Dietary crude protein reduction on growth and carcass performance of 22 to 42-day-old broilers reared under different temperatures

Abstract

This study was conducted to verify the effects of dietary crude protein reduction on growth and carcass performance of 22-42-day-old broilers reared under different temperatures. Treatments were set up in a five by two factorial arrangement, with five crude protein levels (220, 210, 200, 190 and 184 g/kg) and two temperatures (21.6 and 32.2 o C). Diets were isocaloric and essential amino acid-to-lysine ratio was maintained constant in all treatments. There was no interaction between crude protein reduction and environmental temperature for any of the parameters evaluated. Crude protein had no influence on feed intake. Nevertheless, weight gain and feed conversion ratio were linearly influenced by crude protein reduction. Worse performance was also observed in birds exposed to heat stress as compared with birds kept under thermoneutral temperature. There was no effect of crude protein reduction on breast and legs. Birds kept under heat stress had lower breast yield and higher leg yield as compared with broilers reared at 21.6 o C. Any crude protein reduction in the range of 220 to 184 g/kg for 22 to 42-day-old broilers has a negative effect on their performance. Heat stress worsens broiler performance and breast yield.

Ameliorative effects of betaine and ascorbic acid on erythrocyte osmotic fragility and malondialdehyde concentrations in broiler chickens during the hot-dry season

“…The RH values obtained were predominantly outside the optimal range of 65-70% for broilers between the ages of three and seven weeks (Akyuz & Boyaci 2010). The findings of the present study agree with that of de Olivieira et al (2013), who showed that the optimum AT and RH values for broiler chickens are 21°C and 74%, respectively. The high THI recorded in the present study, with values exceeding 20.8 (Purswell et al 2012), showed that the thermal environmental conditions were stressful to the broiler chickens.…”

Effects of low-protein diets supplemented with antioxidants on histopathology of testis and testosterone and performance of male Japanese quail ( Coturnix coturnix japonica )

“…It is concluded that the amount of dietary protein is one of the effective factors in FBW; lower amounts of dietary protein resulted in a clear decrease in FBW, while intake of E-selenium, as a natural antioxidant, could improve FBW. In agreement with several studies (Hashiguchi and Yamamoto, 2006;Tarasewicz et al, 2007;Oliveira et al, 2013), the results from this study demonstrated that low levels of dietary protein lead to decreased FBW in broilers under different temperatures. Hashiguchi and Yamamoto (2006) reported that no significant differences were observed in FBW levels between groups receiving 24% and 19% dietary protein.…”

“…However, Kamran et al (2008) reported that lowprotein diets severely increase feed intake in broilers. In addition, Oliveira et al (2013) revealed that reduced crude protein diets failed to influence feed intake in broilers. Fan et al (2009) demonstrated that daily supplementation with different concentrations of selenium lack the ability to affect feed intake in broilers.…”

“…Reduced serum protein levels, due to reduced protein diets, are one of the reasons for reduced performance (Surai, 2007). Additionally, Oliveira et al (2013) reported that reduced crude protein diets lead to increased FCR levels in broilers under different temperatures. Fan et al (2009) demonstrated that intake of different concentrations of selenium results in improved FCR in broilers.…”

Cloacal temperature responses of broiler chickens administered with betaine and ascorbic acid during the hot-dry season

“…Also, brain-gut neuropeptides which regulate food intake are altered by heat stress, leading to decreased feed consumption (Lei et al 2013). Heat stress diminishes broiler performance and breast yield (Oliveira et al 2013); it also exerts adverse effects on the immune system, activating the central nervous system and increasing corticosterone levels, which decreases the body immune system and, increases susceptibility to Salmonella spp. (Palermo-Netoa et al 2013).…”