The tryptophan requirement of the kitten

To estimate the tryptophan requirement of the kitten, six male and six female kittens were presented diets containing 0.7, 0.9, 1.1, 1.3, 1.5 and 3.0 g tryptophan/kg diet for six experimental periods lasting 10 d in accordance with a 6 X 6 balanced Latin-square design. Mean daily weight gain and nitrogen retention (N intake minus urinary and faecal N) plateaued at 1.1 g tryptophan/kg diet indicating that the minimal tryptophan requirement of the kitten was 1.1 g/kg diet. Plasma tryptophan concentration exhibited a marked increase at dietary tryptophan concentrations above 1.3 g/kg diet.