Experiments were designed to test the influence of L-tryptophan supplementation of the extender on the sperm motility parameters and bacterial flora of brook trout (Salvelinus fontinalis) and rainbow trout (Oncorhynchus mykiss). The extender containing 0.3 M glucose in 10% Dimethyl sulfoxide (DMSO) was supplemented with 0, 0.5, 1, 2, and 4 mM L-tryptophan. Sperm samples stored for up to 12 days at 4°C for brook trout were motile while motility was not observed after six days of storage for rainbow trout. Diluted sperm samples were spread-plated onto Plate Count Agar (PCA) (Total Bacteria Count), Rose Bengal Agar (RBC) (Yeast-Mold Count), Violet Red Bile Dextrose (VRBD) (Enterobacteriaceae count) and Mannitol Salt Agar (MSA) (Micrococcus/Staphylococcus count) and counts were performed in duplicate and sampling occurred on day 0, 2, 4, 6, and 12 of cold storage. L-tryptophan supplementation of the extender yielded a positive effect, significantly prolonging sperm motility in S. fontinalis and O. mykiss compared to the control group (p < 0.05). The ideal results were obtained above a concentration of 0.5 mM for both species. Total bacteria count in fresh sperm (undiluted samples) was not detectable and not detected in sperm samples treated with different L-tryptophan concentrations. Yeast-mold, Enterobacteriaceae and Micrococcus/Staphylococcus were not detected from fresh and treated sperm brook trout and rainbow trout. On the basis of the results, L-tryptophan-based extender is useful for maintaining sperm quality in short-term storage. L-tryptophan had a negative effect on the bacterial flora. The results of the current study encourages further studies related to long-term storage and reproduction management.

Abbreviations: DMSO: dimethyl sulfoxide; PCA: plate count agar; RBC: rose Bengal agar; VRBD: violet red bile dextrose; MSA: mannitol salt agar; SCA: sperm class analyzer; CFU: colony-forming unit

设计实验来测试补充L-色氨酸的补充剂对溪鳟（Salvelinus fontinalis）和虹鳟（Oncorhynchus mykiss）精子运动参数和细菌菌群的影响。在10％二甲基亚砜（DMSO）中的0.3M葡萄糖补充剂中补充0、0.5、1、2和4 mM L-色氨酸。虹鳟鱼在4°C下最多可储存12天的精子样本能活动，而虹鳟鱼在储存6天后未观察到活力。将稀释的精子样品铺板接种到平板计数琼脂（PCA）（细菌总数），玫瑰孟加拉琼脂（RBC）（酵母菌计数），紫红色胆汁右旋糖（VRBD）（肠杆菌科计数）和甘露醇盐琼脂（MSA）上）（微球菌/葡萄球菌计数）一式两份，并在冷藏的第0、2、4、6和12天进行采样。与对照组相比，补充补充剂的L-色氨酸产生了积极的作用，显着延长了S. fontinalis和O. mykiss的精子活力（p <0.05）。两种物种的浓度均高于0.5 mM时可获得理想结果。新鲜精子（未稀释样品）中的总细菌数无法检测到，并且在用不同的L-色氨酸浓度处理的精子样品中也未检测到。酵母菌，肠杆菌科和微球菌/葡萄球菌未从新鲜和处理过的精子溪鳟鱼和虹鳟鱼中检出。根据结果​​，基于L-色氨酸的补充剂可用于在短期储存中维持精子质量。L-色氨酸对细菌菌群有负面影响。本研究的结果鼓励对与长期储存和繁殖管理有关的进一步研究。

缩写： DMSO：二甲亚砜；PCA：平板计数琼脂；RBC：孟加拉玫瑰琼脂；VRBD：紫红色胆汁葡萄糖；MSA：甘露醇盐琼脂；SCA：精子类分析仪；CFU：菌落形成单位