Objective—To determine effects of age and sex on
plasma lipid and lipoprotein metabolism in cats.
Animals—33 kittens and 16 adolescent, 23 adult, and
10 senior cats.
Procedure—Plasma concentrations of cholesterol,
triglyceride, and lipoprotein-cholesterol and activities
of lipoprotein lipase, hepatic lipase, and lecithin:cholesterol
acyl transferase (LCAT) were measured and
compared within and among groups.
Results—Plasma cholesterol and triglyceride concentrations
were significantly higher in 5- and 7-week-old
kittens, compared with the same kittens after weaning
and cats in the other age groups. Cholesterol concentration
was significantly less in 20-week-old kittens,
compared with adolescent and adult cats. Lipid
and lipoprotein-cholesterol concentrations were not
significantly different among the adolescent, adult,
and senior groups, nor did sex influence lipid and
lipoprotein-cholesterol concentrations in these
groups. Activities of lipoprotein and hepatic lipases
were significantly less in senior cats, compared with
the other groups. Activity of LCAT was highest in 20-week-old kittens and was greater in sexually intact
adult and adolescent females, compared with their
male counterparts. After castration, activities of
hepatic lipase and LCAT significantly decreased in
adolescent male cats.
Conclusions and Clinical Relevance—The upper
limits of reference ranges for plasma cholesterol and
triglyceride concentrations should be increased for
kittens < 8 weeks of age. Low cholesterol concentrations
in adolescent cats likely reflect high tissue
demands for growth and steroidogenesis. Decrease
in lipoprotein and hepatic lipase activity in senior cats
could predispose this age group to hypertriglyceridemia,
particularly in insulin-resistant cats or those
fed a high fat diet. (Am J Vet Res 2001;62:331–336)
Objective—To determine the effects of increases in dietary intake of polyunsaturated and saturated fatty acids on plasma lipid and lipoprotein concentrations and activity of associated enzymes in healthy domestic cats.
Procedures—A baseline diet (40% energy from fat) and 4 test diets, with increased amounts of fat (51% and 66% energy from fat) from the addition of polyunsaturated and saturated fatty acids, were fed for 6 weeks each. Plasma cholesterol, triglyceride, and lipoprotein cholesterol concentrations, along with activities of lipoprotein lipase, hepatic lipase, and lecithin-cholesterol acyl transferase, were measured at the end of each feeding period.
Results—Diet, amount of fat, or ratio of polyunsaturated to saturated fatty acids had no effect on plasma concentrations of cholesterol, triglycerides, and very–low-density or high-density lipoproteins or the activity of lecithin-cholesterol acyl transferase. Low-density lipoprotein concentrations were significantly lower in cats fed a high-fat diet containing polyunsaturated fatty acids. Lipoprotein concentration and hepatic lipase activity were significantly higher in cats fed the fat-supplemented diets, and this was unrelated to whether diets were enriched with polyunsaturated or saturated fatty acids.
Conclusions and Clinical Relevance—Diets containing up to 66% of energy from fat were tolerated well by healthy cats and did not affect plasma lipid concentrations. Therefore, high-fat diets probably will not contribute to hypercholesterolemia or hypertriglyceridemia incats.