Effects of dietary glycyl-glutamine on growth performance, small intestinal integrity, and immune responses of weaning piglets challenged with lipopolysaccharide1

Abstract

The objectives of this study were to determine the effects of dietary glycyl-glutamine (Gly-Gln) on postweaning growth, small intestinal morphology, and immune response of stressed or nonstressed piglets. Pigs (n = 144; initially 4.49 kg and 14 d of age) were randomly allocated to 24 pens (6 pigs/pen) in an environmentally controlled nursery and assigned to Escherichia coli lipopolysaccharide (LPS) challenge (PBS vs. LPS) and Gly-Gln supplementation (0 vs. 0.15%) in a 2 x 2 factorial arrangement of treatments with 6 pens/treatment. The LPS was the stress-inducing agent, and it was injected on d 7 and 14 of the 21-d experiment. Inflammatory challenge with LPS reduced ADG (P < 0.05) and tended to reduce ADFI (P = 0.06) of piglets from d 7 to 21 of the experiment. Supplementation of Gly-Gln increased ADG and G:F from d 0 to 21 (P < 0.05). On d 21 (1 wk after the second LPS injection), there was an LPS challenge x diet Gly-Gln interaction for ADFI (P < 0.05), but it was difficult to ascertain whether Gly-Gln increased ADFI. A trend for an LPS challenge x diet Gly-Gln interaction was observed for ADG (P = 0.07). There were no differences in lymphocyte proliferation among treatments. The LPS challenge increased crypt depth (CD) of the duodenum and decreased the ratio of villus height (VH) to CD of the ileum (P < 0.05) on d 14 (1 wk after the first LPS injection), whereas dietary supplementation of Gly-Gln increased VH of the ileum and VH:CD of the duodenum (P < 0.05). The concentration of peripheral blood IL-1beta was increased by injection of LPS (P < 0.05) and was decreased by dietary Gly-Gln supplementation during the experimental period (P < 0.05); however, there was no interaction of LPS challenge x Gly-Gln addition for IL-1beta concentration. Concentrations of peripheral blood IL-2 tended to increase at d 14 (P = 0.09) and soluble IL-2 receptor tended to decrease at d 7 (P = 0.06) in piglets supplemented with Gly-Gln; therefore, the peripheral blood IL-2/soluble IL-2 receptor system tended to favor the secretion of IL-2 during the first 2 wk of the experiment. In conclusion, considerable suppression of growth and immune function occurred in early weaning piglets challenged with LPS, and such depression could be alleviated by dietary Gly-Gln supplementation independent of the LPS challenge.

Effects of housing conditions and glutamine levels on growthperformance of post-weaning piglets

“…These results are in line with another study (YI et al, 2005), in which there was no effect of treatment throughout the overall experimental period. In contrast to our findings, some studies demonstrated that dietary supplementation with GLN or glycyl-GLN dipeptide improved growth performance in the first week after weaning in piglets challenged with E. coli K88+ or LPS (YI et al, 2005;JIANG et al, 2009). These results suggest that at an older age (28 days post-weaning) these effects might be overshadowed by normal physiologic growth.…”

“…However, it is noteworthy to mention that the level of 0.3 µg of LPS used in the present experiment is much lower than the level used by other authors e.g. 200 µg kg -1 body weight of LPS in Jiang et al (2009). In a previous study, Lozano et al (2014) showed that challenging weaned pigs with 0.3 μg of LPS per pig per day did not promote any moderate or transient cortisol alterations.…”

Effects of yeast products on the intestinal morphology, barrier function, cytokine expression, and antioxidant system of weaned piglets

“…Early weaning results in a sudden cessation of passive immunity from the milk of sows, when the immune system of piglets is still immature, making them vulnerable to diseases such as diarrhea (Ushida et al, 2008). Dietary supplementation with specific nutrients or immunomodulators could improve the performance and health of weaning piglets (Jiang et al, 2009). Cytokines are small peptides that play important roles in the regulation of immune and inflammatory responses (Pié et al, 2004).…”

Effect of sodium butyrate on intestinal inflammatory response to lipopolysaccharide in broiler chickens

“…Studies have indicated that immunological stress can cause damage to the intestinal barrier structure and function (Dickinson et al 1999;Ding et al 2004;Jiang et al 2009). Nutritional regulation of the immune status through feed additives may have beneficial effects and provide a simple way of improving poultry health.…”