Nutrition Laboratory, Smithsonian Conservation Biology Institute, Washington, District of Columbia, USA.
Indianapolis Zoo, Indianapolis, Indiana, USA.
Zoo Biol. 2021 May;40(3):192-200. doi: 10.1002/zoo.21599. Epub 2021 Mar 11.
We assayed 31 milk samples collected from two African elephant cows housed at the Indianapolis Zoo across lactation (birth to calf age 973 days) for macronutrient composition (water, fat, protein, sugar, gross energy [GE], ash, calcium, and phosphorus). All assays were performed at the Smithsonian National Zoological Park Nutrition Laboratory, Washington, DC (SNZP) using standard methods developed at SNZP. Milk constituents are expressed on a weight-per-weight basis (%) and as a proportion each constituent contributes to milk energy. Calf weights were recorded, and growth rate calculated. The macronutrient composition of the African elephant milk samples was compared to previously published results for Asian elephants using analysis of covariance. African elephant milk is similar to Asian elephant milk, being moderately high in fat and energy and low in sugar. The mean values across lactation (excluding colostrum; n = 28) are 5.6 ± 0.3% crude protein, 3.1 ± 0.3% sugar, 13.0 ± 1.0% fat, and GE of 1.63 ± 0.10 kcal/g. Milk composition did not differ between cows. Milk composition significantly changed over lactation; fat and protein increased, and sugar decreased with calf age, comparable to previously reported data for African and Asian elephant milk. The proportion of milk energy from fat increased and that from sugar decreased over lactation, but the energy from protein was relatively constant. Protein contributed a higher proportion of energy to African elephant milk compared to Asian elephant milk (20.6% vs. 17.0%, p = .001). Despite this, calf growth rate was similar between the species, with the calves in this study gaining about 0.8 kg/day for the first 6 months.
我们检测了在印第安纳波利斯动物园饲养的两头非洲象母象在哺乳期（从分娩到小牛 973 天）的 31 个奶样，检测了宏量营养素组成（水、脂肪、蛋白质、糖、总能量[GE]、灰分、钙和磷）。所有检测均在华盛顿特区史密森国家动物园营养实验室（SNZP）使用在 SNZP 开发的标准方法进行。奶成分按重量计算（%），并表示为每种成分对奶能量的贡献比例。记录了小牛的体重，并计算了生长速度。使用协方差分析比较了非洲象奶样的宏量营养素组成与以前发表的亚洲象结果。非洲象奶与亚洲象奶相似，脂肪和能量含量适中较高，糖含量较低。整个哺乳期（不包括初乳；n=28）的平均值分别为 5.6±0.3%粗蛋白、3.1±0.3%糖、13.0±1.0%脂肪和 1.63±0.10 kcal/g 的 GE。奶牛之间的奶成分没有差异。奶成分在哺乳期内发生显著变化；随着小牛年龄的增长，脂肪和蛋白质增加，糖减少，与以前报道的非洲和亚洲象奶的数据相似。脂肪提供的奶能量比例增加，糖提供的奶能量比例减少，但蛋白质提供的能量相对稳定。与亚洲象奶相比，蛋白质为非洲象奶提供的能量比例更高（20.6%比 17.0%，p=0.001）。尽管如此，两种物种的小牛生长速度相似，本研究中的小牛在前 6 个月每天增加约 0.8 公斤。
