Comparison of true metabolisable energy and true amino acid availability between normal maize and quality protein maize (Shandan 17)

A precision-fed assay was conducted to determine true metabolisable energy and true amino acid digestibility in Chinese quality protein maize (QPM) compared with normal maize (NM). Thirty adult roosters, kept in individual cages, were made to fast for 48h and then tub-fed 50g QPM or NM per bird and their excreta was colleted for the subsequent 48h. Additional fifteen roosters were made to fast in order to estimate endogenous losses of energy and amino acids (AA) in excreta. Gross energy of the two types of maize were similar; the lysine content in NM and QPM were 0.27% and 0.41% (DM basis), respectively. True metabolisable energy (TME) and true metabolisable energy nitrogen corrected (TMEn) values of QPM and NM were not significantly different (P>0.05). Digestibility of some AA, including lysine and methionine, in QPM were higher than those in NM (P<0.05). The results of this study indicated that the nutritive value of QPM might be higher than that of NM.