Regulation of Feed Intake

1. Regulation of Feed Intake ANS/NUTRS 520 February 28,2012

3. Neural feedback • Ventromedial nucleus of hypothalamus (leptin) • Stimulation decreases feed intake • Lesions increase feed intake • Lateral hypothalamus • Stimulation increases feed intake • Lesions decrease feed intake

4. CNS http://www.vivo.colostate.edu/hbooks/pathphys/digestion/pregastric/foodintake.html

5. Metabolic limits • Satiety signals • Energy balance

6. Metabolic • Absorbed compounds-or direct result of an absorbed compound • Fermentation products (VFA-mainly acetate, propionate) • Ammonia (urea)

7. Endocrine • Steroids, FSH, LH, PRL, ST-secondary effects

8. Hormonal Feedback J Physiol Pharmacol. 2007 Dec;58 Suppl 6:23-52.

9. Regulatory peptides • 36 AA neural peptide • Secreted from hypothalamus • Increases feed intake • Stimulates fat production • Production may increase due to cold stress or aggressive behavior (Nat Med. 13:7, 2007) • 41 AA peptide produced in hypothalamus • Decreases feed intake

10. Leptin • Signal of body energy (fat) and senses energy balance • Inhibits neuropeptide Y • In fed state • Correlates with body fat mass • Fasted state (12-48 h) • Rapid drop in leptin expression

12. Ob/ob mouse

13. Leptin Feedback Molecular Psychiatry (2005) 10, 132–146

14. Leptin lactation curve J. Dairy Sci. 86:799-807

15. CCK • Released from enterocytes to stimulate release of enzymes and bile into duodenum

16. Ghrelin • Stimulates release of GH from pituitary • Signals energy status

17. Wertz-Lutz et al., 2006

18. Leptin and Ghrelin Feedback

19. VFA Feedback Tahir et al., 2008

20. VFA Effects on DMI • P metabolism in liver to glucose leads to insulin release • Increased insulin decreases DMI • Dose VFA intravenously-no effect • Infuse VFA into portal vein-decrease meal size

21. Propionate effects on DMI Oba and Allen, J Nutr 133:1094

22. Bradford and Allen, 2007 JDS 90:2305

23. Bradford and Allen, 2007 JDS 90:2305

24. Additive Effects