Olanrewaju H A, Thaxton J P, Dozier W A, Branton S L
USDA/ARS, South Central Poultry Research Laboratory, Mississippi 39762, USA.
Poult Sci. 2007 Jul;86(7):1363-71. doi: 10.1093/ps/86.7.1363.
We compared the acid-base balance in broiler chickens provided diets containing 2 dietary electrolyte balances (DEB), and administered with either adrenocorticotropic hormone (ACTH) or saline solution. Diets were moderate (174 mEq/kg) or high (241 mEq/kg) DEB formulated by altering Na-K-Cl based on actual analysis. The experiment was designed as a split plot, with the main unit consisting of 4 treatments and the factorial treatment structure arranged in a completely randomized design. Osmotic pumps delivered 8 IU of ACTH in saline/kg of BW per d for 7 d, or the same saline volume as used in ACTH at 1 microL/h for 7 d was implanted on d 35. Venous blood samples were collected on d 35 before the pumps were implanted and on d 42 and 49. Birds fed the high DEB diet exhibited significantly higher Na(+) and Ca(2+) levels than birds provided the moderate DEB diet on d 35. Infusion of ACTH significantly increased (P < or = 0.05) hematocrit, hemoglobin, partial pressure of CO(2) (pCO(2)), corticosterone, osmolality, and HCO(3)(-) and reduced pH, BW, partial pressure of O(2) (pO(2)), and plasma concentrations of Na(+) and Cl(-) in both diets compared with the control group on d 42. Similarly, the ACTH treatment significantly increased hematocrit, hemoglobin, Ca(2+), corticosterone, and osmolality and reduced (P < or = 0.05) pO(2), glucose, and BW on d 49. The diet formulated for high DEB partially lowered pCO(2) on d 42. Significant DEB x ACTH interactions were observed for pCO(2) and pO(2) on d 49. However, there was a reduction in pO(2) along with a concomitant increase in erythropoiesis under the ACTH treatment for both diets, compared with the saline control, because of the increased need for O(2) to support gluconeogenic energy production. This adaptive response provided greater numbers of erythrocytes and thus a higher amount of circulating hemoglobin to deliver O(2) for metabolism. The diet formulated for high DEB partially attenuated the adaptive stress condition in broiler chickens.
我们比较了采食含两种日粮电解质平衡（DEB）日粮的肉鸡的酸碱平衡，并分别给予促肾上腺皮质激素（ACTH）或生理盐水。日粮根据实际分析通过改变钠 - 钾 - 氯来配制，分为中等（174 mEq/kg）或高（241 mEq/kg）DEB。实验设计为裂区试验，主区由4种处理组成，析因处理结构采用完全随机设计。渗透泵以每千克体重每天8国际单位的ACTH溶于生理盐水中给药，持续7天，或在第35天植入以1微升/小时的速率输注与ACTH组相同体积生理盐水的泵，持续7天。在植入泵前的第35天以及第42天和第49天采集静脉血样。在第35天，采食高DEB日粮的鸡的钠（Na⁺）和钙（Ca²⁺）水平显著高于采食中等DEB日粮的鸡。与对照组相比，在第42天，两种日粮中输注ACTH均显著增加（P≤0.05）红细胞压积、血红蛋白、二氧化碳分压（pCO₂）、皮质酮、渗透压和碳酸氢根（HCO₃⁻），并降低pH值、体重、氧分压（pO₂）以及血浆钠（Na⁺）和氯（Cl⁻）浓度。同样，在第49天，ACTH处理显著增加红细胞压积、血红蛋白、钙（Ca²⁺）、皮质酮和渗透压，并降低（P≤0.05）pO₂、葡萄糖和体重。高DEB日粮在第42天使pCO₂有所降低。在第49天，观察到pCO₂和pO₂存在显著的DEB×ACTH交互作用。然而，与生理盐水对照组相比，在两种日粮的ACTH处理下，由于支持糖异生能量产生对氧气的需求增加，pO₂降低同时红细胞生成伴随增加。这种适应性反应产生了更多的红细胞，从而有更高量的循环血红蛋白来输送氧气用于代谢。高DEB日粮部分减轻了肉鸡的适应性应激状况。
