazunoko lipid diet groups though
Kazunoko lipid contained lots of cholesterol. This result indicates that influence ofEPA and DHA overcome the effect of dietary cholesterol on plasma cholesterol level.
Plasma glucose level was significantly lower in 3% and 6% Kazunoko lipid
diet groups than in lard diet group. Plasma insulin, leptin and adiponectin levels of
Kazunoko lipid diet groups tended to be higher than those of lard diet group.
Plasma adiponectin level was significantly higher in 6% Kazunoko lipid diet groupthan in lard and 1% Kazunoko lipid diet groups.
These results suggest that Kazunoko lipid intake induces the reduction of plasma
lipid and glucose levels.