Strickland J R, Gulino-Klein L F, Ross T T, Slate S, Peterson M K, May T, Taylor J B
Department of Animal and Range Sciences, New Mexico State University, Las Cruces 88003-8003, USA.
Vet Hum Toxicol. 1998 Oct;40(5):278-84.
Two replicate trials determined the effects of dietary supplementation on snakeweed toxicity in beef cows of poor condition. Cows were stratified by weight and randomly assigned to 3 dietary treatments. Dietary treatments were control (n = 3/trial; medium quality hay, 9.49% crude protein), corn supplementation (n = 3/trial; control diet + 628 g cracked corn), and protein supplementation (n = 3/trial; control diet + 800 g 42% protein supplement). Corn and protein dietary treatments were fed to be isocaloric. Each trial consisted of 2 phases (68 days/phase). Phase 1 consisted of dietary treatments without snakeweed. In phase 2 dietary treatments contained snakeweed as 10% of the dry matter. Phase 1 and 2 dietary treatments were isocaloric/isonitrogenous. Dry matter intake of the control diet was limited to 1.3% of body weight/d. Body condition score and back fat were measured on days 0, 21 and 68 of each phase. Serum samples were collected at the onset of each trial and on days 28, 42 and 56 of each phase. Serum bromosulphthalein (BSP) elimination half life (t1/2) was estimated during week 6 of each phase. Serum BSP elimination t1/2 was higher for the control diet versus corn and protein treatments. Increased blood urea nitrogen (BUN) was found by day 28 of phase 2. Serum total bilirubin increased by day 28 in phase 2 compared to baseline for the control and corn dietary treatments. Additionally, serum indirect bilirubin was higher by day 28 in phase 2. Likewise, serum direct bilirubin increased during phase 2 on day 28 in the corn diet, but decreased by day 28 for the protein diet. Alkaline phosphatase levels were higher (P < 0.05) in the controls by day 28, but lower in the protein treatment by day 28 in phase 2. Changes were noted during phase 2 for some of the serum clinical profiles; however, these changes appear due to dietary restriction. In contrast, changes during phase 2 point to possible hepatotoxic and renal toxic effects of snakeweed. Phase 2 data suggest a benefit of protein supplementation for improving animal tolerance to snakeweed.
两项重复试验确定了日粮补充对体况较差的肉牛蛇麻草毒性的影响。奶牛按体重分层，随机分为3种日粮处理组。日粮处理分别为对照组（每次试验n = 3；中等质量干草，粗蛋白含量9.49%）、玉米补充组（每次试验n = 3；对照日粮 + 628克碎玉米）和蛋白质补充组（每次试验n = 3；对照日粮 + 800克42%蛋白质补充剂）。玉米和蛋白质日粮处理组的热量摄入相等。每项试验包括2个阶段（每个阶段68天）。第1阶段为不含蛇麻草的日粮处理。在第2阶段，日粮处理中蛇麻草占干物质的10%。第1阶段和第2阶段的日粮处理热量和氮含量相等。对照日粮的干物质摄入量限制为体重的1.3%/天。在每个阶段的第0天、第21天和第68天测量体况评分和背部脂肪。在每项试验开始时以及每个阶段的第28天、第42天和第56天采集血清样本。在每个阶段的第6周估计血清溴磺酞钠（BSP）消除半衰期（t1/2）。对照日粮的血清BSP消除t1/2高于玉米和蛋白质处理组。在第2阶段的第28天发现血尿素氮（BUN）升高。与对照和玉米日粮处理的基线相比，第2阶段第28天血清总胆红素升高。此外，第2阶段第28天血清间接胆红素更高。同样，玉米日粮在第2阶段第28天血清直接胆红素升高，但蛋白质日粮在第28天降低。在第2阶段第28天，对照组碱性磷酸酶水平较高（P < 0.05），但蛋白质处理组较低。在第2阶段观察到一些血清临床指标有变化；然而，这些变化似乎是由于日粮限制。相比之下，第2阶段的变化表明蛇麻草可能具有肝毒性和肾毒性作用。第2阶段的数据表明补充蛋白质有利于提高动物对蛇麻草的耐受性。
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