Objective—To determine whether dietary fatty acids
affect indicators of insulin sensitivity, plasma insulin
and lipid concentrations, and lipid accumulation in
muscle cells in lean and obese cats.
Animals—28 neutered adult cats.
Procedure—IV glucose tolerance tests and magnetic
resonance imaging were performed before (lean
phase) and after 21 weeks of ad libitum intake of
either a diet high in omega-3 polyunsaturated fatty
acids (3-PUFAs; n = 14) or high in saturated fatty acids
Results—Compared with the lean phase, ad libitum
food intake resulted in increased weight, body mass
index, girth, and percentage fat in both groups.
Baseline plasma glucose or insulin concentrations and
glucose area under the curve (AUC) were unaffected
by diet. Insulin AUC values for obese and lean cats fed
3-PUFAs did not differ, but values were higher in obese
cats fed SFAs, compared with values for lean cats fed
SFAs and obese cats fed 3-PUFAs. Nineteen cats that
became glucose intolerant when obese had altered
insulin secretion and decreased glucose clearance
when lean. Plasma cholesterol, triglyceride, and nonesterified
fatty acid concentrations were unaffected by
diet. Ad libitum intake of either diet resulted in an
increase in both intra- and extramyocellular lipid.
Obese cats fed SFAs had higher glycosylated hemoglobin
concentration than obese cats fed 3-PUFAs.
Conclusions and Clinical Relevance—In obese cats,
a diet high in 3-PUFAs appeared to improve long-term
glucose control and decrease plasma insulin concentration.
Obesity resulted in intra- and extramyocellular
lipid accumulations (regardless of diet) that likely
modulate insulin sensitivity. (Am J Vet Res