养猪微生物发酵床真菌空间分布特性研究

微生物发酵床养猪是一种新型环保的养殖方式,发酵床中的微生物在分解消纳、去污除臭方面发挥着重要的作用。为了解大栏养猪微生物发酵床的真菌空间分布特性,通过空间格局采样、分离鉴定发酵床中的真菌并统计其在不同空间的种类与含量;利用空间分布频次、空间分布型指数、多样性指数和生态位特征等指标,评估发酵床真菌种群的空间分布特性,为养猪发酵床管理、猪粪资源化利用、猪病防控等提供理论依据。结果表明:从32个空间样本中共分离鉴定出真菌18个种,归于10个属,其中种最多的是曲霉属,包含7个种。发酵床不同空间样本的真菌种与数量存在明显差异,种数为1~4,数量为4×102~5.8×105菌落数·g-1。高频次分布的种有总状毛霉和橘青霉,分布频次大于10次;高数量分布的种有短柄帚霉、构巢曲霉和亮白曲霉,大于2.00×105菌落数·g-1。利用6个空间分布型指数和Taylor幂法则的分析结果表明:发酵床的真菌种群呈聚集分布型。32个空间样本种群多样性指数分析结果表明:除两个空间样本仅分离到1个种类外,其他30个空间样本呈现明显的空间分布多样性,为集聚分布和不均匀分布。空间样本2-A和3-D真菌种群具有较高的丰富度、均匀度和优势度,包含出现频次和数量较高种类,如总状毛霉、尖孢枝孢菌、橘青霉和构巢曲霉。空间样本1-A和1-B的真菌数量最大、种类也较多,但它们的丰富度、均匀度和优势度均较低,所包含的多为出现频次低于3次的种类,如亮白曲霉、短柄帚霉和白地霉。生态位特征的分析表明:发酵床中真菌的生态位宽度与生态位重叠没有明显的正相关性。总状毛霉和尖孢枝孢菌生态宽度值大,分别为7.60和5.18,为广适应种;而亮白曲霉、薛氏曲霉、土曲霉、短柄帚霉、水贼镰刀菌和毛壳属菌等6个种的生态位宽度值较小,仅介于1.00~1.10,为窄适应种。总状毛霉可与其他12个种存在重叠,但尖孢枝孢菌仅与其他2个种存在重叠。总之,养猪微生物发酵床的真菌种群呈现明显的群落多样性,空间分布特性为聚集分布和不均匀分布,总状毛霉和尖孢枝孢菌为优势种群,在发酵床中分布广、适应性强。

Spatial distribution characteristics of fungal population in microbial fermentation bed for pig rearing

Pig rearing on microbial fermentation bed system is a new environmentally-friendly breeding method. Micro-organisms are critical for deodorization and decomposition of pig excrement. The aim of this study was to investigate the spatial distribution characteristics of fungal population in the litters of microbial fermentation bed at Fuqing Agriculture Modern Facilities Base, Fujian Academy of Agricultural Sciences, China. A total of 32 litter samples were collected in space and culturable fungi in each sample isolated and identified based on morphological characteristics and molecular identification. The spatial distribution characteristics of the fungal population in the fermentation bed were evaluated by analyzing spatial distribution frequency, spatial distribution index, diversity index and niche characteristics. This was critical for laying the needed basis for the management of pig fermentation beds, utilization of pig manure and control of pig diseases. From the study, a total of 18 fungal species were isolated from 32 samples, belonging to 10 different genera. The dominant genus was Aspergillus, which had 7 species. There were significant differences in the species and amount of fungi at different spatial samples. There were 1-4 species and 4.0×10²-5.8×10⁵ colonies·g^-1 of each species. Mucor racemosus and Penicillium citrinum had high frequency and population with a frequency distribution above 10. The amounts of Scopulariopsis brevicaulis, A. nidulans and A. candidus exceeded 2.0×10⁵ colonies·g^-1, belonging to the high population amount. Based on the results of the 6 spatial distribution indices and the Taylor power law test, the distribution of fungal population in fermentation beds had an aggregated distribution pattern. The results of population diversity index analysis for the 32 spatial samples showed that fungal population had obvious diversity, with aggregated and uneven distribution pattern in fermentation beds. Fungal population had higher richness, evenness and dominance in both 2-A and 3-D samples, which included species with higher frequency and population. This included M. racemosus, Cladosporium oxysporum and A. nidulans. However, fungal population had lower richness, evenness and dominance in both 1-A and 1-B samples that harbored more fungi with a frequency less than three times. This included A. candidus, S. brevicaulis and Geotrichum candidum. The analysis of the fungal population niche characteristics showed no positive correlation between niche breadth and overlap of the fungi. M. racemosus and C. oxysporum were the widest adaptability species, with ecological width of 7.60 and 5.18, respectively. However, the six fungal species (A. candidus, A. chevalieri, A. terreus, S. brevicaulis, F. equiseti and Chaetomium sp.) were the narrow adaptability species, with ecological width range of 1.00-1.10. For niche overlap, M. racemosus overlapped with 12 species, but C. oxysporum overlapped with only two species. In conclusion, fungal population had obvious community diversity in microbial fermentation bed system for pig rearing. The spatial distribution characteristics of fungi had aggrega-tion and uneven distribution pattern. M. racemosus and C. oxysporum were the dominant species, with a wide distribution and strong adaptability.