Department of Animal Biosciences, Ontario Agricultural College, University of Guelph, Guelph, ON N1G 2W1, Canada.
Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, ON N1G 2W1, Canada.
J Anim Sci. 2021 Sep 1;99(9). doi: 10.1093/jas/skab223.
Grain-based ingredients are replaced in part by pulse ingredients in grain-free pet foods. Pulse ingredients are lower in methionine and cysteine, amino acid (AA) precursors to taurine synthesis in dogs. Although recent work has investigated plasma and whole blood taurine concentrations when feeding grain-free diets, supplementation of a grain-free diet with various nutrients involved in the biosynthesis of taurine has not been evaluated. This study aimed to investigate the effects of supplementing a complete grain-free dry dog food with either methionine (MET), taurine (TAU), or methyl donors (choline) and methyl receivers (creatine and carnitine; CCC) on postprandial AA concentrations. Eight healthy Beagle dogs were fed one of the three treatments or the control grain-free diet (CON) for 7 d in a 4 × 4 Latin square design. On day 7, cephalic catheters were placed and one fasted sample (0 min) and a series of nine post-meal blood samples were collected at 15, 30, 60, 90, 120, 180, 240, 300, and 360 min. Data were analyzed as repeated measures using the PROC GLIMMIX function in SAS (Version 9.4). Dogs fed MET had greater plasma and whole blood methionine concentrations from 30 to 360 min after a meal (P < 0.0001) and greater plasma homocysteine concentrations from 60 to 360 min after a meal (P < 0.0001) compared with dogs fed CON, TAU, and CCC. Dogs fed TAU had greater plasma taurine concentrations over time compared with dogs fed CON (P = 0.02) but were not different than dogs fed MET and CCC (P > 0.05). In addition, most AAs remained significantly elevated at 6 h post-meal compared with fasted samples across all treatments. Supplementation of creatine, carnitine, and choline in grain-free diets may play a role in sparing the methionine requirement without increasing homocysteine concentrations. Supplementing these nutrients could also aid in the treatment of disease that causes metabolic or oxidative stress, including cardiac disease in dogs, but future research is required.
谷物成分在无谷物宠物食品中部分被豆类成分替代。豆类成分中的蛋氨酸和半胱氨酸含量较低，而蛋氨酸和半胱氨酸是犬体内牛磺酸合成的氨基酸（AA）前体。虽然最近的研究已经调查了饲喂无谷物日粮时犬血浆和全血牛磺酸浓度，但尚未评估用各种参与牛磺酸生物合成的营养素来补充无谷物日粮。本研究旨在调查补充完整的无谷物干狗粮中的蛋氨酸（MET）、牛磺酸（TAU）或甲基供体（胆碱）和甲基受体（肌酸和肉碱；CCC）对餐后 AA 浓度的影响。8 只健康的比格犬在 4×4 拉丁方设计中饲喂其中 3 种处理或对照无谷物日粮（CON）7d。第 7 天，放置头静脉导管，在空腹样本（0 分钟）和一系列 9 个餐后血液样本中采集 15、30、60、90、120、180、240、300 和 360 分钟。使用 SAS（版本 9.4）中的 PROC GLIMMIX 函数对数据进行重复测量分析。与饲喂 CON、TAU 和 CCC 的犬相比，饲喂 MET 的犬在餐后 30-360 分钟时具有更高的血浆和全血蛋氨酸浓度（P < 0.0001），并且在餐后 60-360 分钟时具有更高的血浆同型半胱氨酸浓度（P < 0.0001）。与饲喂 CON 的犬相比，饲喂 TAU 的犬具有随时间推移的更高的血浆牛磺酸浓度（P = 0.02），但与饲喂 MET 和 CCC 的犬没有差异（P > 0.05）。此外，与禁食样本相比，所有处理组在餐后 6 小时时大多数 AA 仍显著升高。在无谷物日粮中补充肌酸、肉碱和胆碱可能有助于在不增加同型半胱氨酸浓度的情况下节省蛋氨酸需求。补充这些营养素也可能有助于治疗导致代谢或氧化应激的疾病，包括犬的心脏病，但需要进一步的研究。
