High levels of inorganic sulfate cause diarrhea in neonatal piglets.

Artificially reared neonatal piglets were used to study the effect of inorganic sulfate on bowel function in human infants. Two experiments were conducted to evaluate the effect of high levels of inorganic sulfate on the growth, feed intake and feces consistency of artificially reared piglets, and to determine the dose at which at least 50% of piglets develop nonpathogenic diarrhea. The effect of sulfate level on kidney weight and concentration of inorganic sulfate in urine was also assessed. In each experiment, 40 pigs with an average initial age of 5 d were individually caged and reared with an automatic feeding device. Ten pigs per dietary treatment were fed one of four diets containing the following levels of added inorganic sulfate (mg/L of diet), as anhydrous sodium sulfate (USP): 0, 1200, 1600 and 2000 for Experiment 1 (18-d study), and 0, 1800, 2000 and 2200 for Experiment 2 (16-d study). The levels of added sulfate did not affect (P > 0.05) the growth of piglets, or their feed intake. Whereas 1200 mg added sulfate/L had essentially no effect on feces consistency, levels > 1800 mg/L of diet resulted in a persistent, nonpathogenic diarrhea in neonatal piglets. Added sulfate did not affect (P > 0.05) relative kidney weight. Inorganic sulfate in urine reached maximum concentration (P < 0.05) in pigs fed diets with 1600 and 1800 mg added sulfate/L in Experiments 1 and 2, respectively, but declined at higher levels. The results suggest that the level of added dietary inorganic sulfate at which 50% of piglets develop nonpathogenic diarrhea is between 1600 and 1800 mg/L.