Fecal D- and L- Lactate, Succinate, and Volatile Fatty Acid Levels in Young Dairy Calves

Abstract

For evaluation of physiologically significant organic anions in the colonic environment, 87 samples of normal feces were collected from the rectum of 15 calves less than 60 days old. The calves were fed milk replacer with free access to starter diet and hay. After fecal extraction with water, pH, D- and L-lactate, succinate, and volatile fatty acid (VFA) concentrations were determined. There was wide variation in fecal pH (4.3 to 7.7). Higher lactate concentrations were observed in feces samples with lower pH, and most of these samples were collected during the first 4 weeks of life. Elevated lactate concentrations included both the D- and L-isomers, and the D-isomer comprised approximately 30-50% of total lactate. Elevated succinate concentrations were observed in only 8 fecal samples, while other samples had lower or trace amounts of succinate. Elevated fecal succinate showed no relationship with fecal pH or VFA concentrations. Fecal VFA concentrations were lower in samples collected in the early postnatal stage, but fecal VFA concentrations were not necessarily related to age. We confirmed that fecal D- and L-lactate concentrations increased with a concomitant decrease of VFA in the acidic lumen of the colon, although acidic feces were not necessarily accompanied by elevated concentrations of lactate. In contrast, succinate production was not related to fecal pH or VFA concentrations.

Flow Behavior of Digesta and the Absorption of Nutrients in the Gastrointestine

“…Sufficient fermentable carbohydrates such as moltitol and oligosaccharides in the diet induce diarrhea through the accumulation of succinic and lactic acids in the large intestine (53,54). Succinic (pK, 4.2) and lactic acids (pK, 3.7) are stronger acids compared with short-chain fatty acids (pK, 4.8-4.9) and are intermediates in the global fermentation cascade of short-chain fatty acids (55).…”

Increased Fecal Lactate and Decreased Volatile Fatty Acid (VFA), Particularly n-Butyrate Concentrations in Diarrheic Young Calves

“…However in the present study, the diarrheic data in each calf were averaged for describing the outline of calf diarrhea. Thirdly, the present data were divided into 2 stages of < 3 wk and 3-8 wk old, because neonatal calves within few weeks after birth had an immature flora and marked fluctuations in gut fermentation compared with the calves of the following stage despite the same feedings [9]. Even so, these fluctuations in the early life were far from the metabolic and hormonal changes caused by the development of solid feed intake [1].…”

“…Comparing with adults, the colon of young mammals is a primary site of microbial colonization because they get most nutrients from liquid milk, not from solid diets. Moreover, gut flora of neonatal mammals is less developed [3] and the immature flora produce large quantities of intermediates such as lactate, succinate and alcohols in calves [8,9]. With advancing age and gut flora, most of these intermediates are converted mainly to volatile fatty acid (VFA) which consist predominant anions in the large bowel [2].…”

“…Since the fecal profiles had large individual difference during the neonatal period irrespective of the same feeding of milk [8,9], a comparative study of…”

“…Since the fecal profiles had large individual difference during the neonatal period irrespective of the same feeding of milk [8,9], a comparative study of fecal profiles among the calves has serious difficulties in explanation. Therefore, the present data were compared between normal and diarrheic feces in the individuals, and not between the normal and diarrhea of different calves.…”