Níveis dietéticos de lisina e de metionina + cistína digestíveis para frangos de corte cobb

• Autor(a) principal: Bernal, Luis Ernesto Páez
• Data de Publicação: 2008
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/1775
• topic: Frango de corte; Nutrição; Metionina; Lisina; Aminoácidos; Broiler chikens; Nutrition; Methionine; Lysine; Amino acids; CNPQ::CIENCIAS AGRARIAS::ZOOTECNIA::NUTRICAO E ALIMENTACAO ANIMAL

Eight experiments was carried out, at the animal husbandry department at UFV, to establish the requirement of digestible Lysine and also methionine + cystine requirement for male and female Cobb broilers. Four different phases were study: 1 to 10, 11 to 21, 22 to 35 and 35 to 49 days of age. At the Lysine experiment, five increasing digestible Lysine levels were use for each phase: 1,12%; 1,18%; 1,24%; 1,30% e 1,36% (1 to 9 days of age); 1,06; 1,12; 1,18; 1,24 e 1,30 (10 to 21 days of age); 0,92; 0,98; 1,04; 1,10 e 1,16% (22 to 35 days of age); 0,84; 0,90; 0,96; 1,02; 1,08% (37 to 49 days of age). At the Methionine + Cystine experiment five different dietary digestible Met. + Cys. / Lys. ratios (64, 68, 72, 76 and 80%), for males and females, respectively, were produced . To avoid excess lysine in the experimental diets the digestible Lysine content will be calculated to be about 95% of the Brazilian Tables recommendations (Rostagno et al., 2005). Lysine levels were 1,24% (1 to 10 days, male and female); 1,10% (10 to 21 days, male and female); 1,030% (22 to 35 days, male); 0,970% (22 to 35 days, female); 0,950% (37 to 49 days male) and 0,900% (37 to 49 days female). Two control (C+) treatments, one for males and another for females, containing adequate lysine (1,35%) and Met + Cis (1,080% = 80% of Lys.) were included in the experimental design.Therefore, each study phase had twelve treatments. Studying Lysine levels for the 1 to 9 days of age phase, it was found a linear effect for weight gain and feed conversion rate on males and a quadratic effect on females. Into 10 to 21 days of age there was a quadratic effect of Lysine levels for the weight gain and feed conversion rate, on males and females. At the 22 to 35 of age days phase, in was observed a quadratic effect for lysine levels over weight gain an feed conversion rate on males, while females had a linear reply for the same variables. For carcass yield parameters and fine cuts males showed linear effect for Breast whit bone and filet yield, while females only showed linear effect for filet yield. At the final Phase (31 to 49 days) there was a quadratic effect by lysine levels on weight gain and feed conversion rate as well for males as females. Only females presented linear response for reduction of the abdominal fat percentage. At digestible methionine + cystine study there was linear effect over weight gain and feed conversion rate for males on 11 to 21 days age phase. Moreover females showed quadratic response for weight gain and linear response for fed conversion rate. At the 11 to 21 day of age phase there was a quadratic effect of Lysine levels on weight gain and feed conversion rate for males, while females respond linearly for weight gain and quadratically for weight gain. From 22 to 35 days age it was observed a linear effect on weight gain and quadratic effect on feed conversion rate for males. In females, there was not effect of methionine + cystine levels on weight gain and only quadratic effect on feed conversion rate. Abdominal Fat yield, breast whit bone and filet have a quadratic response by females. In male broilers at 37 to 49 days of age, it was observed a linear effect of methionine + cystine levels on weight gain and a quadratic effect on feed conversion rate. Females in that phase had a quadratic response for both variables. About carcass parameters, female´s minimum abdominal fat varied quadratically as well as male´s breast whit bone yield. Based on statistical analyses and the studied parameters, it was concluded that digestible lysine requirements for maximum performance in Cobb broiler chickens, male and female, respectively are 1,35 and 1,29% (1 to 9 days of age); 1,22 and 1,24% (10 to 21 days of age); 1,16 and 1,16% (22 to 35 days of age) and, 1,02 and 1,08% (37 to 49 days of age). For Methionine + Cystine, it was concluded that requirements for maximum performance in Cobb broiler chickens, male and female, respectively are 0,960 and 0,960% (1 to 9 days age); 0,801 and 0,812% (10 to 21 days age); 0,751 and 0,723% % (22 to 35 days age) and, 0,692 and 0,630 (37 to 49 days age), for diets containing 1,16% digestible Lysine from 1 to 10 days,1,06% dig Lysine from 11 to 21 days for both sexes and 0,99% for males and 0,88% for females from 22 to 35 days age and 0,91% for males and 0,86% for females from 37 to 49 days of age.