Nitrogen, body content

Nitrogen balance The difference between the intake of nitrogenous compounds (mainly protein) and the output of nitrogenous products from the body. Positive nitrogen balance occurs in growth, when there is a net increase in the body content of protein negative nitrogen balance means that there is a loss of protein from the body. 

The diet must provide those amino acids which the body cannot synthesize (essential amino acids, EAA) and nitrogen in the form of nonessential amino acids (NEA). Both EAA and NEA are required for biosynthesis of proteins and other nitrogen-containing compounds necessary for homeostasis or growth. Thus, the total nitrogen content of a specific food must be considered to be nutritionally significant. 

The total nitrogen content in the whole body is about 24 g per kg body wt. 

There are also changes in the rates of metabolism as red blood cells appear and aerobic processes intensify (Lasker and Theilacker, 1962 Laurence, 1975 Timeyko and Novikov, 1991) during the early phases of ontogenesis. Oxygen consumption increases, as do the number of mitochondria and their protein contents (Abramova and Vasilyeva, 1973 Ozemyuk, 1993). The adenyl nucleotide pool (ATP and ADP) decreases (Milman and Yurovitsky, 1973 Boulekbache, 1981), while the activity of cytochrome oxidase increases (Ozemyuk, 1993). The increased energy metabolism corresponds to a considerable extent with motor activity (Reznichenko, 1980). In the yolk sac, the activity of proteinase, which supplies nitrogenous materials to the embryo, increases, as does the rate of amino acid incorporation into the body proteins. 

Nitrogen supplies in water bodies are replenished due to the bacterial decomposition of organic sediments and dissolved organic matter. Let us consider component D as the content of dead organic matter in water. On such a basis, we can write Hf = DD [Pg.239]

Research findings reviewed by Ravindran and Blair (1993) suggest that the type of insect preferred by poultry is soft-bodied. Insects are high in CP, with contents ranging from 420 to 760 g/kg (Ravindran and Blair, 1993). Accurate determination of protein levels in insect meals, however, requires correction for the non-protein nitrogen contributed by the chitin. 

Homeostasis at the cellular and, especially, at the organismal level includes equilibrium between the formation of reactive oxygen species (ROS) and reactive nitrogen species (RNS) and reactions of antioxidants maintaining appropriate levels of ROS and minimizing their unspecific reactions with vital biomolecules. Understanding this aspect of homeostasis is the reason for interest in antioxidant levels in the body and the antioxidant content of food and beverages. 

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