Threonine imbalance, deficiency and neurologic dysfunction in the kitten

The effect of feeding threonine-imbalanced and threonine-deficient purified diets (containing L-amino acids as the only source of dietary nitrogen) on food intake, weight gain and blood plasma amino acid pattern has been examined in growing kittens. The imbalance was created by adding 17.5% of amino acid mixture lacking threonine to a low amino acid basal diet containing 17.5% amino acid mixture including 0.4% threonine. A depression in food intake and weight gain occurred while feeding the imbalanced diet which was corrected by adding an additional 0.2% threonine to the imbalanced diet. There was no adaptation with time in the form of increased food intake or weight gain while feeding the imbalanced diet. Plasma threonine was consistently and similarly depressed (10 to 35% of normal) while feeding the basal, imbalanced and corrected diets and increased to normal when the standard diet with 1.4% threonine was fed. Plasma threonine and total amino acid concentrations of kittens fed the imbalanced diet did not differ from those observed in kittens fed the basal diet. Signs of neurologic dysfunction and/or lameness developed in 14 of the 17 kittens fed threonine-imbalanced or deficient diets, which resolved as dietary threonine was increased.