Hall D D, Cromwell G L, Stahly T S
University of Kentucky, Lexington 40546.
J Anim Sci. 1991 Feb;69(2):646-55. doi: 10.2527/1991.692646x.
Three factorial experiments were conducted to evaluate the effects of various Ca:P ratios (1:1, 2:1 and 3:1) in diets having deficient (.3%), adequate (.6%) and excess (.9%) levels of dietary P on rate and efficiency of gain and bone strength of 192 pigs from 18 to 40 kg BW. A corn-soybean meal diet fortified with minerals and vitamins (but not vitamin K) was fed. Levels of Ca and P were achieved by adjusting the amounts of dicalcium phosphate and ground limestone in the diet. The corn was free of detectable mycotoxins. A hemorrhagic condition occurred in Exp. 1 in pigs fed the higher dietary Ca levels; all eight of the pigs fed 2.7% dietary Ca died of internal hemorrhage within the initial 28 d of the experiment. Vitamin K (5 mg menadione [as menadione dimethylpyrimidinole bisulfite]/kg) was added to half of the diets of the remaining animals and the experiment was continued for an additional 14 d. Prothrombin and whole blood clotting times were increased (P less than .01) in pigs fed high Ca without vitamin K but were normal in pigs fed high Ca with added vitamin K. Similar trends in clotting times occurred in a second experiment. A third experiment was conducted to determine whether the addition of vitamin K could reverse the hemorrhagic condition induced by feeding high dietary Ca for 28 d. As in the other two experiments, clotting times were increased (P less than .01) in pigs fed high Ca and no vitamin K. Addition of vitamin K after 28 d resulted in a return to basal prothrombin values by d 50. In regard to the original objectives, increasing the Ca:P ratio from 1:1 to 2:1 or 3:1 tended to reduce rate and efficiency of gain at all levels of P. Increasing the Ca:P ratio to 2:1 resulted in increased bone strength only when P was at or above the dietary requirement.
进行了三项析因试验，以评估日粮中不同钙磷比（1:1、2:1和3:1），以及低磷（0.3%）、适宜磷（0.6%）和高磷（0.9%）水平对192头体重18至40千克猪的生长速度、生长效率和骨骼强度的影响。日粮为添加矿物质和维生素（但不含维生素K）的玉米-豆粕型日粮。通过调整日粮中磷酸氢钙和石灰石粉的添加量来达到不同的钙磷水平。玉米未检测出霉菌毒素。在试验1中，采食高钙日粮的猪出现了出血症状；采食2.7%日粮钙的所有8头猪在试验开始后的最初28天内死于内出血。给其余动物一半日粮中添加维生素K（5毫克甲萘醌[以甲萘醌二甲基嘧啶亚硫酸氢盐形式]/千克），试验又持续了14天。采食高钙且未添加维生素K的猪凝血酶原和全血凝血时间延长（P<0.01），而采食高钙且添加维生素K的猪凝血时间正常。在第二项试验中也出现了类似的凝血时间变化趋势。进行了第三项试验，以确定添加维生素K是否可以逆转采食高钙日粮28天所诱发的出血症状。与其他两项试验一样，采食高钙且未添加维生素K的猪凝血时间延长（P<0.01）。在28天后添加维生素K，到第50天时凝血酶原值恢复到基础水平。关于最初的目标，在所有磷水平下，将钙磷比从1:1提高到2:1或3:1往往会降低生长速度和生长效率。仅当磷达到或高于日粮需要量时，将钙磷比提高到2:1才会增加骨骼强度。
