Dietary Calcium Availability and Reproduction in Birds
Dietary Calcium Availability and Reproduction in Birds
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DOI：
10.1007/978-1-4419-6421-2_2
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发表时间：
2010
期刊：
影响因子：
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通讯作者：
S. Reynolds;C. Perrins
中科院分区：
文献类型：
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作者：
S. Reynolds;C. Perrins
繁殖在能量上是昂贵的。鸟类的蛋形成需要37-55%的基础代谢率，鸭子和南方褐猕猴桃需要160-216%的基础代谢率(Walsberg，1983)。鸡蛋的生产需要充足的水、大量营养素(碳水化合物、蛋白质和脂肪)和微量营养素(必需脂肪酸、氨基酸、维生素和离子)。在后一组营养素中，钙可能是产蛋鸟所需的最有限的微量营养素(Burley和Vadehra，1989)；蛋壳的干燥质量的98%由方解石组成，方解石是碳酸钙(CaCO3)的结晶形式(Romanoff和Romanoff 1949)。在孵化期间，蛋壳包裹着胚胎发育和存活所需的所有营养物质，防止发育中的雏鸟被孵化的成虫挤压。外壳还保护胚胎免受脱水，防止病原体从外部环境进入，并允许气体交换。它也是胚胎骨骼发育的钙来源。从骨架上退出会导致蛋壳从∼中自然变薄6%(例如，Balkan等人)。到21%(例如，Booth和Seymour，1987)，因为胚胎在孵化过程中从壳中吸收钙。在产蛋后，许多物种的成年鸡在饲养期间必须保持较高的钙需求量，此时鸟类给其幼鸟喂食富钙食物(见Graveland 1996a中的表3)，以使其骨骼继续矿化(Starck 1998)。
Reproduction is energetically costly. Egg formation in birds requires 37–55% of basal metabolism for small passerines and 160–216% for ducks and the Southern Brown Kiwi (Apteryx australis) (Walsberg 1983). The production of eggs requires an adequate supply of water, macronutrients (carbohydrate, protein, and fat), and micronutrients (essential fatty acids, amino acids, vitamins, and ions). Of this latter group of nutrients, calcium is probably the most limiting micronutrient required by the laying bird (Burley and Vadehra 1989); 98% of the dry mass of the eggshell consists of calcite, a crystalline form of calcium carbonate (CaCO3) (Romanoff and Romanoff 1949). The eggshell encases all of the nutrients required for embryonic development and survival during the incubation period, preventing the developing chick from being crushed by the incubating adult. The shell also protects the embryo from dehydration, prevents the entry of pathogens from the external environment, and allows gaseous exchange. It also acts as a source of calcium for skeletal development of the embryo. The withdrawal from the skeleton results in “natural thinning” of the eggshell from ∼6% (e.g., Balkan et al. 2006) to 21% (e.g., Booth and Seymour 1987) as the embryo absorbs calcium from the shell during incubation. After egg production, the calcium requirements of the adult in many species must remain elevated during chick-rearing, when birds feed calcium-rich foods to their young (see Table 3 in Graveland 1996a) for the continued mineralization of their skeletons (Starck 1998).