EFFECTS OF FEED PROCESSING ON THE APPARENT ILEAL DIGESTIBILITY OF AMINO-ACIDS IN PIG DIETS CONTAINING WHEAT BRAN OR WHEAT MIDDLINGS

The effects of feed processing on the apparent ileal digestibility of amino acid and the utilisation of nitrogen (N) in diets containing whe at by-products were studied in five castrated male pigs (live weight 4 0-109 kg). A T-cannula was surgically fitted into the caecum of the pi gs at a live weight of 27 kg using the steered ileo-caecal valve techn ique. The experiment was conducted with a 6 x 5 cyclic change-over des ign in which six diets were arranged 2 x 3 factorially. The correspond ing factors were type of wheat by-product in the diets: wheat bran (15 2 g/kg) or wheat middlings (328 g/kg), and method of feed processing: steam pelleting, expanding or extrusion. The other dietary feed ingred ients were barley and soya bean meal. The feed-processing method or di etary wheat by-product had no effect on the apparent ileal digestibili ty of amino acids and crude protein. The pigs on diets containing whea t middlings tended to retain more N per intake (p<0.10) than did those on wheat bran diets. The wheat middlings diets also tended to have hi gher biological values than did the wheat bran diets (p<0.10). Further , daily N retention tended to be better with expanding than with pelle ting (p<0.10). The N retention differences were mainly caused by the d ifferences in N intakes of the treatments. In conclusion, feed process ing at a moderate temperature or wheat by-product in the diets had no influence on the apparent ileal digestibility of amino acids.