Iron and Zinc Homeostasis and Interactions: Does Enteric Zinc Excretion Cross-Talk with Intestinal Iron Absorption?

Iron and zinc are essential micronutrients required for growth and health. Deficiencies of these nutrients are highly prevalent among populations, but can be alleviated by supplementation and food fortification. Cross-sectional studies in humans showed positive association of serum zinc levels with hemoglobin and markers of iron status. Dietary restriction of zinc or intestinal specific conditional knock out of ZIP4 (SLC39A4), an intestinal zinc transporter, in experimental animals demonstrated iron deficiency anemia and tissue iron accumulation. Similarly, increased iron accumulation has been observed in cultured cells exposed to zinc deficient media. These results together suggest a potential role of zinc in modulating intestinal iron absorption and mobilization from tissues. Studies in intestinal cell culture models demonstrate that zinc induces iron uptake and transcellular transport via induction of divalent metal iron transporter-1 (DMT1) and ferroportin (FPN1) expression, respectively. It is interesting to note that intestinal cells are exposed to very high levels of zinc through pancreatic secretions, which is a major route of zinc excretion from the body. Therefore, zinc appears to be modulating the iron metabolism possibly via regulating the DMT1 and FPN1 levels. Herein we critically reviewed the available evidence to hypothesize novel mechanism of Zinc-DMT1/FPN1 axis in regulating intestinal iron absorption and tissue iron accumulation to facilitate future research aimed at understanding the yet elusive mechanisms of iron and zinc interactions.

Is Moxifloxacin a Treatment Option for Pancreatic Infections? A Pharmacometric Analysis of Serum and Pancreatic Juice.

Postoperative local infection is a major complication after pancreatic surgery. The aim of this prospective clinical trial was to assess the potential of moxifloxacin (MXF) to treat pancreatic infections from a pharmacokinetic (PK)/pharmacodynamic (PD) perspective. The PK of MXF in serum and pancreatic juice, via an inserted tube in the pancreatic duct, was determined in 19 patients up to day 7 after pancreatoduodenectomy. PK data in both specimens was analyzed with NONMEM 7.3. Intraoperative swipes were performed for microbiological examination. PK/PD target attainment was assessed in both matrices using unbound area under the plasma concentration-time curve/minimum inhibitory concentration (MIC) targets of ≥30 and ≥100, for gram-positive and gram-negative pathogens, respectively. A 2-compartment population PK model in which the measurements in pancreatic juice were assigned to a scaled peripheral compartment best described the PK in both specimens simultaneously. Median (10th-90th percentile) area under the plasma concentration-time curve values after the third dose were 28.9 mg · h/L (18.6-42.0) in serum and 55.8 mg · h/L (23.7-81.4) in pancreatic juice. Target attainment rate for the intraoperatively isolated bacterial strains was ≥0.88 after the third MXF dose. For gram-negatives, high probability of target attainment ≥0.84 was observed in serum for MIC ≤ 0.125 mg/L and in pancreatic juice for MIC ≤ 0.25 mg/L. For gram-positives, the probability of target attainment was 0.84-1 in serum for MIC ≤ 0.5 mg/L and in pancreatic juice for MIC ≤ 1 mg/L. In conclusion, penetration of MXF into pancreatic juice was substantial. The PK/PD analysis indicated that treatment of pancreatic infections by isolates with MIC ≤ 0.25 mg/L (gram-negative) and ≤1 mg/L (gram-positive) should be evaluated in further studies.

In vitro gastric and intestinal digestion of a walnut oil body dispersion.

An oil body dispersion (11.3% fat) was prepared by wet disintegration of walnuts and was then subjected to a two-step model of in vitro digestion. In a gastric environment, proteolysis by pepsin led to the destabilization and coalescence of the oil bodies. Aggregation of the coalesced oil bodies was apparent under a confocal microscope, with aggregates up to 275 µm in size. Pepsin-resistant peptides and proteins remained at the surface of the oil bodies, and some were further resistant to intestinal proteases. Under intestinal conditions, the hydrolysis of walnut triglycerides led to the spontaneous formation of a new type of multiple emulsions, ranging from 2 to 45 µm in size and with protein material inside the inner water droplets. Transmission electron microscopy revealed the presence of a liquid-crystalline phase of bile salts and lipolytic products at the surface of the oil droplets and some bile salt crystals at the surface of the inner water droplets.

Behavior of almond oil bodies during in vitro gastric and intestinal digestion.

An aqueous suspension of almond oil bodies (about 10% lipids) was prepared and subjected to in vitro gastric (with pepsin) and intestinal (with bile salts and pancreatin) digestion, simulating fasting conditions. The physicochemical and structural changes of the almond oil body emulsion were examined. The almond oil body emulsion behaved similarly to a protein-stabilized emulsion, with flocculation of the oil bodies occurring under gastric conditions. Proteins, peptides, and phospholipids covered the surface of the oil bodies throughout gastric digestion. Under intestinal conditions, bile salts displaced the interfacial peptides and phospholipids, and disrupted the flocs. Gastric pepsinolysis of almond proteins was a prerequisite for their digestion in the duodenum. The oil body membrane had a negative impact on the efficiency of gastric digestion, and long chain fatty acids, the main lipolytic products, accumulated at the surface of the oil bodies and therefore limited the activity of pancreatic lipase.

Defatted bovine colostrum-supplemented diet around weaning improves exocrine pancreatic secretion by means of volume, digestive enzymes, and antibacterial activity.

OBJECTIVES: Exocrine pancreatic secretion contributes to limit pathogenic bacteria-associated diarrhea. Bovine colostrum, used in the treatment of diarrhea, reduces symptoms originating from gut pathogenic bacteria overgrowth. We hypothesized that bovine colostrum may stimulate the exocrine pancreatic secretion. METHODS: Eighteen piglets fitted with 2 permanent catheters (for pancreatic juice collection and reintroduction) were allocated to 1 of the following 2 dietary treatments for 5 days: a control diet or a diet supplemented with defatted bovine colostrum. Pancreatic juice was collected daily, and digestive enzyme activities and antibacterial activity were determined. RESULTS: The prandial pancreatic juice outflow, the basal and prandial lipase output, and the basal secretion of the antibacterial activity were, respectively, 60% (P = 0.08), 154% (P = 0.08), 92% (P = 0.06), and 72% (P < 0.05) higher in piglets fed a diet supplemented with defatted bovine colostrum. CONCLUSIONS: With defatted bovine colostrum, the increased antibacterial activity secretion against Escherichia coli may limit pathogenic bacteria overgrowth of the gut and reduce diarrheal episodes. The role of secretin in the increased pancreatic juice flow and lipase secretion was considered.

Physiological evaluation of the severity of pancreatic exocrine dysfunction during endoscopy.

OBJECTIVES: Despite the advances in pancreatic imaging, there continues to be a need to measure exocrine function to determine which patient requires enzyme supplementation. To evaluate the potential use of a rapid endoscopic test that can be conducted by nonacademic centers, we investigated whether concentration of trypsin in food-stimulated secretion is related to trypsin synthesis and secretion. METHODS: Subjects include 22 chronic pancreatitis patients (10 mild, 5 moderate, and 7 severe radiological disease) and 11 healthy controls. During upper gastrointestinal endoscopy, pancreatic secretion was stimulated by a single 30-mL duodenal injection of an enteral diet, followed 5 minutes later by periampullary juice aspiration (endoscopic pancreatic function test [ePFT]). This was followed by a conventional 2-hour marker-perfusion diet-stimulated pancreatic trypsin secretion and synthesis study (2-hour PFT [2hPFT]). RESULTS: Severity of radiological disease was associated with a progressive loss of enzyme secretion measured by the 2hPFT. The endoscopic PFT correlated positively with 2hPFT (r2 = 0.48; P < 0.0001) and an activity of less than 5% of the average normal had a 96% specificity and 75% sensitivity for the detection of pancreatic insufficiency as defined by a loss of greater than 90% of pancreatic secretion. CONCLUSIONS: The diagnostic power of endoscopy may be enhanced by the collection of a pancreatic juice sample after enteral feed stimulation because measurement of the trypsin content will identify chronic pancreatitis patients who will be benefited by enzyme supplementation.

Effect of parenteral and enteral nutrition combined with octreotide on pancreatic exocrine secretion of patients with pancreatic fistula.

AIM: To evaluate the effect of parenteral and enteral nutrition combined with octreotide on pancreatic exocrine secretion of the patients with pancreatic fistula. METHODS: Pancreatic juice, drained directly from the pancreatic fistula, was collected, and the volume, protein, amylase, HCO(3)(-), K(+), Na(+) and Cl(-) were determined on d 1, 4 and 7 before and after 7-d treatment with octreotide, respectively. RESULTS: No differences in exocrine pancreatic secretion were observed during the enteral and parenteral nutrition period (t = 2.03, P > 0.05); there were significant decreases in pancreatic juice secretion volume, protein, amylase, HCO(3)(-), K(+), Na(+) and Cl(-) after parenteral and enteral nutrition combined with octreotide compared with octreotide pretreatment (t = 4.14, P < 0.05). CONCLUSION: There is no stimulatory effect on the pancreatic secretion by intrajejunal nutrition and parenteral nutrition. Octreotide is effective on the reduction of pancreatic fistula output.

Effect of Bak Foong pills on exocrine pancreatic-bile secretion.

We have recently demonstrated that Bak Foong Pills (BFP), a well-known Chinese medicine widely used for treating gynecological disorders, stimulates human colonic epithelial anion secretion, which was mediated by intracellular cAMP and Ca(2+). The present study further investigated the effect of BFP on exocrine pancreatic-bile secretion using in vivo and in vitro approaches. Duodenal infusion of BFP ethanol extract (1 g/kg) in rats produced increases in the volume and protein output of pancreatic-bile juice, but did not affect its pH. Surgical ablation of vagal neural pathway slightly reduced the effect of BFP on the protein output and volume, indicating that the vagal nerve pathway was not the major player in medicating the effect of BFP on exocrine pancreatic-bile secretion. Using CAPAN-1 cell line, a human pancreatic duct cell line, in conjunction with the short-circuit current (I(SC)) measurements, we further demonstrated that BFP could directly stimulate pancreatic HCO(3)(-) secretion. Basolateral addition of BFP (600 microg/ml) produced averaged charges transported of 2100+/-382.5 microC/cm(2), which was blocked by apical addition of Cl(-) channel blocker. Removal of HCO(3)(-) from the Krebs-Henseleit (K-H) solution inhibited the BFP-induced I(SC) by more than 95%. The present results suggest that BFP could improve digestive function by stimulating pancreatic protein and HCO(3)(-) secretion.

Role of leptin in the control of postprandial pancreatic enzyme secretion.

Leptin released by adipocytes has been implicated in the control of food intake but recent detection of specific leptin receptors in the pancreas suggests that this peptide may also play some role in the modulation of pancreatic function. This study was undertaken to examine the effect of exogenous leptin on pancreatic enzyme secretion in vitro using isolated pancreatic acini, or in vivo in conscious rats with chronic pancreatic fistulae. Leptin plasma level was measured by radioimmunoassay following leptin administration to the animals. Intraperitoneal (i.p.) administration of leptin (0.1, 1, 5, 10, 20 or 50 microg/kg), failed to affect significantly basal secretion of pancreatic protein, but markedly reduced that stimulated by feeding. The strongest inhibition has been observed at dose of 10 microg/kg of leptin. Under basal conditions plasma leptin level averaged about 0.15 +/- 0.04 ng/ml and was increased by feeding up to 1.8 +/- 0.4 ng/ml. Administration of leptin dose-dependently augmented this plasma leptin level, reaching about 0.65 +/- 0.04 ng/ml at dose of 10 microg/kg of leptin. This dose of leptin completely abolished increase of pancreatic protein output produced by ordinary feeding, sham feeding or by diversion of pancreatic juice to the exterior. Leptin (10(-10)-10(-7) M) also dose-dependently attenuated caerulein-induced amylase release from isolated pancreatic acini, whereas basal enzyme secretion was unaffected. We conclude that leptin could take a part in the inhibition of postprandial pancreatic secretion and this effect could be related, at least in part, to the direct action of this peptide on pancreatic acini.

Food and secretagogue stimulation decrease the digestive enzyme content remaining in the rat pancreas.

The aim of the study reported here was to investigate changes in the digestive enzyme content in the pancreas after food and secretagogue stimulation. Rats from which food had been withheld overnight were either fed (between 6 and 8 a.m.) or not before euthanasia and pancreatic excision (at 8 a.m.: 21 not fed and 21 fed) and at 4 (12 p.m.: six not fed and six fed) and 8 h later (4 p.m.: six not fed and six fed). Another 16 rats were anesthetized, fitted with jugular vein and pancreatic duct catheters, and infused with the secretagogues, CCK-33 and secretin, during 1.5 h of pancreatic juice collection before euthanasia and pancreatic excision. The pancreata were homogenized, and total soluble protein and individual enzyme (trypsin and amylase) tissue contents were analyzed. Results indicated lower amounts of protein and enzymes remaining in the pancreata of the fed, compared with non-fed rats. Enzyme values indicated recovery within four hours in fed rats, but non-fed rats also had increased values during daytime. High enzyme secretion during the high dose of hormonal stimulation was reflected in lower enzyme values remaining in the pancreas, compared with that in response to low-dose stimulation. Results indicated that stimulation of the pancreas, either by food ingestion or exogenous secretagogues, lowers the amounts of digestive enzymes remaining in the pancreas, and imply that stimulation and circadian rhythms influence the pancreatic enzyme content at euthanasia. This finding should be borne in mind in interpretation of data from pancreatic studies.

Exocrine pancreatic secretion is stimulated in piglets fed fish oil compared with those fed coconut oil or lard.

An experiment was conducted to study the effect of feeding diets containing fat sources with different fatty acid composition (fish oil, coconut oil or lard, 10 g/100 g diet) on exocrine pancreatic secretion in piglets after weaning. A total of 16 barrows were weaned at 4 wk of age; 3 d later, they were surgically fitted with a catheter in the pancreatic duct for continuous collection of pancreatic juice. Collections of pancreatic juice were made every other day starting 4 d postsurgically. Piglets fed the fish oil diet secreted a significantly greater volume of pancreatic juice than piglets fed the coconut oil or lard diets. The output [U/(h. kg(0.75))] of lipase was higher in piglets fed fish oil than in piglets fed lard or coconut oil. The output of colipase was greater in piglets fed fish oil and coconut oil than in those fed lard. The dietary treatments did not affect the output of carboxylester hydrolase. The output of trypsin was significantly lower in piglets fed lard than in piglets fed fish oil or coconut oil diets and the output of carboxypeptidase B was greater in those fed the fish oil diet. Protein, chymotrypsin, carboxypeptidase A, elastase and amylase outputs did not differ among the dietary treatment groups. The apparent digestibilities of nutrients and energy were measured in feces and did not differ among groups. Thus, the greater output of lipase in fish oil-fed piglets did not result in a greater digestibility of fat in this diet.

Influence of intraduodenally infused olive and coconut oil on postprandial exocrine pancreatic secretions of growing pigs.

The effect of dietary vegetable oils differing in fatty acid composition that were infused directly into the duodenum on exocrine pancreatic secretions in pigs has not previously been studied. The objective of the present study was to determine the acute response of the exocrine pancreas to vegetable oils with various fatty acid profiles under prandial conditions. Six growing pigs (BW 13.2 kg) were surgically prepared with pancreatic duct catheters and duodenal reentrant T-cannulas. The animals were fed twice a day (1000 and 1600) a commercial weaner diet at a rate of 2% of BW. Beginning with the morning feeding, olive oil, coconut oil, or saline as a control were infused in boluses every 5 min in total 0.1% of BW over a period of 1 h directly into the duodenum according to a 3 x 3 Latin square design. Pancreatic juice was collected over a period of 4 h, beginning 1 h preprandially (0900) until 3 h postprandially (1300). A time effect was observed after the infusion of olive oil on the volume of secretion, on protein contents and outputs, as well as on lipase contents and outputs and on colipase contents. The infusion of saline and coconut oil changed the runs of the curves for lipase and colipase outputs. No time x treatment interactions were observed regarding volume of secretion, protein contents and outputs, trypsin contents and outputs, and lipase outputs. The runs of the curves for lipase contents were different between the olive oil and saline treatment and between the olive oil and coconut oil treatment. The runs of the curves for the olive oil and saline treatment differed from each other regarding colipase contents. Pooled values of colipase outputs were elevated after coconut oil treatment, and a positive correlation between trypsin and colipase contents was found. Under prandial conditions, the exocrine pancreas responds differently in its acute secretion to different vegetable oils due to the differences in the fatty acid profiles.

Regulation of PSP/reg in rat pancreas: immediate and steady-state adaptation to different diets.

Pancreatic stone protein/reg protein (PSP/reg) is a secretory pancreatic protein of hitherto unknown function. It is precursor to a spontaneously precipitating peptide called pancreatic thread protein, which is found in protein plugs within the pancreatic ductal system. Increasing PSP/reg concentrations in pancreatic juice might augment the risk of intraductal plug formation and therefore be a condition predisposing to chronic pancreatitis. Malnutrition is associated with a high incidence of chronic pancreatitis in tropical countries. In a diet study with rats, we tested the hypothesis that protein malnutrition leads to increased PSP/reg concentrations in pancreatic juice. A highly sensitive and reliable enzyme-linked immunosorbent assay (ELISA) for rat PSP/reg was newly established. Male Sprague-Dawley rats were allocated to three nearly isocaloric experimental diets, which contained 0, 45, or 82% casein, respectively, or to a control diet (22% casein). We evaluated PSP/reg expression under these four dietary conditions on the RNA and on the protein level, performing a time-course study over a period of 28 days. Our results demonstrate that PSP/reg expression is not increased because of a protein-deficient diet if investigated under steady-state conditions. After a temporary increase in PSP/reg levels due to a carbohydrate-deficient high-protein diet, we could not find signs of a diet-dependent regulation of this protein. The regulation of PSP/reg thus differs from that of most other pancreatic secretory proteins. Our findings contradict earlier reports that had drawn conclusions based solely on messenger RNA levels.

[Effects of the centipede aqueous extract on animal gastrointestinal function].

In order to investigate the mechanism of Centipede on the function of animal gastrointestinal digestion, we studied the effects of cetipede aqueous extract on animal digestion, secretion and intestional movement. The results showed that the Centipede extract increased the volume of gastric juice and acid, activity of pepsin, volume of pancreatic juice and protein in rat. The Centipede extract also accelerated the mice intestinal movement. The above results revevaled that Centipede could regulate the function of the gastrointestinal digestion, secretion and movement.

[The effect of blood-pancreatic juice barrier on 5-fluorouracil in post-pancreatoduodenectomy patients].

OBJECTIVE: To observe the distribution and the relationship of 5-Fu in the plasma and the pancreatic juice in post-pancreatoduodenectomy patients after 5-Fu given intravenously. METHODS: After 5-Fu (1.0 g/m(2)) was given intravenously in post-pancreatoduodenectomy patients, blood and pancreatic juice were collected. The 5-Fu concentrations were determined by HPLC and at last the penetration ratio (PR) of 5-Fu was studied with PCNONLIN. RESULTS: 5-Fu in the plasma penetrated the pancreatic tissue and crossed the blood-pancreatic juice barrier (BPJB) in post-pancreatoduodenectomy patients (PR = 1.01 +/- 0.49). The concentration of 5-Fu in pancreatic juice was much higher than that in plasma. CONCLUSIONS: 5-Fu is suitable for adjuvant chemotherapy of pancreatic adenocarcinoma after pancreatoduodenectomy.

Stimulative effects of saponin from kikyo-to, a Japanese herbal medicine, on pancreatic exocrine secretion of conscious rats.

Our previous report stated that kikyo-to, a Japanese herbal medicine, consisting of the roots of Platycodon grandiflorum and Glycyrrhiza sp., stimulates the pancreatic exocrine secretion of conscious rats. The present study focused on the effective components of kikyo-to and the mechanism of stimuli to pancreatic secretion of rats. When 10 to 100 mg of platycodin D, a saponin from the root of Platycodon grandiflorum, was intragastrically administered, the pancreatic secretion of rats was stimulated. At the same time, the plasma CCK concentration increased. On the other hand, the stimulative effects of glycyrrhizin, a saponin from the root of Glycyrrhiza sp. were weak compared to platycodin D. The effects of 10 mg/kg of platycodin D on pancreatic secretion were inhibited by loxiglumide (50 mg/kg, i.g.), a CCK receptor antagonist. In contrast, the suppressive effect of atropine (300 micrograms/kg/h, i.v.) on pancreatic secretion was reduced by administering 10 mg/kg of platycodin D. In addition, up to 1 mM of platycodin D did not inhibit the trypsin activities in vitro. In conclusion, kikyo-to serves to stimulate pancreatic exocrine secretion mainly because platycodin D causes gastrointestinal hormones, particularly, CCK to be released from the duodenum.

[The effect of blood-pancreatic juice barrier on antitumor drugs excretion].

Chemotherapy is one of important adjuvant therapies for patients with pancreatic adenocarcinoma, but the mechamism 5-FU and MMC distributed over the pancreas is not known at home and abroad. Based on determining the ratio of the concentration of several kinds of antibioticsin plasma and pancreatic juice, we used fourteen dogs to study the distribution and the relationship of agents in plasma and pancreatic juice after giving 5-FU and MMC intravenously. At the same time, we observed some patients who received Whipple's operation. The results showed that 5-FU and MMC in plasma can penetrate the pancreatic tissue and cross the blood-pancreatic juice barrier (BPJB). Both agents suitable for the adjuvant chemotherapy of pancreatic adenocarcinoma.

Effects of the amount and type of dietary fat on exocrine pancreatic secretion in dogs after different periods of adaptation.

Mongrel dogs were fed, from weaning to 6 months of age, on one of two 9% lipid diets that differed only in the type of fat content (sunflower oil or virgin olive oil) to study their effects on exocrine pancreatic secretion, in the basal period and in response to food. In addition, the results were compared with those obtained in a previous work performed by us on dogs adapted for 8 months to diets containing a higher (15%) amount of the same dietary fats to further evaluate the influence of the amount of dietary fat and the length of the adaptation period. The results from the present study show that both the volume and bicarbonate secreted in the absence of stimuli are unaffected by the quality of dietary fat. In contrast, in response to food, the pancreatic juice flow and the bicarbonate output were significantly higher in the group of animals given the sunflower oil diet. The differences seem to be related with the oleic acid content in the diets and the effectiveness of this fatty acid in triggering the release of inhibitory peptides such as pancreatic polypeptide and peptide YY. The comparison between the results from our present and previous studies supports the afore-mentioned hypothesis and confirms the existence of a clear influence of the amount and type of dietary fat, especially the oleic acid content, upon the pancreatic response to food, without ruling out a role for the duration of the adaptation period.

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.

Effect of dietary canola oil and its degree of oxidation on exocrine pancreatic secretions in growing pigs.

Four barrows, average initial weight 35 kg, were fitted with permanent pancreatic re-entrant cannulas and used to determine the effect of level and quality of dietary fat on exocrine pancreatic secretions. The pigs were fed four corn starch-based diets that contained 15% crude protein from isolated soy protein. Diet 1 contained no canola oil (C-0); diet 2, 15% canola oil (C-15); diet 3, 15% canola oil that was heated under vacuum at 180 degrees C for 12 h (C-15/12); diet 4, 15% canola oil that was heated under vacuum at 180 degrees C for 24 h (C-15/24). Heat treatment resulted in a 4- to 5-fold increase in the content of malonaldehyde which is derived from the oxidation of fatty acids and which is closely related to odour and rancidity in lipids. The experiment was carried out according to a 4 x 4 Latin square design. The pigs were fed twice daily, at 08:00 and 20:00 h, 900 g each meal. Following an adaptation period of 7 d, pancreatic juice was collected continuously for 24 h at 2-h intervals from 08:00 on d 8 until 08:00 on d 9 and from 08:00 on d 10 until 08:00 on d 11 during each experimental period. The volume of secretion of pancreatic juice peaked 6-10 h postprandially and was similar (P > .05) during day (08:00-20:00 h) and night (20:00-08:00 h). Replacement of 15% starch by 15% canola oil resulted in a decrease (P < .05) in the secretion of alpha-amylase and an increase (P < .05) in the secretion of lipase. The inclusion of oxidized fat caused a further increase (P < .05) in total lipase activities. It can be concluded that the exocrine pancreas is able to adapt to variations in the level and quality of dietary lipids.