The impact of ergot toxicosis on livestock industries is detrimental and treatments are needed in many countries. The objective of this study was to evaluate effects of acute exposure to ergot alkaloids and 5-hydroxytryptophan (5-HTP) supplementation on feed intake, serotonin metabolism and blood metabolites in cattle. Eight Holstein steers (538 ± 18 kg) fitted with ruminal cannulas were used in a replicated 4 x 4 Latin Square design experiment with a 2 x 2 factorial treatment structure. The treatments were the combination of 0 (E-) or 15 µg ergovaline/ kg BW (E+) and 0 (5HTP-) or 0.5 mg of 5-hydroxy-L-tryptophan/ kg BW (5HTP+) administered daily for 6 d. Toxic endophyte-infected tall fescue seed was used to supply the daily dose of ergovaline. Endophyte-free seed was used to equalize seed intake between treatments. Ground seed was placed into the rumen immediately before feeding. The 5-HTP was dissolved in water and infused into the abomasum via the reticulo-omasal orifice. Blood was collected from a jugular vein catheter at 0, 1, 2, 4, 8 and 24 h after treatment administration. Ergovaline without 5-HTP (E+/5HTP-) decreased dry matter intake (DMI) in comparison to steers without ergovaline and 5-HTP (E-/5HTP-). However, 5-HTP infusion in association with ergovaline (E+/5HTP+) normalized the DMI. Although E+ did not affect (P > 0.05) the area under curve (AUC) of serum 5-HTP, 5-hydroxyindoleacetic acid, tryptophan and kynurenine, serum and plasma serotonin concentrations were decreased (P < 0.05). The infusion of 5-HTP increased (P < 0.05) the AUC of serum 5-HTP, serum and plasma serotonin and serum 5-hydroxyindoleacetic acid. In conclusion, acute exposure to ergot alkaloids reduced DMI and circulating serotonin in cattle but 5-HTP administration showed potential to normalize both circulating serotonin and feed intake.

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标题：5-羟基色氨酸可减轻麦角生物碱的影响

麦角中毒对畜牧业的影响是有害的，许多国家都需要治疗。本研究的目的是评估急性暴露于麦角生物碱和补充 5-羟色氨酸 (5-HTP) 对牛采食量、血清素代谢和血液代谢物的影响。八头装有瘤胃插管的荷斯坦公牛 (538 ± 18 kg) 用于具有 2 x 2 阶乘处理结构的重复 4 x 4 拉丁方设计实验。治疗是每天给予 0 (E-) 或 15 µg 麦角瓦林/kg BW (E+) 和 0 (5HTP-) 或 0.5 mg 5-羟基-L-色氨酸/kg BW (5HTP+) 的组合，持续 6 天。使用有毒内生菌感染的高羊茅种子来提供麦角瓦林的每日剂量。使用不含内生菌的种子来平衡处理之间的种子摄入量。在饲喂前立即将磨碎的种子放入瘤胃中。将 5-HTP 溶解在水中并通过网状皱胃孔注入皱胃。在治疗施用后0、1、2、4、8和24小时从颈静脉导管收集血液。与不含麦角缬氨酸和 5-HTP (E-/5HTP-) 的阉牛相比，不含 5-HTP (E+/5HTP-) 的麦角缬氨酸降低了干物质摄入量 (DMI)。然而，5-HTP 输注联合麦角瓦林 (E+/5HTP+) 可使 DMI 正常化。尽管E+不影响(P＞0.05)血清5-HTP、5-羟基吲哚乙酸、色氨酸和犬尿氨酸的曲线下面积(AUC)，但血清和血浆5-羟色胺浓度降低(P＜0.05)。输注5-HTP增加了血清5-HTP、血清和血浆血清素以及血清5-羟基吲哚乙酸的AUC（P＜0.05）。总之，急性接触麦角生物碱会降低牛的 DMI 和循环血清素，但 5-HTP 给药显示有可能使循环血清素和采食量正常化。