摘要：海洋酵母作为重要的微生物资源越来越受到重视. 本实验以从红树林沉积物中分离的海洋酵母?Pichia guilliermondii SY-19菌株作实验材料，制成质量浓度分别为5%、7.5%及10%的细胞悬液，用蜗牛酶法、双酶法（甘露聚糖酶和-葡聚糖酶）及热碱法等3种方法分组进行破壁处理12 h，每3 h检测1次酵母细胞数量及多糖、蛋白质、氨基氮和核酸等营养物质的含量，计算得率，确定合适的方法制备酵母提取物；对经有害无机氮胁迫处理2周的凡纳滨对虾，分别以配合饲料、菌液拌料和酵母提取物拌料投喂3周，比较对虾的存活率及生长状况. 结果表明，热碱法处理的破壁率和核酸提取量最高，但其他营养物含量稳定性差；而双酶法处理的蛋白质、氨基氮和多糖的得率最高且营养保留效果较好，以该法最佳条件即5% 酵母悬液处理12 h制备酵母提取物作为饲料添加剂。胁迫过的对虾经3周的饲养恢复，其增重和存活率表现为酵母提取物拌料饲喂的对虾最高（77.674.62%, 2.790.11g），菌液拌料饲喂的次之（62.009.90%, 2.440.16 g），未拌料的最低（53.6712.91%, 2.190.02 g），对虾存活率上三组有显著差异（p0.05），添加酵母提取物的与未拌料对照组的终体重存在显著差异（p0.05）。本文的研究结果表明该菌株在对虾健康养殖中具有较好的潜在价值.
Abstract: Marine yeasts have been attracting more and more attention as an important resource. In this present, the strain Pichia guilliermondii SY-19 isolated from mangrove sediment was cultured in the liquid medium, and the yeast cells were collected for preparing cell suspensions at concentrations of 5%, 7.5% and 10% (w/w). Then the yeast cell suspensions were subjected to disruption treatment for 12 h with snailase, bienzymes with mannanase and glucanase, and hot alkali, respectively. The percentages of cell disruption and these extracts were calculated after the density of yeast cells and the contents of polysaccharides, protein, amino nitrogen and nucleic acid were detected at 3 h intervals, to select a suitable method for prepartion of yeast extract . And shrimps subjected to ammonia and nitrite stress for 2 weeks were fed for 3 weeks on a diet with no yeast (NY), yeast cells (YC), and yeast extract (YE), then the survive rate and growth performance of shrimps were compared among NY, YC and YE. The results showed that the cell suspensions exhibited the highest rate of cell disruption rate and nucleic acids content, poorer stability of nutrients with hot alkali extraction, the greatest yield percentages of protein, amino nitrogen and polysaccharides, better nutrient retention with bienzymes treatment. Yeast extract as additive was obtained by bienzymes treatment from cell suspensions at concentrations of 5% for 12 h (optimum condition). After 3 weeks, the highest survive rate and final weight of shrimps was obtained in YE (77.674.62%, 2.790.11g) than YC (62.009.90%, 2.440.16 g) and NY (53.6712.91%, 2.190.02 g), significantly different among all groups in survive rate (p0.05), remarkably diferent between YE and NY in final weight (p0.05). These results implied great potential practical application of the strain Pichia guilliermondii SY-19 in shrimp culture.