Influence of 4 weeks of bovine colostrum supplementation on neutrophil and mucosal immune responses to prolonged cycling

Bovine colostrum ( COL ) has been advocated as a nutritional countermeasure to exercise‐induced immune dysfunction. The aims of this study were to identify the effects of 4 weeks of COL supplementation on neutrophil responses and mucosal immunity following prolonged exercise. In a randomized double‐blind, parallel group design, participants [age 28 ± 8 years; body mass 79 ± 7 kg; height 182 ± 6 cm; maximal oxygen uptake ( V ˙ O 2 m a x) 55 ± 9 mL/kg/min] were assigned to 20 g per day of COL ( n  = 10) or an isoenergetic/isomacronutrient placebo ( PLA ; n  = 10) for 4 weeks. Venous blood and unstimulated saliva samples were obtained before and after 2.5 h of cycling at 15% Δ (∼55–60%V ˙ O 2 m a x). A significantly greater formyl‐methionyl‐leucyl phenylalanine‐stimulated oxidative burst was observed in the COL group compared with PLA group ( P  < 0.05) and a trend toward a time × group interaction ( P  = 0.06). However, there was no effect of COL on leukocyte trafficking, phorbol‐12‐myristate‐13‐acetate‐stimulated oxidative burst, bacterial‐stimulated neutrophil degranulation, salivary secretory IgA , lactoferrin or lysozyme ( P  > 0.05). These findings provide further evidence of the beneficial effects of COL on receptor‐mediated stimulation of neutrophil oxidative burst in a model of exercise‐induced immune dysfunction.