M. Stachon et al., The influence of different dietary fat sources on tissue corticosterone concentration in rats, J ANIM FEED, 10(2), 2001, pp. 341-354
Forty-one rats were divided into six groups assigned to one of six diets co
ntaining three different fat types (sunflower oil, lard or 50:50 (wiw) blen
d of sunflower and lard) at one of two levels (5 or 30%) to determine the e
ffect on the corticosterone (Cs) level in the cytosol fraction of the adren
al glands, heart muscle and aorta in rats. Plasma cholesterol concentration
s and body composition were also measured.
The diet with 5% lard significantly increased adrenal Cs compared with diet
s with 5% sunflower oil or 5% blend. Marked elevations in Cs level in the a
orta were evident in rats fed diets with 5 and 30% sunflower oil in compari
son with rats fed the 5 and 30% blend of lard and sunflower oil. In additio
n, the Cs level in the aorta in rats fed the diet with 30% sunflower oil wa
s significantly higher than in rats fed the diet with 30% lard. The diet co
ntaining 5% sunflower oil markedly elevated the Cs level in rat heart muscl
e compared with the diet containing a 5% blend of the two fats. Unexpectedl
y, there were no significant effects of the experimental diets on plasma ch
olesterol concentrations. Moreover, rats fed diets containing 30% fat had h
igher body dry matter and fat percentages, but lower protein and ash percen
tages compared with the rats fed diets containing 5% fat. The percentages o
f fat, protein and ash in the body were not affected by the type of dietary
fat, but rats offered lard diets had a higher percentage of dry matter and
fat than rats fed mixed fat diets.