Trevizan Luciano, de Mello Kessler Alexandre, Brenna J Thomas, Lawrence Peter, Waldron Mark K, Bauer John E
Department of Animal Science, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS 91540-000, Brazil.
Lipids. 2012 Apr;47(4):413-23. doi: 10.1007/s11745-011-3651-0. Epub 2012 Jan 12.
Cats have limited Δ6 desaturase activity. However, γ-linolenate (GLA) feeding may by-pass the Δ6 desaturase step allowing arachidonate (ARA) accumulation via Δ5-desaturation. Alternatively, high dietary linoleate (LNA) may induce limited Δ6 desaturase also resulting in ARA accumulation. Fatty acid profiles were determined after feeding high LNA, high GLA, or adequate LNA diets. Adult female cats (n = 29) were assigned to one of three groups and fed for 8 weeks. Plasma samples were collected at weeks 0, 2, 4 and 8 for plasma triacylglycerol (TAG), total cholesterol (TC), lipoprotein (LP), and plasma and red blood cell membrane phospholipid fatty acid determinations. Time, but no diet, effects were observed for TAG, TC, and LP fractions at weeks 2 and 4 with significant increases likely due to increased dietary fat. However, all values were within feline normal limits. The GLA diet resulted in increased dihomo-γ-linolenic acid (DGLA) and ARA as early as week 2, supporting a ∆5 desaturase. Further evidence of Δ5 desaturase was found at high dietary LNA with the appearance of a novel fatty acid, 20:3 ∆7, 11, 14, apparently formed via ∆5 desaturation and chain elongation of LNA. However, Δ6 desaturase induction at high dietary LNA concentration was not observed. Cats are able to maintain plasma and red blood cell ARA when fed a practical diet containing GLA using what appears to be an active Δ5 desaturase enzyme.
猫的Δ6去饱和酶活性有限。然而，喂食γ-亚麻酸（GLA）可能绕过Δ6去饱和酶步骤，通过Δ5去饱和作用使花生四烯酸（ARA）积累。另外，高膳食亚油酸（LNA）可能诱导有限的Δ6去饱和酶，也导致ARA积累。在喂食高LNA、高GLA或适量LNA饮食后测定脂肪酸谱。成年雌性猫（n = 29）被分为三组之一，并喂食8周。在第0、2、4和8周采集血浆样本，用于测定血浆三酰甘油（TAG）、总胆固醇（TC）、脂蛋白（LP）以及血浆和红细胞膜磷脂脂肪酸。在第2周和第4周观察到时间而非饮食对TAG、TC和LP组分有影响，显著增加可能是由于膳食脂肪增加所致。然而，所有值均在猫的正常范围内。GLA饮食早在第2周就导致二高-γ-亚麻酸（DGLA）和ARA增加，支持了Δ5去饱和酶的存在。在高膳食LNA时发现了Δ5去饱和酶的进一步证据，出现了一种新的脂肪酸20:3Δ7,11,14，显然是通过LNA的Δ5去饱和作用和链延长形成的。然而，未观察到高膳食LNA浓度下的Δ6去饱和酶诱导。当给猫喂食含有GLA的实用饮食时，猫似乎能够利用活跃的Δ5去饱和酶来维持血浆和红细胞中的ARA水平。
