Animal digestive system

Bailey JA, Jones AM, Roy DR. 1973. Effects of silver from cloud seeding on microflora of animal digestive systems. Report to US Bureau of Reclamation, Division of Atmospheric Water Resources... 

Methane is formed in anaerobic environments, e.g., in fresh water or marine sediments, flooded soils, anaerobic sludges, but also in the animal digestive system, from complex organic compounds such as carbohydrates, proteins, and lipids. In the rumen, methane appears to be almost exclusively produced by reduction of CO2. In nongastrointestinal habitats methane appears to be built chiefly from acetate and secondarily from CO2. In both types of habitats the main hydrogen source is molecular H2. 

IF and CP are glycoproteins. IF promotes the absorption of vitamin B12 in human and animal digestive systems. It is capable of binding the tiny amounts of vitamin B12 (3-5 mg per day in humans), present in the digested meal, in a complex resistant to digestion and to absorption by intestinal microorganisms. Cbl from the complex is transported in an energy dependent process across the intestinal epithelium. Once inside the ileal cell. 

Wool, as a keratin, is a highly cross-linked, insoluble proteinaceous fiber, and few animals have developed the specialized digestive systems that aUow them to derive nutrition from the potential protein resource. In nature, these few keratin-digesting animals, principally the larvae of clothes moths and carpet beetles, perform a useful function in scavenging the keratinous parts of dead animals and animal debris (fur, skin, beak, claw, feathers) that ate inaccessible to other animals. It is only when these keratin-digesting animals attack processed wool goods that they are classified as pests. Very often they enter domestic or industrial huildings from natural habitats such as birds nests. 

Cobalt is one of twenty-seven known elements essential to humans (28) (see Mineral NUTRIENTS). It is an integral part of the cyanocobalamin [68-19-9] molecule, ie, vitamin B 2> only documented biochemically active cobalt component in humans (29,30) (see Vitamins, VITAMIN Vitamin B 2 is not synthesized by animals or higher plants, rather the primary source is bacterial flora in the digestive system of sheep and cattle (8). Except for humans, nonmminants do not appear to requite cobalt. Humans have between 2 and 5 mg of vitamin B22, and deficiency results in the development of pernicious anemia. The wasting disease in sheep and cattle is known as bush sickness in New Zealand, salt sickness in Florida, pine sickness in Scotland, and coast disease in AustraUa. These are essentially the same symptomatically, and are caused by cobalt deficiency. Symptoms include initial lack of appetite followed by scaliness of skin, lack of coordination, loss of flesh, pale mucous membranes, and retarded growth. The total laboratory synthesis of vitamin B 2 was completed in 65—70 steps over a period of eleven years (31). The complex stmcture was reported by Dorothy Crowfoot-Hodgkin in 1961 (32) for which she was awarded a Nobel prize in 1964. 

What determines the differenee in 5 C between eollagen and bone carbonate apatite (bioapatite) for animals with different diets or digestive systems ... 

Many of the animals harbor endosymbiotic bacteria that are sulflde oxidizers, such as the giant tube worms Riftta pachyptila), which reach lengths of 1 m. As shown in Figure 19.19, the tube worms are essentially a closed sac, having no mouth, digestive system, or other means of processing particulate food. 

Threatened or wounded sea cucumber Holothuraided) will contract its body exposing the small skeletal bones that make up the body wall, which can act as hooks to the mouths of predators. For most species, the connective tissue that makes up the greater part of the body wall is the primary deterrent to predators.The contracted body not only makes a more compact body to bite, but increases the stiffness of the body wall. The sea cucumber also has a very unusual defense mechanism. Many species use the Cuvierian tubules, which are located in the digestive system of the animal to confuse... 

There are many modifications of this method, they may be to make the process more representative of the ruminant digestive system, or the desired residue may be just the plant cell walls. It is not always possible to say that one procedure is better than another, therefore the chosen procedure may be that which has been used by workers involved in animal nutrition over a number of years in a certain geographical area. The decision may be to use the usual procedure favoured by the referees for research papers in a particular journal. 

It is particularly useful to be able to do this in the case of young animals whose digestive systems are not fully mature. Later in this chapter (section 3.4) the animal-feed enzymes are worked out further. 

Humans do not produce the enzymes, called cellulases, necessary to digest cellulose. Bacteria possessing cellulase inhabit the digestive tracts of animals such as sheep, goats, and cows giving these animals the ability to digest cellulose. Cellulase bacteria also exist in the digestive systems of... 

Van Helmont, the most prominent of the seventeenth-century iatro-chemists, made the acid-alkali reaction the chemical model for a theory of animal digestion. One of his pupils, Sylvius by name, carried this idea into a total system by claiming that all bodily functions were acid-alkali reactions, and that all body fluids were either acidic or alkaline. This theory... 

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