Differential effects of intestinal short- and long-chain fatty acid infusions on ingestive behavior in rats

Soojeong Ji, Purdue University

Abstract

The physiological mechanism(s) by which fatty acids in the small intestines can suppress short-term intake is still not fully understood, and attempts to identify the pathways have been complicated by the lack of a test paradigm that can measure short-term intake suppression latencies. The present experiment employed a test paradigm that protracted meal consumption duration and thus assessed the latencies for infused fatty acids to suppress ongoing intake. In order to evaluate the effectiveness of long-chain (sodium oleate) and short-chain (sodium butyrate) fatty acids, both of which have been shown to activate vagal afferents innervating the intestines (Lal et al., 2001), in inhibiting within-meal food intake, food deprived rats had a fatty acid infused into the intestine and their within-meal liquid diet intake was measured. To further explore underlying satiety mechanism(s) induced by fatty acid infusion, rats were locally administered the CCK receptor blocker devazepide (Dev) and the neural blocker lidocaine (Lido). In a separate experiment, a conditioned flavor preference test was performed to investigate the possibility of adverse effect of fatty acid infusions. The infusion of sodium oleate (1% and 2%) suppressed intake significantly and dose-dependently, while infusion of sodium butyrate (1% and 2%) was ineffective in suppressing intake significantly, suggesting the two fatty acids may involve different pathways or mechanisms. The suppression seen with 1% sodium oleate infusion was partially reversed by pretreating with Dev. Neither the rats infused with the long chain fatty acid nor those infused with the short chain fatty acid showed any clear preference for flavors paired with the lipid infusions (CS+) or flavors paired with control infusions of water (CS-).

Degree

M.S.

Advisors

Powley, Purdue University.

Subject Area

Behavioral psychology

COinS