Serum and tissue thiocyanate concentrations in growing pigs fed cassava peel or corn based diets containing graded protein levels.

Thiocyanate concentrations of serum, liver, kidney, spleen and longissimus dorsi were determined in 64 growing Large White x Landrace pigs offered 8 experimental isocaloric diets containing different levels of cassava peel and crude protein. Cassava peel increased serum thiocyanate on day 60 (P less than 0.01) and day 90 (P less than 0.01) of the trial, while the crude protein level increased it (P less than 0.05) on days 30 and 90, respectively. Interaction of the two factors was significant on day 30 (P less than 0.05) and day 90 (P less than 0.05). There was a correlation between cyanide intake and serum thiocyanate level. Coefficient of determination revealed that cyanide alone accounted for 28.5; 60.6 and 48.8% variation in serum thiocyanate on days 30, 60 and 90, respectively. Liver, spleen and longissimus dorsi thiocyanate were affected by dietary protein intake (P less than 0.05). Thiocyanate concentration was higher (P less than 0.05) on cassava peel diet. Generally, crude protein at 5% reduced organ and muscle thiocyanate concentrations. A diet containing 112.2-117.3 mg/kg hydrocyanic acid (HCN) affected serum but not organ and muscle thiocyanate in protein-sufficient diets.