Intense Exercise and Aerobic Conditioning Associated with Chromium or L-Carnitine Supplementation Modified the Fecal Microbiota of Fillies.
Authors: Almeida Maria Luiza Mendes de, Feringer Walter Heinz, Carvalho Júlia Ribeiro Garcia, Rodrigues Isadora Mestriner, Jordão Lilian Rezende, Fonseca Mayara Gonçalves, Carneiro de Rezende Adalgiza Souza, de Queiroz Neto Antonio, Weese J Scott, Costa Márcio Carvalho da, Lemos Eliana Gertrudes de Macedo, Ferraz Guilherme de Camargo
Journal: PloS one
Summary
# Editorial Summary Mounting evidence from human and rodent research suggests that exercise alters the composition of intestinal microbiota, yet comparable data in athletic horses remain scarce despite their regular exposure to intense training. This Brazilian study examined twelve young Mangalarga Marchador fillies across four treatment groups—control, exercise alone, exercise plus 10g daily L-carnitine, and exercise plus 10mg daily chelated chromium—subjecting conditioned groups to 42 days of treadmill training at 70–80% of lactate threshold intensity, with faecal samples collected before and 48 hours after incremental exercise testing. Both acute exercise and aerobic conditioning significantly altered the structure and composition of the fillies' fecal microbiota (dominated by Firmicutes at 50.22% and Verrucomicrobia at 15.13%), with notable decreases in Chlamydiae and Mycobacterium populations following the second exercise test; however, neither L-carnitine nor chromium supplementation produced microbiotal changes substantially different from the exercised control group. For practitioners, these findings suggest that training itself—rather than the ergogenic aids tested—drives shifts in the equine hindgut microbial ecosystem, and that while neither supplement offered additive microbiotal benefits, further investigation with larger cohorts across varied fitness levels and ages is warranted before dismissing their potential roles in metabolic performance. Understanding how routine conditioning reshapes the microbiota may ultimately inform nutritional strategies and probiotic interventions to support gastrointestinal health and metabolic efficiency in athletic horses.
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Practical Takeaways
- •Exercise and training programs naturally modify the intestinal microbiota in athletic horses; these changes appear part of normal adaptation rather than requiring supplemental intervention.
- •Chromium and L-carnitine supplementation at these doses do not provide additional microbiota benefits beyond standard exercise conditioning, suggesting their use for ergogenic purposes may need reconsideration or different dosing protocols.
- •Monitor fecal pH as a practical indicator of microbiota diversity during conditioning programs, though larger studies across different fitness levels are needed before changing management practices.
Key Findings
- •Intense exercise and aerobic conditioning over 42 days significantly altered fecal microbiota composition and structure in fillies, with decreased Chlamydiae and Mycobacterium after exercise testing.
- •Chromium (10 mg/day) and L-carnitine (10 g/day) supplementation induced only moderate changes in microbiota that did not differ significantly from non-supplemented exercised controls.
- •Firmicutes (50.22%) and Verrucomicrobia (15.13%) were the dominant phyla regardless of treatment group.
- •Fecal pH showed positive correlation with microbial diversity (Simpson's index) while plasma pH correlated negatively.