Effect of dietary β-1,3/1,6-glucan supplementation on growth performance, immune response and plasma prostaglandin E2, growth hormone and ghrelin in weanling piglets

The experiment was conducted to evaluate the effect of beta-1,3/1,6-glucan on growth performance, immunity and endocrine responses of weanling piglets. One hundred and eighty weanling piglets (LandracexLarge White, 7.20 +/- 0.25 kg BW and 28 +/- 2 d of age) were randomly fed 1 of 5 treatment diets containing dietary beta-1,3/1,6-glucan supplemented at 0, 25, 50, 100 and 200 mg/kg for 4 wks. Each treatment was replicated in 6 pens containing 6 pigs per pen. On d 14 and 28, body weight gain, feed consumption and feed efficiency were recorded as measures of growth performance. Peripheral blood lymphocyte proliferation and serum immunoglobulin G (IgG) were measured to study the effect of dietary beta-1,3/1,6-glucan supplementation on immune function. Plasma prostaglandin E-2 (PGE(2)), growth hormone (GH) and ghrelin were measured to investigate endocrine response to beta-1,3/1,6-glucan supplementation. Our results suggest that average daily gain (ADG) and feed efficiency had a quadratic increase trend with dietary beta-1,3/1,6-glucan supplementation from d 14 to 28, whereas it had no significant effect on average daily feed intake (ADFI). The treatment group fed with 50 mg/kg dietary beta-1,3/1,6-glucan supplementation showed a numerical increase in ghrelin, a similar change trend with ADG and no significant effect on GH. Lymphocyte proliferation indices, serum IgG and plasma PGE2 concentrations varied linearly with dietary supplementation levels of beta-1,3/1,6-glucan on d 14. Higher levels of beta-1,3/1,6-glucan may have a transient immuno-enhancing effect on the cellular and humoral immune function of weanling piglets via decreased PGE2. Taking into account both immune response and growth performance, the most suitable dietary supplementation level of beta-1,3/1,6-glucan is 50 mg/kg for weanling piglets.