| The maintenance of the diversity of the intestinal microbial community is of great significance to the life activities of animals.Food is one of the important factors affecting the composition of the intestinal microbial community,and the seasonal changes of food also affecting the composition of the microbial community.As a large migratory waterbird,the hooded crane is listed as a vulnerable(VU)species in the IUCN Red Species List.Wetlands in the middle and lower Yangtze River floodplain are important habitats for the wintering cranes.In recent years,habitat degradation has resulted in the decrease of food resources,leading to adaptive changes in their feeding habits.Therefore,the effect of dietary changes on the composition of their intestinal microbiota deserves our attention.In this research,a total of54 fecal samples from three wintering periods of hooded cranes in Shengjin Lake were collected.The food composition of the cranes was understood through microscopic analysis of feces.High-throughput sequencing technology was used to sequence the V4-V5 region of intestinal bacteria 16 S r RNA in the faecal samples of the hooded crane.Bioinformatics and statistical methods were used for subsequent analysis of the obtained data,and the relationship between food composition and intestinal bacterial community diversity was studied.The main results were as follows:1.A total of 22 species,22 genera and 13 families were identified from the feces of overwintering cranes in Shengjinhu Lake,and the main genera were Polygonum,Carex and Oryza.The main families are Polygonaceae,Cyperaceae and Poaceae.In terms of relative density(RD),the main foods were Polygonum criopolitanum(33.33 ± 15.09%)and Carex thunbergii(21.16 ± 13.75%)and Oryza sativa(19.27 ± 21.61%),accounting for 73.76% of the total food.In the early period of wintering,P.criopolitanum(47.13 ± 9.01%)and C.thunbergii(29.36 ± 9.74%)were the main food for the crane.In the middle period,O.sativa(46.49 ± 7.00%)and P.criopolitanum(20.66 ± 5.54%)were the main food for the crane.In the later period,P.criopolitanum(32.76 ± 15.09%)and C.thunbergii(28.48 ± 11.94%)were the main food.2.The intestinal bacterial community composition of hooded cranes was significantly different in the three wintering periods.The number of specific intestinal bacterial groups in the late wintering period was significantly higher than that in the early and middle wintering period.The most abundant indicator species of intestinal bacteria in the middle and late wintering period was Lactobacillus acidipiscis.There were four dominant phyla in the intestinal bacteria of wintering cranes(relative abundance > 1.00%),Firmicutes(68.84%),Proteobacteria(19.11%),Actinobacteria(8.38%)and Bacteroidetes(1.59%).The relative abundance of Actinobacteria in the early period was significantly lower than that in the middle and late periods,while there was no significant difference in the other three phyla during the three periods.The number of specific bacteria in late wintering period was significantly higher than that in early and middle periods.The change of relative abundance of ASV＿0360 L.acidipiscis(21.65%)and ASV＿0001 Clostridium metallolevans(11.23%)was the main reason for the difference in intestinal bacterial community composition between early and middle periods.ASV＿0002 L.acidipiscis(12.76%)and ASV＿0001 C.metallolevans(11.92%)in the early and late periods,and ASV＿0360 L.acidipiscis(22.93%)in the middle and late periods.ASV＿0001 C.metallolevans and ASV＿0003 Bacillales were the most abundant indicator bacteria with relative abundance of 8.68% and 7.34%,respectively.In the middle period,the most abundant indicator species of intestinal bacteria was ASV＿0360 L.acidipiscis,with a relative abundance of 16.82%.ASV＿0002 L.acidipiscis is the most abundant indicator species with a relative abundance of 7.43%.The relative abundance of L.acidipiscis increased significantly in the middle and late wintering period when food resources were relatively scarce,indicating that intestinal bacteria of cranes can actively adapt to the change of food composition and alleviate the negative effects caused by the decrease of food resources,which is crucial for the survival of cranes.3.The main foods of the wintering cranes were significantly related to the composition of intestinal bacteria and the composition of potential pathogenic bacteria,especially the main foods such as P.criopolitanum,O.sativa and C.thunbergii.The results of Mantel test showed that the main foods of the cranes were significantly correlated with the composition of intestinal bacteria,as well as the composition of potential pathogenic bacteria.The α-diversity of food increased from the middle period,and the α-diversity of intestinal bacteria increased from the late period.The food composition and intestinal bacterial community composition of the hooded cranes in different periods had obvious aggregation,and the difference was the least in the early and late wintering period.In this study,the association between the food composition and the intestinal bacterial composition of the wintering hooded cranes in Shengjinhu Lake was analyzed for the first time,and the influence of the food composition on the intestinal bacterial diversity of the cranes was studied.The results provided basic data for the physiological ecology and population protection of the hooded cranes,and was of important scientific significance for the protection of wild birds. |
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