Nutrition nutrient requirements

Fertilization of ponds to increase productivity is the next level of intensity with respect to fish culture, followed by provision of supplemental feeds. Supplemental feeds are those that provide some additional nutrition but caimot be depended upon to supply all the required nutrients. Provision of complete feeds, those that do provide all of the nutrients required by the fish, translates to another increase in intensity. Associated with one or more of the stages described might be the appHcation of techniques that lead to the maintenance of good water quaUty. Examples are continuous water exchange, mechanical aeration, and the use of various chemicals used to adjust such factors as pH, alkalinity, and hardness. 

Derived plant and animal products make better use or upgrade the nutritional quaHty of already existing materials or products. Synthetic and manufactured products arose from knowledge of the functional properties of food ingredients and of human and animal nutrition that involved more precise definition of nutrient requirements for growth, reproduction, lactation, and body maintenance in both humans and domestic Hvestock. Pood products have been developed to meet human needs under abnormal environments, eg, military rations for arctic, tropical, or desert environments, and special products for astronauts ia space flights. 

Nutritional Requirements. The nutrient requirements of mammalian cells are many, varied, and complex. In addition to typical metaboHc requirements such as sugars, amino acids (qv), vitamins (qv), and minerals, cells also need growth factors and other proteins. Some of the proteins are not consumed, but play a catalytic role in the cell growth process. Historically, fetal calf semm of 1—20 vol % of the medium has been used as a rich source of all these complex protein requirements. However, the composition of semm varies from lot to lot, introducing significant variabiUty in manufacture of products from the mammalian cells. 

Generation of data on the nutrient content of agricultural products and foods forms the basis for estimating nutrient intakes of populations via dietary surveys, nutritional labelling for consumer protection, nutrition education for consumer food choice, home and institution menu planning and food purchase, and for research in nutrient requirements and metabolism, toxicant chemical composition is used to assess effects of farm management practices, crop culture, and food processing on chemical content and implications for human health. 

The first step before delivering specialized nutrition support is to perform a nutritional assessment and determine nutrient requirements based on the patient s nutritional status and clinical conditions. Collect subjective and objective data to determine a patient s level of nutrition, to identify patients with malnutrition or at risk for malnutrition, and to identify risk factors that may put a patient at risk for nutrition-related problems.1 A nutrition assessment should include 1,19... 

Assessment of nutrient requirements must be made in the context of patient-specific factors (e.g., age, gender, size, disease state, clinical condition, nutrition status, physical activity). 

National Research Council (NRC). (1978). Nutrient Requirements of Nonhuman Primates. Panel on Nonhuman Primate Nutrition, National Research Council, Washington, D.C. 

Over the next six years Hopkins pursued, intermittently, the search for the other nutrients required to keep an animal alive and in good health. In 1912 came the published results of his research and while he confirmed them in publications of 1913 (12) and 1920 (13), it appears that other pioneers in nutritional studies, Osborne and Mendel in particular, were unable to repeat or reproduce his results. 

Besides local toxicity, discussed above, there are numerous other modes of potential adverse interactions involving excipients (19,20). Many of these pose little threat provided the amounts of excipients are constrained to certain levels. Excessive amounts, however, can cause problems, particularly for patients who are intolerant of even modest levels. Commonly used phosphate buffers may cause calcium loss with formation of insoluble calcium phosphates when such buffers are administered in over-ambitious amounts (21). Calcium phosphate precipitation has been noted particularly in nutritional parenteral admixtures for neonates because of the high nutrient requirements. Similarly, renal toxicity has been associated with depletion of zinc and other trace metals caused by large parenteral doses of ethylenediaminete-traacetic acid (EDTA) (22). Excessive absorption of glycine solutions, when used as irrigants during transurethral resections, can cause hyponatremia, hypertension, and confusion (23). The use of preservatives has been associated with cardiac effects in a few patients (24). Premature neonates were found to be at risk for receiving toxic amounts of benzoic acid or benzyl alcohol in bacteriostatic solutions used to flush intravenous catheters (25). 

Committees of experts organized by the Food and Nutrition Board of the National Academy of Sciences have compiled Dietary Reference Intakes (DRIs)—estimates of the amounts of nutrients required to prevent deficiencies and maintain optimal health. DRIs replace and expand on Recommended Dietary Allowances (RDAs), which have been published wih periodic revisions since 1941. Unlike the RDAs, the DRIs establish Lpper limits on the consumption of some nutrients, and incorporate the role of nutrients in lifelong health, going beyond deficiency diseases. Boh the DRIs and the RDAs refer to long-term average daily nutrient itakes, because it is not necessary to consume the full RDA every day. 

Acamovic, T. (2002) Review Nutritional Standards for Livestock Nutrient Requirements and Standards for Poultry. BSAS/DEFRA Report, pp. 1-16. Available at www.bsas.org.uk/ downloads/reports/FinalPoultry.pdf... 

Thus, feed grains meet part of the requirement for dietary nutrients. Other feed components are needed to balance the diet completely. Combining the grains and other ingredients into a final dietary mixture to meet the bird s nutritional needs requires information about the nutrient content of each feedstuff and its suitability as a feed ingredient. 

An important aspect of biopesticide production using insect cell lines is the maximization of cell growth. Culture media must satisfy the environmental and nutritional requirements of the cell line. Hence, many studies have been carried out to characterize the nutrient requirements and metabolic pathways of these cells (see Chapters 4 and 5). 

Chromium(III) is an essential nutrient required for normal energy metabolism. The National Research Council recommends a dietary intake of 50-200 pg/day (NRC 1989). The biologically active form is an unidentified organic complex of chromium(ni) often referred to as GTF. Chromium(in) picolinate is a common form of chromium(III) nutritional supplementation. 

Calcium Effects on Zinc Bioavailability for the Rat and the Human. It should be pointed out at this juncture that the nutrient requirement of calcium for the rat is much higher than for man. In fact, the molar ratio of calcium to zinc in excess of 660 1 is recommended for rat diets, while for man the ratio is between 80 1 and 160 1. To feed rats molar ratios of calcium and zinc similar to human requirements would necessitate either a very calcium deficient diet or one containing zinc at a level well in excess of the requirement. Neither choice is nutritionally suitable for demonstrating an effect of phytate on zinc availability. 

Optimal nutrition therapy requires defining the patient s nutrition goals, determining the nutrient requirements to achieve those goals, delivering the required nutrients, and assessing the nutrition regimen. 

Beaton G (1988) Nutrient requirements and population data. Proceedings of the Nutrition Society 47, 63-78. 

Donnelly JG (2001) Nutrient requirements in health and disease. In Pood and Nutritional Supplements Their Role in Health and Disease, JK Ransley, JK Donnelly, and NW Read (eds.), pp. 29 4. Berlin Springer. 

The NRC subcommittees prepare extensive critical reviews when updating nutrient requirements for different species. Their reports probably have the broadest consensus of any available sources of nutritional information. 

Pet foods are the main products, regulated by the Association of American Feed Control Officials, that reach urban and suburban households. AAFCO has chosen to establish its own nutrient requirements, rather than enforce the NRC nutrient requirements (8, 10). The following information was taken from the NRC recommendations (8, 10) and perhaps are still the most broadly examined and published consensuses available on dog and cat nutrition. 

The recommended dietary allowances (RDAs) for various nutrients arc discussed. RDAs are the quantities in the diet of all nutrients required to maintain human health. RDAs are established by the Food and Nutrition Board of the National Academy of Sciences, and are published by the National Academy Press-The RDA values are revised periodically on the basis of new scientific evidence. 

Elia M. Changing concepts of nutrient requirements in disease implications for artificial nutritional support. Lancet 1995 345(8960) 1279-84. 

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