The effect of dietary methionine concentrations on the efficiency of energy utilisation in broiler chickens

摘要

Dietary protein has a lower efficiency of utilisation of metabolisable energy than other dietary nutrients in poultry feeds. The utilisation of a dietary protein supply is dependent upon its amino acid composition and the effects of amino acid imbalances on the growth of poultry have been well established (Morris et al, 1999). The possibility of amino acid balance on the efficiency of energy utilisation is understood (MacLeod, 1994) but these effects have not been quantified. Imbalances of dietary lysine within the protein supply have significant effects on the efficiency of energy utilisation (Priyankarage et al., 2006) in poultry. The efficiency of energy retention of broiler chickens was increased with a deficiency of dietary lysine, however, theefficiency of energy retention was markedly reduced with the excess levels. There is no further evidence of the effects of other essential amino acids on the efficiency of energy utilisation. Methionine is also an important limiting amino acid in poultry feeding therefore an experiment was conducted to examine its effects on efficiency of energy utilisation. Carcass energy deposition and efficiency of energy utilisation in broiler chickens were observed with six different methionine levels (27, 34, 42, 49, 74 and 98 g methionine/kg crude protein).