Validating the current amino acid and energy requirements of coloured broiler chickens

Abstract

AbstractBackground: Coloured broilers are gaining popularity in the Indian subcontinent. However, very scanty reports are available on their dietary requirements for amino acid (AA) and energy. An experiment was conducted involving three levels of amino acids (115, 100 and 85% AA level of the NRC), at three levels of energy (13.40, 12.55 and 11.72 MJ kg−1 diet) for 0–28 days of age. Results: Body weight gain and feed conversion ratio (FCR) in the 115% AA group was better than those fed diets with 100 and 85% AA. Dietary energy levels did not influence body weight gain up to 14 days of age but thereafter it was higher (P < 0.01) in birds offered the 13.40 MJ ME kg−1 diet. The exponential regression equation had better curve fitting for daily body weight gain over daily AA intake and the power regression model for FCR. Nitrogen retention was higher in birds offered the diets with 115 and 100% AA than 85% AA, although nitrogen retention was not affected by dietary energy level. Thymus weight (P < 0.036) and in vivo response to PHA‐P (P < 0.006) was significantly higher in birds offered the 85% AA diet. Dietary energy levels had no effect on the immune response of the birds. Weight of gizzard, proven‐triculus and small intestine was higher in birds offered the 85% AA diet. Conclusion: Body weight of coloured broilers may be optimised by feeding higher level of AA and immune response can be optimised by feeding 12.55 kJ ME kg−1 diet and 15% lower level of AA as suggested by the US National Research Council. Copyright © 2007 Society of Chemical Industry