A well-balanced amino acid profile in the feedstuffs for livestock is essential to support adequate growth. This is well studied for monogastric species but still not well understood for ruminants and especially for the most unconventional species, like cervids. This study investigated the influence of ruminally protected lysine (Lys) and methionine (Met) supplementation during the fattening period, as well as two slaughter seasons (late autumn (LA) v. late winter (LW)), on the growth, carcass traits, body condition and blood plasma metabolites of fallow deer (Dama dama). Forty-five yearlings of fallow deer bucks were allocated into three groups, balanced by weight (40.2 ± 2.7 kg). The deer were pasture-fed and supplemented with barley, free-choice mineral premix, silage during the winter period, and varying levels of ruminally protected Lys and Met: no amino acids (Control), 9 g/day of Lys, and 9 g/day of Lys plus 3 g/day of Met (Lys+Met). Animals were slaughtered in two separate seasons, LA (six animals per group), and LW (nine animals per group). Animals culled in LA had higher average daily weight gain than LW (P = 0.002), due to the reduced growth during winter typical for seasonal cervids in temperate zone, mediated by the photoperiod. Dressing percentage was significantly higher in LW and in the Lys+Met group (P = 0.002). Body condition score (P = 0.024), kidney fat index (KFI) (P = 0.005), and internal fat (P < 0.001) increased significantly with Lys+Met supplementation. During LW, KFI (P = 0.004) and kidney fat (P = 0.001) were also significantly higher than in LA. Blood creatinine concentration increased significantly for deer receiving Lys (P = 0.002) and Lys+Met (P < 0.001). Also, triglycerides level increased in Lys group (P < 0.001). These findings highlight the effects of Lys and Met supplementation on the growth and internal fat storage for winter survival, suggesting a different use of the supplemented resource according to the season. Also, the observed effects on protein and fat metabolism of fallow deer may influence the production of farmed animals, and offer interesting insights about the physiology of the species.

中文翻译：

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反刍动物保护氨基酸在两个淘汰期对小鹿育肥的差异作用。

牲畜饲料中氨基酸平衡的状况对于支持充足的生长至关重要。对于单胃物种，对此进行了充分的研究，但对于反刍动物，尤其是对于最非常规物种，如鹿种，仍缺乏很好的了解。这项研究调查了在育肥期以及两个屠宰季节（深秋（LA）诉冬末（LW））中添加反刍动物赖氨酸（Lys）和蛋氨酸（Met）对生长，car体性状的影响鹿的体质，身体状况和血浆代谢产物。四十五岁的小鹿雄鹿按体重（40.2±2.7公斤）分为三组。鹿是牧场饲喂的，冬季则补充大麦，自由选择的矿物质预混料，青贮饲料，瘤胃保护的Lys和Met水平各不相同：没有氨基酸（对照），Lys 9 g /天，Lys 9 g /天，Met 3 g /天（Lys + Met）。在两个不同的季节宰杀动物，LA（每组六只）和LW（每组九只）。在洛杉矶淘汰的动物的平均日增重高于LW（P = 0.002），这是由于光周期介导的冬季温带地区季节性宫颈典型的生长减少。LW和Lys + Met组的换药率显着更高（P = 0.002）。补充Lys + Met后，身体状况评分（P = 0.024），肾脏脂肪指数（KFI）（P = 0.005）和内部脂肪（P <0.001）显着增加。在LW期间，KFI（P = 0.004）和肾脂肪（P = 0.001）也显着高于LA。接受Lys（P = 0.002）和Lys + Met（P <0.001）的鹿的血肌酐浓度显着增加。此外，Lys组甘油三酯水平升高（P <0.001）。这些发现强调了赖氨酸和蛋氨酸补充剂对冬季生存的生长和内部脂肪储存的影响，表明根据季节不同使用补充资源的方法。同样，观察到的对小鹿蛋白质和脂肪代谢的影响可能会影响养殖动物的生产，并提供有关该物种生理学的有趣见解。建议根据季节不同使用补充资源。同样，观察到的对小鹿蛋白质和脂肪代谢的影响可能会影响养殖动物的生产，并提供有关该物种生理学的有趣见解。建议根据季节不同使用补充资源。同样，观察到的对小鹿蛋白质和脂肪代谢的影响可能会影响养殖动物的生产，并提供有关该物种生理学的有趣见解。