Intestinal mucin dynamics: Response of broiler chicks and White Pekin ducklings to dietary threonine

Abstract

Mucin dynamics may be particularly sensitive to a Thr deficiency due to the high concentration and structural importance of Thr in the mucin protein backbone. Intestinal mucin secretion, expression of mucin gene (MUC2), and histological characteristics were investigated in male broilers and White Pekin ducklings offered diets containing 3.3, 5.8, or 8.2 g of Thr/kg in 4 studies. Seventy-two birds of each species were fed a standard broiler starter diet from 1 to 14 d of age followed by assignment to 3 dietary treatments in a randomized complete block design for a 7-d feeding trial in experiment 1 (broilers) and experiment 2 (ducklings). The dietary treatments consisted of an isonitrogenous corn-soybean meal-based diet with the addition of crystalline amino acids and graded levels of Thr. Dietary treatments contained 3.3, 5.8, or 8.2 g of Thr/kg. Dietary formulation and experimental design for experiments 3 (broilers) and 4 (ducklings) were similar to experiments 1 and 2 except that birds were fed 3.3 or 8.2 g of Thr/kg for durations of 7 or 14 d. For chicks, increased dietary Thr resulted in higher levels of intestinal crude mucin excretion in experiment 1 (P=0.04) but not in experiment 3, whereas intestinal sialic acid excretion increased in experiment 3 (P=0.02) but not in experiment 1. Furthermore, there was no effect of Thr on intestinal goblet cell density or MUC2 mRNA abundance for broilers. For ducklings, there was an increase in intestinal crude mucin excretion in both experiments (P<0.05) as dietary Thr increased, although there was no effect of Thr on intestinal sialic acid excretion. There was a tendency for an increase in intestinal goblet cell density (cells/microm of villus length; P=0.09) as dietary Thr increased in experiment 2. For experiment 4, intestinal MUC2 mRNA abundance increased (P=0.03) as dietary Thr increased for the 14-d feeding trial but not for the 7-d feeding trial. The data establish a link between dietary Thr and intestinal crude mucin dynamics in chicks for experiment 1 and ducklings for both experiments.

Effect of Non-Starch Polysaccharide (NSP) of Wheat and Barley Supplemented with Exogenous Enzyme Blend on Growth Performance, Gut Microbial, Pancreatic Enzyme Activities, Expression of Glucose Transporter (SGLT1) and Mucin Producer (MUC2) Genes of Broiler Chickens

“…MUCIN layers are divided in two parts, including loose and tight layers, which action and composition are different. Tight layers have several membrane conjunction sites to catch and transmit nutrients into enterocyte cells (Montagne et al, 2004;Horn et al, 2009).…”

“…A review of literature indicates that the presence of anti-nutritive compounds in the digestive tract of birds, cause predominant negative changes in the gut such as increasing the product shelf life, physicochemical properties of digesta (viscosity and pH), and impede the action of indigenous enzymes through the gut (Choct & Annison, 1992 a,b;Hetland et al, 2004), along with some changes in the intestinal environment and structure of the lining surface with the impact on the quantity and quality of relevant gene expression (Ferraris, 2001;Smirnov et al, 2004;Tanabe et al, 2005). Associate gene transporting nutrients through the gut enterocytes such as glucose, amino acids, peptides and genes involved in production and secretion of mucin as an important ingredient of mucus coating the intestinal tissue are the most effective factors in the intestinal environment and structural changes (Smirnov et al, 2006;Horn et al, 2009;Gilbert et al, 2010).…”

Physiology, cell dynamics of small intestinal mucosa, and performance of broiler chickens under heat stress: a review

“…Thus, mucus is the first barrier the nutrients have to interact with; they have to diffuse into the mucus to be absorbed and gain access to the circulatory system and their target organs (Bansil and Turner, 2006). Environmental factors able to induce changes in the dynamics of mucins have the potential to affect viscosity and integrity of the mucus layer and nutrient transportation (Horn et al, 2009). Therefore, interruption of intestinal homeostasis leads to changes in the mucus barrier that protects the enteric mucosa.…”

“…Different physiological responses may occur during heat stress and they depend on the intensity, severity, and duration of heat stress (Azad et al, 2010), thereby causing higher or lower levels of glucocorticoid release (Gonzalez-Esquerra and Leeson, 2006). These physiological responses are: changes in the functional integrity of the intestinal mucosa (Horn et al, 2009), body temperature increase (Marchini et al, 2007;Mitchell and Lemme, 2008), muscle degradation (Zuo et al, 2015), and increase in mortality rate (Estrada-Pareja et al, 2007) when high environmental temperatures coincide with the age to market (Arjona et al, 1988).…”

GUT IMMUNITY IN BIRDS: FACTS AND REFLECTIONS (review)

“…Amino acids threonine, serine, and cysteine significantly affect the production of mucin, as they are its components: e.g., threonine is about 11 % amino acid sequence of mucin. Suppressed synthesis of mucin in birds may be harmful for intestinal mucosa and reduce local utilization of nutrients (13).…”