Ortolani Enrico Lippi, Machado Carlos Henrique, Sucupira Maria Claudia Araripe
Department of Clinical Science, College of Veterinary Medicine, University of São Paulo, Av Corifeu de Azevedo Marques, 2720 V Lageado, Cep 05508-000, São Paulo, SP, Brazil.
Vet Hum Toxicol. 2003 Dec;45(6):289-93.
Sixteen male Suffolk lambs fed a 8 ppm Cu basal diet were randomly assigned to 2 groups: 12 copper-loaded (CL) and 4 controls (C). The CL sheep were drenched initially with 3 mg Cu/kg bw daily for a week. Every week an additional dose of 3 mg Cu/kg bw was included in the drench until signs of copper poisoning appeared; the control sheep were drenched with saline solution. The onset of copper poisoning occurred between 42 and 55 d. Food intake and body weight were recorded daily. Blood samples were collected weekly to measure the activity of the liver enzymes gamma-glutamyltransferase (gammaGT), aspartate aminotransferase (AST), sorbitoll dehydrogenase (SDH) and acid phosphatase (AF). The following changes were significantly recorded in the CL sheep in the weeks or days previous to the hemolytic crisis: higher levels of gammaGT were found on the -28th d increasing slowly but continuously until the hemolytic crisis; SDH fluctuated during the period presenting higher levels on the -28th, -14th and -7th d; AST and AF activities increased from the -14th and -7th d respectively; sharp decreases in the activities of SDH and AF at the hemolytic crisis; lower feed intake and body weight gain from the -7th d; and sheep ceased eating concentrates from the -9th d and became anoretic the day before the hemolytic crisis. Plasma copper concentration increased only the day before the hemolytic crisis. There were no changes in respiratory and heart rates, rectal temperature or rumen movements throughout the pre-hemolytic phase. The higher the amount of cumulative copper drenched, the higher was the gammaGT and AST activities. It was concluded that gammaGT followed by AST are the best enzymes to assess copper-load in sheep during the pre-hemolytic phase. Sheep fed copper-rich diets with high plasma activity of these enzymes, decreased feed consumption and subtle loss of body weight are most likely to present with a hemolytic crisis in a few days.
16只饲喂含8 ppm铜基础日粮的雄性萨福克羔羊被随机分为两组：12只铜负荷组（CL）和4只对照组（C）。CL组绵羊最初每天按3 mg铜/千克体重灌服，持续一周。此后每周在灌服剂量中额外增加3 mg铜/千克体重，直至出现铜中毒症状；对照组绵羊则用盐溶液灌服。铜中毒症状在42至55天之间出现。每天记录采食量和体重。每周采集血样以测定肝脏酶γ-谷氨酰转移酶（γGT）、天冬氨酸转氨酶（AST）、山梨醇脱氢酶（SDH）和酸性磷酸酶（AF）的活性。在溶血危机前的几周或几天里，CL组绵羊出现了以下显著变化：在第-28天γGT水平升高，之后缓慢持续上升直至溶血危机；SDH在此期间波动，在第-28天、-14天和-7天出现较高水平；AST和AF活性分别从第-14天和-7天开始增加；在溶血危机时SDH和AF活性急剧下降；从第-7天开始采食量和体重增加减少；绵羊从第-9天开始停止采食精饲料，并在溶血危机前一天出现厌食。血浆铜浓度仅在溶血危机前一天升高。在溶血前期，呼吸频率、心率、直肠温度或瘤胃蠕动均无变化。累积灌服的铜量越高，γGT和AST活性越高。得出的结论是，在溶血前期，γGT其次是AST是评估绵羊铜负荷的最佳酶。饲喂富含铜日粮且这些酶血浆活性高、采食量减少和体重轻微下降的绵羊很可能在几天内出现溶血危机。
