Low crude protein diets for broiler chickens aged 8 to 21 days should have a 50% essential-to-total nitrogen ratio

Effect of crude protein reduction in blood, performance, immunological, and intestinal histological parameters of broiler chickens

“…Until certain reduction in dietary CP, animals can reduce the nitrogen excretion, increasing the available nitrogen for amino acids synthesis and maintaining the same performance (Deschepper & deGroote, 1995). However, with an excessive reduction in dietary CP, even with the supplementation of EAA, animals can present a reduction in performance, as observed in this and other studies (Awad et al, 2015;Corzo et al, 2005;Jiang et al, 2005;Maia et al, 2021).…”

“…NEAA can be synthesized from EAA and from the nitrogen pool, however, defining that the optimal EAA to NEAA ratio is challenging, varying according to different physiological demands (Herger, 2003; Hou et al, 2015). If the proportion of EAA to NEAA is higher, as expected with the supplementation of EAA in a low CP diet, this may impair performance, probably due to the lack of nonspecific nitrogen needed to synthesize NEAA, increasing EAA utilization for this synthesis (Maia et al, 2021).…”

Research Note: The influence of different isoleucine: lysine ratios on the growth performance of broiler chickens fed low-protein diets

“…The development of unbound amino acids ( AA ) (crystalline or synthetic) has allowed a considerable reduction in the protein content of diets and had entailed many benefits related to feeding cost, gut health, nitrogen excretion and environmental pollution ( Maia et al, 2021 ). However, it is crucial to understand the dietary amount of crude protein ( CP ) that could be decreased to avoid AA imbalance and antagonism, especially for branched-chain amino acids ( BCAA ).…”

The effects of arginine supplementation through different ratios of arginine:lysine on performance, skin quality and creatine levels of broiler chickens fed diets reduced in protein content

“…For many years, diets have been formulated to meet broiler requirements according to crude protein ( CP ) content, which may result in some amino acid ( AA ) levels above the recommended levels. Consequently, there is considerable interest in the successful development of reduced CP diets associated with feeding costs and decreased nitrogen excretion and environmental pollution ( Maia et al, 2021 ). The inclusion of unbound AAs (crystalline or synthetic) enables a substantial reduction in the protein levels, in which low-protein diets plus unbound AAs are formulated to meet the requirements for all AAs and are expressed as a percentage of lysine, the reference AA ( Emment and Baker, 1997 ).…”