Factors influencing the structure and function of the small intestine in the weaned pig: a review

At weaning, the young pig is subjected to myriad of stressors (e.g. change in nutrition, separation from mother and littermates, new environment) which cause reduced growth. This post-weaning 'growth check' continues to represent a major source of production loss in many commercial piggeries. Associated with weaning are marked changes to the histology and biochemistry of the small intestine, such as villous atrophy and crypt hyperplasia, which cause decreased digestive and absorptive capacity and contribute to post-weaning diarrhoea. In this review we have outlined the major factors implicated in the aetiology of these changes, such as the role of enteropathogens, transient hypersensitivity to dietary antigens, and the withdrawal of milk-borne, growth-promoting factors. Special attention has been paid to the role of food (energy) intake as a mediator of intestinal structure and function after weaning, although other influences such as the source of protein added to the diet may interact with food intake to alter,out structure and function. This is clearly an area of production concern, and future research into areas such as manipulation of the immature digestive tract with exogenous growth factors and (or) dietary supplementation with 'non-essential' amino acids such as glutamine, appear warranted. (C) 1997 Elsevier Science B.V.