Performance of broilers fed nutrient restricted diets at different stages of growth

초록

This study investigated the effects of dietary nutrient restriction (energy and/or protein) during different phases (starter and finisher) on performance, nutrient digestibility, blood metabolites and carcass traits in male broilers. In Experiment 1, birds were fed a Control diet or diets restricted in energy (10%, T1), protein (20%, T2) and both (10% energy and 20% protein, T3) during starter phase (0 to 3 wk). Then all the birds were fed a common finisher diet (4 to 6 wk). Feeding of nutrients restricted starter diets resulted in lower body weights, feed efficiency, serum cholesterol, glucose, total protein, dressing percent and breast meat, but improved metabolizability coefficients of CP and EE in comparison to birds fed Control diet. At the end of 6 wk final body weight of birds fed protein restricted starter diet was lowest while birds fed starter diet restricted in both protein and energy had lower serum cholesterol and total protein. In Experiment 2, birds were fed a common starter diet from 0 to 3 wk and during finisher phase (4 to 6 wk) birds were fed either Control diet or diets restricted in energy (10%, T1), protein (10%, T2) and both (10% energy and 10% protein, T3). Birds fed protein restricted finisher diet had final body weight similar to birds fed Control diet, while birds fed diets restricted in energy and both (energy and protein) had lower final body weight. Restriction of nutrients in finisher diets resulted in higher EE and CP metabolizability coefficient in birds fed energy and protein restricted finisher diets, respectively. Nutrient restriction of finisher diets had no influence on blood metabolites, organ weights, dressing and breast meat yield except for the lower serum glucose and abdominal fat in birds fed energy restricted diets. These results suggest that 10% of energy and 10% protein can be reduced in starter and finisher diets respectively, without having any negative impact on growth performance.

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