Feeding a diet with a decreased protein content reduces both nitrogen content in the gastrointestinal tract and post-weaning diarrhoea, but does not affect apparent nitrogen digestibility in weaner pigs challenged with an enterotoxigenic strain of Escherichia coli

This study evaluated possible nutritional and physiological mechanisms to explain why feeding a diet of decreased protein content reduces PWD. A total of 48 male pigs weaned at 21 d (initial BW 6.9 ± 0.11 kg; mean ± SEM) was used in a 2 × 2 × 2 factorial arrangement of treatments with the respective factors being: (1) PL (HP 239 g/kg vs. LP 190 g/kg CP); (2) presence or absence of an ETEC challenge; and (3) duration of feeding after weaning until euthanasia (D; 7 d vs. 14 d). No dietary antimicrobial compounds were used, and diet LP contained crystalline AA including isoleucine and valine to achieve an ideal AA pattern. Pigs were offered the experimental diets on an ad libitum basis. Feeding a LP diet decreased total N intake, ileal N flow, PUN and NH3-N contents at the ileum and all sites in the large intestine (P 0.05) the AID of N and AA at either d 7 or d 14, except for serine which was lower in pigs fed the LP diet (P 0.05). Pigs fed diet LP had decreased pH in the jejunum and ileum (P