Supplemental Effects of Nucleotides on Gut Health and Growth of Newly Weaned Pigs

Gut damages upon weaning could increase the needs of nucleotides for rebuilding villi. Dietary supplementation of nucleotide may enhance gut health and thus growth of newly weaned pigs. The objective of this study was to evaluate supplemental effects of increasing levels of nucleotides on growth performance and gut health in newly weaned pigs. Fifty newly weaned pigs (19-d-old, 25 barrows and 25 gilts, 4.8 ± 0.4 kg BW) were individually housed and allotted to 5 treatments with increasing levels of nucleotides (0, 0.005, 0.015, 0.025, and 0.05%) and based on a randomized complete block design with the initial BW and sex as blocks. Nucleotides were provided from YT500 (5% nucleotides; Hinabiotech, Guangzhou, China) replacing equal amounts of soybean meal. Nucleotides were composed of CMP (19.9%), UMP (23.3%), GMP (23.3%), and AMP (33.2%), which were originated from yeast cells. Pigs were fed for 21 d based on 2 phases (Phase 1: 11 d and Phase 2: 10 d) following NRC (2012). Feed intake and BW were recorded weekly. Titanium oxide (0.4%) was added to all diets as an indigestible marker from d 17. Plasma samples were collected on d 18 to measure tumor necrosis factor-α (TNF-α), IL-6, and malondialdehyde (MDA). Pigs were euthanized on d 21 to collect tissues to evaluate TNF- α, IL-6, MDA, morphology, and crypt cell proliferation rate in the jejunum. Ileal digesta were collected to measure ileal nutrient digestibility. Data were analyzed using contrasts in the MIXED procedure of SAS. Nucleotide supplementation increased (P < 0.05) ADFI (218 vs. 260 g) in phase 1. Nucleotide supplementation at 0.005 and 0.015% increased (P < 0.05) ADG (190 vs. 236 g) in phase 1, whereas increased (P < 0.05) ADFI (335 vs. 401 g) and tended to increase (P = 0.082) ADG (280 vs. 323 g) in overall period. Increasing nucleotide supplementation increased (quadratic, P < 0.05) villus height-crypt ratio from 2.0 to 2.2 (at 0.025%) and decreased (linear, P < 0.05) crypt cell proliferation rate (20.0 to 17.1%) in the jejunum. Increasing nucleotide supplementation tended to reduced (quadratic, P = 0.074) plasma MDA from 17.9 to 12.9 μM (at 0.023%). Increasing nucleotide supplementation tended to increase (P = 0.072) ileal digestibility of energy (70.9 vs. 75.3%). Nucleotide supplementation at 0.005 and 0.015% increased (P < 0.05) ileal digestibility of energy (70.9 to 76.1%) and ether extract (73.5 to 78.3%). In conclusion, nucleotide supplementation especially at 0.005 and 0.025% could enhance gut structure increasing nutrient digestibility, feed intake, and growth of newly weaned pigs.