放牧藏猪、舍饲藏猪与商品猪粪便真菌群落组成及其与饲粮纤维消化的相关性研究

Fungal community in the feces of grazing Tibetan pigs, captive Tibetan pigs, and commercial pigs and its interaction with dietary fiber digestion

摘要:

【目的】研究饲养在西藏高原的放牧藏猪、舍饲藏猪和商品猪（杜长大猪，DLY猪）粪便中真菌群落组成的差异性，获取与饲粮粗纤维消化相关的真菌群落。【方法】以饲养在西藏高原的5月龄放牧藏猪、舍饲藏猪和DLY猪为研究对象，采用消化试验测定放牧藏猪、舍饲藏猪和DLY猪对饲粮粗纤维的表观消化率。采集粪便样品利用单分子实时测序技术（SMRT），测定粪便真菌ITS基因全长序列，分析粪便真菌群落的结构和多样性，采用Pearson相关分析获取饲粮粗纤维表观消化率与真菌群落的相关性。【结果】在放牧藏猪、舍饲藏猪和DLY猪的粪便样品中共鉴定出了4个门、13个纲、23个目、39个科、55个属、58个种，放牧藏猪在各分类水平的分类单元数均显著高于舍饲藏猪与DLY猪（P<0.05）。子囊菌门（Ascomycota）和担子菌门（Basidiomycota）是优势菌门，在门水平下，放牧藏猪、舍饲藏猪和DLY猪间无显著差异（P ≥ 0.05），但在纲、目、科、属、种水平下，放牧藏猪多个真菌类群相对丰度显著高于舍饲藏猪与DLY猪（P<0.05）。放牧藏猪具有更高的菌群丰富度和独有分类操作单元（OTU）（P<0.05），通过主坐标分析发现放牧藏猪粪便真菌群落与舍饲藏猪和DLY猪之间差距明显。放牧藏猪对饲粮粗纤维的表观消化率显著高于舍饲藏猪与DLY猪（P<0.05），Pearson相关性分析表明，Phialemonium atrogriseum、Phialemonium inflatum、Podospora communis与饲粮粗纤维表观消化率呈显著正相关（P<0.05）。【结论】放牧藏猪具有较强的纤维消化能力，可以从其肠道内鉴定出更丰富的真菌类群并进行深入开发，有利于进一步研究藏猪耐粗饲等优良特性。

关键词:藏猪;商品猪;真菌群落;纤维消化;相关性分析

Abstract:

[Objective] This study aimed to investigate the differences in the structure of fungal community in the feces of grazing Tibetan pigs, captive Tibetan pigs, and commercial pigs[Duroc×Landrace×Yorkshire (DLY) pigs, aged 5 months] in the Tibet Plateau and to obtain the fungi associated with the digestion of dietary crude fiber.[Methods] The apparent digestibility of dietary crude fiber of grazing Tibetan pigs, captive Tibetan pigs, and DLY pigs was determined via digestion experiments. The full-length ITS region of fecal fungi was determined by single molecule real-time sequencing technology to analyze the structure and diversity of fungal community. The Pearson correlation analysis was performed between apparent digestibility of dietary crude fiber and fungal community.[Results] A total of 58 fungal species belonging to 4 phyla, 13 classes, 23 orders, 39 families, and 55 genera were identified. At each taxonomic level, the fungal taxa in the feces of grazing Tibetan pigs were more than those of either captive Tibetan pigs or DLY pigs (P<0.05). Ascomycota and Basidiomycota were the dominant phyla, and the fungal abundance at the phylum level had no significant difference among the

grazing Tibetan pigs, captive Tibetan pigs, and DLY pigs (P ≥ 0.05). At the levels of class, order,

family, genus, and species, the fungal abundance of grazing Tibetan pigs was significantly higher than that of either captive Tibetan pigs or DLY pigs (P<0.05). The grazing Tibetan pigs had the most diverse fungi with unique operational taxonomic units (P<0.05). The principal coordinate analysis revealed that grazing Tibetan pigs had different fecal fungi compared with captive Tibetan pigs and DLY pigs (P<0.05). The grazing Tibetan pigs had higher apparent digestibility of dietary crude fiber than captive Tibetan pigs and DLY pigs (P<0.05). Pearson correlation analysis showed that Phialemonium atrogriseum, Phialemonium inflatum, and Podospora communis had a positive correlation with the apparent digestibility of dietary crude fiber (P<0.05).[Conclusion] The grazing Tibetan pigs had stronger fiber digestibility than the captive Tibetan pigs and DLY pigs. In the future, we could identify more fungal groups from their gut. This information would be helpful in studying the excellent characteristics of Tibetan pigs, such as their tolerance to roughage.

Key words:Tibetan pigs;commercial pigs;fungal community;fiber digestion;correlation analysis