49.下列何種必需脂肪酸在貓需由膳食獲得，而犬隻可以自行在體內合成？
(A)亞麻油酸（linoleic acid）
(B)α-次亞麻油酸（α-linolenic acid）
(C)花生四烯酸（arachidonic acid）
(D)牛磺酸（taurine）

The National Research Council (NRC) [16] recognizes that the dog is a carnivore anatomically but has many metabolic characteristics of omnivores, including the conversion of β-carotene to vitamin A, tryptophan to niacin, cysteine to taurine, and linoleic acid to arachidonic acid. Dogs also differ from cats in many of these aspects. For example, unlike cats that require much more dietary protein (expressed as % of diet) than provided in grains and vegetables, most breeds of dogs can thrive on taurine-free vegetarian diets that are properly balanced and sufficient in non-taurine nutrients through supplementation with those either absent from plants or inadequately synthesized de novo [16]. Regardless of their sources of food, adequate knowledge of nutrient metabolism and requirements by cats and dogs is crucial to ensure their optimal growth, development, and health. The major objective of this article is to highlight the nutrition and metabolism of amino acids (AAs) in cats and dogs. Unless indicated, AAs except for glycine and taurine refer to the L-isomers herein.

資料來源: https://link.springer.com/article/10.1186/s40104-022-00827-8

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