Faculty Mentor: Mark Anderson, Assistant Professor
Department of Agricultural Sciences and Engineering Technology
Student Team Members: Phil Urso & Julia Swyden
Funding provided by the College of Sciences Dean’s Office
Faculty Report
Obesity continues to be widespread and is a leading public health concern in the U.S. In the U.S. today, health is a growing concern especially since obesity rates have more than doubled in adults and children since the 1970s. Conjugated linoleic acid (CLA) has attracted interest because it can potentially alter body composition by reducing fat mass and increasing muscle mass. CLA has also been shown to have the potential to prevent cancer, heart disease, and diabetes. However, these positive benefits have not been well tested in obese humans for long term effect while on a consistent controlled diet. In the current study, obese pigs are used in place of humans because of our similar digestive tracts and it allows us to have better control over the diet of the animals. As a result, the objective of this research was to determine if feeding CLA to obese pigs would alter the amount of fat and muscle tissue in obese male and female pigs that were either supplemented with CLA or with a second control oil (soybean oil).
To do this 24 obese pigs (12 males and 12 females; ~280 lbs) were acquired and assigned into treatment groups. Male and female groups were further divided in a CLA treatment group and a control group. This resulted in four groups with 6 animals in each group: Male control group (mCont), female control group (fCont), male CLA treatment group (mCLA), and female CLA treatment group (fCLA). With this arrangement we were able to look for differences between males and females and between the CLA group and our control, soybean oil, group.
These animals were then feed over 90 days the previously described diets. The animals were fed twice a day and at a lower intake to mimic a human on a restricted calorie diet. On the first day of the study blood samples, ultrasound measurements of the loin muscle and backfat, and the body weight were measured and recorded. We continued to measure body weight every week.
Blood collection and backfat measurements were recorded every two weeks, and the loin muscle area were recorded at the beginning and end of the trial.
While the results from the blood work are still being processed, the results from the physical traits measured (body weight, loin muscle area, and backfat), did not show any differences between the CLA group as a whole or the control soybean oil group. This outcome, while not expected, has been seen in the past with heavier weight animals. However, we did see that males with CLA supplementation had a greater fat loss and greater increases in muscle mass than the females receiving CLA. Because females will have a greater amount of the female sex hormones, particularly estrogen, it is reasonable to believe that they are the cause of this difference. This suggests that females may be less responsive to the effects of CLA, and may explain the lack of consistency in the response of CLA from previous trials. It will be important for future trials to focus not only on the CLA supplementation, but also on differences between females and males. From the bloodwork we hope to shed light on the incorporation of CLA along with the monitoring alterations to the fatty acid profile. Additionally, this study has given us insight into the differences between males and females in terms of CLA supplementation.
Together this information will help us to better understand how CLA supplementation may be used in obese adult humans as a method to reduce fat and increase lean muscle mass.