Expression studies of six human obesity-related genes in seven tissues from divergent pig breeds.

Obesity has reached epidemic proportions globally and has become the cause of several major health risks worldwide. Presently, more than 100 loci have been related to obesity and metabolic traits in humans by genome-wide association studies. The complex genetic architecture behind obesity has triggered a need for the development of better animal models than rodents. The pig has emerged as a very promising biomedical model to study human obesity traits. In this study, we have characterized the expression patterns of six obesity-related genes, leptin (LEP), leptin receptor (LEPR), melanocortin 4 receptor (MC4R), fat mass and obesity associated (FTO), neuronal growth regulator 1 (NEGR)1 and adiponectin (ADIPOQ), in seven obesity-relevant tissues (liver; muscle; pancreas; hypothalamus; and retroperitoneal, subcutaneous and mesenteric adipose tissues) in two pig breeds (production pigs and Göttingen minipigs) that deviate phenotypically and genetically from each other with respect to obesity traits. We observe significant differential expression for LEP, LEPR and ADIPOQ in muscle and in all three adipose tissues. Interestingly, in pancreas, LEP expression is only detected in the fat minipigs. FTO shows significant differential expression in all tissues analyzed, and NEGR1 shows significant differential expression in muscle, pancreas, hypothalamus and subcutaneous adipose tissue. The MC4R transcript can be detected only in hypothalamus. In general, the expression profiles of the investigated genes are in accordance with those observed in human studies. Our study shows that both the differences between the investigated breeds and the phenotypic state with respect to obesity/leanness play a large role for differential expression of the obesity-related genes.

Exocrine pancreatic secretions in growing pigs fed diets containing fish oil, rapeseed oil or coconut oil.

Two experiments were performed to study the effect of feeding diets containing oils with different fatty acid composition on exocrine pancreatic secretions in growing pigs using two different methods to collect pancreatic juice. In the first experiment, three barrows (initial weight 37 kg) were fitted with a pancreatic pouch re-entrant cannula. An isolated pouch was prepared where the pancreatic duct enters the duodenum. In the second experiment, also using three barrows (initial weight 32 kg), a catheter was inserted into the pancreatic duct. Three wheat starch and fish meal-based diets were formulated to contain either 15 g fish oil, rapeseed oil or coconut oil/100 g. In both experiments, the diets were fed according to a 3 times 3 Latin square design. The volume of pancreatic juice secreted, pH and secretion of bicarbonate, protein, amylase, trypsin, lipase and colipase were not significantly affected by the diets in the first experiment. In the second experiment, chymotrypsin secretion was significantly greater in pigs fed the coconut oil diet, and secretion of carboxyl ester hydrolase was significantly higher in pigs fed the fish oil diet. When compared qualitatively, pigs in Experiment 2 secreted more pancreatic juice; the pancreatic juice had a higher pH, and trypsin, carboxyl ester hydrolase and colipase secretions were substantially higher whereas amylase secretion was lower than for pigs in Experiment 1. The fatty acid composition of the different oils had minor effects on exocrine pancreatic secretion in growing pigs. However, there were considerable differences between the two surgical methods used to collect pancreatic juice, and these differences may be explained by physiological changes induced by the two methods.