The National Academies of Science’s National Research Council (NRC, now NASEM) Nutrient Requirements reports have periodically been published since 1940s, and are updated occasionally. The 2024 poultry report builds on the 1994 report and those that preceded it. The length, number of peer-reviewed publications, scientific rigor, and transparency of decision processes for specific recommendations have increased with time. The Committee’s recommendations do not include a margin of safety for its nutrient recommendations, they are minimums based on the relevant research. However the report provides many new chapters for adjusting formulated levels to avoid nutrient deficiencies or excesses based on ingredients fed and their digestibility or bio availability. In some cases recommendations could not be given with a high degree of confidence and tentative recommendations based on speculative guidance are provided and are clearly identified in the text and by the fonts used in the tables.
Computer models for nutrient requirements were used in the broiler and layer chapters. These models are in early stages of development and the committee recommends new research be undertaken to inform the development of models that can predict optimal dietary nutrient levels across a wide range of genetics, management conditions, and market demands.
