Effect of mannan oligosaccharide supplementation on blood and intestinal immune cells, bacteria numbers and performance in weaned pigs

In animal production, alternative strategies to the use of antibiotic growth promoters have stimulated research of dietary supplements to increase resistance, reduce post-weaning gut disorders and growth checks in pigs. This study was performed to determine the influence of dietary mannan oligosaccharide as a potential alternative to antibiotic growth promoters in weaned pigs on: (1) proliferation of circulating and intestinal immune cell subsets, (2) incidence and severity of diarrhoea, and (3) performance during 35 days of trial. Forty-six pigs from a commercial farm were divided into two groups comprising 23 pigs each and treated at 4 weeks of age as follows: controls received standard weaner diet, whereas diet for principals was supplemented with 0.2% of mannan oligosaccharide. The pigs were monitored/sampled on daily, weekly or monthly basis for feed efficiency, growth rate, diarrhoea severity scores, blood samples, rectal swabs and intesinal samples for bacterial isolation/counts and immunohistology/histomorphometry analyses. The principals were heavier (P < 0.05) at 28 days and grew faster between days 7 and 28 compared to controls. Total diarrhoea score recorded in these pigs was decreased by 20.37%. Total bacterial load in jejunum was decreased in these pigs (23 × 107 vs. 19 × 108 colony forming units/ml) at day 35. Between days 28 and 35 or days 21 and 28, the principals increased in proportions of circulating CD45+, CD4+, CD21+, CD8+ cells (P < 0.01), respectively. These pigs had increased (P < 0.05) the number of CD45RA+ cells in interfollicular and follicular areas of ileal Payer’s patches at day 35. We concluded that dietary modulation with mannan oligosaccharide resulted in stimulation of immune responses and reduced number of gut microbiota, but not necessarily promoting the growth of pigs