Mechanisms Controlling Feed Intake in Large-type Goats Fed on Dry Forage

  • Sunagawa, K. (Faculty of Agriculture, University of the Ryukyus) ;
  • Ooshiro, T. (Faculty of Agriculture, University of the Ryukyus) ;
  • Murase, Y. (Faculty of Agriculture, University of the Ryukyus) ;
  • Hazama, R. (Faculty of Agriculture, University of the Ryukyus) ;
  • Nagamine, I. (Faculty of Agriculture, University of the Ryukyus)
  • Received : 2006.09.28
  • Accepted : 2007.03.17
  • Published : 2007.08.01


An intracerebroventricular (ICV) infusion of somatostatin 1-28 (SRIF) was used as a thirst-controlling peptide antagonist to investigate whether or not thirst-controlling peptides are involved in the significant decrease in feed intake during the initial stages of feeding large-type goats on dry forage. A continuous ICV infusion of SRIF was conducted at a small dose of $4{\mu}g$ ml/h for 27 h from day 1 to day 2. Goats (n = 5) were fed roughly crushed alfalfa hay cubes for 2 h twice daily and water was given ad libitum. Feed intake was measured during ICV infusion of artificial cerebrospinal fluid (ACSF) and SRIF. The feed intake during SRIF infusion increased significantly compared to that during ACSF infusion. In comparison to the ACSF treatment, plasma osmolality during the SRIF treatment significantly decreased during the first half of the 2 h feeding period. The factor causing the decrease in plasma osmolality during the ICV infusion of SRIF was a decrease in plasma Na, K, Cl, and Mg concentrations. In comparison to the ACSF infusion treatment, parotid saliva secretion volumes during the 2 h feeding period in the SRIF infusion treatment were significantly larger. While there was no significant difference in cumulative water intake (thirst levels) between the SRIF and the ACSF treatments upon conclusion of the 2 h feeding period, based on the plasma osmolality results it is thought that thirst level increases brought about by alfalfa hay cube feeding in the first half of the feeding period were reduced. It is thought that the somatostatin-induced increases in feed intake during the 2 h feeding period in the present experiment were caused by decreases in plasma osmolality brought about by the somatostatin infusion. As a result, it is suggested that the significant decrease in feed intake during the initial stages of feeding in large-type goats given roughly crushed alfalfa hay cubes, was due to the actions of thirst-controlling peptides.


  1. Atack, J. R., M. F. Beal, C. May, J. A. Kaye, M. F. Mazurek, A. D. Kay and S. I. Rapoport. 1988. Cerebrospinal fluid somatostatin and neuropeptide Y. Concentration in aging and in dementia of the Alzheimer type with and without extrapyramidal signs. Arch. Neurol. 45:269-274.
  2. Beaudet, A., D. Greenspun, J. Raelson and G. S. Tannenbaum. 1995. Patterns of expression of SSTR1 and SSTR2 somatostatin receptor subtypes in the hypothalamus of adult rat: relationship to neuroendocrine function.
  3. Black, P. M. 1982. Neuropeptides in cerebrospinal fluid. Neurosurgery. 11:550-555.
  4. Blair-West, J. R. and A. H. Brook. 1969. Circulatory changes and renin secretion in sheep in response to feeding. J. Physiol. 204:15-20.
  5. Brazeau, P., W. Vale, R. Burgus, N. Ling, M. Butcher, J. Rivier and R. Guilemin. 1973. Hypothalamic polypeptide that inhibits the secretion of immunoreactive pituitary growth hormone. Sci. 179:77-79.
  6. Cameron, V. A., E. A. Espiner, M. G. Nicholls, M. R. MacFarlane and W. A. Sadler. 1986. Intra-cerebroventricular captopril reduces plasma ACTH and vasopressin responses to hemorrhagi stress. Life Sci. 38:553-559.
  7. Danguir, J. 1988. Food intake in rats is increased by intracerebroventricular infusion of the somatostain analogue SMS 201-995 and is decreased by somatostatin antiserum. Peptides. 9:211-213.
  8. Feifel, D. and F. J. Vaccarino. 1990. Central somatostatin: a reexamination of its effects on feeding. Brain Res. 535:189-194.
  9. Fisher, L. A. and M. Brown. 1984. Corticotropin-releasing factor and angiotensin II: comparison of CNS actions of influence neuroendocrine and cardiovascular function. Brain Res. 296:41-47.
  10. Fitzsimons, J. T. 1979. Thirst and the cause of drinking. Page 59 in The physiology of thirst and sodium appetite. Cambridge University Press, Cambridge, UK.
  11. Guyton, A. C. and J. E. Hall. 1996. Central nervous system centers for thirst. Page 361 in Textbook of Medical Physiology. W. B. Saunders Company, Philadelphia. PA.
  12. Ho, L. T., Y. F. Chern and M. T. Lin. 1989. The hypothalamic somatostatinergic pathways mediate feeding behavior in the rat. Experientia. 45:161-162.
  13. Kato, Y. 1988. Analysis of chemical components of feed. In Shiryo Bunseki Kijun Kyoukai (ed.), Shiryo Bunseki Kijun Tyukai. Nihon Shiryo Kyoukai. Tokyo. pp. 1-16.
  14. Mann, J. E. F., A. K. Johnson and D. Ganten. 1980. Plasma angiotensin II: Dipsogenic levels and angiotensin-generating capacity of rennin. Am. J. Physiol. 238:R372-R377.
  15. Mathai, M., M. D. Evered and M. J. McKinley. 1997. Intracerebroventricular losartan inhibits postprandial drinking in sheep. Am. J. Physiol. 272:R1055-R1059.
  16. McKinley, M. J., D. A. Denton, S. Hatzikostas and R. S. Weisinger. 1979. Effect of angiotensin II on parotid saliva secretion in conscious sheep. Am. J. Physiol. 237:E56-E60.
  17. McKinley, M. J. and A. K. Johnson. 2004. The physiological regulation of thirst and fluid intake. News Physiol. Sci. 19:1-6.
  18. Meyer, A. H., W. Langhans and E. Scharrer. 1989. Vasopressin reduces food intake in goats. Quar J. Exp. Physiol. 74:465-473.
  19. Prasetiyono, B. W. H. E., K. Sunagawa, A. Shinjo and S. Shiroma. 2000. Physiological relationship between thirst level and feed intake in goats fed on alfalfa hay cubes. Asian-Aus. J. Anim. Sci. 13:1536-1541.
  20. SAS. 1990. SAS/STAT User's Guide. Volume 2, Version 6, Fourth Edition. SAS Institute Inc., SAS Campus Drive, Cary, NC27513.
  21. Sasaki, Y., S. Watanabe, Y. Sato and S. Kato. 1975. Effect of intravenous infusion of artificial saliva on changes in acid-base status of sheep during eating. Jap. J. Zootech. Sci. 46:449-453.
  22. Shibasaki, T., Y. S. Kim, N. Yamauchi, A. Masuda, T. Imaki, M. Hotta, H. Demmura, I. Wakabayashi, N. Ling and K. Shimizu. 1988. Antagonistic effect of somatostatin on corticotropinreleasing factor induced anorexia. Life Sci. 42:329-334.
  23. Shibasaki, T., N. Yamauchi, K. Takeuchi, S. Ishii, H. Sugihara and I. Wakabayashi. 1998. The growth hormone secretagogue KP- 102-induced stimulation of food intake is modified by fasting, restraint stress, and somatostatin in rats. Neurosci. Lett. 255:9-12.
  24. Sunagawa, K., Y. Nakatsu, Y. Nishikubo, T. Ooshiro, K. Naitou, and I. Nagamine. 2002. Effects of intraruminal saliva flow on feed intake in goats fed on alfalfa hay cubes. Asian-Aust. J. Anim. Sci. 15:1738-1746.
  25. Sunagawa, K., Y. Nakatsu, Y. Nishikubo, T. Ooshiro, K. Naitou and I. Nagamine. 2003. Effect of parotid saliva secretion on dry forage intake in goats. Asian-Aust. J. Anim. Sci. 16:1118- 1125.
  26. Sunagawa, K., T. Ooshiro, N. Nakamura, I. Nagamine, S. Shiroma and A. Shinjo. 2005. Controlling factors of feed intake and salivary secretion in goats fed on dry forage. Asian-Aust. J. Anim. Sci. 18:1414-1420.
  27. Sunagawa, K., R. S. W. Weisinger, M. J. McKinley, B. S. Purcell, C. Thomson and P. L. Burns. 2001a. The role of brain somatostatin in the central regulation of feed, water and salt intake in sheep. Asian-Aust. J. Anim. Sci. 14:929-934.
  28. Sunagawa, K., R. S. Weisinger, M. J. McKinley, B. Purcell, C. Thomson and P. L. Burns. 2001b. The role of angiotensin II in the central regulation of feed intake in sheep. Canadian J. Anim. Sci. 81:215-221.
  29. Wang, X., J. J. Tresham, J. P. Coghlan and B. A. Scoggins. 1987a. Intracerebroventricular infusion of a cyclic hexapeptide analogue of somatostatin inhibits hemorrhage-induced ACTH release. Neuroendocrinol. 45:325-327.
  30. Wang, X., J. J. Tresham, M. Congiu, J. P. Coghlan and B. A. Scoggins. 1987b. Somatostatin inhibits vasopressin secretion during haemorrhage. Brain Res. 436:199-203.
  31. Weisinger, R. S., J. R. Blair-West, D. A. Denton and E. Tarjan. 1991. Central administration of somatostatin suppresses the stimulated sodium intake of sheep. Brain Res. 543:213-218.