Effects of dietary protein level and zinc oxide supplementation on performance responses and gastrointestinal tract characteristics in weaner pigs challenged with an enterotoxigenic strain of Escherichia coli.

摘要

The interactive effects of dietary protein level, zinc oxide (ZnO) supplementation and infection with an enterotoxigenic strain of Escherichia coli (ETEC) on performance responses and gastrointestinal tract characteristics were examined. Ninety-six individually housed, 21-day-old pigs (1:1 gender ratio) with initial bodyweight (BW) of 7.2+or-0.69 kg, were used in a split plot experiment, with the whole plot being challenge or no challenge with ETEC and the dietary treatments used as subplots and arranged in a completely randomised 2x2 factorial design, with the factors being (i) two dietary protein levels (251 versus 192 g/kg crude protein) and (ii) addition or no addition of 2.5 g/kg ZnO. No antibiotic was added to the diet. The ETEC infection decreased average daily gain (P<0.001) and increased feed conversion ratio (P<0.01). Protein level had no effect on performance of pigs while ZnO supplementation increased (P<0.001) average daily gain and average daily feed intake and hence decreased feed conversion ratio (P<0.001). There were no 2- or 3-way interactions for growth performance indices (P