Lagerkvist G, Tauson A H
Department of Animal Breeding and Genetics, Swedish University of Agricultural Sciences, Uppsala.
Arch Tierernahr. 1993;45(2):155-60. doi: 10.1080/17450399309386096.
In a 5-generation selection experiment, separate lines of mink (Mustela vison) were selected for litter size at 3 weeks (F-line) and body weight in September (BS-line). One unselected line served as a control (C). Nutrient digestibility was studied in a balance experiment with four male kits from each line in the last generation. Carcass composition was determined for four 4th-generation F- and BS-males each that had been killed on September 21. The feed consumption rate was higher in the BS-line animals in the balance experiment than in the F- and C-animals (1687 versus 1532 and 1504 kJ/animal and day). These differences reflected the higher average live weights measured on August 25, of the BS-males (1831 g versus 1728 and 1619). CP and CHO digestibility were similar in all lines, whereas a numerically small but significant difference in apparent fat digestibility was found between the F- and BS-lines (95%) and the C-line (93%). Average body weights of animals in the carcass composition evaluation were 2607 g (BS-line) and 2023 g (F-line). Retained protein, fat, and energy were significantly affected by line. The amount of protein retained per kg metabolic weight (kg0.75) was nearly equal in the two lines, indicating that the animals' genetic capacity for protein retention was similar and probably utilized to its full extent. Retained fat and energy per kg0.75 were higher in the BS-line, indicating that the animals had been selected for fat deposition rather than for body size. Hence, selection for body size in mink should be performed by using a selection criterion with which the negative effects of increased fat deposition on reproductive performance can be avoided.
在一项五代选择实验中，分别选择水貂（鼬属水貂）品系，对3周龄时的窝仔数（F系）和9月时的体重（BS系）进行选择。一个未选择的品系用作对照（C系）。在平衡实验中，对上一代每个品系的4只雄性幼貂研究了营养物质消化率。测定了9月21日处死的4只第四代F系和BS系雄性水貂的胴体组成。在平衡实验中，BS系动物的采食量高于F系和C系动物（分别为1687千焦/动物·天、1532千焦/动物·天和1504千焦/动物·天）。这些差异反映出8月25日测得的BS系雄性水貂平均活重较高（1831克，而F系为1728克，C系为1619克）。所有品系的粗蛋白和碳水化合物消化率相似，而F系和BS系（95%）与C系（93%）之间的表观脂肪消化率存在数值上较小但显著的差异。胴体组成评估中动物的平均体重分别为2607克（BS系）和2023克（F系）。品系对保留的蛋白质、脂肪和能量有显著影响。两个品系每千克代谢体重（千克0.75）保留的蛋白质量几乎相等，表明动物保留蛋白质的遗传能力相似，且可能得到了充分利用。每千克0.75体重保留的脂肪和能量在BS系中较高，表明这些动物是被选择用于脂肪沉积而非体型选择。因此，水貂体型选择应采用能避免脂肪沉积增加对繁殖性能产生负面影响的选择标准。
