ARTICLE 80 FEED & ADDITIVE MAGAZINE April 2023 limitations. Thus, it can be stated that we have a reasonably clear picture of the ideal amino acid profile needs of current broiler strains. However, there are some indications that the ideal ratios might be affected under certain circumstances. One factor is, as described above, the age or body weight of the birds. Other factors, which might interfere with ideal amino acid ratios can be due to environmental conditions. Prominent examples are the Arginine: Lysine and Threonine: Lysine ratios. CURRENT SUGGESTIONS FOR AN IDEAL PROTEIN It can be stated that – although there are different methods to determine an ideal protein – available results are fairly similar. Apparent differences could be attributed to the method applied for ideal protein determination but also to interactions between amino acid requirements and other animal related and/or environmental factors. The most important factors are age, climate, management as well as genetic factors like sex or strain. Applying the ideal protein concept – regardless of small variations – has been shown to be effective. The ideal Crude Protein concept directly fits into the concept of precision nutrition for poultry. 1. By setting amino acid requirements using ratios to lysine, and by adhering to use of digestible amino acid levels, the IICP concept eliminates over- and under-fortification of diets with amino acids of importance, in addition to lowering nitrogen excretion. 2. Accurate requirement estimates for amino acids other than lysine can be determined for later growth periods using IICF', but it is appropriate to confirm estimates for older birds with empirical data. 3. Recent data suggest that the lysine requirement for maintenance may be substantially greater than previously thought, bringing into question the validity of increasing the ratio of amino acids to lysine during later growth periods. Ideal protein can be defined as one that provides the exact balance of amino acids needed for optimum performance and maximum growth (e.g., size, carcass weight, yield, and body composition). Formulating a feed based on an ideal protein is an effective way of using less protein in the diet to meet amino acid requirements. Maximizing the effective use of protein and minimizing the amount needed in feeds can substantially reduce production costs, increase farm profitability, and reduce harvest of wild fish used for fishmeal. Nitrogen pollution arising from fish production can also be reduced by applying the concept of ideal protein to the formulation of fish feed, just as it is already being applied successfully to feeds for poultry and swine. Fish do not have a specific protein requirement but rather a definite requirement for essential amino acids that comprise proteins. In other words, it is essential amino acids in dietary protein that a fish requires and not the protein per se. When protein is digested, the amino acids comprising it are released and absorbed into the body as either individual amino acids or shorter chains of amino acids, the di- and tri-peptides. There are about 20 known amino acids used as building blocks for the proteins in all living organisms. Ten amino acids are essential, and they must be incorporated into diets because fish either cannot synthesize them or can synthesize them at a rate that is inadequate for cellular demand. The other amino acids are classified as dispensable or dietary
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