Ruminal micro-organisms

B. H. Howard, Hydrolysis of the soluble pentosans of wheat flour and Rhodymenia palmata by ruminal micro-organisms, Biochem. J., 67 (1957) 643—651. 

Significant differences in the extent of distribution of drugs, particularly lipid-soluble organic bases, are usual between ruminant and monogastric species. After parenteral administration, lipophilic bases diffuse passively from the systemic circulation into ruminal fluid (pH 5.5-6.5), where they become trapped by ionization. These drugs are slowly reabsorbed or, if they possess fimctional groups suitable for metabolism by hydrolysis or reduction, they may be partially inactivated by ruminal micro-organisms. 

Ruminant milk fats contain a high level of butanoic add (C4 0) and other short-chain fatty acids. The method of expressing the results in Table 3.6 (%, w/w) under-represents the proportion of short-chain adds-if expressed as mol %, butanoic acid represents c. 10% of all fatty acids (up to 15% in some samples), i.e. there could be a butyrate residue in c. 30% of all triglyceride molecules. The high concentration of butyric (butanoic) acid in ruminant milk fats arises from the direct incorporation of jS-hydroxybutyrate (which is produced by micro-organisms in the rumen from carbohydrate and transported via the blood to the mammary gland where it is reduced to butanoic acid). Non-ruminant milk fats contain no butanoic or other short-chain adds the low concentrations of butyrate in milk fats of some monkeys and the brown bear require confirmation. 

The biochemical pathways of milk fat synthesis are well established and have been reviewed (Dimick et al.y 1970 Storry, 1980 Smith, 1980 Patton and Jenson, 1976 Moore and Christie, 1979). Similarly lipid digestion in the ruminant has received intensive research (Christie, 1979 Dawson and Kemp, 1970 Carton, 1974 Harrison and Leat, 1975 Moore and Christie 1979). The complexity of milk fat fatty acids arises from a number of factors including (a) the synthesis of short-chain acids (C4-C10) within the mammary gland, (b) micro-organisms in the rumen which fully or partially hydrogenate Cis fatty acids in... 

Synthesis of vitamins in the body may occur in the tissues themselves or through the agency of parasitic micro-organisms. In the case of vitamin C, animals which do not require it in their diet, such as the ruminants and rodents, appear to synthesize it in their tissues. With the B group, however, such synthesis as occurs is brought about largely by micro-organisms. A... 

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