Animal requirement

The chloride and chromate are also important compounds. Zinc is an essential element in the growth of human beings and animals. Tests show that zinc-deficient animals require 50 percent more food to gain the same weight as an animal supplied with sufficient zinc. 

Intensive or extensive culture of aquatic animals requires chemicals that control disease, enhance the growth of cultured species, reduce handling trauma to organisms, improve water quality, disinfect water, and control aquatic vegetation, predaceous insects, or other nuisance organisms. The aquacultural chemical need for various species have been described for rainbow trout, Oncorhjnchus mjkiss (1) Adantic and Pacific salmon, Salmo and Oncorhjnchus sp. (2) channel catfish, Ictaluruspunctatus (3) striped bass, Morone saxatilis (4) milkfish, Chanos chanos (5) moUusks (6) penaeid (Penaeus sp.) shrimp (7) and a variety of other marine species (8). 

There are two distinct groups of aldolases. Type I aldolases, found in higher plants and animals, require no metal cofactor and catalyze aldol addition via Schiff base formation between the lysiae S-amino group of the enzyme and a carbonyl group of the substrate. Class II aldolases are found primarily ia microorganisms and utilize a divalent ziac to activate the electrophilic component of the reaction. The most studied aldolases are fmctose-1,6-diphosphate (FDP) enzymes from rabbit muscle, rabbit muscle adolase (RAMA), and a Zn " -containing aldolase from E. coli. In vivo these enzymes catalyze the reversible reaction of D-glyceraldehyde-3-phosphate [591-57-1] (G-3-P) and dihydroxyacetone phosphate [57-04-5] (DHAP). 

We tend to think of metals as lustrous solids copper, tin, gold, silver, iron. We are less likely to think of individual metal atoms in biological machines. Nevertheless, plants and animals require the presence of tiny amounts of transition metals. Humans require most of the elements in the first transition metal series and at least one element from the second transition metal series, molybdenum. 

The term alternative includes all procedures which can completely replace the need for animal experiments, reduce the number of animals required, or diminish the amount of distress or pain suffered by animals in meeting the essential needs of man and other animals. Its purpose is to promote the development and implementation of new methods to Replace, Reduce, Refine (the 3 Rs ) animal testing with modem alternative approaches. Russell and Burch [4] proposed the framework of the 3 Rs more than 40 year ago. The authors proposed that all research using animals should be evaluated to see if the 3 Rs could be applied. Since that landmark publication, significant progress has been made, especially in the arena of regulatory testing [5]. 

Tables relating numbers of animals required to obtain values of critical size, a and fj are given in Kraemer and Thiemann (1987) and Gad (1998) and software is also available for this purpose. As a rule of thumb, to reduce the critical difference by a factor of n for a given a and fi, the number of animals required will have to increased by a factor of n2.

That individual monkeys have distinctive niacin needs was shown by recent work of Tappan and co-workers.59 One animal, for example, required only 11 weeks to show niacin deficiency weight loss by this animal was halted only when 30 mg. of niacin was given. Another animal required 9 months to show a niacin deficiency and then grew adequately when only 6 mg. of niacin per week was furnished. This seems to show a several-fold range in niacin needs within a small group of fine animals. The tryptophane needs of the different monkeys, as judged by growth responses, were found to vary under comparable conditions from 1 to about 3.5 gm. per week. 

No animals required Prediction of intestinal absorption before synthesis of compound... 

A particularly important consequence of bioirrigation and bioturbation is the introduction of relatively 02-rich bottom water into the sediments. This enhancement in O2 supply is analogous to the aeration of soil by earthworms. Bioturbation can occur as deeply as 1 m below the sediment surface, but is most intense in the top 10 cm. The depth of O2 penetration is also strongly influenced by the flux of sedimenting POM. High accumulation rates of organic-rich particles can fuel bacterially mediated aerobic respiration supporting rates of O2 removal that exceed the benthic animals abilities to reaerate the sediments. In this case, anoxic conditions result. Since animals require O2, bioturbation does not occur in anoxic sediments. Thus, the effects of bioturbation are limited to the oxic portion of the sediments. 

Positive carcinogenic findings in animals require careful evaluation to determine their relevance to humans. Of key importance is the mechanisms/mode(s) of action of tumor induction. The WHO/IPCS has developed a conceptual framework to provide a strucmred and transparent approach for the assessment of the overall weight of evidence for a posmlated mode of induction for each mmor type observed (Sonich-Mullin et al. 2001). The framework promotes confidence in... 

Although chemical sensitization is a more complex process than immunosuppression, by far most of the efforts on developing in vitro assays are in this field. An important reason for this is that from the various fields of immunotoxicity, most of the animals are used for sensitization testing. In fact the number of animals required for sensitization is second only after developmental toxicity testing. 

The only real advantage of the combined study is a reduction in the number of animals required in comparison with separate fertility and embryo-fetal developmental toxicity studies. However, this is only true if male fertility is also assessed in the same investigation. If this is the case, the number of animals is reduced to approximately 100 males and 100 females compared with at least 80 males and 180 females in separate studies. If male fertility has to be assessed separately (see Subheading 1), there is no particular advantage since untreated females would also have to be procured for mating. 

All living organisms can synthesize amino acids. However, many higher animals are deficient in their ability to synthesize all of the amino acids they need for their proteins. Thus, these higher animals require certain amino... 

The financial cost of performing studies to define these toxicities increases according to their duration and complexity further, the rarer the occurrence of the effect anticipated, the greater will be the number of animals required for its detection. These several factors combine to ensure that very few chronic toxicity data are available for chemicals that fail to occupy key commercial or environmental positions. 

TRACE ELEMENT (Mlcronutrient). An element essential to plant and animal nutrition in trace concentration, i.e., minute fractions of 1% (1000 ppm or less). Plants requite iron, copper, boron, zinc, manganese, potassium, molybdenum, sodium, and chlorine. Animals require iron, copper, manganese, cobalt, selenium, and potassium. Such elements are also called micronutrients. Do not confuse with tracer. 

A deficiency of the vitamin can result in lymphopenia, convulsions, dermatitis, irritability, and nervous disorders in humans. A defidency in monkeys may cause arteriosclerosis, while in rats, acrodynia. Research indicates that all animals require vitamin Bg, Bacteria in intestines generate some of this vitamin, but relatively little is available to humans in this form. Endogenous sources are available to plants, fungi, and some bacteria. 

As a brief introductory summary, vitamin D substances perform the following fundamental physiological functions (1) promote normal growth (via bone growth) (2) enhance calcium and phosphorus absorption from the intestine (3) serve to prevent rickets (4) increase tubular phosphorus reabsorpiion (5) increase citrate blood levels (6) maintain and activate alkaline phosphatase m bone (7) maintain serum calcium and phosphorus levels. A deficiency of D substances may be manifested in the form of rickets, osteomalacia, and hypoparathyroidism. Vitamin D substances are required by vertebrates, who synthesize these substances in the skin when under ultraviolet radiation, Animals requiring exogenous sources include infant vertebrates and deficient adult vertebrates, Included there are vitamin D (calciferol ergocalciferol) and vitamin D< (activated 7-dehydrocholesterol cholecalciferol). 

Allogeneic mixed thymocyte medium (4) is a conditioned medium used to aid cells recover from the fusion process. It also encourages division of hybridoma cells after dilution cloning when colonies derived from single cells are required. Rat thymi are used for this purpose to minimise the number of animals required to produce adequate numbers of cells. The medium contains a number of helper cytokines produced by the thymocytes. It is important that the thymocytes used are derived from two different rat strains as this causes co-stimulation and enhanced cytokine secretion by the cells. Mixed thymocyte medium must always be diluted with RPMI 1640 medium containing 15% FBS and is usually used at a dilution of 10-15%. 

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