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Function of the cecal microflora in sage grouse nutrition




Barber, Thomas Amos, author
Nagy, Julius G., advisor
Nagy, Julius G., advisor
Mayeux, Jerry V., committee member
Ryder, Ronald, committee member
Mayeux, Jerry V., committee member
Ryder, Ronald, committee member

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An investigation of the cecal bacteria of sage grouse (Centrocercus urophasianus) was undertaken in an effort to obtain information on the function of the cecal microflora in the nutrition of this species. The project included experiments in three main areas: (1) isolation and characterization of cecal bacteria; (2) gas chromatographic analysis of cecal contents for VFA produced by bacterial fermentation; (3) chemical analysis of sage grouse feed and droppings. Cultures of bacteria from the cecal contents of sage grouse showed a large bacterial population to be p re sent. Predominant organisms in cecal contents were similar to normal avian enteric types. Organisms resembling Actinomyces bifidus and a streptococcus-like form were the most numerous types in the ceca. Solid media including the supernate of centrifuged cecal contents ( CFAM) and clarified rumen fluid (RFAM) proved to be superior to all other media tested for total counts of cecal bacteria; the use of these media was a necessity for the culture of the two predominant types of cecal organisms. Total culture counts of cecal bacteria in winter-killed birds showed a mean of 18 X 109 organisms per gram of wet cecal contents as compared to 30 X 109 for those collected in summer. Only insignificant numbers of cellulose-digesting organisms were cultured despite use of several enrichment media. Large amounts of volatile fatty acids (VFA) were produced by the cecal microbial fermentations. Higher levels of VFA were present in ceca in winter when the birds were on total sagebrush leaf diets and lower total numbers of cecal bacteria were present. Analysis of cecal contents showed that they contained only about 3% fiber (of a 10-16% dry weight). The high concentration of fiber in rectal droppings accounts for nearly the total amount ingested in sagebrush leaves. Essential oils of sagebrush are present in greater amounts in the Type A-3 sagebrush leaves selected by the grouse examined as summer food. Crops of winter-killed birds contain a mixture of all three subtypes of sagebrush; total oil levels in the digestive tract at this season were higher than in the summer when forbs comprised a portion of the diet.


Covers not scanned.
Print version deaccessioned 2023.

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Cecum -- Bacteriology
Sage grouse


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