Endocrine-nutrition interactions in birds

Abstract

This review will discuss the uses of avian models, particularly the chicken, to examine nutrition-endocrine interactions. The chicken has been employed extensively to examine nutritional effects. The effects of fasting, protein deficiency and calcium deficiency on endocrine status have been the subject of intense investigation in young chicks and adult female chickens. The ratio of circulating concentrations of triiodothyronine (T3) and thyroxine (T,) is substantially changed by fasting or protein deficiency. Similarly, protein deficiency reduces circulating concentrations of insulin-like growth factor I (IGFI) while protein deficiency increases growth hormone (GH). Moreover, protein deficiency increases the sensitivity and responsiveness of adrenocortical cells. The chicken also has advantages for studying diabetes, endocrine pancreatic functioning due to the splenic lobe of the pancreas being predominantly endocrine in nature, and the cellular mechanism of GH on chicken adipose tissue. The adult female chicken with its high calcium requirement is a unique system for examining nutritional effects on reproduction.The present paper will discuss the use of the chicken as a model for nutrition, the effects of fasting on endocrine status, the relationship between nutrition and growth-related hormones, the influence of nutrition on reproduction and in examining pancreatic hormones, particularly in relation to diabetes. The use of non-conventional models (particularly the chicken) for studying the hormones controlling calcium homeostasis is covered elsewhere in this publication.

Topics in Transcriptional Control of Lipid Metabolism: from Transcription Factors to Gene-Promoter Polymorphisms

“…The gene products targeted by these TFs include metabolic proteins, lipid transport proteins, and those that impart hormone responsiveness on the adipocyte 18, 31. The ultimate fate of adipocyte precursor cells is determined by several factors including the immediate endocrine/paracrine environment, adhesion to the extracellular matrix, the specific milieu of transcription and regulatory factors, and nutrient availability 22, 25, 32, 33. The balances of pro- and anti-adipogenic factors present in the local environment dictate the commitment to, and progression through adipogenic cascades 34.…”

Effects of Starvation and Refeeding on Gonadotropin and Thyrotropin Subunit mRNAs in Male Japanese Quail

“…In birds, food availability is one of the major environmental factors that affect functions of endocrine systems such as the hypophysio-gonadal, -thyroidal and -adrenocortical systems (Scanes and Griminger, 1990). It is well known that starvation affects reproductive activity in various vertebrates including birds (Hosoda et al ., 1955;Morris and Nalbandov, 1961;Vigersky et al ., 1977;Brake and Thaxton, 1979;Glass and Swerdloff, 1980;Hoffer et al ., 1986).…”

Delay in feed access and spread of hatch: importance of early nutrition

“…In combination, they also found that these conditions resulted in a decreased serum T 3 level and an increased serum T 4 level, which was the reverse to that observed for chicks that were fed before cold exposure. This effect of feed restriction on the thyroid hormone levels was substantiated by King et al (1977), May (1978), Harvey and Klandorf (1983), Klandorf and Harvey (1985), Scanes and Griminger (1990), Kühn et al (1991), Darras et al (1995Darras et al ( , 1998 and Van der Geyten et al (1999). According to the study of Van der Geyten et al (1999), hepatic D 3 , an iodothyronine deiodinase that inactivates T 3 or T 4 by inner ring deiodination (St. Germain and Galton, 1997) appears to play a central role in the regulation of plasma T 3 during fasting and re-feeding in the chicken.…”