Níveis de lisina digestível da ração e temperatura ambiente para frangos de corte em crescimento

Abstract

RESUMO -Este estudo foi conduzido para avaliar os efeitos dos níveis de lisina digestível da ração e da temperatura ambiente sobre o desempenho e as características de ABSTRACT -This study was aimed to evaluate the effects of the dietary digestible lysine levels and environmental temperature on performance and carcass characteristics of broiler chickens from 22 to 42 days-old. Six hundred seventy two males Ross ® broiler chickens with an average weight of 726 g were allotted to a completely randomized design, in a 4 × 4 factorial arrangement with six replicates and seven birds per experimental unit. The chickens were fed with different digestible lysine levels in the diet (0.934, 1.009, 1.084, and 1.159%) and kept under different environmental temperatures (18.5, 21.1, 24.5, and 27.0°C). There were no interactions between environmental temperature and lysine levels in the diet for the studied variables. Feed intake and the weight gain (WG) were not influenced by lysine levels in the diet. Feed intake linearly reduced with the environmental temperature and the WG increased up to the estimated temperature of 21.5°C. The feed:gain ratio improved up to the estimated digestible lysine level in the diet of 1.085%. The weights of carcass (CW), boned breast (BBW), thigh (TW) and drumstick (DW) increased up to the estimated temperatures of 21.9, 21.7, 22.7, and 23.7°C, respectively. The yields of carcass (CY), thigh (TY) and drumstick (DY) increased, whereas the deboned breast weight (DBW), the boned breast yield (BBY) and deboned breast yield (DBY) linearly decreased with the environmental temperature. The TW and TY increased, whereas the DY linearly decreased with the lysine levels in the diet. The lysine levels did not influence the CW, BBW, DW, CY, BBY and DBY. The environmental temperature in the range from 18.5 to 27.0°C did not influence the lysine requirements of the birds. The condition that provided better feed:gain ratio during the experimental period was obtained with the digestible lysine level in the diet of 1.085% and the estimated environmental temperature of 23.3°C.

Digestible lysine levels obtained by two methods of formulation of diets for 22-to-42-day-old broilers

“…This result differs from those found by Lana et al (2005), Siqueira et al (2007) and Viola et al (2009b), who observed linear increase in the absolute weights of drumstick and thigh of broilers as the lysine levels of the diet were increased.…”

“…However, the thigh yield was influenced (P<0.01) by the lysine levels of the supplemented diet and reduced linearly according to the equation: Ŷ = 15.0951 − 0.231023X (r 2 = 0.80). This result is in accordance with Siqueira et al (2007), who observed a decrease in thigh yield as a consequence of increase in the dietary lysine levels. However, it differs from those obtained by Lana et al (2005), who did not observe changes in the thigh yield according to the lysine levels, and also diverges from the results found by Mukhtar et al (2007), who observed improvement in the thigh yield of chickens fed diets containing increasing lysine levels.…”

Digestible Lysine on Live Performance of Chicken Type Naked Neck During the Starter Phase

“…The following equation predicted lysine intake: LI = −0.42202 + 7.44780*LYS (R 2 = 0.95). A linear increase of LI as a function of increasing levels of dietary lysine was also observed in previous studies (Siqueira et al, 2007;Haese et al, 2012 andOliveira et al, 2013).…”

Effects of dietary lysine on broiler performance and carcass yield - meta-analysis

“…(5) Nascimento (2003) found that increasing dietary lysine levels promoted higher muscle deposition and weight gain, and reduced abdominal fat, leading to better feed conversion ratio. Siqueira et al (2007) reported 1.64 kg/kg feed conversion ratio in broiler chickens fed 1.085% lysine, which is close to the results of the present study and to the recommendation of Rostagno et al (2005) of 1.045% lysine for broiler chickens. Accordingly, Lana et al (2005) reported optimal feed conversion ratio with 1.075% dietary lysine level fed 22-to 42-day-old broiler chickens reared in zone of least thermoregulatory effort (23.8ºC).…”