Diet influences development of the pig (Sus scrofa) intestine during the first 6 hours after birth

Effect of low colostrum intake on gastrointestinal development and uterine and cervical morphometrical architecture in the neonatal gilt

To assess the importance of natural variation in colostrum intake on piglet gastrointestinal and reproductive development, two equally sized female piglets from each of 27 litters were selected, one with low (average 226 g) and one with high (average 401 g) colostrum intake. At weaning (23 d of age), piglets were euthanised to perform macromorphological measurements on ileum, colon, cervix and uterus tissues, and to obtain tissue samples from the cervix and uterus for histology. Sections of uterine and cervical preparations were analysed using digital image analysis. Despite being selected for the same birth weight (average 1.1 kg, standard deviation 0.18 kg), piglets with low colostrum intake weighed 5.91 ± 0.17 kg and piglets with high colostrum intake weighed 6.96 ± 0.19 kg at weaning (P < 0.05). Most of the micro- and macroscopic measures such as length and weight of ileum and colon, cervix and uterus, luminal size of cervix and uterus, number of cervical crypts and uterine glands, were greater in gilts with high colostrum intake. The histological architecture of the uterus and cervix in gilts with high colostrum intake showed more complexity, reflecting more advanced development in these piglets. In conclusion, these data demonstrate that independent of birth weight, natural variation in colostrum intake is related to the overall development of neonatal piglets, affecting body growth, as well as growth and development of the gut and reproductive tract.

Equine Stomach Development in the Foetal Period of Prenatal Life—A Histological and Histometric Study

Simple Summary

The prenatal development of equine stomach has been rarely elaborated. The majority of accessible literature focused on the embryonal period (ca. to the 45–50th day of gestation). The histological study of the stomach wall, including the metric measurements and the gastric gland development, filled the lack of detailed information about the processes taking place in more advanced periods of pregnancy (the foetal period). The achieved results showed that the growth rate of subsequent layers of the stomach wall provided differences comparing with the isometric growth rate of whole foetus length (CRL). The blind ventricular sac, the plicated edge margin, and the pyloric part growth rates were lower than CRL increase. The body of stomach showed a higher growth rate than the whole foetus length. The non-glandular and glandular part of gastric mucosa was distinguishable from the beginning of foetal period. The gastric glands developed the most rapidly in the body of stomach, especially in the late pregnancy. The parietal cells were visible in the gastric glands in the middle of foetal period and the chief cells could be identified in the late pregnancy. The dynamic processes occurring in the prenatal life did not finish in the moment of birth, but postnatally.

Abstract

Histological and morphometrical analysis of the stomach wall was performed during the foetal period divided into three age groups (4th–11th month of gestation). The material was taken from non-glandular (the blind ventricular sac) and glandular parts (the plicated edge margin/cardiac part, the body of stomach and the pyloric part) of the stomach. It was preserved and prepared according to the standard protocol. The histological slides were stained (H-E, Masson-Goldner and PAS). The analyses were performed using the light microscope. All measurements were statistically elaborated. The crown-rump length growth rate was estimated as isometric. The blind ventricular sac growth rate was lower than CRL (negative allometric) and the partition of stomach mucosa into non-glandular and glandular part occurred in the 1st age group. The plicated edge margin/cardiac part and the pyloric part shoved similar tendencies. Only the body of stomach demonstrated a higher growth rate than CRL (positive allometric), which can be explained due to the strongest development of fundic glands. Moreover, comparing the adult reference group to the three parts of the foetal period, all metric values were lower than those achieved prenatally. The blind ventricular sac was covered with the multiple plane epithelium. The glandular parts of stomach that formed the superficial concave areas were covered with the simple columnar epithelium in the 1st age group, which developed to the cardiac, fundic, and pyloric glands in the 2rd and 3rd age groups. The propria mucosae was built with the mesenchyme, which differentiated later to the loose connective tissue. The muscular layer of mucosa was not clearly distinguishable in the 1st age group. The muscular layer of the stomach wall was formed with myoblasts in the 1st age group and later in the 2nd and the 3rd age groups built with fusiform myocytes divided into internal and external layers. The non-differentiated cells of glandular epithelium transformed into the parietal and chief cells. The first were visible in the gastric glands of the 2nd age group. Both of them were present in the 3rd age group gastric mucosa. The PAS staining proved a moderate PAS-positive reaction in the 2rd age group, while it was estimated as intense Pas-positive in the gastric glands in the 3rd age group and was comparable to postnatal observation (the adult reference group).

Effect of Niacin on Growth Performance, Intestinal Morphology, Mucosal Immunity and Microbiota Composition in Weaned Piglets

Simple Summary

The protective effect of niacin on growth performance and gut health of weaned piglets and the underlying mechanism remains unclear despite it being a common additive in pig diets. The present study aimed to investigate the effect of niacin on growth performance, intestinal morphology, intestinal mucosal immunity, and colonic microbiota in weaned piglets. Our results show that niacin supplementation significantly improved the growth performance in piglets as compared with those given a niacin receptor antagonist. Niacin also significantly improved the relative abundance of beneficial bacteria in the colon and alleviate the inflammatory response in the intestinal mucosa as compared with control piglets and those given a niacin receptor antagonist. These results provide new insight into the beneficial effects of niacin on growth performance and gut health in weaned piglets.

Abstract

This study aimed to investigate the effects of niacin on growth performance, intestinal morphology, intestinal mucosal immunity, and colonic microbiota in weaned piglets. A total of 96 weaned piglets (Duroc × (Landrace × Yorkshire), 21-d old, 6.65 ± 0.02 kg body weight (BW)) were randomly allocated into 3 treatment groups (8 replicate pens per treatment, each pen containing 4 males; n = 32/treatment) for 14 d. Piglets were fed a control diet (CON) or the CON diet supplemented with 20.4 mg/kg niacin (NA) or an antagonist for the niacin receptor GPR109A (MPN). The results showed that NA or MPN had no effect on ADG, ADFI, G/F or diarrhea incidence compared with the CON diet. However, compared with piglets in the NA group, piglets in the MPN group had lower ADG (p = 0.042) and G/F (p = 0.055). In comparison with the control and MPN group, niacin supplementation increased the villus height and the ratio of villus height to crypt depth (p < 0.05), while decreasing the crypt depth in the duodenum (p < 0.05). Proteomics analysis of cytokines showed that niacin supplementation increased the expression of duodenal transforming growth factor-β (TGF-β), jejunal interleukin-10 (IL-10) and ileal interleukin-6 (IL-6) (p < 0.05), and reduced the expression of ileal interleukin-8 (IL-8) (p < 0.05) compared with the control diet. Piglets in the MPN group had significantly increased expression of ileal IL-6, and jejunal IL-8 and interleukin-1β (IL-1β) (p < 0.05) compared with those in the control group. Piglets in the MPN group had lower jejunal IL-10 level and higher jejunal IL-8 level than those in the NA group (p < 0.05). The mRNA abundance of duodenal IL-8 and ileal granulocyte-macrophage colony-stimulating factor (GM-CSF) genes were increased (p < 0.05), and that of ileal IL-10 transcript was decreased (p < 0.05) in the MPN group compared with both the control and NA groups. Additionally, niacin increased the relative abundance of Dorea in the colon as compared with the control and MPN group (p < 0.05), while decreasing that of Peptococcus compared with the control group (p < 0.05) and increasing that of Lactobacillus compared with MPN supplementation (p < 0.05). Collectively, the results indicated that niacin supplementation efficiently ensured intestinal morphology and attenuated intestinal inflammation of weaned piglets. The protective effects of niacin on gut health may be associated with increased Lactobacillus and Dorea abundance and butyrate content and decreased abundances of Peptococcus.

Management and Feeding Strategies in Early Life to Increase Piglet Performance and Welfare around Weaning: A Review

The performance of piglets in nurseries may vary depending on body weight, age at weaning, management, and pathogenic load in the pig facilities. The early events in a pig's life are very important and may have long lasting consequences, since growth lag involves a significant cost to the system due to reduced market weights and increased barn occupancy. The present review evidences that there are several strategies that can be used to improve the performance and welfare of pigs at weaning. A complex set of early management and dietary strategies have been explored in sows and suckling piglets for achieving optimum and efficient growth of piglets after weaning. The management strategies studied to improve development and animal welfare include: (1) improving sow housing during gestation, (2) reducing pain during farrowing, (3) facilitating an early and sufficient colostrum intake, (4) promoting an early social interaction between litters, and (5) providing complementary feed during lactation. Dietary strategies for sows and suckling piglets aim to: (1) enhance fetal growth (arginine, folate, betaine, vitamin B12, carnitine, chromium, and zinc), (2) increase colostrum and milk production (DL-methionine, DL-2-hydroxy-4-methylthiobutanoic acid, arginine, L-carnitine, tryptophan, valine, vitamin E, and phytogenic actives), (3) modulate sows' oxidative and inflammation status (polyunsaturated fatty acids, vitamin E, selenium, phytogenic actives, and spray dried plasma), (4) allow early microbial colonization (probiotics), or (5) supply conditionally essential nutrients (nucleotides, glutamate, glutamine, threonine, and tryptophan).

The role of lactose in weanling pig nutrition: a literature and meta-analysis review

Lactose plays a crucial role in the growth performance of pigs at weaning because it is a palatable and easily digestible energy source that eases the transition from milk to solid feed. However, the digestibility of lactose declines after weaning due to a reduction in endogenous lactase activity in piglets. As a result, some lactose may be fermented in the gastrointestinal tract of pigs. Fermentation of lactose by intestinal microbiota yields lactic acid and volatile fatty acids, which may positively regulate the intestinal environment and microbiome, resulting in improved gastrointestinal health of weanling pigs. We hypothesize that the prebiotic effect of lactose may play a larger role in weanling pig nutrition as the global feed industry strives to reduce antibiotic usage and pharmacological levels of zinc oxide and supra-nutritional levels of copper. Evidence presented in this review indicates that high dietary lactose improves growth performance of piglets, as well as the growth of beneficial bacteria, particularly Lactobacillus, with the positive effects being more pronounced in the first 2 weeks after weaning. However, the risk of post-weaning diarrhea may increase as pigs get older due to reduced lactase activity, high dietary lactose concentrations, and larger feed intakes, all of which may lead to excessive lactose fermentation in the intestine of the pig. Therefore, dietary lactose levels exert different effects on growth performance and gastrointestinal physiological functions in different feeding phases of weanling pigs. However, no formal recommendation of lactose for weanling pigs has been reported. A meta-analysis approach was used to determine that diets fed to swine should include 20%, 15%, and 0 lactose from d 0–7, d 7–14, and d 14–35 post-weaning, respectively. However, sustainable swine production demands that economics must also be taken into account as lactose and lactose containing ingredients are expensive. Therefore, alternatives to lactose, so called “lactose equivalents” have also been studied in an effort to decrease feed cost while maintaining piglet performance with lower dietary lactose inclusions. In summary, the present review investigated dose-response effects of dietary lactose supplementation to exert positive responses and begin to elucidate its mechanisms of action in post-weaning pig diets. The results may help to replace some or all lactose in the diet of weanling pigs, while improving production economics given the high cost of lactose and availability in some swine production markets.

Effects of soft pellet creep feed on pre-weaning and post-weaning performance and intestinal development in piglets

Objective

This study aimed to determine the effects of soft pellet creep feed (SPCF) on growth performance and intestinal development in piglets.

Methods

A total of 18 sows and their litters of crossbred piglets (14±2 days, 3.73±0.72 kg) were assigned to one of three dietary groups receiving i) powder creep feed (PCF), ii) hard pellet creep feed (HPCF) or iii) SPCF during the pre-weaning period. After weaning, piglets were selected for continuous evaluation of the three diets on growth performance and intestinal health.

Results

In the pre-weaning period, the average daily feed intake and average daily dry matter intake were significantly higher in the SPCF group than the HPCF group (p<0.05). In the post-weaning and entire experimental period, the different diets had no significant effect on growth performance. At 10 d after weaning, the serum glucose concentration was lower in the SPCF group (p<0.05) than the other groups; a higher (p<0.05) villus height and lower (p<0.05) crypt depth in the jejunum were also observed in the SPCF group than the other groups; Meanwhile, in the duodenum and jejunum, the SPCF group had a higher (p<0.05) villus height to crypt depth ratio than the other groups; Furthermore, the higher (p<0.05) threshold cycle values of lactic acid bacteria and lower (p<0.05) threshold cycle values of Clostridium, Enterobacter and Escherichia coli were also observed in the SPCF group, and the sucrase and maltase activity was higher (p<0.05) in the SPCF group than the other groups in duodenum and ileum.

Conclusion

The SPCF improved pre-weaning feed intake and decreased the negative effects of weaning stress in the intestine in piglets.

Gut-Brain Axis in the Early Postnatal Years of Life: A Developmental Perspective

Emerging evidence suggests that alterations in the development of the gastrointestinal (GI) tract during the early postnatal period can influence brain development and vice-versa. It is increasingly recognized that communication between the GI tract and brain is mainly driven by neural, endocrine, immune, and metabolic mediators, collectively called the gut-brain axis (GBA). Changes in the GBA mediators occur in response to the developmental changes in the body during this period. This review provides an overview of major developmental events in the GI tract and brain in the early postnatal period and their parallel developmental trajectories under physiological conditions. Current knowledge of GBA mediators in context to brain function and behavioral outcomes and their synthesis and metabolism (site, timing, etc.) is discussed. This review also presents hypotheses on the role of the GBA mediators in response to the parallel development of the GI tract and brain in infants.

The growth performance, intestinal digestive and absorptive capabilities in piglets with different lengths of small intestines

The small intestine is an important digestive organ and plays a vital role in the life of a pig. We tested the hypothesis that the length of the small intestine is related to growth performance and intestinal functions of piglets. A total of 60 piglets (Duroc × Landrace × Yorkshire), weaned at day 21, were fed an identical diet during a 28-day trial. At the end of the study, all piglets were sacrificed, dissected and grouped according to small intestine lengths (SILs), either short small intestine (SSI), middle small intestine (MSI) or long small intestine (LSI), respectively. Positive relationships between SIL and BW, average daily gain (ADG), average daily feed intake (ADFI) and gain-to-feed ratios (G : F) were observed. Final BW, ADG, ADFI and G : F significantly increased (P < 0.05) in MSI and LSI piglets compared with SSI piglets. Short small intestine and MSI had greater jejunal mucosa sucrase and alkaline phosphatase activities (P < 0.05) than LSI piglets. The mRNA level of solute carrier family 2 member 2 (Slc2a2) in the jejunal mucosa of SSI piglets was the greatest. The MSI piglets had a greater (P < 0.05) ileal villus height than other piglets and greater (P < 0.05) villus height-to-crypt depth ratios than LSI piglets. However, the LSI piglets had a greater (P < 0.05) ileal crypt depth than SSI piglets. No significant differences in duodenal, jejunal, caecal and colonic morphologies were detected among the groups. Moreover, luminal acetate, propionate, butyrate and total short-chain fatty acid contents were greater (P < 0.05) in SSI and MSI piglets than those in LSI piglets. In addition, there was greater serum glucose concentration in MSI piglets than other piglets. Serum albumin concentration in SSI piglets was the lowest. In conclusion, these results indicate that SIL was significantly positively associated with growth performance, and in terms of intestinal morphology and mucosal digestive enzyme activity, the piglets with a medium length of small intestine have better digestion and absorption properties.

Amino Acids Influencing Intestinal Development and Health of the Piglets

Simple Summary

The health of piglets is an important issue in pig production. Nutritional support for intestinal development is a significant component of piglet care, and amino acids are essential for intestinal growth and development. For suckling piglets, the sows’ milk and the maternal environment shape the structure and support the function of the intestinal tract. The composition of milk affects intestinal morphology and the digestive, absorption and barrier function. After weaning, the optimal nutritional strategies of their diet are necessary to guarantee the piglets’ intestinal development and growth performance. Amino acids are the most important ingredient in piglet diets. The aim of this review is to collect and analyze the relationship between amino acid nutrition and intestinal development of piglets, and elucidate the impacts on piglet health.

Abstract

The amino acids and other components of diet provide nourishment for piglet intestinal development and maturation. However, early-weaned piglets struggle with tremendous stress, impairing normal intestinal health and leading to intestinal dysfunction and even death. The high prevalence worldwide of post-weaning diarrhoea syndrome (PWDS) in piglets has led to much interest in understanding the important role of nutrients in the establishment and maintenance of a functional intestinal tract. In particular, the impacts of amino acids on these functions must be considered. Amino acid levels greatly influence intestinal development in weaning piglets. The lack of amino acids can cause marked structural and functional changes in the intestine. Therefore, a comprehensive understanding of the functions of amino acids is necessary to optimize amino acid requirements of the developing intestinal tract to maximize piglet health and growth performance. This review summarizes the role of specific amino acids (arginine, glutamate, threonine, sulphur-containing amino acids (SCAAs), and branched-chain amino acids (BCAAs)) that have been proven to be beneficial for the intestinal health of weaned piglets.

The Risk of Necrotizing Enterocolitis Differs Among Preterm Pigs Fed Formulas With Either Lactose or Maltodextrin

OBJECTIVES

When breast milk is unavailable for preterm infants, formulas are needed that won't increase the risk of necrotizing enterocolitis (NEC). Adding novel ingredients to formula to reduce NEC has not been effective clinically. Instead, we tested the prediction that NEC can be reduced by removing the maltodextrin now included in preterm formulas.

METHODS

The preterm pig model of spontaneous NEC was used to evaluate growth, health, and intestinal responses to 6 to 7 days of feeding formulas that were identical except for the source of carbohydrate; either 100% lactose or maltodextrin; colostrum was used as the control.

RESULTS

Formula with maltodextrin resulted in a 50% incidence of NEC with 30% mortality. The lactose formula and colostrum resulted in a 0% incidence of NEC. Growth was highest for pigs fed the formula with lactose, intermediate with maltodextrin, and minimal when bovine colostrum was fed (P < 0.05). Although the small intestine was larger when colostrum was fed (P < 0.05), because rates of glucose uptake were lower (P < 0.05), total small intestine capacities to transport glucose were similar for healthy pigs in all 3 groups.

CONCLUSIONS

If lactose-based formulas reduce NEC clinically, the transition of preterm infants to enteral feeding can be accelerated, improving growth and development, and shortening reliance on parenteral nutrition. Although colostrum protects against NEC, chronic feeding does not promote body weight gain after preterm birth. The preterm pig can be used for preclinical studies that evaluate the mechanisms by which carbohydrates and other ingredients influence growth, development, health, and risk of NEC.

Distinct roles for the mTOR pathway in postnatal morphogenesis, maturation and function of pancreatic islets

While much is known about the molecular pathways that regulate embryonic development and adult homeostasis of the endocrine pancreas, little is known about what regulates early postnatal development and maturation of islets. Given that birth marks the first exposure to enteral nutrition, we investigated how nutrient-regulated signaling pathways influence postnatal islet development in mice. We performed loss-of-function studies of mechanistic target of rapamycin (mTOR), a highly conserved kinase within a nutrient-sensing pathway known to regulate cellular growth, morphogenesis and metabolism. Deletion of Mtor in pancreatic endocrine cells had no significant effect on their embryonic development. However, within the first 2 weeks after birth, mTOR-deficient islets became dysmorphic, β-cell maturation and function were impaired, and animals lost islet mass. Moreover, we discovered that these distinct functions of mTOR are mediated by separate downstream branches of the pathway, in that mTORC1 (with adaptor protein Raptor) is the main complex mediating the maturation and function of islets, whereas mTORC2 (with adaptor protein Rictor) impacts islet mass and architecture. Taken together, these findings suggest that nutrient sensing may be an essential trigger for postnatal β-cell maturation and islet development.

Comparative digestive physiology

In vertebrates and invertebrates, morphological and functional features of gastrointestinal (GI) tracts generally reflect food chemistry, such as content of carbohydrates, proteins, fats, and material(s) refractory to rapid digestion (e.g., cellulose). The expression of digestive enzymes and nutrient transporters approximately matches the dietary load of their respective substrates, with relatively modest excess capacity. Mechanisms explaining differences in hydrolase activity between populations and species include gene copy number variations and single-nucleotide polymorphisms. Transcriptional and posttranscriptional adjustments mediate phenotypic changes in the expression of hydrolases and transporters in response to dietary signals. Many species respond to higher food intake by flexibly increasing digestive compartment size. Fermentative processes by symbiotic microorganisms are important for cellulose degradation but are relatively slow, so animals that rely on those processes typically possess special enlarged compartment(s) to maintain a microbiota and other GI structures that slow digesta flow. The taxon richness of the gut microbiota, usually identified by 16S rRNA gene sequencing, is typically an order of magnitude greater in vertebrates than invertebrates, and the interspecific variation in microbial composition is strongly influenced by diet. Many of the nutrient transporters are orthologous across different animal phyla, though functional details may vary (e.g., glucose and amino acid transport with K+ rather than Na+ as a counter ion). Paracellular absorption is important in many birds. Natural toxins are ubiquitous in foods and may influence key features such as digesta transit, enzymatic breakdown, microbial fermentation, and absorption.

Evaluation of marine algae Undaria pinnatifida and Porphyra purpurea as a food supplement: composition, nutritional value and effect of intake on intestinal, hepatic and renal enzyme activities in rats

BACKGROUND

There is a long tradition in Eastern countries of consuming seaweeds, although demand for these organisms has also increased in Western countries. However, knowledge of the effects of consumption of algae is limited. In this study the proximate composition and amino acid profile of Undaria pinnatifida (Harvey) Suringar (wakame) and Porphyra purpurea (Olivi) De Toni (nori) were determined. The effects of feeding diets containing 100 g kg(-1) of wakami or nori for 4 weeks on food intake, growth, protein efficiency ratio, diet conversion ratio and some organ weights in growing rats were evaluated. The effects on intestinal, hepatic and renal enzyme activities were also studied.

RESULTS

Both algae are a good source of protein, particularly nori, and contain essential amino acids. There was no effect of alga consumption on trophic balance. Intestinal disaccharidase and hepatic and renal γ-glutamyl transpeptidase activities were lower in alga-fed rats than in the control group, while intestinal leucine aminopeptidase activity was higher in rats fed algae.

CONCLUSION

Both seaweeds are a good source of protein and carbohydrates and contain all essential amino acids. The effects of the two algae on enzyme activities were similar. The inhibition of intestinal disaccharidase activity by seaweed ingestion could be interesting in patients with altered glucose homeostasis.

Effect of dietary supplementation of oregano essential oils to sows on colostrum and milk composition, growth pattern and immune status of suckling pigs

This study evaluated the effects of supplementing sow diets with oregano essential oils (OEO) during gestation and lactation on sow colostrum and milk composition and on the growth pattern and immune status of suckling pigs. A total of 70 second-parity sows were randomly assigned to 1 of 2 gestation dietary treatments within 24 h after service: control (CON) or CON + 250 mg/kg of OEO (OREG). In lactation, sows were again assigned to either the CON or OREG dietary treatment. Thus, the lactation treatments were CON-CON, CON-OREG, OREG-CON, and OREG-OREG. Colostrum and blood samples were collected from 6 sows per lactation dietary treatment. Thymus lymphocyte (T lymphocyte) subpopulations (γδ, cluster of differentiation 8, and 32 cluster of differentiation 4) were enumerated in blood and mammary secretions along with IGF-1, IgG, and IgA concentrations. Piglet growth rate were determined from 18, 17, 17, and 18 litters from the CON-CON, CON-OREG, OREG-CON, and OREG-OREG lactation dietary treatments, respectively. Growth rates were determined in 630 piglets, and piglets were individually identified and weighed on 1, 5, 9, 12, 16, and 19 d of age. Oregano essential oil supplementation during gestation or lactation had no effect (P > 0.05) on GE, CP, GE:CP, GE:fat, and IGF-1 in sow milk. Reductions of the fat percentage in milk on d 7 (P < 0.05) and d 14 (P = 0.07) were found in sows supplemented with OEO during lactation compared with those in the CON treatment. Milk from sows supplemented with OEO during lactation had the greatest number of T lymphocytes compared with those in the lactation CON treatment on d 14 of lactation (P < 0.01). The number of T lymphocytes in milk was greater for sows in the CON-OREG treatment compared with those other treatments on d 14 of lactation (P < 0.05). Energy intake was greater on d 1 to 5 in piglets from sows fed OEO during gestation than those from sows in the CON treatment (P < 0.05). A trend (P = 0.10) for greater milk intake was observed in piglets from sows supplemented with OEO during gestation compared with those from sows in the CON treatment. Similarly, a tendency for an increase in ADG on d 1 to 5 was found in piglets from sows supplemented with OEO during gestation compared with those from sows in the CON treatment (P = 0.10). Insulin-like growth factor-1 at birth and on d 7 and 14 of lactation did not differ among piglets from sows assigned to the different dietary treatments. Oregano essential oil supplementation of sow diets did not affect (P > 0.05) immunoglobulin concentrations in piglets after suckling. Supplementing sow diets with OEO during gestation or lactation did not affect (P > 0.05) the T lymphocytes, percentage of T-lymphocyte subpopulations, and natural killer cell activity of piglets during lactation. Supplementing sow diets with 250 mg/kg of OEO during gestation and lactation did not affect the growth potential of and immune responses in suckling piglets.

Nutritional programming of gastrointestinal tract development. Is the pig a good model for man?

The consequences of early-life nutritional programming in man and other mammalian species have been studied chiefly at the metabolic level. Very few studies, if any, have been performed in the gastrointestinal tract (GIT) as the target organ, but extensive GIT studies are needed since the GIT plays a key role in nutrient supply and has an impact on functions of the entire organism. The possible deleterious effects of nutritional programming at the metabolic level were discovered following epidemiological studies in human subjects, and confirmed in animal models. Investigating the impact of programming on GIT structure and function would need appropriate animal models due to ethical restrictions in the use of human subjects. The aim of the present review is to discuss the use of pigs as an animal model as a compromise between ethically acceptable animal studies and the requirement of data which can be interpolated to the human situation. In nutritional programming studies, rodents are the most frequently used model for man, but GIT development and digestive function in rodents are considerably different from those in man. In that aspect, the pig GIT is much closer to the human than that of rodents. The swine species is closely comparable with man in many nutritional and digestive aspects, and thus provides ample opportunity to be used in investigations on the consequences of nutritional programming for the GIT. In particular, the 'sow-piglets' dyad could be a useful tool to simulate the 'human mother-infant' dyad in studies which examine short-, middle- and long-term effects and is suggested as the reference model.

Effect of dietary level of protein and fiber on the productive performance and health status of piglets

To study the interaction between the levels of protein and fiber on the productive performance and health status of piglets, ninety-six 35-d-old piglets (9.11 +/- 0.60 kg of BW) were placed in 32 pens of 3 animals each and allotted to 4 dietary treatments for 21 d. The 4 diets were based on rice, dairy products, and soybean meal in a 2 x 2 factorial arrangement of treatments, with 2 levels of CP (15.4 vs. 19.4%, as-fed basis) and 2 levels of dietary fiber [DF; low fiber (LF) 5.3% NDF and high fiber (HF) 7.15% NDF, as-fed basis]. The HF diet was developed by supplementing the basal diet with 40 g/kg of wheat bran and 20 g/kg of sugar beet pulp. Animal performance was obtained weekly with samples of feces collected for microbiology on the first and the last experimental day and scored from 1 (liquid) to 4 (hard). On the last day, 1 pig from each pen was sampled for blood analyses of the acute-phase protein, major acute-phase protein of pigs (PigMap) and subsequently killed to register the digestive tract weight (including contents) and colon histology. Pigs fed the HF diets had greater ADG (390 vs. 457 g; P < or = 0.001) and large intestine weight (4.4 vs. 5.4% of BW; P < or = 0.05). This coincided with a greater (P < or = 0.05) short-chain fatty acid concentration (especially of acetic and butyric acids), a decrease in Escherichia coli counts (7.77 vs. 6.86 log of cfu/g of feces, P < or = 0.05), and an increase in the ratio of lactobacilli:enterobacteria (0.76 vs. 1.37, P < or = 0.05). However, CP level did not modify the productive performance, but 20% CP increased P < or = 0.05) the relative weight (% of BW) of the small (6.5 vs. 7.7) and large intestine (3.8 vs. 4.3). In the large bowel, the 20% CP diet increased the numbers of goblet cells (4.6 vs. 5.4/100 microm; P < or = 0.05) and reduced the numbers of intraepithelial lymphocytes (1.8 vs. 1.3/100 microm; P < or = 0.05). In relation to health status, increasing DF was dependent of the dietary CP content. Supplementing the 16% CP diet with DF reduced the fecal score and increased the antibiotics interventions, whereas the opposite was the case in the 20% CP diet. Pigs fed the 20% CP diet showed decreased (P < or = 0.05) PigMap concentrations than pigs fed 16% CP diets. As a whole, CP showed major effects on the gastrointestinal weight and gut barrier integrity, whereas DF increased the productive performance and promoted major changes in the microbial colonization and fermentation variables.

Postnatal ontogeny of intestinal GCPII and the RFC in pig

In humans and pigs, hydrolysis of dietary polyglutamyl folates is carried out by intestinal brush border folate hydrolase [glutamate carboxypeptidase II (GCPII)], whereas the transport of the monoglutamyl folate derivatives occurs via the intestinal brush border reduced folate carrier (RFC). The study objective was to measure the expression of intestinal GCPII and RFC during postnatal development of pigs and their effects on plasma and liver folate concentrations. Duodenum, jejunum, ileum, liver, and plasma samples were collected from female Yorkshire pigs at birth, 24 h, 1 wk, 3 wk, and 6 mo (n=6 at each time point). GCPII mRNA transcripts and protein (normalized using beta-actin), and enzyme activity (normalized per mg mucosal protein) were highest in all segments of small intestine at birth and were undetectable in ileum after 1 wk, whereas jejunal protein and activity predominated at 6 mo. RFC mRNA transcripts were present in all segments of small intestine at birth and declined significantly throughout development to 6 mo. Conversely, RFC protein increased twofold during the first 24 h and remained constant throughout development in all segments of small intestine. Liver RFC mRNA transcripts were detected at birth but were reduced by 6 mo. Liver folate concentration increased throughout postnatal development, whereas plasma folate levels increased during the first 24 h but decreased over time, reflecting the pattern of RFC expression in small intestine. These findings show that intestinal GCPII and intestinal and hepatic RFC all exhibit ontogenic changes in the pig that are reflected in postnatal folate status.

Intestinal microbiota differentially affect brush border enzyme activity and gene expression in the neonatal gnotobiotic pig

To study microbial influence on intestinal development pertaining to nutrient digestion, two separate gnotobiotic experiments were performed, each with 16 piglets allocated to four treatment groups: germfree (GF), monoassociation with Escherichia coli, monoassociation with Lactobacillus fermentum or conventionalization with faecal bacteria (CV). Enzyme activity and gene expression of lactase phlorizin hydrolase (LPH) and aminopeptidase N (APN) were measured in isolated enterocytes, harvested on day 14, using specific substrates and quantitative PCR respectively. Enterocytes of CV pigs had reduced APN activity, but had increased gene expression relative to GF, making the specific activity:mRNA (A:G) ratio dramatically lower (p < 0.05). Similarly, LPH A:G ratio was significantly reduced (p < 0.05) in enterocytes of CV pigs as compared with GF. The results of co-incubation of L. fermentum, E. coli and faecal bacteria with APN indicate a direct relationship between enzyme inactivation and specific A:G ratio in enterocytes. We conclude that enterocyte up-regulation of APN expression occurs as either a direct response to microbial colonization or as a feedback mechanism in response to reduced enzyme activity through microbial degradation. This mechanism may play a role in ensuring effective competition of the host with the intestinal microbiota for available nutrients.

Glucagon-like peptide 2 has limited efficacy to increase nutrient absorption in fetal and preterm pigs

Exogenous glucagon-like peptide 2 (GLP-2) prevents intestinal atrophy and increases nutrient absorption in term newborn pigs receiving total parenteral nutrition (TPN). We tested the hypothesis that the immature intestine of fetuses and preterm neonates has a diminished nutrient absorption response to exogenous GLP-2. This was accomplished using catheterized fetal pigs infused for 6 days (87-91% of gestation) with GLP-2 (25 nmol.kg(-1).day(-1) iv; n = 7) or saline (n = 7), and cesarean-delivered preterm pigs (92% of gestation) that received TPN with GLP-2 (25 nmol.kg(-1).day(-1) iv; n = 8) or saline (n = 7) for 6 days after birth. Responses to GLP-2 were assessed by measuring intestinal dimensions, absorption of nutrients (glucose, leucine, lysine, proline) by intact tissues and brush border membrane vesicles, and abundance of sodium-glucose cotransporter mRNA. Infusion of GLP-2 increased circulating GLP-2 levels in fetuses, but did not increase intestinal mass or absorption of nutrients by intact tissues and brush border membrane vesicles, except for lysine. Administration of exogenous GLP-2 to preterm TPN-fed pigs similarly did not increase rates of nutrient absorption, yet nutrient absorption capacities of the entire small intestine tended to increase (+10-20%, P < 0.10) compared with TPN alone due to increased intestinal mass (+30%, P < 0.05). GLP-2 infusion did not increase sodium-glucose cotransporter-1 mRNA abundance in fetuses or postnatal preterm pigs. Hence, the efficacy of exogenous GLP-2 to improve nutrient absorption by the intestine of fetal and preterm pigs is limited compared with term pigs and more mature animals and humans.

The Nonantibiotic Anti-Inflammatory Effect of Antimicrobial Growth Promoters, the Real Mode of Action? A Hypothesis

Societal concern and government regulations increasingly press for restricting the use of antibiotics as antimicrobial growth promoters (AGP). The search for alternatives is on, hampered by a lack of knowledge about the exact mechanism of AGP. Feed additives, such as AGP and alternatives, interact with the intestine. In the intestine, feed components, microbiota, and the mucosa interact in a very complex and dynamic way. Various mechanisms for AGP have been proposed, invariably based on the direct antibiotic influence on the microbial composition of the intestines. In the literature on antibiotics, however, the direct effects of antibiotics on host cells, in particular inflammatory cells, have been described. It is curious that this has never been considered in the literature on AGP. Presently, a case is being made that AGP most likely work as growth permitters by inhibiting the production and excretion of catabolic mediators by intestinal inflammatory cells. Concomitant or subsequent changes in microflora are most likely the consequence of an altered condition of the intestinal wall. This common, basic mechanism potentially offers an excellent explanation for the highly reproducible effects of AGP, as opposed to those obtained by alternatives aimed at microflora management. Therefore, the search for alternatives could be aimed at nonantibiotic compounds with an effect on the inflammatory system similar to that of AGP.

Formula-feeding reduces lactose digestive capacity in neonatal pigs

The intestine of newborn pigs develops rapidly during the first days postpartum. We investigated if feeding milk replacer (infant formula) as an alternative to colostrum has compromising effects on nutrient digestive function in the neonatal period. Nineteen piglets born at termwere assigned to one of four treatments: (1) newborn controls; (2) natural suckling for 24h; (3) tube-fed formula for 24h; (4) tube-fed porcine colostrum for 24h. All three fed groups showed significant increases in small-intestinal and colonic weights, villous heights and widths, maltase and aminopeptidase A activities, and decreases in dipeptidylpeptidase IV activity, relative to newborn pigs. Following oral boluses of mannitol, lactose or galactose, formula-fed pigs showed significantly reduced plasma levels of mannitol and galactose compared with colostrum-fed pigs. Activity of intestinal inducible NO synthase and plasma levels of cortisol were significantly increased, whereas intestinal constitutive NO synthase and α-tocopherol were decreased in formula-fed pigs compared with colostrum-fed pigs. Although formula-fed pigs only showed minor clinical signs of intestinal dysfunction and showed similar intestinal trophic responses just after birth, as those fed colostrum, lactose digestivecapacity was markedly reduced. We conclude that formula-feeding may exert detrimental effects on intestinal function in neonates. Formula-induced subclinical malfunction of the gut in pigsborn at term was associated with altered NO synthase activity and antioxidative capacity.

Glucagon-like peptide 2 stimulates intestinal nutrient absorption in parenterally fed newborn pigs

OBJECTIVES

Parenteral nutrition is a critically important intervention for children with intestinal dysfunctions. However, total parenteral nutrition (TPN) with no enteral feeding is associated with small intestine atrophy and malabsorption, which complicate the transition to enteral nutrition. The objective of the present study was to evaluate the therapeutic potential of the intestinotrophic peptide glucagon-like peptide 2 (GLP-2), which reduces TPN-associated atrophy and maintains nutrient absorption in adult rats, for preventing nutrient malabsorption in neonates receiving TPN.

METHODS

Term pigs obtained by cesarean delivery received from birth TPN alone (TPN; n = 7) or TPN with GLP-2 (25 nmol . kg(-1) . d(-1); GLP-2; n = 8) or were fed sow milk enterally (n = 7). The small intestine was removed on postnatal day 6 to measure morphological responses and absorption of glucose, leucine, lysine and proline by intact tissues and brush border membrane vesicles and to quantify the abundances of mRNA and protein for enterocyte glucose transporters (SGLT-1 and GLUT2).

RESULTS

Relative to TPN alone, administration of GLP-2 resulted in small intestines that were larger (P < 0.01), had greater abundances of mRNA and protein for SGLT-1, but not for GLUT2, and had higher capacities to absorb nutrients (P < 0.01). Moreover, the intestines of GLP-2 pigs were comparable in size and absorptive capacities with those of pigs fed sow milk enterally.

CONCLUSIONS

Providing GLP-2 to neonates receiving TPN prevents small intestine atrophy, results in small intestine absorptive capacities that are comparable to when nutrients are provided enterally and may accelerate the transition from TPN to enteral nutrition.

Dimensions and histologic characteristics of the small intestine of dogs during postnatal development

OBJECTIVE

To quantify dimensions of the small intestine of dogs and describe changes in histologic characteristics of the mucosa during postnatal development.

SAMPLE POPULATION

Gastrointestinal tract tissues obtained from 110 Beagles (15 adult females and 95 puppies of both sexes).

PROCEDURE

Several variables (length, total weight, mucosal weight, and nominal surface area) of the small intestine were measured in puppies at birth but before suckling; 1 day after birth and subsequent suckling, 21, 42, and 63 days after birth, and in the adult dams of the puppies. Tissue structure was examined and quantified at each time point by use of routine histologic examination and ocular micrometry of formalin-fixed specimens stained with H&E.

RESULTS

Small intestinal dimensions increased throughout development with the greatest proportional changes during the first day after birth and onset of suckling. Villus height decreased during suckling but had consistent values from 42 days after birth to maturity, whereas crypt depth increased from birth to maturity. Vacuolated enterocytes were evident from birth to 21 days but not thereafter.

CONCLUSIONS AND CLINICAL RELEVANCE

Increases in intestinal dimensions provide growing dogs with a greater capacity for digestion and absorption. Changes in mucosal architecture and cell populations coincided with shifts in dietary inputs. These findings may assist in the diagnosis of small intestinal diseases and nutritional responses during growth and development of dogs.

Ontogenic development of intestinal disaccharidases in the precocial rodent Octodon degus (Octodontidae)

We studied the ontogeny of the intestinal brush border disaccharidases sucrase and lactase in the precocial rodent Octodon degus. Sucrase hydrolyze sugars from plants while lactase hydrolyzes sugars from milk. Enzyme expression varied inversely with dietary changes according to the developmental pattern. All new-born pups had high lactase and low sucrase activities. Also, a negative correlation between sucrase and lactase activity was found, supporting the economic design hypothesis for the intestinal tract. Profiles for development of sucrase expression exhibit some differences among precocial species, and in O. degus is correlated with the slower transition from milk to solid food consumption at weaning.

Preterm birth affects the intestinal response to parenteral and enteral nutrition in newborn pigs

Maturation of gastrointestinal (GI) function in neonates is stimulated by enteral nutrition, whereas parenteral nutrition induces GI atrophy and malfunction. We investigated whether preterm birth alters the GI responses to parenteral and enteral nutrition. Pigs were delivered either preterm (107 d gestation) or at term (115 d gestation) and fed total parenteral nutrition (TPN) or enteral sow's milk (ENT) for 6 d after birth. Immaturity of the preterm pigs was documented by reduced blood pH, oxygen saturation and neutrophil granulocyte function, impaired intestinal immunoglobulin G uptake from colostrum, and altered relative weights of visceral organs (small intestine, liver, spleen, pancreas, and adrenals). For both ages at delivery, increases occurred in pancreatic weight (30-75%) and amylase activity (0.5- to 13-fold) after birth, but much more in ENT than in TPN pigs (P < 0.05). Six days of TPN feeding was associated with reduced intestinal weight for both delivery groups (60% of values in ENT, P < 0.001), but only in term TPN pigs was the weight lower than at birth (-20%, P < 0.05). Likewise, it was only in term TPN pigs that intestinal maltase activity increased, compared with ENT, and the absorption of glucose and proline decreased. Only in preterm pigs did TPN feeding increase lactase activity (+50% compared with ENT, P < 0.05). For both delivery ages, the mRNA of lactase-phloridzin hydrolase and sodium-coupled glucose transporter 1 (SGLT-1) were increased in TPN, compared with ENT. In conclusion, the trophic effect of enteral vs. parenteral nutrition on the GI tract is also present after preterm birth, but the postnatal maturation of many GI functions is modified, compared with term birth. The effects of nutritional regimen on the maturation of the gut epithelium in neonates depend on gestational age at birth.

The effect of fermented liquid feeding on the faecal microbiology and colostrum quality of farrowing sows

This study investigated the effects of fermented liquid feed (FLF) on the lactic acid bacteria (LAB):Coliform (L:C) ratio in the faeces of farrowing sows and the quality of sow colostrum. Eighteen multiparous sows were randomly allocated to one of three dietary treatments for approximately 2 weeks prior to farrowing and for 3 weeks after parturition. The three dietary treatments were dry pelleted feed (DPF), nonfermented liquid feed (NFLF), and fermented liquid feed (FLF). A rifampicin-resistant mutant of Lactobacillus plantarum was used to ferment liquid feed. Coliforms and lactic acid bacteria (LAB) in the faeces of farrowing sows and piglets were estimated by standard microbiological techniques. Intestinal epithelial cells (IEC-6) and blood lymphocytes were used to evaluate the mitogenic activity of colostral samples taken at parturition. Results demonstrated that while the LAB population was not significantly affected by dietary treatment, significant differences in coliform population were observed in the sow faecal samples taken 7 days after parturition. Faeces excreted from sows fed FLF had significantly (P < 0.001) lower numbers of coliforms than sows fed NFLF or DF. Piglets from sows fed FLF excreted faeces that were higher in LAB (7.7 vs. 7.3 log10 CFU g (-1); P < 0.01) and lower in coliforms (7.5 vs. 8.1 log10 CFU g (-1); P < 0.001) than faeces from the piglets of DF-fed dams. Colostrum from sows fed FLF had a significantly greater (P < 0.001) mitogenic activity on both intestinal cells (IEC-6) (79326 +/- 3069 CPM) and blood lymphocytes (1903 +/- 204 CPM) compared with colostrum from dry feed fed sows (53433 +/- 1568 and 1231 +/- 61.4 CPM, respectively). The combined effects of enhanced maternal/passive immunity and the reduction in the level of environmental contamination with faecal pathogens, achieved by FLF, may be important in achieving improved health status for both sows and piglets.

Prenatal development of gastrointestinal function in the pig and the effects of fetal esophageal obstruction

Maturation of the fetal gastrointestinal tract (GIT) is influenced by both luminal stimuli (e.g. swallowed fluid) and hormonal factors (e.g. endogenous cortisol release). The aims of the present study were 1) to investigate GIT growth and maturation during the last 20% of gestation in pigs (term = 114 +/- 2 d), and 2) to investigate the effect of esophageal ligation, to prevent fetal swallowing, at 80% to 91% gestation. In normal fetuses, marked increases occurred during late gestation in body weight (+95%), relative intestinal weight (+79%, g kg(-1) body weight), activity of some digestive enzymes (1.5- to 10-fold), and absorption of glucose and intact proteins (3- to 6-fold). Fetuses with ligated esophagi had lowered body weight (-20%), reduced intestinal weight (-43%), aminopeptidase A activity (-24%), and glucose absorption (-27%), while lactase, sucrase, and dipeptidylpeptidase IV activities were increased (+40-50%), compared with sham-operated fetuses (all p < 0.05). Other parameters of GIT function remained unchanged by esophageal obstruction (absorption of amino acids and immunoglobulin, activity of chymosin, amylase, trypsin, chymotrypsin, maltase, aminopeptidase N -- all expressed per gram GIT tissue). Ligated fetuses had elevated cortisol levels, which is known to stimulate fetal GIT maturation. We conclude that the rapid development of GIT function in late gestation is diminished by esophageal obstruction, mainly due to slower GIT growth and not inhibition of normal functional development of enterocytes.

Long-term impact of neonatal breast-feeding on body weight and glucose tolerance in children of diabetic mothers

OBJECTIVE

Offspring born to women with pregnancies complicated by diabetes are at increased childhood risk of developing obesity and impaired glucose tolerance (IGT). In population-based studies, breast-feeding has been shown to be protective against obesity and diabetes later in life. To date, the role of breast-feeding on offspring of diabetic mothers (ODM) has not been investigated in this context.

RESEARCH DESIGN AND METHODS

A total of 112 ODM (type 1 diabetes, n = 83; gestational diabetes, n = 29) were evaluated prospectively for impact of ingestion of either diabetic breast milk (DBM) or nondiabetic banked donor breast milk (BBM) during the early neonatal period (day 1-7 of life) on relative body weight and glucose tolerance at a mean age of 2 years.

RESULTS

There was a positive correlation between the volume of DBM ingested and risk of overweight at 2 years of age (odds ratio [OR] 2.47, 95% CI 1.25-4.87). In contrast, the volume of BBM ingested was inversely correlated to body weight at follow-up (P = 0.001). Risk of childhood IGT decreased by increasing amounts of BBM ingested neonatally (OR 0.19, 95% CI 0.05-0.70). Stepwise regression analysis showed volume of DBM to be the only significant predictor of relative body weight at 2 years of age (P = 0.001).

CONCLUSIONS

Early neonatal ingestion of breast milk from diabetic mothers may increase risk of becoming overweight and, consequently, developing IGT during childhood. Additional studies are needed to assess long-term consequences that might result from the type of neonatal nutrition in ODM.

Advances in methods to evaluate gastrointestinal transport function

Malnutrition is a serious problem, and malabsorption of nutrients is believed to be partially responsible for its prevalence. A wide variety of innovative methods have been developed to study gastrointestinal transport function. Some of the first research into gastrointestinal function was conducted in the 1700's with animal and human models. Methodological advancements continue to allow scientists to innovatively assess gastrointestinal function in animal models, cellular preparations and clinical settings. For this update, the methods are divided into in vivo, ex vivo, isolated cells and membranes, and molecular biology approaches. The in vivo methods discussed include animal and human models to measure nutrient disappearance, catheterized animal models, models with isolated intestinal segments, and a new procedure for sampling luminal fluid from patients. The ex vivo approaches discussed obtain measurements with intact tissue, such as the everted sleeves method and Ussing chambers. The utility of novel cellular preparations, membrane fractionation procedures and various molecular biology techniques is included. Various aspects of these methods are evaluated to provide a detailed overview of recent methodological developments.