Effects of non-digestible oligosaccharides on inflammation, lung health and performance of calves

Our objective was to determine the effects of nondigestible oligosaccharides (NDO) on lung health and performance. Three hundred male Holstein-Friesian calves aged 18.0 ± 3.6 d received 1 of 6 treatments for 8.5 wk (period 1). Treatments included a negative control (CON), galacto-oligosaccharides (GOS) administered as a spray via the nose once daily (SPR), GOS administered via the milk replacer (MR) at 1% (GOS-L) and 2% (GOS-H), fructo-oligosaccharides administered via the MR at 0.25% (FOS) and a combination of GOS and fructo-oligosaccharides administered via the MR at 1% and 0.25%, respectively (GOS-FOS). Milk replacer was fed twice daily. Feeding levels were equal between calves and increased progressively in time. Body weight was measured every 4 wk and clinical health was scored weekly. Blood and broncho-alveolar lavage fluid (BALF) samples were collected bi-weekly from a subset of calves (n = 120). After period 1, all calves received the same control MR for 18 wk until slaughter (period 2), during which general performance and clinical health were measured. Generally, infection pressure was high, with clinical scores and BALF proinflammatory TNFα concentrations increasing with time in period 1, which resulted in a high number of required group antimicrobial treatments (6 group antimicrobial treatments in 13 wk, supplied to all calves). Average daily gain adjusted to equal solid feed intake was increased for GOS-L (+61 g/d) compared with CON calves from experimental wk 1 to 5. Plasma white blood cell concentration tended to be lowered by GOS-L, plasma IL-8 concentration was reduced by all orally supplemented NDO, plasma IL-6 was reduced by all NDO treatments except GOS-FOS and plasma IL-1β was reduced by all NDO treatments compared with CON, although this differed per time point for SPR. The neutrophil percentage in BALF was reduced by GOS-L in wk 6, which was associated with a relative increase in macrophages. The BALF concentration of TNFα and IL-8 was reduced or tended to be reduced by GOS-L and GOS-H, while IL-6 was or tended to be reduced by SPR, GOS-L, GOS-H, and GOS-FOS, and IL-1β was reduced by SPR, GOS-L, GOS-H, and FOS. Generally, feeding the combination of GOS and FOS was not more effective than feeding GOS or FOS alone, because feeding GOS-FOS resulted in higher concentrations of plasma and BALF cytokine and chemokine concentrations compared with feeding GOS-L alone, and resulted in higher plasma cytokine concentrations compared with feeding FOS alone. None of the BALF and plasma cytokine or chemokine concentrations differed between the GOS-L and GOS-H treatment. Performance and clinical scores in period 2 did not differ among treatments. Altogether, all tested NDO reduced systemic and lung inflammation in calves under high natural infection pressure and for GOS-fed calves, this increased performance during the first 4 wk. Combining GOS and FOS did not have a synergistic effect. The intranasal administration of GOS also lowered systemic and lung inflammation, but tended to negatively affect performance. Overall, this study demonstrates the potential of NDO to alleviate systemic and respiratory inflammation in calves.