| The fecal score can effectively reflect the digestive and health status of the animal.Currently,Bristol stool score has been widely used to evaluate the severity of diarrhea in animals,with most related studies focused on disease evaluation and digestive physiological status in young animals.However,there is limited research on fecal changes and the relationship between fecal score,phenotype,and microbiota in mature ruminants.Therefore,in this study,514 male and female Hu sheep were used as the research subjects.Fecal score standards during the fattening period were established through fecal morphology observation and fecal water content measurement.The relationship between fecal score and growth traits,carcass traits,body composition traits,blood physiological and biochemical indicators,and digestive microbiota were analyzed.The following research results were obtained:(1)Based on fecal morphology and water content,Hu sheep fecal score standards during the fattening period were established.Level one is characterized by scattered pellet-like feces with a water content of approximately 67%;level two is characterized by intact pellet-like feces that are stuck together,with a water content of approximately 69%;level three is characterized by elongated feces with grooves on the surface and a water content of approximately 75%;level four is characterized by elongated feces with a smooth surface and a water content of approximately 81%;level five is characterized by indistinctly-shaped feces that are soft and watery,with a water content of approximately 88%.(2)Based on the average fecal score at 140 d,160d,and 180 d,all tested sheep were divided into four groups: F1 group(1 ≤ fecal score < 2),F2 group(2 ≤ fecal score < 3),F3 group(3 ≤ fecal score < 4),and F4 group(4 ≤ fecal score < 5).At the same time,it was found that the F3 group had significantly higher growth traits(body weight,body height,body length in middle-to-late stages,average daily weight gain and average daily feed intake from 80-180d),body composition traits(absolute weight of hoof,fur,liver,lung,kidney,rumen,reticulum,omasum,duodenum,caecum,and colon),and carcass traits(carcass chest girth,carcass hip girth,and leg bone circumference)than the F1 and F2 groups(P < 0.05).There were significant differences in the levels of aspartate aminotransferase(AST),serum glucose(GLU),total bilirubin(TBIL),and red blood cell count(RBC)between the groups(P < 0.05).(3)There were significant differences in the alpha diversity index(Simpson and Chao1)of rumen microbiota among different fecal score groups in Hu sheep(P <0.05).The dominant phyla in the rumen of Hu sheep were Bacteroidota,Firmicutes,and Spirochaetota.The dominant genera included Prevotella,Treponema,and Saccharofermentans.Four core different phyla and five core different genera were identified in the rumen of Hu sheep.LEf Se analysis identified three different microbes: s＿Eubacterium＿sp＿AB3007,g＿Pseudoxanthomonas,and s＿uncultured＿organism＿g＿Alloprevotella.The results of correlation analysis showed that the relative abundance of g＿norank＿f＿Bacteroidales＿UCG-001 was closely related to the growth performance,while the relative abundance of Ralstonia was closely related to the fecal score.(4)There were significant differences in the PD＿whole＿tree index of colon microbiota among different fecal score groups in Hu sheep(P < 0.05).The dominant phyla in the colon of Hu sheep were Firmicutes,Bacteroidota,and Proteobacteria.The dominant genera included Rikenellaceae＿RC9＿gut＿group,UCG-005,and Bacteroides.LEf Se analysis identified 11 different microbes.The results of correlation analysis showed that the relative abundance of Actinobacteria and Peptostreptococcaceae was closely related to the fecal score.The Caproiciproducens group was identified as the key bacterial group influencing growth performance.(5)There were significant differences in the PD＿whole＿tree index of rectal microbiota among different fecal score groups in Hu sheep(P < 0.05).The dominant phyla in the rectum of Hu sheep were Euryarchaeota,Halobacterota,and Thermoplasmatota.The dominant genera included g＿Rikenellaceae＿RC9＿gut＿group,g＿UCG-005,and g＿Treponema.LEf Se analysis identified 21 different microbes.The results of correlation analysis showed that Acidaminococcales group,Gammaproteobacteria,and Proteobacteria were the key bacterial genera influencing fecal score.The Muribaculaceae,norank,and Oscillospiraceae-uncultured groups were identified as the critical bacterial groups influencing growth performance and immunity.In summary,the fecal scoring criteria developed in this study can be used for the preliminary assessment of production performance and health status of Hu sheep.Hu sheep with fecal score of 3-4 had better production performance,and their gut microbiota composition was closely related to the fecal score. |
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