A Comparison of the Anorexic Effects of Chicken, Porcine, Human and Bovine Insulin on the Central Nervous System of Chicks

Authors: SHIRAISHI, JUN-ICHI - HIROSHIMA UNIVERSITY; YANAGITA, KOUCHI - HIROSHIMA UNIVERSITY; NISHIKAWA, FUMIYA - HIROSHIMA UNIVERSITY; TAHARA, YUKI - HIROSHIMA UNIVERSITY; FUJITA, MASANORI - HIROSHIMA UNIVERSITY; McMurtry, John; BUNGO, TAKASHI - HIROSHIMA UNIVERSITY

Submitted to: International Journal of Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/14/2009
Publication Date: 1/1/2009
Citation: Shiraishi, J., Yanagita, K., Nishikawa, F., Tahara, Y., Fujita, M., McMurtry, J.P., Bungo, T. A . 2009. Comparison of the Anorexic Effects of Chicken, Porcine, Human and Bovine Insulin on the Central Nervous System of Chicks. Journal of Poultry Science. 46:144-148.

Interpretive Summary: In mammals, many endocrine factors are known to be integral to the regulation of ingestive behavior. Whether similar mechanisms exist in poultry are unknown. Insulin is a well-documented hormone which regulates overall metabolism in all species. Previous research has shown that mammalian insulins (porcine, human, bovine) influence feeding behavior in chickens. Whether chicken insulin functions in a similar manner has not been reported. The purpose of this study was to compare the anorexic properties of chicken insulin versus mammalian insulins when administered into the brain of the chicken. The results of this study show that chicken insulin decreases feed intake to a greater degree than insulins of mammalian origin. In addition, this also strongly suggests that circulating insulin is an important regulator of feed intake in poultry. The results of this study will be of interest to other scientists.

Technical Abstract: The aim of the present study was to determine if some naturally-occurring substitutions of amino acid residues of insulin could act differentially within the central nervous system (CNS) of neonatal chicks to control ingestive behavior. Intracerebroventricular (ICV) administration of chicken insulin (20 ng) inhibited food intake in ad libitum chicks over the 120-min experiment period. A lower dose (2 ng) also shows a suppressive effect at 60 min post-injection, but not at 30 and 120 min. Similar to chicken insulin, a higher dose of porcine insulin (20 ng) significantly inhibited food intake at 60 and 120 min post-injection, but a significant difference is not detected at 30 min post-injection. Treatment with human and bovine insulin had no effect in this study. Finally, we compared the effect of ICV injection of chicken and porcine insulin on food consumption in starved chicks. The results of the present study indicate that chicken insulin has a higher potent ability to depress feeding behavior in the CNS compared with porcine, human, and bovine insulin. Therefore, it seems that the ranking in order of potency of the insulins on the anorexic effect in neonatal chicks is chicken insulin > porcine insulin > human insulin > bovine insulin. It is suggested that the 8th–10th amino acids of the A-chain and the C-terminal amino acid of the B-chain in insulin have an important role in bioactivity in the central nervous system with special reference to feeding behavior.