Responses of Ileal and Fecal Microbiota to Withdrawal of Pancreatic Enzyme Replacement Therapy in a Porcine Model of Exocrine Pancreatic Insufficiency

Little is known regarding the interplay between microbiota and pancreas functions in humans as investigations are usually limited to distal sites, namely the analyses of fecal samples. The aim of this study was to investigate both ileal and fecal microbiota in response to pancreatic enzyme replacement therapy (PERT) in a porcine model of exocrine pancreatic insufficiency (EPI). PERT was stopped for ten days in ileo-cecal fistulated minipigs with experimentally induced EPI (n = 8) and ileal digesta as well as fecal samples were obtained before withdrawal, during withdrawal and after the reintroduction of PERT. Profound community changes occurred three days after enzyme omission and were maintained throughout the withdrawal phase. A reduction in α-diversity together with relative abundance changes in several taxa, in particular increases in Bifidobacteria (at both sites) and Lactobacilli (only feces) were observed. Overall, dysbiosis events from the ileum had accumulating effects in distal parts of the gastrointestinal tract with additional alterations occurring only in the colon. Changes were reversible after continuing PERT, and one week later, bacterial communities resembled those at baseline. Our study demonstrates the rapid and profound impacts of enzyme withdrawal in bacterial communities, contributing to our understanding of the interplay between pancreas function and microbiota.

Influences of exocrine pancreatic insufficiency on nutrient digestibility, growth parameters as well as anatomical and histological morphology of the intestine in a juvenile pig model

In a pig model, pancreatic duct ligation (PL) leads to a complete loss of exocrine function, causing an exocrine pancreatic insufficiency (EPI) without affecting endocrine function, allowing research of clinical effects and therapy options. This study aimed to investigate effects of experimentally induced EPI in juvenile pigs on digestion and intestinal morphology. Eight female juvenile cross-bred pigs (BW 54.8 kg at the start of the study) were included. Three animals were considered as a control (CON group), and in five animals the ductus pancreaticus accessorius was ligated (PL group). During the 10-week trial period, body weight and body measurements were recorded regularly. At the end of the trial, gastrointestinal tract (GIT) was investigated macroscopically and histologically and weight and digesta samples of individual segments were obtained. The pigs in the CON showed a significantly higher apparent total tract digestibility of crude protein and crude fat (87.8 and 79.9%, respectively) compared to PL (52.4 and 16.6%, respectively). Significant differences were noted in relative weights of duodenum, jejunum and colon (with and without digesta) and also in absolute weights of jejunum and colon. The mean number of nuclei in the transverse section in stratum circulare were significantly higher in all intestinal segments in CON compared to PL. Overall, EPI results in impaired nutrient digestibility with a greater filling of the GIT with digesta. The elongation of the small intestine does not represent "stretching" of the intestine, but rather increased synthesis of intestinal tissue.

Endogenous praecaecal and total tract losses of nitrogen in pancreatic duct-ligated minipigs

The pancreatic duct-ligated minipig (PL) is an established model of pancreatic exocrine insufficiency (PEI) with a significant decrease of nutrient digestibility. This study aimed to quantify and compare endogenous losses of nitrogen (N) (ileal and faecal) in minipigs receiving an almost N-free diet. Altogether, 12 Göttingen minipigs (7 PL and 5 control animals) fitted with an re-entrant ileo-caecal fistula were used. In Study 1, ileal digesta was collected over a period of 12 h on seven consecutive days, including one 24 h collection, when animals were fed a diet containing 0.49 g N/kg dry matter (DM). In Study 2, faeces were collected for 10 consecutive days. In Group PL, the amount and DM content of ileal digesta were higher (p < 0.05), while N concentration was lower than in the Control. The ileo-caecal N flux [g/kg DM intake] was about 2.5 times higher in Group PL (5.47 ± 1.15) than in the Control (1.91 ± 0.59) (p < 0.05). The amount of faeces did not differ, but faecal N losses were higher in Group PL (p < 0.05). Endogenous faecal N losses [g N/kg DM intake] of the Control group (1.17 ± 0.72) were comparable with earlier studies, while those of Group PL were 2.6 times higher (3.09 ± 1.34). In contrast, urinary excretion of N did not differ between the Control and Group PL. In conclusion, PEI caused markedly increased endogenous N losses. Therefore, the impact of reduced digestibility of nutrients on endogenous N losses might be relevant for apparent protein digestibility rates and should be taken into account.