Ruminant animal

Although /3-oxidation is universally important, there are some instances in which it cannot operate effectively. For example, branched-chain fatty acids with alkyl branches at odd-numbered carbons are not effective substrates for /3-oxidation. For such species, a-oxidation is a useful alternative. Consider phy-tol, a breakdown product of chlorophyll that occurs in the fat of ruminant animals such as sheep and cows and also in dairy products. Ruminants oxidize phytol to phytanic acid, and digestion of phytanic acid in dairy products is thus an important dietary consideration for humans. The methyl group at C-3 will block /3-oxidation, but, as shown in Figure 24.26, phytanic acid a-hydroxylase places an —OFI group at the a-carbon, and phytanic acid a-oxidase decar-boxylates it to yield pristanie add. The CoA ester of this metabolite can undergo /3-oxidation in the normal manner. The terminal product, isobutyryl-CoA, can be sent into the TCA cycle by conversion to succinyl-CoA. 

By far, the most suitable method to quantify individual ruminant animal CH4 measurement is by using respiration chamber, or calorimetry. The respiration chamber models include whole animal chambers, head boxes, or ventilated hoods and face masks. These methods have been effectively used to collect information pertaining to CH4 emissions in livestock. The predominant use of calorimeters has been in energy balance experiments where CH4 has been estimated as a part of the procedures followed. Although there are various designs available, open-circuit calorimeter has been the one widely used. There are various designs of calorimeters, but the most common one is the open-circuit calorimeter, in which outside air is circulated around the animal s head, mouth, and nose and expired air is collected for further analysis. 

Shibata, M. Terada, F. Factors affecting methane production and mitigation in ruminants. Anim. Sci. J. 2010, 81, 2-10. 

The requirements of dairy cattle for B-vitamins, determined almost half a century ago, concluded that a ruminant animal does not require an exogenous supply of B-vitamins because its rumen microflora should synthesise enough of these compounds to avoid deficiency. Since then, dairy cows have greatly increased their average milk and milk component yields. More recent studies have shown that B-vitamin supply in dairy cows is increased by supplementation, although losses in the rumen are extensive (Santschi et al., 2005). Whilst there are few reports of B-vitamin supplementation affecting milk quality, supplemental biotin has been shown to directly improve milk yield (Majee et al., 2003). 

Odd numbered carbon branched and straight chain fatty acids (Q5, C17 and Qg), positional isomers of octadecenoic acid Fat from ruminant animals [5]... 

Byers, F. M. and Schelling, G. T. (1988) Lipids in ruminant nutrition. In The Ruminant Animal Digestive Physiology and Nutrition (Ed. Church, D. C.). Prentice Hall, Inglewood Cliffs, pp. 298 310. 

Christie, W. W. (1981) The effects of diet and other factors on lipid composition of mminant tissues and milk. In Progress in Lipid Research. Supplement 1. Lipid Metabolism in Ruminant Animals (Ed. Christie, W. W.), Pergamon Press, Oxford, pp. 193 226. 

Vernon, R.G. (1981). Eipid metabolism in the rumen. In Lipid Metabolism in the Adipose Tissue of Ruminant Animals, ed. Christie, W.W., Pergamon, Oxford, pp. 279-362. 

Soils have also been examined directly, not for evidence of possible contamination, but as a study of manuring practice in medieval to early modern Orkney, Scotland. The sterols campesterol, sitosterol, and 5/1-stigmastanol were used as biomarkers for ruminant animal manure and coprostanol for omnivorous animal manure, with hyodeoxycholic acid used to further define the manure as coming from pigs (Bull et al. 1999, Simpson et al. 1999). It is rare to be able to extract sterols from such samples because their natural abundance is generally low. If they can be found, however, then they are useful as unambiguous biomarkers for either plants or animals. 

Major structural or physiological differences in the alimentary tract (e.g., species differences or surgical effects) can give rise to modifications of toxicity. For example, ruminant animals may metabolize toxicants in the GI tract in a way that is unlikely to occur in nonruminants. 

A number of measures have been taken to contain BSE. Thousands of cattle have been culled and there are controls prohibiting the feeding of mammalian proteins to ruminant animals (cows, sheep, and goats). There are also surveillance programs set up to monitor CJD in humans. 

Methane is a greenhouse gas. It comes largely from methanogenic bacteria, ruminant animals, and the activities of man. 

This pathway is also important for ruminant animals, which are dependent on symbiotic microorganisms to break down their food. The microorganisms produce large amounts of propionic acid as a degradation product, which the host can channel into the metabolism in the way described. 

McDowell LR, Willikams SN, Hidiroglou N, Njeru CA, Hill GM, Ochoa L, Wilkinson NS, Vitamin E supplementation for the ruminant. Animal Feed Science Technology 60 273—296, 1996. 

Butyric fatty acid is specific for milk fat of ruminant animals and is responsible for the rancid flavor when it is cleaved from glycerol by lipase action. 

Moir, K.W. (1982) Theory and practice of measuring the cell-wall content of food for ruminant and non-ruminant animals. Laboratory Practice 31, 732-733. Also (1972) Journal of the Agricultural Society, Cambridge 78, 351-353. 

It is anticipated that another author will publish a volume concentrating on chemical analysis dealing with ruminant animal nutrition. To avoid duplication, this volume will not cover that area in depth. 

CLA, the acronym for a series of conjugated dienoic isomers of linoleic acid, occurs naturally in many foods, particularly dairy products and other foods derived from ruminant animals (6). Synthetically prepared CLA inhibits chemically-induced mouse epidermal and forestomach neoplasia (7,8) and rat mammary neoplasia (9). Hence, the effect of CLA on carcinogenesis is opposite that of linoleic acid. 

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