Effect of small peptide chelated iron on growth performance, immunity and intestinal health in weaned pigs

Abstract

Abstract Background: Small peptide chelated iron (SPCI), a novel iron supplementation in pig diets, owns growth-enhancing characteristics. Although a number of researches have been performed, there is no clear-cut evidence to show the exact relationship between the dose and effects of mall peptide chelated minerals.Therefore, we investigated the effect of dietary supplementation of SPCI at different doses in the growth performance, immunity, and intestinal health in weaned pigs. Methods: Twenty-four weaned pigs were randomly assigned into five groups and feed with basal diet containing different levels of SPCI (0, 50, 75, 100, and 125 mg/kg) .On day 22, D-xylose (0.1 g/kg body weight) was orally administrated to each pigs, and blood samples were collected 1 h later. The tissue and intestinal mucosa samples were collected following. Results: Our results showed that the feed to gain ratio (F/G) decreased andthe digestibility of crude protein increased with SPCI addition (P<0.05). Dietary SPCI supplementation at 100 mg/kg not only increased serum ferritin and transferrin, but also elevated the iron content in tibia and tissues (liver, gallbladder, and kidney)(P<0.05). Dietary SPCI (75-100 mg/kg) addition increased the serum immunoglobulins but decreased the serum malondialdehyde (MDA) and D-lactic acid (P<0.05). The serum insulin-like growth factor I (IGF-I) and glutathione peroxidase (GSH-Px) were also elevated by SPCI addition. Interestingly, SPCI supplementation at 75 mg/kg improved the intestinal morphology and barrier function, as suggested by enhanced villus height and villus height/crypt depth (V/C) in duodenum and ileum (P<0.05), as well asjejunum epithelium tight-junction protein ZO-1. Moreover, SPCI supplementation at 75 and 100 mg/kg increased the activity of duodenal lactase and jejunal sucrase (P<0.05). Importantly, SPCI supplementation at 75 mg/kg elevated the expression levels of critical functional genes such as peptide transporter-1(PePT1), sodium/glucose co-transporter-1 (SGLT1), and zinc transporter 1 (ZnT1) in the ileum mucosa (P<0.05). The expression levels of amino acid transporter-1 (CAT1) also elevated by SPCI added at 100 mg/kg. Conclusions: Dietary SPCI supplementation at 75-100 mg improved growth performance, immunity and intestinal health.