Ergot alkaloids can interact with several serotonin (5-hydroxytryptamine [5-HT]) receptors provoking many physiological responses. However, it is unknown whether ergot alkaloid consumption influences 5-HT or its metabolites. Thus, two experiments were performed to evaluate the effect of ergot alkaloid feeding on 5-HT metabolism. In exp. 1, 12 Holstein steers (260 ± 3 kg body weight [BW]) were used in a completely randomized design. The treatments were the dietary concentration of ergovaline: 0, 0.862, and 1.282 mg/kg of diet. The steers were fed ad libitum, kept in light and temperature cycles mimicking the summer, and had blood sampled before and 15 d after receiving the treatments. The consumption of ergot alkaloids provoked a linear decrease (P = 0.004) in serum 5-HT. However, serum 5-hydroxytryptophan and 5-hydroxyindoleacetic acid did not change (P > 0.05) between treatments. In exp. 2, four ruminally cannulated Holstein steers (318 ± 3 kg BW) were used in a 4 × 4 Latin square design to examine the difference between seed sources on 5-HT metabolism. Treatments were: control—tall fescue seeds free of ergovaline, KY 32 seeds (L42-16-2K32); 5Way—endophyte-infected seeds, 5 way (L152-11-1739); KY31—endophyte-infected seeds, KY 31 (M164-16-SOS); and Millennium—endophyte-infected seeds, 3rd Millennium (L108-11-76). The endophyte-infected seed treatments were all adjusted to provide an ergovaline dosage of 15 μg/kg BW. The basal diet provided 1.5-fold the net energy requirement for maintenance. The seed treatments were dosed directly into the rumen before feeding. The experiment lasted 84 d and was divided into four periods. In each period, the steers received seeds for 7 d followed by a 14-d washout. Blood samples were collected on day 0 (baseline) and day 7 for evaluating the treatment response in each period. A 24 h urine collection was performed on day 7. Similar to exp. 1, serum 5-HT decreased (P = 0.008) with the consumption of all endophyte-infected seed treatments. However, there was no difference (P > 0.05) between the infected seeds. The urinary excretion of 5-hydroxyindoleacetic acid in the urine was not affected (P > 0.05) by the presence of ergot alkaloids. In conclusion, the consumption of ergot alkaloids decreases serum 5-HT with no difference between the source of endophyte-infected seeds in the bovine.

中文翻译：

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麦角生物碱可减少牛体内的循环血清素

麦角生物碱可以与几种血清素（5-羟色胺 [ 5-HT ]）受体相互作用，引发许多生理反应。然而，尚不清楚麦角生物碱的摄入是否会影响 5-HT 或其代谢物。因此，进行了两个实验来评估麦角生物碱喂养对 5-HT 代谢的影响。在 exp。1, 12 头荷斯坦公牛 (260 ± 3 kg 体重 [ BW ]) 用于完全随机设计。治疗是麦角瓦林的膳食浓度：0、0.862 和 1.282 mg/kg 膳食。公牛自由采食，保持模拟夏季的光照和温度循环，并在接受治疗前和治疗后 15 天采血。麦角生物碱的消耗量呈线性下降（P= 0.004) 在血清 5-HT 中。然而，血清 5-羟色氨酸和 5-羟吲哚乙酸没有变化（P> 0.05) 治疗之间。在 exp。如图 2 所示，在 4 × 4 拉丁方设计中使用了 4 头瘤胃插管荷斯坦肉牛 (318 ± 3 kg BW)，以检查种子来源对 5-HT 代谢的差异。处理是：对照——不含麦角缬氨酸的高羊茅种子、KY 32种子（L42-16-2K32）；5Way——感染内生菌的种子，5way (L152-11-1739)；KY31——内生菌感染的种子，KY 31 (M164-16-SOS)；和千年——受内生菌感染的种子，第三千年 (L108-11-76)。内生菌感染的种子处理均进行了调整，以提供 15 μg/kg BW 的麦角缬氨酸剂量。基础日粮为维持提供了 1.5 倍的净能量需求。在饲喂前将种子处理剂直接喂入瘤胃。实验历时84 d，分为四个时期。在每个时期，公牛接受种子 7 天，然后进行 14 天的冲洗。在第 0 天（基线）和第 7 天收集血样，用于评估每个时期的治疗反应。在第 7 天进行了 24 小时的尿液收集。类似于 exp。1、血清5-HT下降（P = 0.008）消耗所有内生菌感染的种子处理。然而，感染的种子之间没有差异（P > 0.05）。5-羟基吲哚乙酸在尿中的排泄不受麦角生物碱的影响（P >0.05）。总之，食用麦角生物碱会降低血清 5-HT，而牛体内受内生菌感染的种子来源之间没有差异。