Department of Animal and Aquacultural Sciences, Faculty of Biosciences, Norwegian University of Life Sciences, Ås, Norway.
Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
Arch Anim Nutr. 2020 Feb;74(1):72-86. doi: 10.1080/1745039X.2019.1667711. Epub 2019 Oct 8.
Protein and amino acid (AA) availability of three protein meals of expected different quality were evaluated in young growing and adult mink. Lamb meal (LM), poultry meal (PM) or fishmeal (FM) were used as main protein sources in three extruded diets investigated by determining apparent total tract digestibility (ATTD) and nitrogen balance in 12 growing mink males aged 8-11 weeks in a Latin square design. In adult mink, ATTD of the diets was determined. The diets had lower protein content than recommended for growing mink, protein contributing 23% of total metabolisable energy (ME), to ensure differences in growth response. The LM diet with expected low protein quality revealed lower content of essential AA than the PM and FM diets. The ATTD of major nutrients and essential AA was significantly affected by diet, with the poorest values for LM, intermediate for PM and the highest values for FM. Mink kits revealed lower ATTD values than adults for protein, AA and especially fat, resulting in lower dietary ME content for kits than for adults. The mean difference was greatest for the LM diet with lowest ATTD and smallest for the FM diet with the highest ATTD. Nitrogen retention and growth rate differed significantly among diets and was lowest for diet LM and highest for diet FM, respectively. Different dietary essential AA contents and ATTD, especially of methionine, were the main factors to explain the difference in growth response. Generally, plasma essential AA concentrations did not clearly reflect the different dietary supply and the different growth response. The study shows that a recommended level of 0.31 g apparent total tract digestible methionine per MJ ME covers the minimum requirement with a safety margin. To obtain optimal growth, the lower digestive capacity in young mink kits should be considered when choosing feed ingredients.
三种不同质量的蛋白质饲料的蛋白质和氨基酸（AA）可利用性在生长中的和成年水貂中进行了评估。羊肉粉（LM）、肉粉（PM）或鱼粉（FM）用作三种膨化日粮的主要蛋白质来源，通过在 8-11 周龄的 12 只生长中的雄性水貂中进行的拉丁方设计，测定表观全肠道消化率（ATTD）和氮平衡来进行研究。在成年水貂中，测定了日粮的 ATTD。这些日粮的蛋白质含量低于生长水貂的推荐量，蛋白质占总可代谢能（ME）的 23%，以确保生长反应的差异。预计蛋白质质量较低的 LM 日粮的必需氨基酸（AA）含量低于 PM 和 FM 日粮。主要营养素和必需 AA 的 ATTD 受到日粮的显著影响，LM 的值最差，PM 居中，FM 的值最高。水貂仔的蛋白质、AA 尤其是脂肪的 ATTD 值低于成年水貂，导致仔的日粮 ME 含量低于成年水貂。差异最大的是 ATTD 最低的 LM 日粮，最小的是 ATTD 最高的 FM 日粮。氮保留和生长速度在日粮之间存在显著差异，分别为 LM 日粮最低，FM 日粮最高。不同的日粮必需 AA 含量和 ATTD，尤其是蛋氨酸，是解释生长反应差异的主要因素。一般来说，血浆必需 AA 浓度不能清楚地反映不同的日粮供应和不同的生长反应。研究表明，每 MJ ME 0.31 克表观全肠道可消化蛋氨酸的推荐水平有安全余量，可满足最低需求。为了获得最佳生长，在选择饲料成分时，应考虑幼水貂仔较低的消化能力。
