Studies of nutritional strategies for broiler chikens / Estudos de estratégias nutricionais para frangos de corte

AUTOR(ES)
DATA DE PUBLICAÇÃO

2008

RESUMO

Two experiments were carried to evaluate productive parameters, carcass, abdominal fat, breast fillet yield, ammonia concentration (NH3), retention and excretion of nutrients and economic performance using different nutritional strategies in broiler chickens of 1 to 46 days of age. A random block experimental design was applied, with five treatments of 4 blocks whit 2 replicates for block of 10 birds each. Five different feeds were formulated according to the following rearing phases (1-8, 8-21, 21-33, 33-40, and 40-46 days of age). The following experimental treatments were applied: T1 Basic diet with normal crude protein level and minimum amino acids supplementation ; T2 Dietary protein reduction and supplementation of amino acids on ideal protein basis; 3 Control diet with phytase supplementation; T4 Basic diet with trace mineral supplementation: inorganic-organic sources; T5 Feeding program combining the three nutritional strategies: Dietary protein reduction and supplementation of amino acids on ideal protein basis, phytase supplementation, and inorganic-organic minerals. The first experiment Eight hundred male Cobb 500 broilers were housed in a poultry house. A random block experimental design was applied, with five treatments of 4 blocks whit 2 replicates for block of 20 birds each. In this experiment it was evaluated the performance, the carcass, the abdominal fat, the abdominal fat, the breast fillet yield and ammonia concentration (NH3) It can be conclusion that the diets with different nutritional strategies (T2, T3, T4 and T5) when compared to the control (T1), they had similar (P>0,05) result for the parameters of performance, carcass and breast fillet yields, but T2 and T5 promoted higher (P<0,05) abdominal fat deposition as compared to T1. All treatments had a quadratic effect (P<0.05) on ammonia air levels as a function of age, with lower levels for the diets formulated on ideal protein basis (T2 and T5) as compared to those containing regular protein levels (T1,T3 and T5). The second experiment Four hundred male Cobb 500 broilers were housed from 1 to 46 days of in metabolic cages. A random block experimental design was applied, with five treatments of 4 blocks whit 2 replicates for block of 10 birds each. At the end of each phase, two birds per experimental unit were removed due to bird space reduction. The results to the 21 days of age when compared with control (T1), there was reduction (P <0,05) about the excretion of N, and the retention in g/ave was the similar (P>0,05) for T2 and T5 and high (P <0,05) for T3 and T4, the efficiency of retention of N went superior to all the treatments. At 46 days of age, the treatment T2 and T5 reduced a excretion of N, were similar (P>0,05) in the retention of N in g/ave and in the retention efficiency when compared with T1, however, the other treatments didn t show difference in the balance of N. With respect to P, at 21 days of age, there was significant reduction in the excretion with the treatments T3 and T5, all the treatments had smaller (P <0,05) retention (g/ave) except for the T4 that it was high than the T1, however, when compared with T1, everybody was superior (P <0,05) in the efficiency of less retention the T2 (P>0,05) that was the equal results. At 46 days of age, only the T3 and T5 decreased the excretion and the retention of P in g/ave, even so they were superior (P <0,05) in the retention efficiency when compared with the T1. In function of Ca, to the 21 days, the T3 were only smaller (P <0,05) in the excretion that the T1, there was smaller (P <0,05) retention in g/ave for T4 and T5 and similar for T2 and T3, all the treatments presented the same (P>0,05) retention efficiency. At 46 days of age the reduction in the excretion and the retention g/ave of Ca was influenced (P <0,05) for T3 and T5 and there was the same (P>0,05) retention efficiency for all the treatments in relation to the T1. The excretion of microminerals to the 21 days of age when compared to the control, it was high (P <0,05) in the T2 (Zn), and smaller (P <0,05) in the T3 (Cu and Zn), T4 (Mn) and T5 (Cu, Mn and Zn). At 46 days of age the treatments T3, T4 and T5 reduced (P <0,05) the excretion of Mn. There was not it influences (P>0,05) on the excretion of Zn and Cu in all the treatments in relation to the control (T1). In the third experiment, at 33 days of age, the rations with larger return rates were respectively of T3 T5, when compared with the control (T1). However to the 40 and 46 days of age besides these two mentioned treatments, the ration with T2, also presented larger return rates when compared to the control.

ASSUNTO(S)

nutricao e alimentacao animal metabolism metabolismo broiler chikens performance phytase fitase frango de corte desempenho ideal protein minerals minerais proteína ideal

ACESSO AO ARTIGO

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