Reducing the CP content in broiler feeds: impact on animal performance, meat quality and nitrogen utilization

Abstract

Reducing the dietary CP content is an efficient way to limit nitrogen excretion in broilers but, as reported in the literature, it often reduces performance, probably because of an inadequate provision in amino acids (AA). The aim of this study was to investigate the effect of decreasing the CP content in the diet on animal performance, meat quality and nitrogen utilization in growing-finishing broilers using an optimized dietary AA profile based on the ideal protein concept. Two experiments (1 and 2) were performed using 1-day-old PM3 Ross male broilers (1520 and 912 for experiments 1 and 2, respectively) using the minimum AA:Lys ratios proposed by Mack et al. with modifications for Thr and Arg. The digestible Thr (dThr): dLys ratio was increased from 63% to 68% and the dArg:dLys ratio was decreased from 112% to 108%. In experiment 1, the reduction of dietary CP from 19% to 15% (five treatments) did not alter feed intake or BW, but the feed conversion ratio was increased for the 16% and 15% CP diets (+2.4% and +3.6%, respectively), while in experiment 2 (three treatments: 19%, 17.5% and 16% CP) there was no effect of dietary CP on performance. In both experiments, dietary CP content did not affect breast meat yield. However, abdominal fat content (expressed as a percentage of BW) was increased by the decrease in CP content (up to +0.5 and +0.2 percentage point, in experiments 1 and 2, respectively). In experiment 2, meat quality traits responded to dietary CP content with a higher ultimate pH and lower lightness and drip loss values for the low CP diets. Nitrogen retention efficiency increased when reducing CP content in both experiments (+3.5 points/CP percentage point). The main consequence of this higher efficiency was a decrease in nitrogen excretion (−2.5 g N/kg BW gain) and volatilization (expressed as a percentage of excretion: −5 points/CP percentage point). In conclusion, this study demonstrates that with an adapted AA profile, it is possible to reduce dietary CP content to at least 17% in growing-finishing male broilers, without altering animal performance and meat quality. Such a feeding strategy could therefore help improving the sustainability of broiler production as it is an efficient way to reduce environmental burden associated with nitrogen excretion.

Synthetic and Crystalline Amino Acids: Alternatives to Soybean Meal in Chicken-Meat Production

“…This example unequivocally demonstrates the potential synthetic and crystalline amino acids hold as alternatives to soybean meal in chicken-meat production and is supported by another recent study [37]. Nevertheless, CP reductions of this magnitude may compromise the efficiency of feed conversion with associated increases in fat deposition [38][39][40][41]. The genesis of compromised feed conversion ratios (FCRs) probably stems, at least partially, from an insufficiently accurate identification of essential and non-essential amino acid requirements, or ideal protein ratios, in the context of reduced-CP diets.…”

Differential ammonia metabolism and toxicity between avian and mammalian species, and effect of ammonia on skeletal muscle: A comparative review

“…In addition to optimizing feeding strategies for growth requirements, nitrogen utilization and excretion requires consideration due to the environmental impacts of ammonia on bird health and overall sustainability. Several studies have demonstrated that reducing CP has a significant impact in reducing nitrogen excretion (Aletor, Hamid, Nieß, & Pfeffer, 2000;Belloir et al, 2017;Bregendahl, Sell, & Zimmerman, 2002). One study reported that reducing CP, by as little as 1%, can have up to a 13% decrease in nitrogen excretion (Belloir et al, 2017).…”

“…Several studies have demonstrated that reducing CP has a significant impact in reducing nitrogen excretion (Aletor, Hamid, Nieß, & Pfeffer, 2000;Belloir et al, 2017;Bregendahl, Sell, & Zimmerman, 2002). One study reported that reducing CP, by as little as 1%, can have up to a 13% decrease in nitrogen excretion (Belloir et al, 2017). While the reduction of CP may benefit production from an environmental perspective, diets must be carefully formulated to avoid negative impacts on broiler growth (Aletor et al, 2000;Bregendahl et al, 2002).…”

Enjeux et atouts des productions animales sous signe officiel de qualité pour répondre aux attentes sociétales

“…Différentes approches nutritionnelles déjà existantes pour d'autres espèces ou productions pourraient ainsi avoir un intérêt en production de poulets LR, par exemple l'alimentation séquentielle, qui permet, en outre, d'utiliser de façon directe des céréales produites sur l'exploitation (Umar Faruk et al 2010), ou encore l'alimentation de précision, qui permet d'apporter des rations parfaitement adaptées aux besoins des animaux (Andretta et al 2016), même si pour cette dernière approche, des efforts de recherche sont encore nécessaires pour l'adapter aux spécificités des volailles (gestion à l'échelle du lot, mesure régulière du poids et de la consommation, modèles de prédiction des besoins). Enfin, l'utilisation d'acides aminés de synthèse permet également d'envisager la réduction du taux protéique des rations distribuées aux poulets de chair, sans dégradation des performances et avec des conséquences positives, sur l'excrétion azotée notamment (-13% par point de protéines, Belloir et al 2017).…”