Matte J J, Girard C L
Dairy and Swine R & D Centre, Agriculture and Agri-Food Canada, Lennoxville, Québec.
J Anim Sci. 1999 Jan;77(1):159-65. doi: 10.2527/1999.771159x.
Sows at their second parity were randomly distributed in five groups of seven animals each to determine the dietary concentration of folic acid that optimizes the metabolic utilization of the vitamin during gestation. The groups differed by dietary supplement of folic acid: 0, 5, 10, 15, or 20 ppm. Sows were fed 2.5 kg of diet each day. The response of serum folates and folate binding capacity to treatments and the excretion of urinary folates after an i.v. injection of folic acid were measured. The total daily excretion of urinary folates was corrected according to the response to one i.v. injection of saline on the day preceding the i.v. injection of folic acid. The decrease of total serum folates throughout gestation was less pronounced in the groups fed 15 and 20 ppm of dietary folic acid (supplement x period interaction, P<.06) than it was in the other three treatments. The proportion of i.v. folic acid not recovered in sow urine (injected - excreted) decreased as the amount of dietary folic acid increased to reach a minimum, which differed according to the period (supplement x period interaction, P<.02); it was 15 ppm during wk 1 of gestation and 10 ppm for the other periods studied. The unrecovered folates increased over a dietary concentration of 15 ppm. These minimum values correspond to the most appropriate feed concentration that covered the whole body utilization (tissue and cell metabolism, catabolism, and storage) of folates by the sows and could be interpreted as a reliable index of the requirement.
将处于第二胎次的母猪随机分为五组，每组七头，以确定在妊娠期能使维生素代谢利用率达到最佳的叶酸日粮浓度。各组的叶酸日粮添加量不同：0、5、10、15或20 ppm。母猪每天饲喂2.5千克日粮。测定了血清叶酸和叶酸结合能力对处理的反应以及静脉注射叶酸后尿叶酸的排泄量。根据静脉注射叶酸前一天静脉注射生理盐水的反应，对尿叶酸的每日总排泄量进行校正。在整个妊娠期，饲喂15 ppm和20 ppm日粮叶酸的组中血清总叶酸的下降不如其他三种处理明显（添加量×时期交互作用，P<0.06）。静脉注射的叶酸未在母猪尿液中回收的比例（注射量 - 排泄量）随着日粮叶酸量的增加而降低，直至达到最低值，该最低值因时期而异（添加量×时期交互作用，P<0.02）；在妊娠第1周为15 ppm，在其他研究时期为10 ppm。未回收的叶酸在日粮浓度超过15 ppm时增加。这些最低值对应于能满足母猪对叶酸全身利用（组织和细胞代谢、分解代谢和储存）的最合适饲料浓度，可被视为需求的可靠指标。
