What to know about taurine for dogs and cats

牛磺酸是一种独特的氨基酸，因为它只存在于动物组织之中，而且与其他氨基酸不同，其在体内是游离的，不能并入蛋白质。许多细胞都能产生牛磺酸，但肝脏是主要生产基地。
Taurine is a unique amino acid because it is only found in animal tissues and, unlike other amino acids, it is found free in the body and is not incorporated into protein. Many cells are able to make taurine, but the liver is the primary production site.

牛磺酸浓度最高的组织有心脏、肌肉、中枢神经系统、视网膜和血小板。牛磺酸在保持液体平衡和心脏收缩能力发挥重要作用。
Tissues with the highest taurine concentration are the heart, muscles, central nervous system, retina and platelets in the blood. Taurine plays important roles in maintaining fluid balance and the ability of the heart to contract.

许多因素影响体内的牛磺酸水平，包括膳食摄入量、身体的合成和个体化需求。牛磺酸被认为是猫的必需膳食营养素。必须向猫提供足够的牛磺酸，因为它们身体产生牛磺酸的能力非常有限。如果没有足够的牛磺酸，猫会表现出牛磺酸缺乏症，而后发展成被称为扩张性心肌病（DCM）的心脏病。牛磺酸缺乏也导致猫的视网膜变性、失明、免疫系统受损、耳聋和生殖并发症。
Many factors affect the levels of taurine found in the body, including dietary intake, body synthesis and individual requirements.Taurine is recognized as an essential dietary nutrient in cats. Adequate dietary taurine must be provided to cats because of their limited ability to make taurine.Without adequate dietary taurine, cats will eventually develop taurine deficiency, and a heart condition called dilated cardiomyopathy (DCM) will subsequently develop in a large proportion of deficient cats. Taurine deficiency in cats also results in retinal degeneration, blindness, impaired immune response, deafness and reproductive complications.

针对狗来说，牛磺酸通常不被认为是必需营养素，因为它们能够从其他膳食氨基酸（即甲硫氨酸和半胱氨酸）合成足够的量。饮食中补充蛋氨酸已被证明可以改善狗的牛磺酸水平低下状态。虽然大多数狗能够合成足够量的牛磺酸，但某些特定品种的狗已经被发现有牛磺酸水平低的情况。狗的牛磺酸缺乏会出现扩张型心肌病、视网膜损伤和生殖受损等状况。
In dogs, taurine is generally not recognized as an essential nutrient because they are able to synthesize adequate amounts from other dietary amino acids, namely methionine and cysteine.Dietary supplementation with methionine has been shown to improve taurine status in dogs with low taurine levels. Although most dogs are able to synthesize adequate amounts of taurine, low taurine status has been found in some dogs of particular breeds. Taurine deficiency in dogs is associated with dilated cardiomyopathy, retinal lesions and impaired reproduction.

扩张型心肌病
Dilated cardiomyopathy

扩张型心肌病由心脏左心室扩张引起，导致心脏无法实现最佳表现。DCM的根本原因是尚未得知，但值得提出的因素包括遗传、病毒感染、免疫介导的疾病、心律失常、毒素和营养缺陷。低牛磺酸状态与DCM的某些情况有关。细胞牛磺酸浓度不足导致心脏无法正常收缩。DCM是大型犬中最常见的后天性心脏病。易患牛磺酸缺乏型DCM的狗品种包括美国可卡犬，达尔马提亚犬，拳师犬，纽芬兰犬，葡萄牙水狗，英国赛特犬，阿拉斯加爱斯基摩犬，金毛猎犬和苏格兰梗犬。狗的牛磺酸缺乏似乎与环境和遗传效应有关，并且可能与一些狗的牛磺酸异常代谢有关。
Dilated cardiomyopathy is caused by dilation of the left ventricle of the heart that results in the heart being unable to perform optimally. The underlying cause of DCM is unknown, but proposed factors include genetics, viral infection, immune-mediated disorders, arrhythmias, toxins and nutritional deficiencies.Low taurine status is associated with some cases of DCM. Inadequate cellular taurine concentrations result in the heart being unable to contract properly. DCM is the most common acquired heart disease in large breed dogs. Breeds in which taurine-deficient DCM has been reported include the American cocker spaniel, Dalmatian, boxer, Newfoundland, Portugese water dog, English setter, Alaskan malamute, golden retriever and Scottish terrier. Taurine deficiency in dogs appears to be related to both environmental and genetic effects, and may be related to abnormal taurine metabolism in some dogs.

膳食中的牛磺酸
Dietary taurine

牛磺酸天然存在于动物性食材中，但也可作为补充剂添加到狗和猫的饮食中。因为牛磺酸被认为是猫的必需营养素，许多全面和均衡的猫粮中都会补充足够水平的牛磺酸。狗粮不太可能补充牛磺酸，因为它不是狗所必需的营养素。但是，对于牛磺酸缺乏型DCM风险较高的特殊品种犬，推荐食用添加牛磺酸的狗粮。
Taurine is naturally found in animal-based ingredients, but is also available as a supplement that can be added to dog and cat diets. Because taurine is considered an essential nutrient for cats, many complete and balanced cat foods are supplemented with taurine to ensure adequate levels.Dog foods are less likely to be supplemented with taurine since it is not considered essential for dogs. For breeds that are at higher risk of developing taurine-associated DCM, a food with added taurine is recommended.

膳食蛋白质和其他食材的类型可能会影响牛磺酸状态。例如，在狗粮中，大豆蛋白已显示增加与牛磺酸结合的胆汁酸的排泄速率。在猫粮中，米糠或低质量和热损伤蛋白质的饮食与由于加速了胃肠牛磺酸损失而需要相应增加牛磺酸的补充。有证据表明含有羊肉粉和/或米的饮食可能与牛磺酸缺乏型DCM有关。虽然需要更多的证据来支持这一观点，但作为预防措施，许多以羊肉为蛋白质的配方狗粮都补充了牛磺酸。
The type of dietary protein and other ingredients may affect taurine status. For example, in dogs, soybean protein has been shown to increase the rate of excretion of bile acids that are bound to taurine. In cats, diets containing rice bran or low quality, heat-damaged protein have been associated with an increased dietary taurine requirement due to accelerated gastrointestinal taurine losses.Some evidence has suggested that diets containing lamb meal and/or rice may be associated with taurine-deficient DCM. Although more evidence is needed to support this finding, as a precaution many lamb-based dog diets are supplemented with taurine.

牛磺酸对扩张型心肌病的治疗作用
Taurine supplementation for pets with dilated cardiomyopathy

牛磺酸缺乏型DCM随着牛磺酸的补充显示出回转迹象。为了确定DCM是否与牛磺酸缺乏相关，需要测量血液和血浆牛磺酸水平。建议诊断患有DCM的狗每天补充剂量为500毫克牛磺酸两次。患有DCM的猫每天应补充剂量为250毫克的牛磺酸两次。在心脏功能开始改善之前，需要至少两周的牛磺酸补充时间，在接下来的三到六个月内会持续改善。
DCM due to low taurine status has been shown to be reversible with taurine supplementation. To determine if DCM is related to taurine deficiency, blood and plasma taurine levels need to be measured. It is recommended that dogs diagnosed with DCM begin taurine supplementation at a dosage of 500 mg twice per day.Cats with DCM should receive 250 mg of supplemental taurine twice per day. It takes at least two weeks of taurine supplementation before cardiac function starts to improve, with continued improvement being seen over the next three to six months.

总之，当为您的猫选择粮食时，请确保能提供足量的牛磺酸。仔细阅读主要食材中添加的牛磺酸或联系公司咨询牛磺酸水平。对于狗来说，牛磺酸不是必需的营养成分，但如果您的狗属于DCM高危险的品种，请考虑购买添加牛磺酸的狗粮。
In summary, when choosing a food for your cat, make sure that the diet provides adequate amounts of taurine. Check the ingredient panel for added taurine or contact the company and request information about the taurine level in the food. For dogs, taurine is not an essential nutrient, but if you have a breed that is at high risk for DCM, consider purchasing food with added taurine.