The Effect of Diet-Induced Obesity and Metabolic Syndrome on the Structural Composition of Extraocular Muscle (EOM) in Ossabaw Pigs

The Effect of Diet-Induced Obesity and Metabolic Syndrome on the Structural Composition of Extraocular Muscle (EOM) in Ossabaw Pigs

Ossabaw swine placed on a high fat/fructose (H) diet inclined toward developing obesity and metabolic syndrome, while the lean, active swine on the control (C) diet remained on the healthier end of the spectrum. There were a total of eight samples used: four from the H diet and four from the C diet. The purpose of this experiment was to test the hypothesis that diet- induced obesity and metabolic syndrome would cause an increase in intramyocellular lipid (IMCL) accumulation and change fiber type composition/fiber size in extraocular muscles (EOM) of Ossabaw swine. The rectus medius of the EOM was studied for each pig. Results indicated an increase in the CSA of the fast fibers and all the fibers combined, which was statistically significant and not due to chance. Although slow fibers did show a general increase in size in EOM of swine on H diet, it didn‘t reach thestatistically significant level. This general increase in CSA of the fibers correlates with the presence of obesity and metabolic syndrome. Visual observation, which requires further quantitative measurements to be supported, showed that IMCL accumulation appeared to have decreased in the EOM of swine on the H diet. This is the opposite to previous findings in plantaris and soleus muscles of the same swine. This may be due to the distinctive nature of EOM in composition and function when compared with other types of skeletal muscle.