Attempts to modify changes in the piglet small intestine after weaning.

The possible causes of changes in the piglet small intestine after weaning were investigated. Groups of piglets weaned at three weeks old were either given oral oxytetracycline daily, weaned on to a regularly fed sow-milk replacer or weaned on to specially formulated diets based on casein or hydrolysed casein as the protein source. After five days, changes in small intestinal structure and brush-border enzyme activities were compared with previous findings in weaned and unweaned animals of the same age. The presence of enterotoxigenic Escherichia coli and rota-viruses in the intestines and the occurrence of diarrhoea were also noted. Consumption of the diet based on hydrolysed casein resulted in significant modifications to crypt depth and brush border enzyme activity at sites between 50 and 75 per cent along the length of the small intestine. Possible reasons for this protective effect, which include the low level of antigenicity of the diet, are discussed in relation to normal intestinal changes after weaning.