Ko Kwang S, Backus Robert C, Berg John R, Lame Michael W, Rogers Quinton R
Department of Molecular Biosciences and University of California, Davis, CA 95616, USA.
J Nutr. 2007 May;137(5):1171-5. doi: 10.1093/jn/137.5.1171.
Diet-induced (taurine deficiency) dilated cardiomyopathy is reported more in large than small dogs possibly because taurine biosynthesis rate (TBR) is lower in large than small dogs. The TBR in 6 mongrels (37.9 +/- 2.1 kg) and 6 beagles (12.8 +/- 0.4 kg) was determined from the fractional dilution rate of urinary [1,2-(2)H(2)]-taurine, (d4-tau). All dogs were given a 15.6% protein, 0.60% sulfur amino acid (SAA) diet in amounts to maintain an ideal body condition score. After 3 mo, 14.6 mg/kg body weight of d4-tau was given orally and TBR determined from d4-tau to taurine ratio in urine collected each d for 6 d. Enrichments of d4-tau were determined by GC-MS. Thereafter, mongrels and beagles were paired by ranking of SAA intake per metabolic body weight per kg(0.75). Each pair received the same amount of diet/kg(0.75) for 2 wk, then TBR was again determined. Concentrations of taurine in plasma, blood, and urine and concentrations of plasma thiols were measured during each TBR determination. In Expt. 1, TBR and taurine concentrations in plasma and urine of mongrels were lower (P < 0.05) than those of beagles. In Expt. 2, TBR and taurine concentrations in blood and plasma of mongrels were lower (P < 0.05) than beagles. Together, the results support the hypothesis that large compared with small dogs have lower TBR when fed diets near-limiting in dietary SAA, but adequate to maintain ideal body condition.
据报道，饮食诱导（牛磺酸缺乏）的扩张型心肌病在大型犬中比小型犬中更为常见，这可能是因为大型犬的牛磺酸生物合成率（TBR）低于小型犬。通过尿中[1,2-(2)H(2)]-牛磺酸（d4-牛磺酸）的分数稀释率来测定6只杂种犬（37.9±2.1千克）和6只比格犬（12.8±0.4千克）的TBR。所有犬只均给予15.6%蛋白质、0.60%含硫氨基酸（SAA）的饮食，摄入量以维持理想的身体状况评分。3个月后，口服给予14.6毫克/千克体重的d4-牛磺酸，并根据每天收集的尿液中d4-牛磺酸与牛磺酸的比率来测定TBR，持续6天。通过气相色谱-质谱联用仪测定d4-牛磺酸的富集情况。此后，根据每千克代谢体重（kg(0.75)）的SAA摄入量对杂种犬和比格犬进行配对。每对犬只接受相同量的饮食/kg(0.75)，持续2周，然后再次测定TBR。在每次TBR测定期间，测量血浆、血液和尿液中的牛磺酸浓度以及血浆硫醇浓度。在实验1中，杂种犬的TBR以及血浆和尿液中的牛磺酸浓度均低于比格犬（P<0.05）。在实验2中，杂种犬血液和血浆中的TBR以及牛磺酸浓度低于比格犬（P<0.05）。总体而言，这些结果支持了这样的假设：当喂食接近限制SAA但足以维持理想身体状况的饮食时，与小型犬相比，大型犬的TBR较低。
