The effect of bovine colostrum supplementation on intestinal injury and circulating intestinal bacterial DNA following exercise in the heat

Abstract

Purpose Exercise-induced changes in intestinal permeability are exacerbated in the heat. The aim of this study was to determine the effect of 14 days of bovine colostrum (Col) supplementation on intestinal cell damage (plasma intestinal fatty acid-binding protein, I-FABP) and bacterial translocation (plasma bacterial DNA) following exercise in the heat. Methods In a double-blind, placebo-controlled, crossover design, 12 males completed two experimental arms (14 days of 20 g/day supplementation with Col or placebo, Plac) consisting of 60 min treadmill running at 70% maximal aerobic capacity (30 °C, 60% relative humidity). Blood samples were collected pre-exercise (Pre-Ex), post-exercise (Post-Ex) and 1 h post-exercise (1 h Post-Ex) to determine plasma I-FABP concentration, and bacterial DNA (for an abundant gut species, Bacteroides). Results Two-way repeated measures ANOVA revealed an arm × time interaction for I-FABP (P = 0.005, with greater PostEx increase in Plac than Col, P = 0.01: Plac 407 ± 194% of Pre-Ex vs Col, 311 ± 134%) and 1 h Post-Ex (P = 0.036: Plac 265 ± 80% of Pre-Ex vs Col, 229 ± 56%). There was no interaction (P = 0.904) but there was a main effect of arm (P = 0.046) for plasma Bacteroides/total bacterial DNA, with lower overall levels evident in Col. Conclusion This is the first investigation to demonstrate that Col can be effective at reducing intestinal injury following exercise in the heat, but exercise responses (temporal pattern) of bacterial DNA were not influenced by Col (although overall levels may be lower).

Reliability of gastrointestinal barrier integrity and microbial translocation biomarkers at rest and following exertional heat stress

“…A previous systematic review has suggested an exercise-induced hyperthermia threshold of 38.6°C T core for GI barrier integrity loss (DSAT, I-FABP and endotoxin) to be commonplace (>50% incidence) and of 39.0°C for GI barrier integrity loss to be universal (100% incidence; Pires et al, 2017). Consistently, previous research supports the notion that MT biomarkers (endotoxin) are less responsive to subtle alterations in GI barrier integrity that were otherwise detected by the DSAT or I-FABP following exercise (March et al, 2019;Snipe et al, 2017Snipe et al, , 2018. Positively, no GI barrier integrity or MT biomarker displayed statistical heteroskedasticity in this EHST model, suggestive that absolute reliability was not dependent upon the magnitude of biomarker response.…”

“…This method is particularly favorable given that the phyla Firmicutes and Bacteroidetes comprise >90% of the GI microbiome ( Bacteroides ; Huttenhower et al, ) and <5% of the plasma microbiome (Paisse et al, 2016). Utilizing this hypothesis, March et al () reported that the plasma Bacteroides /16S DNA ratio tended to increase (~25%; p = .07) following a 1‐hr moderate intensity (70% VO 2max ) run in the heat (30°C), though large interindividual variability in responses were evident. In this study, the Bacteroides /16S DNA ratio was unchanged following the EHST and appeared to be systematically lower following exercise in trial two (but not the Δ).…”

“…Positively, no GI barrier integrity or MT biomarker displayed statistical heteroskedasticity in this EHST model, suggestive that absolute reliability was not dependent upon the magnitude of biomarker response. Next, biomarker analysis was limited to a single time‐point after the EHST (at termination), though this can be justified in that peak responses are consistently shown to occur at this instance in comparable exertional heat stress interventions (e.g., I‐FABP , Snipe et al, ; CLDN‐3 , Yeh et al, ; LBP , Moncada‐Jimenez et al, ; Bact./16S , March et al, ). Third, there was statistically significant systematic bias for peak T core and T body responses, which were lower (0.17°C and 0.18°C) following implementation of trial two.…”

“…In general, no GI barrier integrity and MT biomarkers, except DSAT 150 and Δ LBP, were found to correlate. Previous exercise gastroenterology research has shown various combinations of these biomarkers to correlate weakly (r = 0.1-0.6; Yeh et al, 2013;Sessions et al, 2016;March et al, 2019) or not at all (Karhu et al, 2017;Snipe, Khoo, Kitic, Gibson, & Costa, 2018). Several physiological (e.g.…”

“…In comparison with alternative MT measures, one major advantage of bactDNA is an apparent independence of hepatic clearance (Mortensen et al, 2013). One innovative study recently proposed a bactDNA methodology aimed to improve analytical specificity and reliability through targeting a predominant GI bacterial genus (Bacteroides) and correcting for total 16S DNA concentration (March, Jones, Thatcher, & Davison, 2019).…”