Postprandial kinetic of some biotic and abiotic characteristics of the gastric ecosystem of horses fed a pelleted concentrate meal

¹ EVIALIS, 56 250 Saint-Nolff, France; Etablissement National d'Enseignement Supérieur Agronomique de Dijon, 21 079 Dijon, France
² Université de Clermont-ferrand, 63 000 Clermont-ferrand, France
³ Texas A&M University, College Station, TX 77843-4475
⁴ EVIALIS, 56 250 Saint-Nolff, France
⁵ Etablissement National d'Enseignement Supérieur Agronomique de Dijon, 21 079 Dijon, France

^* To whom correspondence should be addressed. E-mail: mvarloud{at}evialis.evls.net.

	Abstract

Our knowledge on microflora of the stomach of the horse is still very limited, even though some data indicate its important role in nutrition. The objective of this experiment was to investigate microbial and biochemical profiles in the stomach of horses and to quantify the disappearance of dietary starch. Total anaerobic bacteria, lactate-utilizing bacteria, lactobacilli, and streptococci were determined, and biochemical characteristics (pH, and DM, D- and L-lactate, D-glucose, NH₃, and VFA concentrations) were measured in chyme collected from 4 horses by naso-gastric intubation aided by endoscopy 30 min before and 60, 120, and 210 min after the meal. The total anaerobic population exhibited a linear increase (5.54 to 6.98 log10 cfu/mL; P = 0.018) within the first postprandial hour and reached 8.32 log10 cfu/mL 210 min after the meal. The concentrations of lactobacilli, streptococci, and lactate-utilizing bacteria in the stomach content were 5.52, 4.82, and 6.95 log10 cfu/mL, respectively. Lactate concentration increased linearly from 0.25 mmol/L before the meal to 7.98 mmol/L at the last collection point (P = 0.013). This increase was mostly due to L-lactate accumulation. The VFA concentration increased linearly (P = 0.002) during the postprandial period from 1.96 to 8.17 mmol/L. Acetate represented, on average, 78 mol/100 mol of total VFA. The average concentration of NH₃ in the stomach content was 2.48 mmol/L. Dietary starch disappearance did not respond during the postparandial period and was not consistent with previous findings. These in vivo data provide complementary information on the postprandial microbial and biochemical kinetics in the stomach of horses and confirm its abundant microbial colonization.

Key Words: bacteria, digestion, equine, fermentation, microflora, stomach