Cell wall content as a predictor of metabolisable energy value of poultry feedingstuffs

Forty eight diets were tested to develop equations for predicting the apparent metabolisable energy values corrected to zero nitrogen retention (AMEn), of practical poultry feedingstuffs.2. The effectiveness of different fibre indicators (crude fibre, acid detergent fibre, lignin, neutral detergent fibre and cell wall content) as predictors of AMEn values was assessed. The most efficient measure proved to be cell wall content obtained by an enzymatic procedure (pronase and α‐amylase).3. The best combinations of variables were, in decreasing order: (1) gross energy (GE), crude protein (CP) and cell wall (CW); (2) ether extract (EE), ash and CW; (3) EE, CP, starch and sugars.4. When GE, CP and CW variables were used, a significant constant appeared in the linear equation. Another equation without a constant was calculated, using an exponent (1·5) for the CW variable. The residual standard deviation (0·20 MJ/kg) of this equation was about the same as that of the equation with the constant.