Effects of Compound Milk Oligosaccharides on Growth Performance, Immune Function, and Intestinal Health of Neonatal Suckling Piglets with Different Birth Weights

This experiment was conducted to investigate the effects of compound milk oligosaccharides (CMO) on growth performance, immune function, and intestinal health of neonatal suckling piglets with different birth weights. Forty neonatal suckling piglets (20 piglets with normal birth body weight (NBW), 20 piglets with low birth body weight (LBW)) from 10 lactating sows with the same parity and litter size (2 normal birth weight piglets and 2 low birth weight piglets from each sow), were allotted to one of four treatments (10 replications with 1 piglet per treatment) in a 2 × 2 factorial design, including two birth body weight (normal or low birth weight) and two CMO doses (0 or 75 mg/d). All piglets were orally administered 2 mL CMO solution (37.5 mg/mL CMO, with a ratio of 3′ SL:2′ FL:6′ SL = 5:4:1) or equivalent volume saline daily, from birth until day 21 of age. At the end of the trial, eight piglets per treatment were used for terminal serum and intestinal measurements, and five piglets per treatment were used for colonic microbiota analysis. As expected, NBW piglets had higher body weight and average daily gain than LBW littermates (p < 0.05), accompanied by a lower colonic abundance of Escherichia-Shigella (p < 0.05). More importantly, oral CMO administration from birth to weaning improved body weight on days 14 and 21, average daily gain, jejunal villus height, and the villus height-to-crypt depth ratio, decreased serum IL-1β, IL-6, and IL-10 concentrations, and inhibited ileal mRNA expression of IL-1β and MyD88 in piglets of both birth weight groups. In addition, CMO markedly downregulated ileal NF-κB expression in LBW piglets (p < 0.05). Interaction analysis indicated that the interaction between birth weight and CMO supplementation specifically decreased ileal TLR4 gene expression, reduced colonic observed species, Chao 1 and ACE indices, and enriched colonic Parabacteroides in LBW piglets (p < 0.05). In summary, these findings demonstrated that a daily oral dose of 75 mg CMO improved growth performance and intestinal health in suckling piglets, and the underlying mechanisms may be closely associated with alleviation of intestinal inflammation, improvement of intestinal morphology, and modulation of gut microbial balance.