Medycyna Wet. 66 (8), 547-550, 2010
Wójcik M., Kosior-Korzecka U., Bobowiec R.
Contribution of L+ and D– lactic acid to metabolic acidosis during neonatal calf diarrhea
Neonatal calf diarrhea is often complicated by lactic acidosis. There are two sources of endogenously produced lactic acid (LA), namely L- and D- LA. Both forms of this metabolite are preferentially generated in the muscles and alimentary tract respectively. Because there are discrepancy about participation of the both forms of LA in development of acidosis in young calves, the aim of this study was to establish the degree of these two optical enantiomers contribution to acidosis in affected animals. To determine particular involvement of each LA izoform in the acid-base disturbances, the HPLC method with chiral column, which permits both accurately separate and quantify the alalysed enatiomers, was used. Moreover, to characterize the origin and importance of this kind of metabolic acidosis, the anion gap was calculated. Calves (n = 29) fed with milk replacer (composition: concentrate of soybean protein, dry sweet whey, vegetal lipids, vitamins mixture, bioactive compounds, calcium formate, probiotics) were divided into three groups: I – healthy calves (control), II – affected calves with mild course of diarrhea and III – calves with severe forms of diarrhea. In the control group of calves, blood pH averaged 7.44 ± 0.02. In the other groups, concomitantly with progress of clinical signs of diarrhea, the pH value systematically decreased. Both diarrhoeic groups of calves demonstrated higher value of anion gap in comparison to healthy animals (14.06 ± 2.25 mEq/l). However, only in third group of calves AG elevated significantly (p £ 0.05) to 27.03 ± 1.26 mEq/l. Among two izoforms of LA present in serum, D(–) enantiomer dominated only in diarrhoeic groups of animals. During mild as well as severe course of diarrhea, D-LA concentration markedly increased to 1.82 ± 0.54 mM/l and 4.74 ± 1.89 mM/l respectively. In calves with severe form of diarrhea there was high positive correlation between D–LA serum level and anion gap (r = 0.722)
Keywords: neonatal diarrhea, lactic acid, anion gap