Comparative Study On Intestinal Microflora Community Of Red-Crowned Crane Under Two Management Modes In Zhalong Nature Reserve

The red-crowned crane(Grus japonensis)is an important indicator species of the wetland environment.Currently,the number of wild populations in the west is gradually decreasing.There are abundant and diverse microorganisms living in the intestinal tract of animals,which play a vital role in the physiological health of the host.Therefore,through the comparative study of the intestinal microflora communities of red-crowned cranes under two management modes(captive and semi-free-range)of exsitu protection in Zhalong Nature Reserve,this study explores the impact of different management modes on the intestinal microflora of red-crowned cranes,to provide some reference for the protection of redcrowned cranes.1.Based on 16 S rRNA high-throughput sequencing technology,the study compared the intestinal microflora community composition and diversity of red-crowned cranes in semi-free-range and captive in Zhalong National Nature Reserve,Heilongjiang Province.The results showed that Proteobacteria(74.39%)and Firmicutes(25.29%)constituted the dominant intestinal flora of red-crowned cranes in Zhalong Nature Reserve.The dominant genera of red-crowned cranes include: Psychrobacter(30.44%),Pseudomonadaceae＿Pseudomonas(17.46%),Lactobacillus(5.76%),Sporosarcina(5.50%),Brochothrix(4.33%),Acinetobacter(4.32%),Lactococcus(1.55%),Carnobacterium(1.52%),Enterobacteriaceae＿Pseudomonas(1.26%),Pantoea(1.06%).There was a significant difference in intestinal microflora community composition between semi-free-range and captive red-crowned cranes(P=0.001),but there was no significant difference in the Alpha diversity of the intestinal microflora community(P>0.05).PICRUSt2 analysis showed that the function prediction of intestinal microflorarelated genes in Zhalong Nature Reserve was mainly metabolic,including amino acid metabolism,carbohydrate metabolism,cofactor and vitamin metabolism,etc.2.The study investigated the effects of gender and age on the intestinal microflora community of redcrowned cranes.There was no significant difference in intestinal microflora community composition of captive red-crowned cranes at the age of 3 and 4 years(P=0.186)and a significant difference in other age groups(P≤0.002).Certain specific microorganisms can be increased significantly due to the different nutritional and physiological requirements of red-crowned cranes at different ages.Pseudomonadaceae＿Pseudomonas of Proteobacteria increased in the intestinal microflora of 4-year-old red-crowned cranes significantly,and the Brochothrix of Firmicutes increased in the intestinal microflora of 2-year-old red-crowned cranes significantly.The Carnobacterium of Firmicutes in 1-year-old redcrowned cranes’ intestinal microflora increased significantly(P<0.05).The Chao1 index of the intestinal microflora community of 2-year-old red-crowned cranes was higher than that of 1-year-old and 4-year-old cranes(P<0.05).PCoA sequencing analysis showed that feeding patterns had a more effect on intestinal microflora than age.There were no significant differences in intestinal microflora community composition and Alpha diversity between male and female semi-free-range red-crowned cranes(P>0.05).The main conclusions of this study are as follows:(1)feeding pattern has a significant effect on the intestinal microbial community composition of the red-crowned crane(P=0.001).(2)Age factors significantly affected the intestinal microflora community structure of red-crowned cranes(P≤0.002),but the intestinal microflora remained relatively stable after adulthood.The richness of intestinal microflora increased first and then decreased with age until it was stable,and 2-year-old was a pivotal transition period.(3)The effect of the feeding pattern was greater than that of age.(4)Gender had no significant effect on the intestinal microflora community structure of red-crowned cranes(P>0.05).