Coeliac disease, better known as “gluten intolerance”, is an autoimmune disorder mainly affecting the small intestine in genetically predisposed people. The disease is caused by an overreaction of the intestinal immune system to gluten, proteins from wheat and other grains such as rye. Broilers can also develop a chronic type of inflammation in the small intestine. A new model based on eggshell composition may assist to select ingredients that induce or relieve symptoms related to coeliac disease.
Coeliac disease affects people of all ages mostly evoking chronic intestinal problems like diarrhoea, malabsorption, loss of appetite, and in children growth retardation. Besides these classical symptoms, coeliac patients may exhibit a wide number of other non-classical symptoms affecting other parts in the body. In about 50% of the patients that did not receive treatment for coeliac disease bone demineralisation is observed.
Broilers lose bone strength
Broilers fed over a long period with a gluten-rich rye diet also develop a chronic type of inflammation in the small intestine. In broilers this chronic inflammatory status evokes shortening of the villi and impaired uptake of nutrients and vital minerals like iron and calcium. A recent study with broilers showed that the shortage of calcium in the body is compensated by demineralisation of bones leading to loss of bone strength.
Insight in calcium level disturbing mechanism
Within the framework of Policy Support Research theme ‘Feed4Foodure, Wageningen Livestock Research and the industrial partners within this framework studied the effect of a gluten-rich rye diet on the immune system and performance of broilers. Gene expression data measured in the intestinal mucosa of these broilers were integrated with in vitro gene expression data of cultured enterocytes exposed to the same diets that were fed to the broilers. A set of so-called “early signalling proteins" secreted by enterocytes complemented the in vivo data and improved insight into gene regulation mechanisms imposed by the gluten-rich rye diet in broilers. For example, a better insight was provided about the mechanism by which the gluten-rich rye disturbed the calcium level in the body of the broilers, and related to this, how it may affect the development of the eggshell in female chickens. Results of this study were published recently in the journal “Genes and Nutrition” [Hulst M, et al. 2017].
Eggshell potential biomarker for bone demineralisation
Our study pointed out that a diet with a high concentration of gluten when fed to female chicken (laying hens or broiler breeders) may also affect the mineral composition of the eggshell, making this shell a potential biomarker for bone demineralisation. Measurement of e.g. levels of calcium carbonate in the eggshell could be an easy and non-invasive method to study the effect of diets containing gluten or other coeliac-inducing plant allergens on bone demineralisation. Such a chicken model for coeliac will be more animal-friendly than the currently used rodents models, and perhaps, also more straight forward in addressing other, until now not well understood, non-classical symptoms of this disorder. The model may assist to select ingredients that induce or relieve symptoms related to coeliac disease.