Somatic and visceral growth, and adiposity in the pig after partial small bowel resection. I. - Variations according to the kinds of operations, to the specific location along the intestinal tract and to the sex of the animals.

The effects of small bowel resection were studied in 123 pure-bred Large White pigs, during 2 separate experiments. The first one aimed at studying the somatic growth in 60 castrated male pigs during a 16 weeks-period, following either a (I) laparotomy, (2) proximal or distal double transsection, or (3) proximal or distal resection of 25 p. 100 of the total small intestine length. Operations were performed at the age of 91 days and 26 kg live weight. Secondly, both grwoth of 63 pigs operated at the age of 97 days and at 28 kg live weight, was studied during a 16 weeks-period, in order to assess the effects of resection of 4m of distal jejunum (i.e. 25 p. 100 of the small intestine), according to the sex of the animals. After slaughtering visceral measurements and indirect measurement of carcass adiposity were made. It appeared that laparotomy was detrimental to continuation of normal growth, whereas resections or sham operations allowed better performances although less than that of control pigs. In short-term studies, proximal resections allowed better results than distal ones; the reverse conclusion could be drawn from long term studies. Small intestine tissue weight was not changed after laparotomy, and was slightly increased after transsection. Sixteen weeks after resection, tissue weight of residual small intestine was not very lower than that of entire small intestine in control pigs. This compensation was better after proximal resection, the apparent local hypertrophy being greater after distal resection. Concerning the sex-dependent effects after partial resection of distal jejunum, there was an improvement of performances (growth/food intake), and a true body growth acceleration in female and castrated male pigs. The morphological compensation of tissue loss was very good in residual small intestine of female pigs, partially assumed by large intestine in normal male pigs, and poor in castrated male pigs. The greatest hypertrophy was always noted in the ileal segment below the resected area. Carcass adiposity (specific gravity) was not significantly modified by the various operations in castrated male pigs, whereas it was significantly decreased after resection in entire male or female pigs.