Rumen, microorganisms

C. S. Stewart, T. Acamovic, FI. Gurung and A. S. Abdullah, in Manipulation of Rumen Microorganisms , Faculty of Agriculture, Alexandria University, Alexandria, Egypt, 1992, p. 150. T. Acamovic, in Developments and Ethical Considerations in Toxicology, ed. M.I. Weitzner, The Royal Society of Chemistry, 1993, p. 129. 

Swanson, S.P. et ah. Metabolism of three trichothecene mycotoxins, T-2 toxin, diacetoxyscirpenol and deox5mivalenol, by bovine rumen microorganisms, J. Chromatogr., 414, 335, 1987. 

In an in vitro fermentation study, rumen microorganisms metabolized both isomers of [ C]DDT o,p- and p,p-) to the corresponding DDD isomers at a rate of 12%/h. With p,//-DDT, 11% of the C detected was an unidentified polar product associated with microbial and substrate residues (Fries et al., 1969). In another in vitro study, extracts of Hydrogenomonas sp. cultures degraded DDT to DDD, l-chloro-2,2-bis(/5-chlorophenyl)ethane (DDMS), DBF, and several other products under anaerobic conditions. Under aerobic conditions containing whole cells, one of the rings is cleaved and p-chlorophenylacetic acid is formed (Pfaender and Alexander, 1972). 

H Brueckner, P Jaek, M Langer, H Godel. Liquid chromatographic determination of D-amino acids in cheese and cow milk. Implication of starter cultures, amino acid racemases, and rumen microorganisms on formation, and nutritional considerations. Amino Acids 2 271-284, 1992. 

Fries GF, Dawson TE, Paustenbach DJ, Mathur DB, Luksemburg WJ (1997) Biosynthesis of Hepta- and Octa-chlorodioxins in Cattle and Evidence for Lack of Involvement by Rumen Microorganisms. Organohalogen Compds 33 296... 

Fay JP, Cheng KJ, Hanna MR, Howarth RE, Costerton JW. 1980. In vitro digestion of bloat-safe and bloat-causing legumes by rumen microorganisms Gas and foam production. J Dairy Sci 63 1273-1281. 

The only non-mammalian /8-glucuronidase that has been subjected to systematic purification is the enzyme from sheep-rumen microorganisms. After repeated ammonium sulfate fractionation, Marsh101 obtained a colorless preparation with a specific activity of 1,900 (400-fold purification and 2% recovery). The final product gave a linear, specific-property, solubility test from which a figure of 2,200 was derived for the ultimate specific activity of the enzyme, but it was considered that the enzyme may have formed a solid solution with inactive protein. 

Simplified procedure for measuring cellulose digestion by rumen microorganisms. Contribs. Boyce Thompson Inst., 17, 337 (1954). With R. Henderson and F. E. Hervat. 

Cottonseed oil has long sold at a slight premium over soybean oil because of greater stability to oxidation, and desirable flavor in fried snack foods such as potato chips. However, gossypol content, and lower protein quality put the meal at a price disadvantage. Feeding whole cottonseed to dairy cattle, whose rumen microorganisms can detoxify... 

It is obvious from these results that dosing by way of the rumen and thus exposing the DDT to metabolism by the rumen microorganisms causes a much greater metabolism of the pesticide than routes of... 

For mminant fat to become directly responsive to dietary unsaturated fats, it is necessary to protect the lipids against saturation by rumen microorganisms. The alteration of the lipid content of mutton by the feeding of such protected oil supplements has been described (14). Also, it has been shown that a diet of extruded soybeans increased the linoleic acid and linolenic acid contents of steer adipose tissue (15). 

Reports suggest that feeding lipid sources rich in linoleic and linolenic acids either as seeds or free oil increases the CLA content of milk when oil is accessible to the rumen microorganisms for biohydrogenation (Dhiman et al., 2000). The scientists found that supplementing the dietary dry matter with 2% or 4% soybean resulted in a 237% or 314% increase in CLA content of milk compared with the control. 

The ruminant animal and rumen microorganisms exist in a reciprocally beneficial relationship, in which cellulose and other plant carbohydrates are fermented by the rumen microbes to form chiefly C02 and volatile fatty acids (VFA). The microorganisms are adapted to live between pH 5.5 and 7.0, in the absence of oxygen,... 

Fat. Fats tend to depress the cellulolytic activity of rumen microorganisms. For example 3% of com oil was sufficient to depress the digestibility of crude fiber in rations high in com cobs and cottonseed hulls, and 10% com oil produced a pronounced depression (42). Addition of alfalfa ash offset this effect when com oil did not exceed 5%... 

The data from the irradiation and alkali treatment experiments amply support the concept that low quality forages contain substantial quantities of PDE which can be made available to rumen microorganisms. 

There is a large volume of work reported on several aspects of the utilization of wood by the ruminant and the relevant literature is reviewed in the following order for the sake of clarity the use of wood and wood by-products as feeding materials for ruminants, factors influencing the availability of cellulose from these products, the physical and/or chemical procedures used by several workers to increase the availability of cellulose to rumen microorganisms, in vitro fermentation procedures designed to screen the efficiency of such treatments, and studies with cellulolytic enzymes from rumen microorganisms. 

Experiment 2. The second feeding trial was designed to study the extent to which non-processed, raw wood added to the ration at various levels would be utilized by the rumen microorganisms. Dry, ground alder wood was added to a basal diet (Table III) and was fed to groups of beef calves for a period of 182 days as outlined below. 

In view of the encouraging results obtained by feeding alder sawdust to beef cattle, as was reported earlier, it seemed worthwhile to develop methods of treatment mat would make the cellulose in low quality roughages more available to rumen microorganisms. In order to assess the merits of various physical and chemical treatments of wood and wood by-products, in vitro rumen fermentation tests were conducted and the extent of availability of nutrients to the microorganisms studied. 

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