Protein levels and environmental temperature effects on carcass characteristics, performance, and nitrogen excretion of broiler chickens from 7 to 21 days of age

Abstract

This trial was conducted to evaluate the utilization of low-protein diets formulated based on the ideal protein concept for broiler chickens from 7 to 21 days of age reared at different environmental temperatures. Nine hundred male Cobb-500 ® chickens were used. At day seven chicks were distributed according to a completely randomized design in a 3 x 3 factorial with four replications of 25 birds each. It was used three crude protein levels in the diet (21.5; 20.0 and 18.5%) and three environmental temperatures (low, thermoneutral and high). The performance, carcass characteristics (yield and chemical composition), and nitrogen ingestion and excretion were assessed. There was no significant interaction among the factors for the evaluated variables. Environmental temperatures affected differently chicken performance. High environmental temperature resulted in lower weight gain and higher wing fat percentage, whereas cold temperature resulted in higher feed conversion. On the other hand, low-protein diets decreased weight gain, breast yield, nitrogen excretion and influenced breast and wings chemical composition. Birds reared at high environmental temperature showed lower nitrogen intake and excretion. The results showed that the decrease in protein levels from 7 to 21 days of age contributed to lower nitrogen excretion in broiler chickens, but impaired performance and carcass characteristics independent of rearing temperature.

Manipulation of dietary methionine+cysteine and threonine in broilers significantly decreases environmental nitrogen excretion

“…Several studies (Cauwenberghe and Burnham, 2001;Si et al, 2004;Faria Filho et al, 2005) Si et al, 2004). Concerning amino acid reduction, the present study shows an exponential decrease in NE, which is age dependent (Figure 3 and Table 3).…”

“…Studies have shown that it is possible to manipulate diets by reducing CP levels and establishing an amino acid profile that meets broilers' requirements without compromising performance. The effect of this manipulation on reducing N excretion has also been shown (Cauwenberghe and Burnham, 2001;Si et al, 2004;Faria Filho et al, 2005;Gomide et al, 2011).…”

“…Studies have shown that it is possible to manipulate diets by reducing CP levels and establishing an amino acid profile that meets broilers' requirements without compromising performance. The effect of this manipulation on reducing N excretion has also been shown (Cauwenberghe and Burnham, 2001;Si et al, 2004;Faria Filho et al, 2005;Gomide et al, 2011).Knowledge of how broilers respond to intake of each amino acid and how each one relates to efficiency of utilisation and PD can be used to develop novel strategies to mitigate this source of pollution. However, we have no knowledge of any study that has focused on reducing N excretion and has related this reduction to individual amino acid.…”

Comparison of qualitative and quantitative properties of the wings, necks and offal of chicken broilers from organic and conventional production systems

“…The proportion of skin in the wings is the highest among all culinary chicken meat portions, representing about 22%, i.e., twice the amount present in thighs (Tomaszewska-Gras and Konieczny 2010). Generally, the data of the present study indicate that the higher dry matter and protein (total and net) content in the wing parts from OC could be due to high dietary calorie-protein ratios (Faria Filho et al 2005) associated with the ingestion of insects and worms in the yard. Higher contents of total protein (in meat with skin) and net protein (in meat) in organic wings could be due to the higher levels of motor activity that is characteristic of birds in organic production systems; levels of myogenesis are higher than those of lipogenesis in the muscles of these birds (Castellini et al 2002;Husak et al 2008).…”

Effects of meal-time feeding and protein restriction on walking ability and some bone and carcass properties in broilers

“…They reported that the birds fed fewer meals had lower BW and also had better feed efficiency than those fed more meals. Cristofri et al (1997) andFaria Filho et al (2005) also reported that restricted birds utilized feed more efficiently during the restriction period and compensatory growth period. The birds fed meal-time feeding regimen were unable to adapt to feed intake and also they did not compensate BW losses until slaughter age.…”