Alterations in the liver of intrauterine growth retarded piglets may predispose to development of insulin resistance and obesity in later life

Intrauterine growth retardation (IUGR) leads to increased predisposition to metabolic syndrome in adult life but the mechanisms remain obscure. Considering a significant number of functional similarities, IUGR piglets appear to be a good model to study the development of this syndrome in humans. The aim of the present study was to investigate the ultrastructure and proteomic profile of the liver in IUGR pig neonates to discover early markers of predisposition to obesity and insulin resistance. In our study intestine and liver tissue samples were investigated in 7 day old IUGR and normal body weight (NBW) littermate piglets using histometry, mass spectrometry, in-tissue cytometry analysis and confocal microscopy. Compared to NBW, the liver in IUGR neonates was characterized by a significantly enhanced ratio of Kupffer cells to hepatocytes and insulin receptor abundance as well as higher percentages of cells expressing receptors for adipokines (resistin and adiponectin), increased expression of TNF-α (as marker of inflammation), and increased expression of insulin receptor and uncoupling protein 3 (UCP3). Moreover, NBW and IUGR differed in proteomic profile, including protein metabolism (proteasomes, cathepsin D, phermitin, phosphoglucomutase), carbohydrate metabolism (hexokinase 1, phosphoglucokinase, galactokinase, aldolase B, glucose-6-phosphate isomerase), oxidative stress and chromatin organization and DNA uptake (histones, lamin a/c). Reduction of hepatocyte numbers concomitant with significant modifications of expression of key hormones and enzymes for protein and carbohydrate metabolism in IUGR neonates may predispose to insulin resistance and obesity in adult life.

Mechanisms involved in the development of the small intestine mucosal layer in postnatal piglets

The use of complementary visualization and measurement techniques allowed accurate description and quantification of changes in the intestinal mucosal architecture and provided a comprehensive outlook on the dynamics of remodelling and maturation processes of the mucosal layer taking place in the small intestine of piglets from birth to weaning. The aim of the study was to examine the early postnatal development of the small intestine in pigs. Three techniques were used: scanning electron microscopy (measurements of villus density and shape, height of enterocytes and microvilli, cell exfoliation, and location of extrusion zones), optical microscopy (cross section, measurement of structures: villus length and width; crypt depth; mucosal thickness), and confocal microscopy (cell localization, apoptosis, exfoliation and migration). The postnatal development of the mucosal layer of the small intestine was reflected in changes in the density, length, width, and shape of villi, crypt depth, replacement of enterocyte population, and arrangement. The presence of deep transverse furrows on villus corpus and vacuolated fetal-type enterocytes in the mucosal layer of the small intestine, which are able to engulf large amounts of colostrum shortly after birth, appears to play an important role in the observed phenomenon of straightening of the villus height and increasing of the villus diameter shortly after birth. We hypothesized that the intestinal mucosal layer is compressed before birth and ready to unfold within a short time after birth.

Invited review: Use of butyrate to promote gastrointestinal tract development in calves

Promotion of microbial butyrate production in the reticulorumen is a widely used method for enhancing forestomach development in calves. Additional acceleration of gastrointestinal tract (GIT) development, both the forestomach and lower parts of the GIT (e.g., abomasum, intestine, and also pancreas), can be obtained by dietary butyrate supplementation. For this purpose, different sources (e.g., butyrate salts or butyrins), forms (e.g., protected or unprotected), methods (e.g., in liquid feed or solid feed), and periods (e.g., before or after weaning) of butyrate administration can be used. The aim of this paper was to summarize the knowledge in the field of butyrate supplementation in feeds for newborn calves in practical situations, and to suggest directions of future studies. It has been repeatedly shown that supplementation of unprotected salts of butyrate (primarily sodium salt) in milk replacer (MR) stimulates the rumen, small intestine, and pancreas development in calves, with a supplementation level equating to 0.3% of dry matter being sufficient to exert the desired effect on both GIT development and growth performance. On the other hand, the effect of unprotected butyrins and protected forms of butyrate supplementation in MR has not been extensively investigated, and few studies have documented the effect of butyrate addition into whole milk (WM), with those available focusing mainly on the growth performance of animals. Protected butyrate supplementation at a low level (0.3% of protected product in DM) in solid feed was shown to have a potential to enhance GIT development and performance of calves fed MR during the preweaning period. Justification of this form of butyrate supplementation in solid feed when calves are fed WM or after weaning needs to be documented. After weaning, inclusion of unprotected butyrate salts in solid feed was shown to increase solid feed intake, but the effect on GIT development and function has not been determined in detail, and optimal levels of supplementation are also difficult to recommend based on available reports. Future studies should focus on comparing different sources (e.g., salts vs. esters), forms (e.g., protected vs. unprotected), and doses of supplemental butyrate in liquid feeds and solid feeds and their effect not only on the development of rumen, abomasum, and small intestine but also the omasum and large intestine. Furthermore, the most effective source, form, and dose of supplemental butyrate in solid feed depending on the liquid feed program (e.g., MR or WM), stage of rearing (e.g., pre- or postweaning), and solid composition (e.g., lack or presence of forage in the diet) need to be determined.

Effect of butyrate infusion into the rumen on butyrate flow to the duodenum, selected gene expression in the duodenum epithelium, and nutrient digestion in sheep

The aim of the study was to determine the effect of butyrate infusion into the rumen on butyrate flow to the duodenum, expression of short-chain fatty acid (SCFA) transporters (monocarboxylate transporter-1, -2, and -4) and receptors (G protein coupled receptor-41 and -43) in the duodenal epithelium and nutrient digestion in sheep. Eight wethers (39.0 ± 3.00 kg; mean ± SD) with ruminal and T-shape duodenal cannulas were allocated to 4 × 4 replicated Latin square design with each experimental period lasting for 21 d (12 d of adaptation and 9 d for data and sample collection). Experimental treatments were: 1) distilled water infusion into the rumen (CONT); 2) 15 g/d of butyric acid infusion into the rumen (BUT15); 3) 30 g/d of butyric acid infusion into the rumen (BUT30); and 4) 45 g/d of butyric acid infusion into the rumen (BUT45). The daily dose of butyrate was infused into the rumen via the rumen cannula, with 200 mL of solution of butyric acid and distilled water, at a constant rate (0.1389 mL/min) throughout the day using a peristaltic pump. Correspondingly, 200 mL/d of distilled water was infused into the rumen of CONT. The wethers were fed daily 900 g of chopped meadow hay and 200 g of concentrate in two equal meals at 0600 and 1800 h. Butyrate infusion into the rumen did not affect total SCFA concentration in the rumen fluid ( > 0.11). Molar proportion of butyrate in total SCFA linearly increased, and molar proportion of acetate and isovalerate linearly decreased ( ≤ 0.02) with an increasing amount of butyrate infused into the rumen. The molar proportion of butyrate in total SCFA in the duodenal digesta linearly increased ( < 0.01), and butyrate flow to duodenum tended to linearly increase ( = 0.06) with an increasing dose of exogenous butyrate delivered to the rumen. Butyrate infusion into the rumen did not affect ( ≥ 0.14) the mRNA expression of monocarboxylate transporter-2 and -4 and G protein coupled receptor-43 in the duodenal epithelium. The G protein coupled receptor-41 and monocarboxylate transporter-1 mRNA expression in the duodenal epithelium was very low in many of the analyzed samples. Digestibility of organic matter, neutral detergent fiber, and acid detergent fiber in the stomach (forestomach and abomasum) decreased for BUT15 and BUT30 and then increased for BUT45 (quadratic, ≤ 0.04); however, neither digestibility in the intestine nor total tract digestibility differed between treatments ( ≥ 0.10).

The role of apelin in the modulation of gastric and pancreatic enzymes activity in adult rats

Apelin is considered as important gut regulatory peptide ligand of APJ receptor with a potential physiological role in gastrointestinal cytoprotection, regulation of food intake and drinking behavior. Circulating apelin inhibits secretion of pancreatic juice through vagal- cholecystokinin-dependent mechanism and reduces local blood flow. Our study was aimed to determine the effect of fundectomy and intraperitoneal or intragastric administration of apelin-13 on pancreatic and gastric enzymes activities in adult rats. Fundectomy is a surgical removal of stomach fundus - maine site apelin synthesis. Three independent experiments were carried out on Wistar rats. In the first and second experiment apelin-13 was given by intragastric or intraperitoneal way twice a day for 10 days (100 nmol/kg b.w.). Control groups received the physiological saline respectively. In the third experiment the group of rats after fundectomy were used. Fundectomized rats did not receive apelin and the rats from control group were 'sham operated'. At the end of experiment rats were sacrificed and blood from rats was withdrawn for apelin and CCK (cholecystokinin) radioimmunoassay analysis and pancreas and stomach tissues were collected for enzyme activity analyses. Intragastric and intraperitoneal administrations of apelin-13 increased basal plasma CCK level and stimulated gastric and pancreatic enzymes activity in rats. In animals after fundectomy decreased activity of studied enzymes was observed, as well as basal plasma apelin and CCK levels. In conclusion, apelin can effects on CCK release and stimulates some gastric and pancreatic enzymes activity in adult rats while fudectomy suppresses those processes. Changes in the level of pancreatic lipase activity point out that apelin may occurs as a regulator of lipase secretion.

Differences in monocarboxylic acid transporter type 1 expression in rumen epithelium of newborn calves due to age and milk or milk replacer feeding

The aim of the present study was to investigate whether besides age and solid feed intake, monocarboxylic acid transporter type 1 (MCT1) expression in the rumen epithelium of calves is affected by liquid feed type [whole milk (WM) or milk replacer (MR)]. Thirty bull calves at the mean age of 5 days were randomly allocated to five experimental groups (six calves/group). Six calves were slaughtered immediately after allocation to the trial (5 days of life), eighteen calves were fed MR and slaughtered at week intervals (on 12, 19, 26 days of life respectively), and six calves were fed WM and slaughtered at the 26 days of life. MCT1 protein abundance and the MCT1 mRNA level were investigated in the dorsal and ventral sack of the rumen. Solid feed intake and short-chain fatty acids (SCFA) concentration in the rumen fluid increased linearly with calves' age. The amount of the MCT1 protein and mRNA in the dorsal sac of rumen as well as the amount of MCT1 protein in the cranial ventral sac of rumen also increased linearly with calves' age. Calves fed WM had greater solid feed intake in the last week of the study as compared to calves fed MR, but SCFA concentration in the rumen fluid was not different. MCT1 mRNA expression in the cranial dorsal sac of rumen and protein MCT1 expression in both dorsal and ventral cranial sack of the rumen were higher in calves fed WM as compared to calves fed MR. This study confirmed age-dependent changes of MCT1 expression in the rumen epithelium of newborn calves and showed that its expression might be affected by liquid feed type.

Early-effect of bariatric surgery (Scopinaro method) on intestinal hormones and adipokines in insulin resistant Wistar rat

Bariatric surgery consists in duodenal exclusion from the food passage in obese patients with coexistent type 2 diabetes. Nowadays bariatric surgery is considered the most effective method of glycemic index normalization and insulin resistance reduction. Recent results on obese and non-obese rats showed remission of type 2 diabetes symptoms within few days after the surgery. The aim of the present work was to analyze the mechanisms of neuro-hormonal regulation responsible for early normalization of metabolic syndrome after bariatric surgery. In present study the concentration of selected intestinal hormones and adipokines in blood plasma and gastrointestinal tissues were analyzed. Study was conducted on Wistar rats. Animals were divided into three groups (each n=6): control (SH) shame-operated rats; animals in which visceral fat tissue was extracted (LP); and rats in which Scopinaro bariatric surgery was performed (BPD). Immunochemistry analysis of blood plasma showed decrease of insulin concentration in BPD and LP and increase of polypeptide YY (PYY) in BPD group as compared to the control. In duodenal mucosa homogenates the tendency to reduce insulin in LP and BPD group, and increase PYY and visfatin in BPD group was observed. Histometry analysis showed reduction of mucosa thickness in excluded segments of gastrointestinal tract in BPD group as compared to the SH and LP. Concluding, model studies on rats allowed better understanding of mechanisms important for early normalization of glycemic index and insulin resistance reduction in rats.

Influence of fundectomy and intraperitoneal or intragastric administration of apelin on apoptosis, mitosis, and DNA repair enzyme OGG1,2 expression in adult rats gastrointestinal tract and pancreas

Apelin, endogenous ligand of G protein-coupled apelin receptor (APJ), is released into the gastrointestinal lumen, however, local effect of luminal apelin on gut epithelium has not been elucidated so far. The present study aimed to determine the effects of fundectomy, and intraperitoneal or intragastric administration of apelin on pancreatic, gastric and intestinal epithelium apoptosis, mitosis and DNA repair enzyme OGG1,2 expression in adult Wistar rats. Apelin-13 was given by intraperitoneal or gastric gavage twice a day for 10 days (100 nmol/kg b. wt./day). Fundectomized rats did not receive apelin. Control groups received saline as placebo. At the end of the experiment the rats were sacrificed and the pancreas, gastric fundus, duodenum, middle jejunum and colon tissue samples were harvested for immunofluorescence studies. Intraperitoneal and intragastric apelin-13 reduced apoptosis, mitosis and number of DNA damages in rats gastrointestinal tract (p≤0.001) as compared to control. In fundectomized rats, the apoptotic index in the pancreas and colon was decreased (p<0.001), and in the stomach and jejunum was increased (p<0.001). Mitotic index was decreased in all gastrointestinal tissues. Number of DNA damages (p≤0.001) in fundectomized rats was reduced except stomach where OGG1,2 expression was increased (p≤0.001) as compared to control. In conclusion, circulating and luminal exogenous apelin-13 caused similar effects on intestinal epithelium. Endogenous (gastric) apelin is important for renewal of intestinal epithelium in adult rats. Pharmacological doses of apelin-13 may reduce the cell turnover in the upper gastrointestinal tract epithelium and pancreas, and improve the overall gut health.

Does different approach during pancreatoduodenectomy influence intestinal migrating myoelectrical complex recovery? Study in experimental pig model

It is said that leaving intact the functional motor unit of the pylorus leads to better gastric emptying and reduces postoperative upper gut motility disturbances. However, despite obvious different surgical approach, both major pancreatoduodenectomies lead to substantial myoelectrical dysfunctions. The latter are not efficiently recognized. We compared Whipple and Longmire-Traverso procedures in terms of electromyography patterns of the upper jejunum musculature and the density of Cajal cells network. Twelve male weaned pigs underwent surgery first to implant bipolar electrodes and telemetry transmitters for continuous electromyography recordings and then, after 1 week recovery, to create Whipple (n=6) and Longmire-Traverso (n=6) pancreatoduodenectomies. The first myoelectric activity was already registered 1-2 hours after both operations. Time to first regular patterns of migrating myoelectrical complex activity was significantly longer in the Whipple than in the Longmire-Traverso group (68.2±12.9 versus 27.8±51 hours, p=0.002). However, the restored patterns were substantially disturbed in both groups. Namely, after Longmire-Traverso operation, migrating myoelectrical complex cycles were very often and significantly shorter versus control ones, with reverse migration in the area of anastomosis while after Whipple procedure migrating myoelectrical complex cycles were less frequent and of short duration, significantly shorter in comparison even with Longmire-Traverso group. Cajal cells network in the vicinity of anastomosis, and distally from it, presented greater destruction after the Whipple operation. In conclusion, the advantage of one of two major pancreatoduodenectomies in terms of myoelectrical activity correctness in upper gut has not been proved in the study.

Structural and functional development of small intestine in intrauterine growth retarded porcine offspring born to gilts fed diets with differing protein ratios throughout pregnancy

Protein level in the maternal diet plays a crucial role in fetal programming during pregnancy. Low or high protein level increases the risk of intrauterine growth retardation (IUGR). The aim of this study was to investigate the structural and functional development of the small intestine in piglets from sows fed a control (C, 12.1% protein), a high protein (HP, 30% protein), or a low protein (LP, 6.5% protein) diet during pregnancy. Newborns were classified as IUGR (birth weight ≤1.18 kg) and non-IUGR (birth weight >1.18 kg). The piglets were euthanized on postnatal day (PD)1, PD28 and PD188. The LP diet in non-IUGR neonates resulted in decreased body weight on PD1. The LP and HP diets resulted in both decreased body weight and delayed catch-up growth in the IUGR piglets. The HP and LP-diets increased the length of villi on PD1 in non-IUGRs but not in IUGRs. At birth, the expressions of Ki67 and active caspase 3 in mid-jejunum epithelium of HP and LP non-IUGR neonates were significantly lower as compared to C non-IUGRs whilst in IUGRs the respective expressions were as high as in C non-IUGRs. The postnatal dynamics of brush border enzyme activities and vacuolated enterocytes disappearance showed significant drop in enterocyte maturation in IUGR as compared to non-IUGR neonates. In conclusion, both HP and LP diets led to retarded development of non-IUGR piglets. In IUGR piglets both HP and LP diets resulted in delayed catch-up growth, without adaptive changes in brush border digestive enzymes.

Effect of method of delivery of sodium butyrate on rumen development in newborn calves

The effect of sodium butyrate (SB) supplementation in milk replacer (MR) or in starter mixture (SM) or in both MR and SM on performance, selected blood parameters, and rumen development in newborn calves was determined. Twenty-eight male calves with a mean age of 5 (±1) d were randomly allocated into 1 of 4 groups (7 animals per group) and fed (1) MR and SM, both without SB (MR(-) and SM(-), respectively); (2) MR(-) and SM supplemented with SB encapsulated within a triglyceride matrix (SM(+), 0.6% as fed; 30:70 butyrate-to-triglyceride matrix); (3) MR supplemented with crystalline SB (MR(+), 0.3% as fed) and SM(-); or (4) MR(+) and SM(+). The MR was offered in an amount equal to 10% of the initial body weight (BW) of each calf. The SM was blended with whole corn grain (50/50; wt/wt) and offered ad libitum as a starter diet (0.3% encapsulated-within-triglyceride matrix SB when SM(+) was fed) from the first day of the trial. Calves were slaughtered at d 21 of a trial (mean age 26±1 d). Addition of SB into MR (MR(+)) positively affected BW and average daily gain, tended to decrease the number of days with electrolyte therapies from d 0 to 7, and tended to positively affect fecal consistency from d 8 to 14 of the trial. Inclusion of SB into SM (SM(+)) increased starter diet intake from d 15 to 21, decreased the number of days with scours, and tended to decrease the number of days with electrolyte therapies in the whole trial period. Both MR(+) and SM(+) increased plasma glucose in the whole trial period and MR(+) increased total serum protein at d 14. The SM(+) increased plasma glucagon-like peptide-2 (GLP-2) concentration at d 7 of the trial when compared with the concentration at d 0. Both MR(+) and SM(+) increased reticulorumen weight and papillae length and width. Based on these results, it can be concluded that addition of SB in MR positively affected BW gain, health, and some metabolic intermediates of calves and it stimulated rumen development indirectly, whereas SB supplementation in SM stimulated rumen development directly. Addition of SB both in MR and SM could be recommended for rearing calves.

The effect of exogenous apelin on the secretion of pancreatic juice in anaesthetized rats

Apelin is known to stimulate cholecystokinin (CCK) and inhibit insulin release, however the mechanisms on pancreatic secretion remain unclear. The present study aimed to determine the expression of apelin and apelin receptor in the pancreas by immunofluorescence studies and the effect of exogenous apelin on the secretion of pancreatic juice in anesthetized rats. Pancreatic-biliary juice (P-BJ) was collected from Wistar rats treated with apelin (10, 20 and 50 nmol/kg b.w., boluses given every 30 min intravenously or intraduodenaly). The same apelin doses were administered to rats subjected to intraduodenal tarazapide, capsaicin or vagotomy. Pancreatic blood flow was measured by a laser doppler flowmeter. Direct effects of apelin were tested on dispersed acinar cells. Apelin receptor was expressed on acinar cells, pancreatic duct and islets cells, whereas apelin in pancreatic acini, but not in the islets. Intravenous apelin decreased P-BJ volume, protein and trypsin outputs in a dose-dependent manner. In contrast, intraduodenal apelin stimulated P-BJ secretion. Pharmacological block of mucosal CCK(1) receptor by tarazepide, vagotomy and capsaicin pretreatment abolished the effects of intravenous and intraduodenal apelin on P-BJ volume, protein and tryspin outputs. Apelin decreased the pancreatic blood flow. Apelin at 10(-6) M increased the release of amylase from non-stimulated and CCK-8-stimulated acinar cells. In conclusion, apelin can affect the exocrine pancreas through a complex mechanism involving local blood flow regulation and is driven by vagal nerves.

Is rumen development in newborn calves affected by different liquid feeds and small intestine development?

The objective of the study was to determine the effect of different liquid feeds on calf small intestine and rumen development. Twenty-one bull calves (5 ± 1 d old) were randomly allocated to 3 groups and fed whole milk (WM), milk replacer (MR; 22% CP and 17.5% fat), or MR supplemented with sodium butyrate (MR+SB; 0.3% as fed). Liquid feed dry matter intake was equal between treatments and amounted to 1% of BW at the beginning of the trial. Starter diet was offered ad libitum. Animals were slaughtered at 26 (± 1) d of age. Calves fed WM had higher average daily gain in the whole trial and higher starter diet dry matter intake between d 15 to 21 of the trial as compared with calves fed MR and MR+SB. Calves fed MR lost on average 1.4 kg of BW within first 14 d of the trial and their BW tended to be lower at d 7, 14, and 21 of the study as compared with calves fed MR+SB. The empty jejunum and ileum weight, crypt depth, mitotic index in the middle jejunum were higher, and apoptotic index tended to be lower in calves fed WM as compared with calves fed MR and MR+SB. Calves fed WM also had higher aminopeptidase N activity in the middle jejunum and tended to have higher maltase activity in the distal jejunum as compared with calves fed MR and MR+SB. The mitotic index was higher and apoptotic index was lower in the middle jejunum, and aminopeptidase A activity tended to be higher in the distal jejunum of calves fed MR+SB as compared with those fed MR. Calves fed WM had greater papillae length and width, and tended to have greater muscle layer thickness as compared with calves fed MR and MR+SB. Reticulorumen weight, reticulorumen weight expressed as percent of whole stomach weight, and papillae length and width were higher in calves fed MR+SB as compared with those fed MR. Additionally, calves fed WM had higher plasma glucose and urea in the whole trial period as compared with calves fed MR and MR+SB, and plasma glucose was higher in calves fed MR+SB as compared with those fed MR. Significant positive Pearson correlations were found between small intestine and reticulorumen weights as well as between activity of brush border lactase, maltase, aminopeptidase A, and aminopeptidase N and reticulorumen weight. Different liquid feeds affect small intestine development, animal growth, solid feed intake and metabolic status of calves and this effect can indirectly influence the development of forestomachs.

Gastrointestinal tract and digestion in the young ruminant: ontogenesis, adaptations, consequences and manipulations

Young calves have to deal with at least three major situations that require profound physiological and digestive adaptations: adaptation to extra-uterine life (up to the first postnatal week), maintenance at a pre-ruminant stage over a long period (3 to 5 months or more), and weaning. This paper reports results obtained on the development (growth and differentiation) of the gastrointestinal tract, and on digestive enzyme activities as well as some aspects of the regulation by gut regulatory peptides. In the newborn calf, the maturation of the small intestine depends on pregnancy duration (preterm vs. full term) and ingestion of colostrum from first milking. The function of gut enterocytes evolves along with the changes from fetal to adult enterocytes. The origin of dietary protein in pre-ruminant and weaning calves modifies SI morphology. Chymosin, elastase II and lactase are typical postnatal enzymes, whereas pepsin, ribonuclease and amylase become important especially following weaning. Nitrogen digestibility increases during the first month of life and is modified by replacement of skim milk powder with non-milk proteins. Milk formula supplementation with Nabutyrate increases pancreatic secretions and digestibility. The gastrointestinal tract development depends on gut regulatory peptides plasma and luminal concentrations. The response to exogenous peptides is in relation with their number and type of functional receptors and with the animal age. Experimental work with young ruminants is important not only for the species involved, but also for its implications to other mammalians.

Adverse effects of nutritional programming during prenatal and early postnatal life, some aspects of regulation and potential prevention and treatments

Nutritional programming, regulation and some ways for prevention/treatment to ameliorate or normalize adverse outcomes of programming are discussed. Epidemiological studies in human and animal experiments showed that nutrition during fetal and neonatal life may lead to related disorders in adulthood. But several argues may question its validity arising the question of the adequate models used to reproduce human situations. Protein level in milk formula intake by infant during neonatal life is discussed. Body weight at birth reflects the product growth trajectory during fetal life. Low birth weight is considered as the result of an adverse growth trajectory and is often associated with later metabolic diseases in adult age. But, the sum of prenatal growth trajectory, rapid growth in early infancy (catch up growth), early adiposity rebound in childhood must be considered to determine the origins of later diseases in adulthood. The review focuses the regulation of nutritional imprinting on hormonal and epigenetic mechanisms which are complementary. The HPA axis and GH-IGF axis may have a crucial role in the regulation induced by nutritional programming. The persistent alterations seem to be a consequence, at least in part, of elevated insulin levels during "critical periods" of pre- and early postnatal development. Also, leptin seems to play an important role in this complex system. New knowledge about these mechanisms involved suggest the development of new, rational, and effective preventive and/or therapeutic options before and/or after birth. Thus, early infancy may provide an opportunity for intervention aimed at reducing later disease risk.

Effect of sodium butyrate supplementation in milk replacer and starter diet on rumen development in calves

Rumen development is an important factor determining early solid feed intake and performance in cattle. A popular trend towards early weaning of newborn dairy calves necessitated looking for ways of accelerating the gastrointestinal tract (GIT) development. The present study aimed to determine the effect of sodium butyrate (NaB) supplementation in milk replacer and starter diet on rumen development in rearing calves. Fourteen bull calves (5-day-old) were randomly allocated to two groups: Control (C) and NaB. The later received 0.3 % NaB in milk replacer and starter diet. Animals were in experiment up to age of 26 days. Addition of NaB to milk replacer and starter diet had no effect on daily growth rate, but reduced the weight loss observed in C calves in first 11 days of age. Additionally, the NaB calves weighed more at the end of the study and tended to have higher growth rate in the whole trial period (P<0.15). The NaB calves showed a tendency toward higher reticulorumen weight (P=0.13) and higher reticulorumen weight expressed as a percent of whole stomach weight (P=0.02) as compared to control. Histometry analysis indicated larger rumen papillae length and width (P<0.01) in NaB group, and no change in muscle layer thickness, as compared to control. Plasma glucagon-like peptide-2 relative increase was higher in NaB group than in C group, and may be involved in rumen development. In conclusion, supplementation of the diet (milk replacer and starter diet) with NaB may enhance rumen development in neonatal calves.

Intestinal MMC-related electric fields and pancreatic juice control the adhesion of Gram-positive and Gram-negative bacteria to the gut epithelium--in vitro study

The adhesion of six different Lactobacillus and Lactococcus and three pathogenic Escherichia and Salmonella strains was studied using Caco-2 cell line. In this in vitro model system the influence of weak electric field (EF) on bacterial adhesion was tested. The EF source was the in vitro reconstruction of spiking potentials recorded in the duodenum of a healthy calf during one myoelectrical migration complex (MMC) cycle. The ability to adhere to Caco-2 cells of bacteria belonging to two groups, Gram-positive lactobacilli and lactococci, and Gram-negative Escherichia and Salmonella differed considerably. The pathogenic bacteria adhered better to well-differentiated Caco-2 cells whereas lactobacilli and lactococci displayed better adhesion to non-differentiated Caco-2 cells. In the presence of MMC-related EF an increased adhesion of Lactobacillus and Lactococcus but not of Salmonella enterica s. Enteritidis and E. coli 269 to Caco-2 cells was observed. Two later strains adhered even less in the presence of EF. The same tendency was found in the presence of pancreatic juice in a cell medium. In conclusion, the myoelectric component of the small intestinal motility, the MMC-related EF, and pancreatic juice may increase the ability of lactic acid bacteria to adhere to GI epithelial cells, creating better environmental conditions for colonization of the intestine and competition with Gram-negative pathogens.

Control of development of gastrointestinal system in neonates

Our recent studies of structure and function of gastrointestinal tract mucosa revealed that the domestification of Sus scrofa corresponds with the significant slowing of the organ development. On top of genetic potential, the nutritional factors (or more precisely - lack of certain biologically active substances in the feed of pregnant sows) are responsible. Moreover, feeding neonates with milk replacers instead of mother's milk further slows down the development. This is manifested by reduced mitotic activity in the crypts and enhanced apoptosis of enterocytes. The negative effects consist of slower replacement of fetal type, vacuolated enterocytes to adult type enterocytes, modified profile of brush border enzymes, alterations in intestinal mucosa barrier, higher susceptibility to infectious agents, and many others. On the other hand, farmers in order to intensify the production, shorten the suckling period imposing the neonatal piglets to be weaned at 3-4 weeks of life and even earlier. Altogether, it makes the weaning disorders one of the most important problems in pig husbandry, and the mortality of piglets in the leading pig-producing countries still reaches 10%. A number of strategies have been developed to counteract the post-weaning problems. One of them is to stimulate the development of the gastrointestinal tract of the neonate by supplementation of the sow diet with certain biologically active substances and plants. The other idea is to speed up the postnatal development of the gut mucosa for example by plant lectins. Lessons from pig studies can be also useful in human nutrition and medicine since the development of porcine gastrointestinal tract shows a great similarity to that of humans.

Role of feed-regulating peptides on pancreatic exocrine secretion

In recent two decades a group of feed intake-regulating peptides (i.e., leptin, apelin, ghrelin, obestatin and orexins) have been discovered. Besides the central nervous system these regulatory peptides are produced and released by the gastrointestinal (GI) endocrine cells and neurons, and functional receptors were found in the GI tract and the pancreas. High expression of feed intake-regulating peptides was found in the stomach; however, they may be expressed in other GI tissues too. The peptides control gastrointestinal functions, modulate orexigenic drive and energy metabolism via different mechanisms. Basal leptin, apelin, ghrelin and obestatin plasma concentrations correlated with BMI, and we observed significant reduction of ghrelin and leptin concentrations following fundectomy in rats. We have shown previously that exogenous leptin and ghrelin (a peptide derived from the same preprohormone as obestatin) inhibit the secretion of rat pancreatic juice through a neurohormonal mechanism. Intravenous obestatin was found to stimulate pancreatic protein output in anaesthetized rat via a CCK-vagal-dependent mechanism, whilst a direct action of obestatin on rat pancreatic acini in vitro resulted in opposite effect. Intravenous boluses of apelin reduced the juice volume, protein and trypsin outputs in a dose-dependent manner. However, apelin administered into the duodenal lumen significantly increased pancreatic protein and trypsin outputs through a vagal mechanism. Orexin A and B were found to stimulate insulin release, though on the rat exocrine pancreas orexin A had no effect, and the effect of orexin B was weak. Concluding, feed intake-regulating peptides participate in controlling the exocrine pancreas.

Gradual disappearance of vacuolated enterocytes in the small intestine of neonatal piglets

The unique feature of enterocytes in newborn mammals is the presence of an apical canalicular system (ACS) leading to production of large vacuoles, important for colostral macromolecule uptake. The vacuolated fetal-type enterocytes (VFE) enable transfer of colostral and milk proteins from the intestinal lumen across the epithelium without loosing their biological activity. First VFE are observed in the pig and lamb fetuses in the second trimester of pregnancy, located at the upper part of villi in the proximal region of the fetal small intestine and subsequently in the middle and distal regions. After birth the VFE are replaced with enterocytes lacking ACS. The present study aimed to investigate the depletion of VFE in the small intestine in the sow reared pig neonates during the first postnatal weeks using scanning electron microscopy (SEM). The SEM analysis demonstrated the gradual disappearance of vacuolated enterocytes in time. VFE remained in the jejunum for a few days after birth, whereas in the duodenum single VFE were present only at birth. In the proximal jejunum, the VFE were localized in the upper part of the villi, and disappeared until the day 3 of life. VFE were present in the mid and distal jejunum, and diminished gradually until day 14 of life. By the day 21 of life, the vacuolated cells were not observed neither in the jejunum nor ileum. In conclusion, morphology analysis of pig small intestinal mucosa suggests that replacement of fetal type vacuolated enterocytes is resumed within 21 days after birth.

Molecular mechanism of programmed cell death in the gut epithelium of neonatal piglets

In the intestinal mucosa of pig, calf and rat neonates, we observed the cells die in the packets which suggests involvement of some paracrine factors. The death signal was transferred via tissue continuum as well as across the gut lumen, and the involvement of TGF-beta1 and TNFalpha was demonstrated. Present study aimed to clarify the molecular mechanisms of programmed cell death in the mucosa of the small intestine of pig neonates. Groups (packets) of cells and the neighboring cells underwent apoptosis, and expressed an enhanced TGF-RII. In the dying cells the death signal promoted via TGF-RII was associated with enhanced expression of active caspase 8, TGF-beta1, TNFalpha and Bid. Quantitative study showed that high expression of TGF-beta1 was positively correlated with expression of BID and negatively with BCL-2, illustrating the transmission of signal from TGF-RII through SMAD cascade and RunX protein. We hypothesize that TGF-beta1 sensitizes the enterocytes for TNFalpha signaling and both cytokines control the apoptosis process in the gut epithelium. Intensive mitosis triggers many errors in DNA replication, and the role of p53 is to detect them and promote either repair or apoptosis. During first days of live all damaged cells were directed towards apoptosis while at day 7 at least some of them were repaired. Autophagy, the second form of programmed cell death, was recognized by its key marker MAP I LC3. Our data showed the colocalization of MAP I LC3 with active caspase 3 thus suggesting a coexistence between these two forms of cell death, at least in the early postnatal life.

The effect of supplementing sow with bioactive substances on neonatal small intestinal epithelium

Development of the small intestinal epithelium in early postnatal period has a significant influence on pig's survival rate and further productivity. The aim of this research was to verify whether the diet supplementation of pregnant and lactating sow with a blend of bioactive substances (flax seed, rapeseed, linden inflorescence, taurine, L-carnitine and tocopherol acetate) had an effect on the development of intestinal epithelium in their offspring. The doses of bioactive substances were calculated to meet the demands for optimal supply of the pig fetuses and newborns. Pig neonates from two groups of sows, control and supplemented, were sacrificed at the day 1, 2, 4, 7 and 14 of life. The samples taken from mid-jejunum were evaluated for mitosis (Ki67), apoptosis (active caspase 3), autophagy (MAP I LC3), and DNA damage (p53). Increase of mitotic index was noticed at day 1, 4 and 7 for supplemented group when compared to the control. Reduction of apoptotic index was observed at day 2 as compared to control. A tendency toward elevated autophagy was observed during the first 2-4 postnatal days in both groups. p53 expression was significantly lower in supplemented group as compared to control. Overall, the mitosis to programmed cell death ratio was increased and the maturation of epithelial cells quickened. We suppose that the supplementation of pregnant and lactating sow diet with bioactive substances enhanced maturation of the small intestinal epithelium in their offspring during the early postnatal period.

Obestatin stimulates the secretion of pancreatic juice enzymes through a vagal pathway in anaesthetized rats - preliminary results

Obestatin is a 23 amino acid peptide derived from the preproghrelin precursor, and originally purified from the rat stomach mucosa. It was shown that obestatin may counteract the effects of its sister peptide, ghrelin, on food intake and gastrointestinal motility but the other roles in controlling the gastrointestinal function remain unknown. The aim of the present study was to determine the influence of exogenous obestatin on the secretion of pancreatic juice. In anesthetized male Wistar rats the external jugular vein was catheterized, and the common biliary-pancreatic duct was cannulated with polyethylene tubing for collection of pancreatic-biliary juice (P-BJ). Obestatin boluses (30, 100 and 300 nmol/kg b. wt.) were injected intravenously or intraduodenally every 30 min. Obestatin was also administered in vagotomized (subdiaphragmatic vagotomy) rats. In the examined rats, obestatin intravenous and intraduodenal boluses did not affect the P-BJ volume. On the other hand, obestatin boluses increased the protein output and trypsin activity. Vagotomy abolished the effects of exogenous obestatin administration. In conclusion, the present study demonstrates for the first time that exogenous obestatin may stimulate the secretion of pancreatic juice enzymes. The effect is dose-dependent and requires intact vagal supply.

Role of leptin, ghrelin, angiotensin II and orexins in 3T3 L1 preadipocyte cells proliferation and oxidative metabolism

There is now growing evidence that the reactive oxygen species have an influence on proliferation and antioxidative status of various cell types. The aim of the study was to investigate the effects of different concentrations of leptin, ghrelin, angiotensin II and orexins on proliferation, culture medium malondialdehyde (MDA) levels and antioxidative enzymes activities: superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (CAT) in 3T3 L1 preadipocytes cell culture. Cell proliferation was measured using [(3)H]tymidine incorporation. In 3T3-L1 cells leptin caused a significant reduction in proliferation (by 36%) compared to control. Ghrelin increased preadipocyte proliferation, and the effect was stronger in higher dose (by 39%), while proproliferatory effect of angiotensin II was stronger in lower doses (by 47%). All used doses of orexin A significantly increased 3T3 L1 cell proliferation (from 21% to 160%), while orexin B caused a marked reduction (from 35% to 70%) of this proliferation. The effects of both orexins were dose-dependent. Leptin and ghrelin increased activity of SOD, CAT, GSH-Px and decreased level of MDA. Angiotensin II treatment stimulated only SOD and CAT activities. Influence of orexins was different on various enzymes. Orexin A increased MDA levels, while orexin B caused a marked decrease in MDA levels. Our results strongly suggest the effects of appetite affecting hormones such as leptin and ghrelin on proliferation and antioxidative enzyme activities of preadipocyte cell lines. Orexin A was found to be the most efficient proliferative-signalling hormone, while orexin B revealed the most significant inhibitory effect on preadipocytes proliferation.

The ghrelin pentapeptide inhibits the secretion of pancreatic juice in rats

Ghrelin, a 28 amino acids polypeptide was recognized as an endogenous ligand for the growth hormone secretagogue receptor. It turned out that the entire sequence of ghrelin is not necessary for performing the above-mentioned functions. It was suggested that 5 residues (Gly-Ser-Ser(n-octanoyl)-Phe, pentaghrelin) constituted functionally active part of the full-length polypeptide. Ghrelin-28 was found to inhibit pancreatic enzyme output in rats, though the effect of pentaghrelin was not studied so far. The study aimed to determine the involvement of pentaghrelin in pancreatic juice secretion in anaesthetized rats. Male Wistar rats (220 +/- 20 g body weight, b. wt.) were anesthetized, the external jugular vein and common biliary-pancreatic duct were cannulated. Pentaghrelin boluses (i.v., 1.2, 12, and 50 nmol kg(-1) b. wt.) were injected every 30 min with or without CCK-8 infusion, duodenal mucosal CCK(1) receptor blockade with tarazepide, vagotomy and capsaicin pretreatment. Pentaghrelin boluses reduced the volume of pancreatic-biliary juice, protein and trypsin outputs both under basal and CCK-8-stimulated conditions in a dose-dependent manner. However, exogenous pentaghrelin failed to affect the pancreatic secretion in rats subjected to vagotomy, capsaicin deactivation of afferents or pretreatment with Tarazepide. In conclusion, pentaghrelin may control exocrine pancreas secretion by affecting duodenal neurohormonal mechanism(s) involving CCK and vagal nerves in rats.

Pancreatic secretion differs according to the genotype of growing pigs

The objective of this study was to investigate the secretion of pancreatic enzymes and antibacterial activity in weaned pigs of three pure breeds, Pietrain, Duroc and Polish synthetic line 990, to look for eventual differences related to the genotype. Six male pigs of each breed, about 24 kg mean body weight, were equipped with chronic pancreatic duct catheters and duodenal cannulas to assess pure pancreatic juice, and jugular vein catheters for blood withdrawal. Pancreatic juice was collected before and after the morning feeding. Protein output and enzyme activities revealed two distinct profiles: strong manifestation of the prandial phase in Pietrain and line 990 pigs, and weak manifestation in Duroc. The antibacterial activity did not follow the enzyme kinetics, and it was the strongest in pancreatic juice from Pietrain pigs. Postprandial insulinaemia was reduced in the order of: line 990>Pietrain>Duroc. A slight (not significant) tendency towards a reduction of leptin after feeding in synthetic line 990 corresponded with elevated secretion of pancreatic enzymes and plasma insulin. The presented results suggest that the prandial secretion of pancreatic juice differs according to genotype, and the differences may be in part related to release of insulin.

Ghrelin in the postnatal development of the gastrointestinal tract

Ghrelin is a 28-amino acid peptide first isolated from rat and human stomachs. Together with the recently discovered 23-amino acid obestatin, it is derived from proghrelin by posttranslational processing. Cells immunoreactive to ghrelin are widely distributed in the gastric mucosa in domestic and laboratory animals and in humans. Ghrelin plays an important role in energy homeostasis, body weight control, and food intake, whereas obestatin seems to induce the opposite effects. Ghrelin and ghrelin receptor expression have been found in developing gastrointestinal foetal and neonatal tissues, and substantial amounts of ghrelin are present in colostrum, thereby suggesting its presumable role in perinatal development. Ghrelin was shown to positively influence weight gain, increase GH, insulin and cortisol secretion. It also stimulates gastrointestinal tissue structure and function development in weaned animals. Surprisingly, responses in suckling neonates were found to be opposite to those in weanlings. Ghrelin retarded gastric, intestinal and pancreatic development and showed a tendency to reduce body weight gain. Recent studies suggest that the biphasic effect of ghrelin in young rats on pancreas and stomach growth seems to be related to age-dependent changes of the release of anabolic IGF-1. In the perinatal period, obestatin is detected in the rat stomach, pancreas and blood plasma. The obestatin concentration in rats is abruptly reduced after birth, contrasting with an increase in the concentration of acylated ghrelin. Further progressive reduction in pancreas obestatin is observed until weaning.

The effect of orexins on intestinal motility in vitro in fed and fasted rats

Orexin-A and -B (OXA, OXB) are peptides involved in many gastrointestinal (GI) functions, including motility. Orexins, their precursors and receptors are present in the GI tract. The expression of orexins increases in the hypothalamus and gastrointestinal tract in response to fasting. We have examined the effect of OXA and OXB on GI motility in vitro in fed and fasted rats. The intestinal segments were mounted in chambers filled with Krebs solution. Isotonic contractions were measured in response to acetylcholine (10(-5) M), electric field stimulation (EFS), and orexins (10(-9)-10(-7) M) alone or in the presence of orexin-1 type receptor antagonist, SB- 334867 (10(-5) M), tetrodotoxin (TTX) 10(-6) M, or atropine (10(-5) M). Orexins caused a dose-dependent increase of intestinal segment contractions with a more pronounced effect of OXB over OXA. Fasting did not influence orexin-induced responses. Incubation with SB-334867 led to a marked decrease in orexin-induced contractions in OXA-treated segments, while those of OXB were not affected. Atropine diminished contractions only in fasted animals, while TTX led to a decreased response to orexins in both groups. The results show that OXB is predominant in inducing gut motility response, that the effect of orexins is not fully dependent on cholinergic and Na(+) transmissions, and that involvement of other transmitters is possible.

Cardiovascular effects of centrally acting orexin A in haemorrhage-shocked rats

Orexin A influences the central cardiovascular regulation, since after intracerebroventricular (icv) administration it evokes short-lasting increases in mean arterial pressure (MAP) and heart rate (HR) in normotensive animals. The aim of the present study was to examine haemodynamic effects of orexin A in haemorrhage-shocked rats. Experiments were carried out in anaesthetized Wistar rats subjected for a critical irreversible haemorrhagic hypotension of 20-25 mmHg, which resulted in the death of all saline icv-treated control animals within 30 min. Orexin A (0.5-1.5 nmol; icv) administered at 5 min of critical hypotension evoked dose-dependent long-lasting increases in MAP, HR and renal, mesenteric and hindquarters blood flows, with a 100% survival of 2 h after treatment (1.5 nmol; icv). Changes in MAP and peripheral haemodynamics were inhibited by intravenous pretreatment with alpha(1)- and alpha(2)-adrenoceptor antagonists prazosin (0.5 mg/kg) and yohimbine (1.0 mg/kg), respectively. Moreover, both antagonists significantly decreased the survival rate to 16.6 and 33.3% (P<0.05 vs. orexin A [1.5 nmol]-treated group). In contrast, beta-adrenoceptor antagonist propranolol (1.0 mg/kg) completely blocked orexin A-induced HR changes, without influence on MAP, peripheral blood flows and the survival rate. Therefore, we conclude that centrally acting orexin A evokes the resuscitating effect in haemorrhage-shocked rats due to the activation of the sympathetic nervous system.

Quantitative study of soybean-induced changes in proliferation and programmed cell death in the intestinal mucosa of young rats

The use of soybean in human and animal nutrition is limited because of high content of bioactive compounds: enzyme inhibitors, polyphenols, goitrogens, phytates, saponins, sugars, and agglutinins. The damage of intestinal mucosa structure was previously observed in animals fed soybean supplemented diets. Hence, the objectives of the presented study were to compare intensity of epithelium remodeling processes in different intestinal segments, and to evaluate the influence of the 1% of soybean dietary supplementation on the processes in intestinal mucosa. The experiment was performed on 30 Wistar rats fed AIN-93 based diets. Animals were divided randomly into three groups: control (CTRL), with 1% of raw soybean (RS) and with 1% of soaked and boiled soybean (BS). The samples of: duodenum (DUO), proximal jejunum (PROX), mid-jejunum (MID), distal-jejunum (DIST) and ileum (ILE) were collected. The following processes in these samples were evaluated: mitosis (Ki-67), apoptosis (Cpp32), autophagy (MAP I LC3) and DNA damage (p53). Present data show that modification of soybean by soaking and subsequent boiling markedly influences the enterocyte turnover in the small intestine mucosa. Increased mitotic ratio in the intestine of rats fed with boiled soybean masks the negative effects of soybean on the small intestine structure.

Central and local (enteric) action of orexins

Orexin-A (OXA, hypocretin-1) and orexin-B (OXB, hypocretin-2) are peptides derived from the same 130 amino acid long precursor (prepro-orexin) that bind and activate two closely related orphan G protein-coupled receptors. Orexins and their receptors were first discovered in the rat brain, and soon after that in peripheral neural structures, including the vagal nerve and enteric nervous system, and in other structures involving the gastrointestinal tract diffuse neuroendocrine system, pancreas tissue, stomach and intestinal mucosa. Orexins and their receptors were also demonstrated in the testes, adrenals, kidneys, and placenta. This review is focused on central and enteric actions. Originally, orexins were considered to be neurotransmitters that centrally stimulate food intake in animals and humans, but it soon became evident that their action is broader due to activation of a large number of neuronal pathways involved in energy homeostasis, sleep-awake behavior, nociception reward seeking, food and drug addiction, as well as reproduction, cardiovascular and adrenal function. In the gastrointestinal tract, orexins have been found so far to affect gastrointestinal motility and gastric, intestinal and pancreatic secretions. The effects were observed following central (intraventricular) or local (intraluminal, intraarterial), but not peripheral (intravenous), administrations of orexins. Since the expression of orexins in the gastrointestinal tract is enhanced during fasting, and fasting reveals many of the orexin gastrointestinal effects, it seems probable that on the local level, orexins keep the gastrointestinal tract functions ready during fasting and play role in brain-gut axis control.