关键词: 盐穗木, 乳酸菌, 分离, 鉴定

Abstract: 【Objective】In order to make rational use of forage resources to provide high quality silage for animal husbandry in southern Xinjiang, the nutritional value and fermentation quality of Halostachys caspica silage after flowering and fruiting stage were discussed in this study, and the Lactobacillus resources were provided for screening silage fermentation quality. 【Method】A small dose natural fermented silage was made in the laboratory of flower and fruit period in the Akesu area of Xinjiang province. After 150 d fermentation, the contents of dry matter, crude protein, soluble sugar, neutral detergent fiber and acid washing fiber were compared before and after silage, and the contents of pH, ammonia nitrogen, lactic acid, acetic acid, propionic acid and butyric acid in silage were measured. Combining with the physiological and biochemical analysis, the pure culture method from silage microbial analysis was adopted to investigate the species, morphological, and physiological-biochemical characteristics of lactic acid bacteria from Halostachys caspica silage in Xinjiang. The DNA Blast technique was used to compare the measured sequence with the GenBank database, thus the species of the known classified status of the highest homology of the tested sequence were selected and downloaded. Together with the sequence of the strains tested in this test, the strains were compared with the Clustal, and the phylogenetic tree was plotted with MEGA5.0 to determine the classification status of the strains and to separate the isolates. As a result, the strains were identified. 【Result】Compared with pre silage, dry matter and soluble sugar content in raw materials decreased after lactic acid bacteria fermentation. At the same time, in the process of silage fermentation, the water-soluble carbohydrates, which were difficult to degrade in the stem, were degraded by lactic acid bacteria to the fibers those were easily used by domestic animals, which led to the increase of the content of neutral detergent fiber and acid washing fiber. Silage pH was 4.254—4.286, and lactic acid content was 60.923—61.283 mg·mL^-1, which belonged to the range of good quality silage. 9 strains of lactic acid bacteria were isolated and were mainly Enterococcus faecium, Enterococcus lactis, Bacillus cereus, Lactobacillus pentosus, Lactobacillus plantarum, Lactobacillus buchneri. 9 strains of lactic acid bacteria were found in the range of pH 4—7, and grew well under the condition of 3% and 6.5% concentration of NaCl, at the same time, the bacteria also grew well between 10 °C and 45 °C. It could also use D- glucose, D- mannose, cellobiose, D- mannitol, D- fructose, sucrose and many other carbon sources. Among them, Lactobacillus pentosus and Lactobacillus buchneri had higher acid production rate and faster growth rate, which showed strong acid and salt tolerance, thrived in the 5—45 °C range, and could be applied to the preparation of silage additives. 【Conclusion】The nutrient content and fermentation quality of the Halostachys caspica were in good level after green storage. The 3 strains of Lactobacillus pentosus, Lactobacillus buchneri, and Lactobacillus plantarum could be selected as additives in the process of making silage.

Key words: halostachys caspica, lactic acid bacteria, isolation, identification