1. Differential Satiating Effects of Fats in the Small Intestine of Obesity-Resistant and Obesity-Prone Rats Danielle Greenberg, Jeanne McCaffery, Jonathan Z. Potack, George A. Bray, and David A. York Jennifer Woodward

2. LOWERED SATIETY FROM FATS LEADS TO GREATER CHANCES FOR OBESITY Hypothesis

3. SATIETY Denotes the effectiveness of a substance in reducing a desire to feed. Greater satiety leads to less food consumed. Reduced consumption = lower caloric intake = reduced chance for obesity

4. THE ROLE OF THE DUODENUM Receives gastric output Presence of fats stimulates release of enzymes via vagal stimulation Absorption of fats Key region for studying effects of fat on digestion http://www.laparoscopic.md/digestion/duodenum

5. SATIATION IN THE PRESENCE OF FATS WILL BE SIGNIFICANTLY GREATER THAN SATIATION IN THE PRESENCE OF NaCl OSBORNE-MENDEL RATS WILL DEMONSTRATE LESS SATIETY IN THE PRESENCE OF FATS THAN S5B/PL RATS Predictions

6. Key Rat Strains Osborne-Mendel Rats (OM) Prefer fats, obesity-prone S5B/PL Rats (S5B) Prefer carbohydrates, obesity-resistant http://www.anim.med.kyoto-u.ac.jp/nbr/images/Photos/OM%20NSlc/731a%20(Large).jpg http://www.allposters.ie/-sp/White-Laboratory-Rat-Sprague-Dawley-Variety-a-Common-Laboratory-Animal-Rattus-posters_i6010439_.htm

7. Rat Digestive Anatomy Highly similar anatomy to humans Genetics and physiology have been extensively researched http://www.behance.net/gallery/The-digestive-system-of-the-rat/6368905

8. SURGICAL INSERTION OF DUODENAL CATHETER, GASTRIC CANNULA Following fasting the rats were anesthetized and fitted with: A chronic gastric cannula: Opening in the stomach closed with a screw-cap Duodenal catheter: Enables fats to be injected directly into the duodenum. Coiled and stored in stomach when not in use. Presence does not inhibit normal feeding http://www.sciencedirect.com/science/article/pii/S0167011504003544

9. SHAM FEEDING Ingestion without digestion 2 Fat Infusions: 0.65 kcal sodium lineolate 5% Intralipid These fats are “particularly potent” in decreasing meal size in Sprague-Dawley rats. 0.15M NaCl as control http://www.flickr.com/photos/obviouszebra/4018501107/

10. Fat infusion and sham feeding test Rats sham fed for 12 minutes prior to fat/NaCl infusion 12 minutes=most potent inhibitory effect Each rat received each fat only once Fat/NaCl comparison: 1-way ANOVA Strain comparison: 2-way ANOVA http://www.flickr.com/photos/62845755@N00/4943737230

11. 0.65 kcal sodium linoleate vs 0.15M NaCl Results support the hypothesis

12. 5% Intralipid vs 0.15M NaCl Results support the hypothesis

13. Summary OM rats and S5B rats achieved satiety through infusion of fats into the duodenum OM rats experienced significantly less satiety following fat infusions The hypothesis that decreased satiety can lead to obesity is supported These results demonstrate that fat satiety is a key component of weight maintenance. Future testing and therapies can be enhanced as a result.