Effects of colostrum feeding on intestinal development in newborn pigs

The role of hormones in the regulation of lactogenic immunity in porcine and bovine species

Colostrum and milk offer a complete diet and vital immune protection for newborn mammals with developing immune systems. High immunoglobulin levels in colostrum serve as the primary antibody source for newborn piglets and calves. Subsequent milk feeding support continued local antibody protection against enteric pathogens, as well as maturation of the developing immune system and provide nutrients for newborn growth. Mammals have evolved hormonal strategies that modulate the levels of immunoglobulins in colostrum and milk to facilitate effective lactational immunity. In addition, hormones regulate the gut-mammary gland-secretory immunoglobulin A (sIgA) axis in pregnant mammals, controlling the levels of sIgA in milk, which serves as the primary source of IgA for piglets and helps them resist pathogens such as PEDV and TGEV. In the present study, we review the existing studies on the interactions between hormones and the gut-mammary-sIgA axis/lactogenic immunity in mammals and explore the potential mechanisms of hormonal regulation that have not been studied in detail, to draw attention to the role of hormones in influencing the immune response of pregnant and lactating mammals and their offspring, and highlight the effect of hormones in regulating sIgA-mediated anti-infection processes in colostrum and milk. Discussion of the relationship between hormones and lactogenic immunity may lead to a better way of improving lactogenic immunity by determining a better injection time and developing new vaccines.

Fate of undigested proteins in the pig large intestine: What impact on the colon epithelium?

Apart from its obvious agronomic interest in feeding billions of people worldwide, the porcine species represents an irreplaceable experimental model for intestinal physiologists and nutritionists. In this review, we give an overview on the fate of proteins that are not fully digested in the pig small intestine, and thus are transferred into the large intestine. In the large intestine, dietary and endogenous proteins are converted to peptides and amino acids (AA) by the action of bacterial proteases and peptidases. AA, which cannot, except in the neonatal period, be absorbed to any significant level by the colonocytes, are used by the intestinal microbes for protein synthesis and for the production of numerous metabolites. Of note, the production of the AA-derived metabolites greatly depends on the amount of undigested polysaccharides in the pig's diet. The effects of these AA-derived bacterial metabolites on the pig colonic epithelium have not yet been largely studied. However, the available data, performed on colonic mucosa, isolated colonic crypts and colonocytes, indicate that some of them, like ammonia, butyrate, acetate, hydrogen sulfide (H₂S), and p-cresol are active either directly or indirectly on energy metabolism in colonic epithelial cells. Further studies in that area will certainly gain from the utilization of the pig colonic organoid model, which allows for disposal of functional epithelial unities. Such studies will contribute to a better understanding of the potential causal links between diet-induced changes in the luminal concentrations of these AA-derived bacterial metabolites and effects on the colon epithelial barrier function and water/electrolyte absorption.

Transcriptome analysis revealed that delaying first colostrum feeding postponed ileum immune system development of neonatal calves

Our objective was to evaluate the effect of colostrum feeding times on genome-wide gene expression of neonatal calves. In total, twenty-seven calves were assigned to three colostrum feeding treatments: within 45 min (TRT0h, n = 9), 6 h (TRT6h, n = 9) and 12 h (TRT12h, n = 9). Ileum tissues were collected at 51 h and transcriptomic analysis was conducted. Uniquely expressed genes were identified in TRT0h group with enriched "Antigen Presentation" function. Meanwhile, the weighted gene co-expression network analysis (WGCNA) identified four significant gene modules (|correlation| > 0.50 and P ≤ 0.05). In particular, Turquoise gene module with the enriched "Cadherin binding involved in cell-cell adhesion" and "Cell-cell adherences junction" GO terms were significantly correlated with Faecalibacterium prausnitzii (R = -0.70, P < 0.01) and Bifidobacterium (R = -0.55, P < 0.01). Our findings suggest feeding colostrum without delay could stimulate the expression of genes involved in immune function development related to host response and microbial colonization in neonatal claves.

Composition and physiological functions of the porcine colostrum

The first secretion, 24-h post parturition of the mammary glands of sows, known as colostrum, is high in protein and low in lactose and fat. As a consequence of an insufficient ingestion of colostrum, more than 50% of piglets fail to reach weaning and die. The composition and some functions of colostrum have been previously reported. For example, colostrum carbohydrates consist of mainly lactose. Lipids in the colostrum are mostly triacylglycerols, but <1% is fatty acids, which may act as homeostasis regulators. Similarly, proteins are found mostly as casein and whey, the latter being ≥80% immunoglobulins. Colostrum-derived immunoglobulins and bioactive proteins such as azurocidin help the immune system of the piglet fend off infections. In addition, leukocytes and exosomes are other minor but nonetheless equally crucial bioactive components in the porcine colostrum. Modern pig farming has achieved increases in pig productivity and litter size, but this has been accomplished in detriment of the health and the survival rate of piglets. Therefore, porcine colostrum is now even more important in pig farming. In the present review, we discuss the current knowledge on the composition and physiological functions of the porcine colostrum and briefly propose future research directions.

Shotgun proteomics of homogenate milk reveals dynamic changes in protein abundances between colostrum, transitional and mature milk of swine

Milk is an easily digestible source of nutrients and bioactive factors, its composition reflects the neonate's needs, and changes from colostrum to transitional and mature milk. Our objective was to measure milk fat, lactose, total carbohydrate, and protein content in parallel with global proteome of homogenate milk samples to characterize changes across the three phases of swine lactation. Milk samples were collected from multiparous sows (n=9) on postnatal day 0 (D0; colostrum), 3 (D3; early transitional), 7 (D7; late transitional) and 14 (D14; mature). On D3, percent fat (16 ± 2.1) and lactose (3.8 ± 0.3) were higher (P<0.05) than on D0 (10 ± 3.9, and 1.5 ± 0.3; respectively). Levels of fat and lactose were not different between D3 and D14. Percent total protein decreased (P<0.05) between D0 (11 ± 2.1) and D3 (5 ± 0.7), but there was no significant change in percent protein between D3 and D14. Total carbohydrates increased (P<0.05) between D3 (944 ± 353 µg/ml) and D14 (1150 ± 462 µg/ml). Quantitative proteomic analysis using liquid chromatography tandem mass spectrometry (LC-MS/MS) of homogenate D0, D3, and D14 milk samples (n=6) identified 772 protein groups which corresponded to 501 individual protein-coding genes. A total of 207 high confidence proteins were detected in n=3 sows/day. Of the high confidence proteins, 81 proteins were common amongst all three days of lactation. Among the proteins that decreased between the days (FDR < 0.05) were multiple apolipoproteins and XDH which decreased between D0 to D3. Proteins that increased across the days (FDR < 0.05) were complement factors and14-3-3 proteins (YWHAQ, YWHAE). Our data provide a good characterization of milk proteome changes that likely reflect mammary function as well as the neonate's phase-specific developmental needs. This data may be useful in developing approaches to enhance the health and welfare of swine.

Fosfomycin residues in colostrum: Impact on morpho-physiology and microbiology of suckling piglets

Fosfomycin is a broad-spectrum bactericidal antibiotic widely used in pig farms for the treatment of a wide variety of bacterial infections. In this study, the elimination of disodium fosfomycin in colostrum/milk of the sow and the impact of this antibiotic on the microbiota and intestinal morpho-physiology of suckling piglets were analyzed. The average amount of fosfomycin eliminated in colostrum (after administration of 15 mg/kg IM) during the first 10 hr postpartum was 0.85 μg/ml, and the mean residual amount ingested by the piglets was 0.26 mg/kg. The elimination profile of fosfomycin concentrations in colostrum occurs at a time of profound changes in the morpho-physiology of the gastrointestinal tract of the piglet. However, the studied concentrations did not produce imbalances on the microbiota or on the morpho-physiology of the gastrointestinal tract of the piglet. Concentrations of fosfomycin were maintained in the mammary gland above the MIC for more than 8 hr for pathogenic bacteria of productive importance. This would indicate that fosfomycin may be considered safe for the specific treatment of bacterial infectious processes in sows during the peri- and postpartum period. This first study with disodium fosfomycin stimulates awareness in the proper use of antimicrobials at farrowing.

Relationships between day one piglet serum immunoglobulin immunocrit and subsequent growth, puberty attainment, litter size, and lactation performance

Colostrum affects gut and uterine gland development in the neonatal piglet, suggesting that subsequent growth and reproductive performance may be affected. Measuring immunoglobulin in piglet serum using the immunoglobulin immunocrit on Day 1 of age provides a simple, inexpensive indication of the amount of colostrum acquired by the piglet in the first day of life. Relationships between serum immunoglobulin immunocrit measures and subsequent growth rates, age at puberty, incidence of puberty failure, litter size, and lactation performance were examined in pigs born and subsequently farrowing between 2009 and 2013. Immunoglobulin immunocrit measures were collected on 16,762 piglets on Day 1 of age. Of these piglets, BW measurements were available from 15,324 (7,684 males and 7,640 females) piglets at a range of ages from weaning to 200 d of age, allowing an assessment of growth rates. Age at puberty was recorded from a subset of 2,857 of the females after observing them for estrous behavior from approximately 170 to 250 d of age. To examine relationships between d 1 immunocrit and puberty failure, gilts with immunocrit measures that failed to reach puberty (n = 119) were matched with littermate gilts with immunocrit measures that achieved puberty (n = 167). Similarly, number born alive was collected on a subset (n = 799) of females from first to fourth parities for which d 1 immunocrits were measured on them as neonates. Finally, d 1 immunocrit effect on adult lactational competence was assessed by measuring litter average (offspring of 440 females) and litter average piglet preweaning growth rate (offspring of 774 females) in females where d 1 immunocrits were available from them as neonates. Results indicated that low d 1 immunocrits were subsequently associated with reduced growth (P < 0.01), increased age at puberty (P < 0.01), reduced number born alive (P < 0.05), reduced litter average immunocrit (P < 0.05), and reduced litter average preweaning growth rate during lactation (P < 0.05). This suggests that management efforts to improve the amount of colostrum ingested by neonatal piglets would result in beneficial changes in production efficiency, particularly for gilts destined for the breeding herd. It also suggests that the immunoglobulin immunocrit can be useful in monitoring colostrum ingestion to maximize the beneficial effects of colostrum on subsequent performance.

The Mammary Gland in Mucosal and Regional Immunity

The mammary gland (MG) lacks a mucosa but is part of the mucosal immune system because of its role in passive mucosal immunity. The MG is not an inductive site for mucosal immunity. Rather, synthesis of immunoglobulin (Ig)A by plasma cells stimulated at distal inductive sites dominate in the milk of rodents, humans, and swine whereas IgG1 derived from serum predominates in ruminants. Despite the considerable biodiversity in the role of the MG, IgG passively transfers the maternal systemic immunological experience whereas IgA transfers the mucosal immunological experience. Although passive antibodies are protective, they and other lacteal constituents can be immunoregulatory. Immune protection of the MG largely depends on the innate immune system; the monocytes–macrophages group together with intraepithelial lymphocytes is dominant in the healthy gland. An increase in somatic cells (neutrophils) and various interleukins signal infection (mastitis) and a local immune response in the MG. The major role of the MG to mucosal immunity is the passive immunity supplied to the suckling neonate.

Dietary insulin affects leucine aminopeptidase, growth hormone, insulin-like growth factor I and insulin receptors in the intestinal mucosa of neonatal pigs

BACKGROUND

Recent studies suggest that milk-borne insulin may regulate the development of the gastrointestinal tract in neonatal mammals.

OBJECTIVES

To explore the mechanism by which milk-borne insulin affects gastrointestinal tract development, we examined the effect of dietary insulin on the expression levels of leucine aminopeptidase (LAP) and insulin-like growth factor I (IGF-I), as well as its effect on growth hormone (GH), IGF-I and insulin receptors in the small intestinal mucosa of neonatal pigs.

METHODS

Five piglets were anesthetized and sampled within 2-4 h after birth. They were not allowed to suckle and were used as newborn controls (group N). Ten other piglets from 5 litters were randomly divided into group M (n=5), which was fed cow's milk, and group MI (n=5), which was fed cow's milk and insulin (2.5 mg/l). Piglets in groups M and MI were artificially fed for 3 days and then sampled. Total RNA in their intestinal mucosa was extracted with Tripure reagents (Roche, USA). Reverse transcription PCR (RT-PCR) was used to semi-quantify mRNA levels of target genes and 18S rRNA was used in an RT-PCR system as an internal control. PCR products were loaded onto a 9% nondenaturing polyacrylamide gel. The gel was stained by silver staining agents. Digital photos were taken and the strength of the band areas was quantified using software.

RESULTS

The results showed that the DNA contents and LAP activity in the small intestines of the piglets in group MI were higher (p<0.05) than in the piglets in group N. Compared with group M, piglets in group MI exhibited significantly increased expression levels of both insulin and GH receptor in the ileum, and LAP in the jejunum (p<0.05); IGF-I receptor expression levels in both the jejunum and ileum were significantly decreased (p<0.01 and p<0.05, respectively), while IGF-I expression was unchanged (p>0.05).

CONCLUSION

Collectively, dietary insulin increased mRNA levels of insulin and GH receptor, which could help explain the effect of dietary insulin on receptor-mediated postnatal development of the small intestine. Dietary insulin suppressed IGF-I receptor expression, which may be the result of negative feedback caused when insulin binds to IGF-I receptors.

The intestinal trophic response to enteral food is reduced in parenterally fed preterm pigs and is associated with more nitrergic neurons

In term neonates, total parenteral nutrition (TPN) induces mucosal atrophy, whereas the first intake of milk is followed by intestinal growth. This may be explained in part by an NO-mediated increased blood flow. We hypothesized that the immature gut has an altered response to TPN and enteral nutrition. In Expt. 1, preterm caesarean-delivered pigs were administered elemental nutrients for 3 d, infused parenterally (TPN, n = 7) or enterally (TENT, n = 7). In Expt. 2, preterm pigs were fed sow's colostrum, cow's colostrum, or infant formula for 2 d after a 3-d TPN period (TPN-SOW, TPN-COW, TPN-FORM, n = 8-11). Intestinal morphology and the number of enteric neurons containing nitric oxide synthase-1 (NOS-1) were quantified. Both the TPN and TENT groups had increases in intestinal mass, circumference, and mucosal mass, volume, and surface density, relative to values at birth (+30-50%, P < 0.05). In Expt. 2, the magnitudes of the intestinal trophic responses to feeding were similar to those in Expt. 1, but were also associated with an increased number of nitrergic myenteric neurons and some mucosal damage, most frequently observed for the formula group. We conclude that 1) a short period of TPN does not induce mucosal atrophy in preterm pigs, whereas elemental nutrients infused luminally do not mimic the trophic response seen with milk diets, 2) enteral feeding of preterm pigs after a short period of TPN is associated with a modest, diet-dependent trophic response that may be related in part to the actions of an increased population of enteric NOS-1 neurons.

Preterm birth makes the immature intestine sensitive to feeding-induced intestinal atrophy

Preterm birth and formula feeding predispose to small intestinal dysfunction, which may lead to necrotizing enterocolitis (NEC). In piglets, we tested whether the physiological and environmental transitions occurring at birth affect the response of the immature intestine to enteral feeding. Pig fetuses (106 days gestation, term = 115 days) were prepared with esophageal feeding tubes and fed either sow's colostrum (n = 8) or infant formula (n = 7) in utero. After 24 h of oral feeding, the pig fetuses were delivered by cesarean section and their gastrointestinal morphology and function were compared with those of preterm newborn (NB) littermates that were not fed (n = 8) or fed colostrum (n = 7) or formula (n = 13) for 24 h after birth. Before birth, both colostrum and formula feeding resulted in marked increases in intestinal mass, brush-border enzyme activities, and plasma glucagon-like peptide 2 concentrations, to levels similar to those in NB colostrum-fed piglets. In contrast, NB formula-fed piglets showed reduced intestinal growth, decreased brush-border enzyme activities, and intestinal lesions, reflecting NEC. NB formula-fed pigs also showed impaired enterocyte endocytotic function and decreased antioxidative capacity, whereas brush-border enzyme mRNA levels were unaltered, relative to NB colostrum-fed pigs. Our results indicate that the feeding-induced growth and enzyme maturation of the immature intestine are not birth dependent. However, with a suboptimal diet (milk formula), factors related to preterm birth (e.g., microbial colonization and metabolic and endocrine changes) make the immature intestine sensitive to atrophy and development of NEC.

Colostrum protein concentrate enhances intestinal adaptation after massive small bowel resection in juvenile pigs

OBJECTIVES

Short bowel syndrome (SBS) usually results from the surgical removal of a large segment of small intestine. Patient outcome depends on the extent of intestinal resection and adaptation of the remaining intestine. We evaluated the impact of colostrum protein concentrate (CPC) on intestinal adaptation after massive small bowel resection in a porcine model of infant SBS.

METHODS

Four-week-old piglets underwent an approximate 75% small bowel resection (R, n = 23) or a control transection operation (C, n = 14). Postoperatively, animals from both groups received either pig chow (R = 6, C = 5), polymeric infant formula (R = 6, C = 3) or polymeric infant formula supplemented with CPC (R = 11, C = 6) for 8 weeks until sacrifice. Clinical outcome measures included weight gain and stool consistency. Morphologic measures were intestinal villus height and crypt depth. Functional outcome measure was mucosal disaccharidase activity.

RESULTS

Resected animals fed polymeric infant formula alone had reduced weight gain compared with controls fed the same diet (P < 0.005). Despite massive small bowel resection, animals fed pig chow or polymeric infant formula supplemented with CPC grew at an equivalent rate to controls fed polymeric infant formula alone. Resected animals supplemented with CPC had increased villus length and crypt depth in the jejunum (P < 0.001) and ileum (P < 0.001) compared with resected animals fed either pig chow or polymeric infant formula alone.

CONCLUSION

In an animal model of SBS, CPC supplementation of polymeric infant formula resulted in normal weight gain and features of enhanced morphologic adaptation.

Introduction of enteral food increases plasma GLP-2 and decreases GLP-2 receptor mRNA abundance during pig development

Glucagon-like peptide 2 (GLP-2) may mediate in part the rapid growth effects of luminal nutrients in the small intestine of newborns. The objectives of this study were to determine plasma GLP-2 concentrations and small intestinal GLP-2 receptor (GLP-2R) mRNA abundance (measured by reverse transcription polymerase chain reaction) during pre- and postnatal development and the relationship between these variables and small intestinal growth in enterally and parenterally fed fetal and newborn pigs (premature and term-delivered, 92 and 100% gestation, respectively). Plasma GLP-2 concentrations increased before birth, peaked in suckling 1-d-old pigs (87 +/- 14 pmol/L, P < 0.05), decreased with weaning-related anorexia (34 +/- 5 pmol/L, P < 0.05) and increased when normal food intake resumed (81 +/- 9 pmol/L, P < 0.05). Plasma GLP-2 concentrations were increased 1 d after enteral infusion of colostrum in fetal pigs at 92% gestation compared with untreated controls (59 +/- 11 vs. 7 +/- 2 pmol/L, P < 0.05). In newborn pigs, plasma GLP-2 was increased 2-6 d after the enteral administration of a milk diet, compared with the parenteral infusion of elemental nutrients, but the time course of the response was delayed in premature newborn pigs. Small intestinal GLP-2R mRNA abundance was highest at birth and decreased with enteral food intake in fetal, suckling and weaned pigs (P < 0.05). In contrast, enteral feeding increased (P < 0.05) relative small intestinal weight and/or villous heights in these pigs. We conclude that the introduction of enteral feeding transiently increases plasma GLP-2 concentrations and decreases small intestinal GLP-2R mRNA levels during pig development. GLP-2 may play a role in the growth of the small intestine around birth and weaning via a response to enteral nutrition.

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.

Characteristic transfer of colostrum-derived biologically active substances into cerebrospinal fluid via blood in natural suckling neonatal pigs

The characteristic transfer of colostral components into cerebrospinal fluid (CSF) via serum after natural suckling has been studied by sodium dodecyl sulphate (SDS) electrophoresis, two-dimensional electrophoresis, immunoblot and enzyme linked immunosorbent assay methods in non-suckling pigs. Total protein concentrations in the serum increased immediately after first suckling, reached a peak value at 12 h, corresponding to a 2.3-fold compared with pre-suckling level. The protein concentration in CSF also increased and reached peak value at 6 h corresponding to 1.6-fold compared with presuckling level. IgG in serum not detected before suckling, increased steeply after suckling, IgG, IgM and IgA transported into the serum were observed in completely intact form by immunoblot method. The IgG transported into serum was quickly transferred into CSF after natural suckling in contrast to the case of bovine IgG. Serum concentration of transferrin was maintained at high level before suckling and was not changed by suckling. Transferrin also detected in CSF was not changed by suckling. Bovine lactoferrin (Lf) administered into the intestinal lumen was transported into serum (0.01%) and also detected in CSF after 6 h as undegraded form (3.1%). Thus, homologous IgG and bovine Lf are transported into CSF, suggesting that the transport of macromolecules into CSF is selective in neonatal pigs.

Insulin-like growth factor-I stimulates Na+-dependent glutamine absorption in piglet enterocytes

Agents that enhance intestinal glutamine transport may be useful under conditions in which intestinal mucosal function is compromised. Here we examined whether oral administration of insulin-like growth factor (IGF-I) stimulates absorption of L-glutamine in piglet intestine. Colostrum-deprived piglets received human recombinant IGF-I (3.5 mg/kg/day) or vehicle orogastrically every 8 hr for four days after birth. Piglets were killed on day 5 and the proximal jejunum was removed. Basal electrical parameters and L-glutamine-stimulated changes in short-circuit current were measured in muscle-stripped tissues, and rates of L-glutamine uptake were measured in everted jejunal sleeves. Oral IGF-I had no effect on jejunal mucosal mass. Short-circuit current responses to mucosal addition of 10 mM L-glutamine were increased by oral IGF-I. Total and carrier-mediated uptakes of L-glutamine per milligram were greater in tissues from IGF-I-treated piglets due to a significantly greater maximal rate of uptake (Jmax). Thus, oral administration of IGF-I stimulates Na+-dependent glutamine absorption in piglet small intestine, an effect that is independent of changes in intestinal mucosal mass.

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.

Development of intestinal immunoglobulin absorption and enzyme activities in neonatal pigs is diet dependent

Uptake of colostrum just after birth is essential to stimulate intestinal growth and function, and in many species, including pigs, colostrum also provides immunological protection via the absorption of immunoglobulin G (IgG). In this study, intestinal growth, IgG absorptive capacity and enzyme activities were investigated in newborn pigs in response to different diets. Newborn piglets were bottle-fed porcine colostrum (PC), bovine colostrum (BC), porcine plasma (PP), porcine milk (PM), bovine colostrum containing porcine plasma (BCP) or a milk replacer (MR) every 3 h (15 mL/kg) for up to 2 d. Bovine serum albumin (BSA) was added to the diets as a macromolecule marker. The percentage of absorbed BSA just after birth was highest for piglets fed the PC diet (30-50%), lower for those fed the BC and BCP diets (23-30%) and lowest for the PP, PM and MR diet-fed piglets (7-20%, P < 0.05 relative to those fed colostrum). Porcine IgG was absorbed more efficiently than bovine IgG. Intestinal closure occurred earlier in MR and BCP piglets (within 12 h after birth) than in PC pigs. At 2 d of age, intestinal mucosal weight (+120% increase from birth) and villus morphology were similar in the PC, BCP and MR groups. All 3 groups also had increased aminopeptidase A activity compared with values at birth (+100% increase). Compared with PC pigs, the BCP group had higher sucrase and maltase activities (+50% and +200%, respectively) and lower aminopeptidase N activity (-50%, P < 0.05). Similarly, MR pigs showed elevated sucrase activity (+40%) and lowered maltase, lactase and aminopeptidase N activities (-20% to -50%, P < 0.05) compared with PC pigs. We conclude that porcine and bovine colostrum contain factors that stimulate the intestinal endocytotic and enzymatic capacity in newborn pigs. A milk replacer can produce normal gut growth, but may be inefficient in mediating normal macromolecule transport and disaccharidase activity. Bovine colostrum mixed with porcine plasma proteins may be a useful substitute for porcine colostrum in artificial rearing of newborn pigs.

Early nutrition and the development of immune function in the neonate

The present review will concentrate on the development of the gut-associated lymphoid tissue and the role of early nutrition in promoting immune function. The intestine is the largest immune organ in the body, and as such is the location for the majority of lymphocytes and other immune effector cells. The intestine is exposed to vast quantities of dietary and microbial antigens, and is the most common portal of entry for pathogens, some of which are potentially lethal. The development of normal immune function of the intestine is therefore vital for survival, and is dependent on appropriate antigen exposure and processing, and also an intact intestinal barrier. In early life innate mechanisms of defence are probably more important than active or adaptive mechanisms in responding to an infectious challenge, since the healthy neonate is immunologically naïve (has not seen antigen) and has not acquired immunological memory. During this period maternal colostrum and milk can significantly augment resistance to enteric infections. The mechanisms of enhancing disease resistance are thought to be passive, involving a direct supply of anti-microbial factors, and active, by promoting the development of specific immune function. A tolerance response to dietary and non-invasive antigens is generally induced in the gut. However, it must also be able to mount an adequate immune response to ensure clearance of foreign antigens. It is now recognized that regulation of tolerance and active immune responses is critical to health, and failure to regulate these responses can lead to recurrent infections, inflammatory diseases and allergies. The education of the immune system in early life is thought to be critical in minimizing the occurrence of these immune-based disorders. During this phase of development maternal milk provides signals to the immune system that generate appropriate response and memory. One factor that has been proposed to contribute to the increase in the incidence of immune-based disorders, e.g. atopic diseases in Western countries, is thought to be the increased prevalence of formula-feeding.

Oral IGF-I enhances nutrient and electrolyte absorption in neonatal piglet intestine

The effect of orally administered insulin-like growth factor-I (IGF-I) on small intestinal structure and function was studied in 5-day-old colostrum-deprived piglets. Human recombinant IGF-I (3.5 mg. kg(-1). day(-1)) or control vehicle was given orogastrically for 4 days. Body weights, jejunal and ileal mucosa wet and dry weights, and serum IGF-I levels were similar in the two groups. Small intestinal villus height and crypt depth and jejunal enterocyte microvillar dimensions were also similar between groups. Oral IGF-I produced higher rates of jejunal ion transport because of increased basal Na+ absorption. Short-circuit current responses to mucosal addition of D-glucose and L-alanine and net transepithelial absorption of 3-O-methylglucose were increased by IGF-I. Carrier-mediated uptake of D-glucose per milligram in everted jejunal sleeves was greater in IGF-I-treated piglets because of a significantly greater maximal rate of uptake. We conclude that rates of net Na+ and Na+-dependent nutrient absorption are enhanced in piglets treated with oral IGF-I, and this effect is independent of changes in mucosal mass or surface area.

The role of enterocytes in gut dysfunction

Stem cells in the intestinal epithelium give rise to enterocytes, goblet cells, enteroendocrine cells, and Paneth cells. Each of these cell lines plays a role in cytoprotection of the intestinal mucosa. In particular, it has been demonstrated that mature enterocytes can act as antigen presenting cells. Parenteral and enteral nutrition are used to nourish critically ill patients. However, these regimens are unfortunately associated with gut atrophy. Glutamine, the preferred intestinal nutrient, reverses this gut atrophy and plays a key role in maintaining the barrier function of the gut. Specific nutrients (putrescine, spermidine, spermine) have been used to modulate intestinal adaption. In addition, ornithine has been shown to act as a regulator of intestinal adaption. In this review, we discuss the relationship between the biology of enterocytes and failure of the gut barrier.

Rat milk and dietary long arginine3 insulin-like growth factor I promote intestinal growth of newborn rat pups

Newborn rat pups were artificially reared by the pup in cup (PIC) method to determine whether dietary long arginine3 IGF-I (long R3 IGF-I), an IGF-I analog with high receptor affinity and low IGF binding protein (IGFBP) affinity, had efficacy on intestinal growth. IGF effects are mediated by IGFBP and receptor interactions, hence dietary-induced changes in intestinal IGF-II receptor patterns and IGFBP-3 message levels were investigated. Intestinal micrographs of pups fed rat milk replacer (RMR) for 3 d showed flattened villi with low cell counts and appeared similar to newborn intestines. Mother-fed (MF) controls and long R3 IGF-I-fed pups showed increased villi height and cell counts when compared with RMR pups, with long R3 IGF-I fed pups showing the greatest increase. At birth IGF-II-specific binding was not uniform in the intestine; specific binding was higher in the proximal intestinal section than in the distal intestinal section. However, after 3 d of MF treatment, specific binding had reversed and the distal section showed higher IGF-II-specific binding. Three days of RMR feeding did not change IGF-II-specific binding from that of the newborn pup. An IGFBP-3 message was identified in intestinal epithelium by in situ hybridization. Northern analysis of IGFBP-3 message showed a decline over time, but the change was not influenced by dietary treatments. In summary, milk-borne growth factors have the potential to affect intestinal growth within 3 d of treatment.

Oral insulinlike growth factor-I stimulates intestinal enzyme maturation in newborn rats

Insulinlike growth factor-I (IGF-I) has been found in the milk of various species. To investigate if milk-borne IGF-I has any effect on postnatal gut development in neonatal animals, newborn rat pups were given orally 1 microg recombinant human IGF-I daily for 3 days. For comparison, a separate group of newborn pups was given 150 microg hydrocortisone, the hormone known to stimulate intestinal maturation in neonatal rats. Oral IGF-I treatment had no significant effect on the animal body weight nor on the weight of the stomach, small and large intestines, and pancreas. Oral administration of hydrocortisone significantly reduced body weight gain, but it had no apparent effect on internal organ weights. Both IGF-I and hydrocortisone treatments, however, significantly increased lactase, maltase and sucrase activities and hydrocortisone significantly increased aminopeptidase activity at the proximal small intestine when compared with the control. The finding supports the hypothesis that milk-borne IGF-I may play a role in regulating postnatal gut development in the suckling young.