抄録
Effectiveness of methionine as a urine acidifier and adverse effects of excess methionine were examined using adult cats. In Experiment 1 (n = 8), cats were divided into four groups, and assigned to four dry foods containing 0,1,2, and 3% of supplemental DL-methionine for 2 weeks. Addition of 3% DL-methionine decreased urinary pH and struvite crystals in urine compared with the control group. However, food intake also decreased during week 1, although adaptation occurred during week 2. Plasma methionine concentrations increased in proportion to the methionine consumption without a decrease in plasma threonine. In Experiment 2 (n = 8), cats were divided into three groups, and assigned to three dry foods supplemented with either 0 or 6% of single DL-methionine, or with 6% DL-methionine plus equimolar amounts of L-arginine and glycine in a Latin square design. For the first 3 days of a period for 8 days per treatment, all cats received the control diet. Feeding the 6% methionine diet resulted in reduced food intake, depressed nitrogen retention and body weight loss, suggesting the occurrence of methionine toxicity. Additional supplements of arginine and glycine did not alleviate the toxicity.
