High-protein–low-carbohydrate diet during pregnancy alters maternal plasma amino acid concentration and placental amino acid extraction but not fetal plasma amino acids in pigs

Short-Chain Fatty Acids Modulate Permeability, Motility and Gene Expression in the Porcine Fetal Jejunum Ex Vivo

Postnatally, short-chain fatty acids (SCFA) are important energetic and signaling agents, being involved in host nutrition, gut imprinting and immune and barrier function. Whether SCFA exert similar effects during the late fetal phase has been insufficiently elucidated. This study aimed to evaluate whether the fetal jejunum senses SCFA and whether SCFA modify the muscle tension and epithelial permeability and related signaling in jejunal tissue from the porcine fetus in late gestation. Exposure of fetal jejunal tissue to a mix of SCFA (70 µmol/mL) in an organ bath for 20 min lowered the muscle tension. Moreover, SCFA decreased the transepithelial conductance while increasing the short-circuit current in the Ussing chamber, indicating reduced permeability and increased SCFA absorption. Gene expression in the tissues harvested from the Ussing chamber after 30 min indicated downregulation of the expression of receptors (i.e., FFAR2 and TLR2), MCT1 and tight-junction and adherens proteins, which may be a negative feedback response to the applied high SCFA concentration compared with the micromolar concentration detected in fetal gastric fluid. Taken together, our data demonstrate that the fetal jejunum senses SCFA, which trigger electrophysiological, muscle contraction and related gene transcription responses. Hence, SCFA may play a role in prenatal gut nutrition and imprinting.

The Effect of Dietary Protein Imbalance during Pregnancy on the Growth, Metabolism and Circulatory Metabolome of Neonatal and Weaned Juvenile Porcine Offspring

Protein imbalance during pregnancy affects women in underdeveloped and developing countries and is associated with compromised offspring growth and an increased risk of metabolic diseases in later life. We studied in a porcine model the glucose and urea metabolism, and circulatory hormone and metabolite profile of offspring exposed during gestation, to maternal isoenergetic low-high (LP-HC), high-low (HP-LC) or adequate (AP) protein-carbohydrate ratio diets. At birth, LP-HC were lighter and the plasma acetylcarnitine to free carnitine ratios at 1 day of life was lower compared to AP offspring. Plasma urea concentrations were lower in 1 day old LP-HC offspring than HP-LC. In the juvenile period, increased insulin concentrations were observed in LP-HC and HP-LC offspring compared to AP, as was body weight from HP-LC compared to LP-HC. Plasma triglyceride concentrations were lower in 80 than 1 day old HP-LC offspring, and glucagon concentrations lower in 80 than 1 day old AP and HP-LC offspring. Plasma urea and the ratio of glucagon to insulin were lower in all 80 than 1 day old offspring. Aminoacyl-tRNA, arginine and phenylalanine, tyrosine and tryptophan metabolism, histidine and beta-alanine metabolism differed between 1 and 80 day old AP and HP-LC offspring. Maternal protein imbalance throughout pregnancy did not result in significant consequences in offspring metabolism compared to AP, indicating enormous plasticity by the placenta and developing offspring.

Maternal yeast-based nucleotide supplementation decreased stillbirth by regulating nutrient metabolism

BACKGROUND

As an enzymatic product of yeast, yeast-based nucleotide (YN) is rich in nucleotides. To test the effects of maternal dietary supplementation with YN during late pregnancy on placental nutrient transport and nutrient metabolism in neonatal piglets, 64 pregnant sows (day 85 ± 3) were assigned into two groups: (i) control (CON) and (ii) treatment (YN; 4 g kg^-1 ). Blood, placenta and liver samples of neonates during delivery were collected.

RESULTS

The results showed that maternal YN supplementation decreased stillbirth rate and intra-uterine growth restriction rate (P < 0.05). In addition, maternal YN supplementation increased total serum protein, albumin and total cholesterol (P < 0.05). Furthermore, in neonatal piglets in the YN group, both serum amino acidand nucleotide profiles were affected, as well as liver amino acid, and fatty acid profiles were regulated (P < 0.05). Moreover, maternal YN supplementation increased liver mRNA expression of SLC28A3, SLC29A1, SLC29A2, PC, PCK1, FBP1, SREBP1c, HSL and CYP7a1 of neonatal piglets (P < 0.05). Meanwhile, there was a decrease in placental gene expression of EAAT2, EAAT3, LAT1 and PAT1, as well as lower protein expression of peroxisome proliferator-activated receptor (PPAR)γ, AKT, phosphorylated-AKT, phosphorylated-mammalian target of rapamycin (mTOR) and Raptor, in the YN group (P < 0.05).

CONCLUSION

Taken together, these results indicate that maternal YN supplementation regulates placental nutrient transport by regulating the mTOR complex 1-PPAR pathway, and affects the liver metabolism of nucleotides, amino acids and fatty acids in neonatal piglets, thereby improving the reproductive performance of sow to a certain extent. © 2020 Society of Chemical Industry.

Dietary Insect Powder Protein Sources Improve Protein Utilization by Regulation on Intestinal Amino Acid-Chemosensing System

Simple Summary

Insect powders, including Tenebrio molitor (TM), Musca domestica larvae (MDL) and Zophobas morio (ZM), as high-quality and renewable protein sources are commonly applied in livestock and poultry feed production. The molecular effect of insect protein on amino acid metabolism in pigs needs to be explored. We found that insect powder as a protein source in feed regulated the mTOR signal pathway and improved amino acid transportation in the intestine for growth promotion. Insect powder may be a potentially promising protein source for pig production.

Abstract

This study was conducted to evaluate the effects of dietary insect powder supplementation as a protein source on plasma amino acid profiles, intestinal amino acid transport and sensing in a piglet model. A total of 144 weanling piglets were randomly assigned to four experimental diets for two phases (Days 1–28 and Days 29–56), to assess the effects on amino acid profiles and transportation in the segments of the intestine. The groups were basal diet (control), control diet plus Tenebrio molitor (TM), control diet plus Musca domestica larvae (MDL) and control diet plus Zophobas morio (ZM). The plasma free amino acid levels were stable comparable among treatments, except that the lysine level was significantly reduced by dietary MDL and ZM supplementation in the first phase (p < 0.05). In the 1st phase, the sensitivity of intestinal segments to the regulation of the amino acid level by insect powder supplementation follows sequence: colon > ileum > jejunum, while the order switched to jejunum > colon > ileum in the 2nd phase. The relative RNA expressions of mitogen-activated protein 4 kinase 3 (MAP4K3), sodium dependent neutral amino acid transporter2 (SNAT2), the transient receptor potential cation channel subfamily V member 1 (TRPV1) and taste 1 receptor member 1/3 (T1R3) in the segments of the intestine were affected by different dietary insect powder supplementation. G protein-coupled receptor family C group 6 member A (GPRC6A) level in the jejunal and colonic mucosa was upregulated by MDL supplementation (p < 0.05). These results indicated that dietary insects improved the metabolism of the amino acid in the prophase (the 1st phase) through regulating the sensing gene and mTOR signal pathway in intestinal mucosa by targeting different receptors. The finding demonstrates that the insect powder is a potentially promising source for protein deposition.

Postnatal growth retardation is associated with intestinal mucosa mitochondrial dysfunction and aberrant energy status in piglets

Individuals with postnatal growth retardation (PGR) are prone to developing chronic disease. Abnormal development in small intestine is casually implicated in impaired growth performance. However, the exact mechanism is still unknown. In this present study, PGR piglets (aged 42 days) were employed as a good model to analyse changes in nutrient absorption and energy metabolism in the intestinal mucosa. The results showed lower serum concentrations of free amino acids, and lipid metabolites in PGR piglets, which were in accordance with the down‐regulated mRNA expressions involved in fatty acid and amino acid transporters in the jejunal and ileal mucosa. The decreased activities of digestive enzymes and the marked swelling in mitochondria were also observed in the PGR piglets. In addition, it was found that lower ATP production, higher AMP/ATP ratio, deteriorated mitochondrial complex III and ATP synthase, and decreased manganese superoxide dismutase activity in the intestinal mucosa of PGR piglets. Furthermore, altered gene expression involved in energy metabolism, accompanied by decreases in the protein abundance of SIRT1, PGC‐1α and PPARγ, as well as phosphorylations of AMPKα, mTOR, P70S6K and 4E‐BP1 were observed in intestinal mucosa of PGR piglets. In conclusion, decreased capability of nutrient absorption, mitochondrial dysfunction, and aberrant energy status in the jejunal and ileal mucosa may contribute to PGR piglets.

Changes in amino acid profiles and liver alterations in pregnant rats with a high carbohydrate/low protein diet

INTRODUCTION AND AIM

Intake of a high-carbohydrate, low-protein diet (HCD/LPD) during pregnancy promotes metabolic disturbances. It has been suggested that liver function during pregnancy contributes to the synthesis of proteins necessary for fetal development during this stage. The liver is a site of response to the synthesis of macronutrients such as proteins. However, it is unknown how HCD/LPD is associated with modifications to the amino acid profiles and hepatic alterations in the maternal environment during pregnancy.

MATERIALS AND METHODS

A transverse longitudinal study was done in primiparous mothers during gestation (G) (G1 day 1, G5 day 5, G15 day 15, and G20 day 20). Histological analysis was used to assess hepatic alterations, and amino acid profiles in the liver were analyzed with high performance liquid chromatography (HPLC). Food and water intake was quantified, and peripheral biochemical indicators in serum were measured.

RESULTS

Mothers with HCD/LPD had increased micro and macro vesicles of fat, necrosis, and inflammation in the liver on G5. The total concentration of hepatic amino acids increased by 40% on G1, 17% on G5, and 25% on G15; and, there was a 12% decrease on G20. The following increases were observed in the liver on G1: arginine 68%, histidine 75%, alanine 18%, methionine 71%, and phenylalanine 51% (p>0.05); on G5: arginine 12%, methionine 34%, and phenylalanine 83% (p>0.05); on G15: arginine and phenylalanine 66%, tryptophan 81% and histidine 60.4% (p>0.05); and on G20: arginine 32% (p>0.05). No weight loss, changes in food consumption, or hepatomegaly occurred.

CONCLUSIONS

HCD/LPD during pregnancy in primiparous mothers may promote development of fat vesicles. Possibly, this condition causes metabolic adaptations and nitrogen management reflected in decreased levels of serum urea and altered amino acid profiles in the liver.

Circulating amino acids are associated with bone mineral density decline and ten-year major osteoporotic fracture risk in older community-dwelling adults

With aging, poor bone mineral density (BMD) and accelerated decrease in BMD are strong risk factors for fracture. Reports of the associations of dietary protein intake with bone strength are inconsistent, possibly owing to differences in protein sources and amino acid (AA) composition. We examined the associations of serum AA with 4-year hip BMD loss and subsequent fracture risk within 10 years in older community-dwelling adults, and further addressed whether lifestyle, dietary protein intake and its source, and body composition would affect the associations. In 1424 men and 1573 women (mean age 72 years), using binary logistic regression, higher serum valine, leucine, isoleucine and tryptophan concentrations were associated (or approaching a borderline significance in case of the last three ones) with less hip BMD decline (defined as BMD loss ≥ 2.8 times the precision error of the BMD measurement at femoral neck) in 4 years later, with the OR (95%CI) /SD of AA increase, ranging from 0.83 (0.75, 0.91) to 0.92 (0.87, 0.98) after multiple adjustments for baseline age, gender, BMI, BMD, estimated glomerular filtration rate (eGFR), dietary protein intake (animal- and plant-derived protein intakes), calcium intake, established lifestyles (physical activity level, smoking and alcohol drinking status), osteoporosis medications, and changes of body fat and lean muscle mass. Higher serum total homocysteine (tHcy) concentration was independently associated with BMD decline 4 years later (OR (95%CI) /SD of 1.16 (1.05, 1.27)). Using multivariate Cox regression, higher serum tryptophan concentration potentially predicted low risk of incident major osteoporotic fractures (MOFs) (HR/SD (95%CI)=0.86 (0.75, 0.98)) after multiple adjustments. Higher serum tHcy was associated with MOFs (HR/SD (95%CI)=1.29 (1.12, 1.50)) risk after multiple adjustments in men. These findings suggest that a specific AA profile correlates with greater BMD and lower subsequent fracture risk, independent of diet and lifestyle factors.

Maternal L-glutamine supplementation during late gestation alleviates intrauterine growth restriction-induced intestinal dysfunction in piglets

Maternal dietary supplementation with L-glutamine (Gln) has been considered as an option to improve fetal growth and to prevent the occurrence of intrauterine growth restriction (IUGR). This study investigated whether maternal Gln supplementation could improve fetal growth as well as the intestinal development during late pregnancy. Sixty pregnant Landrace × Large White multiparous sows were assigned to two groups, either the group fed the control diet or the group with the diet supplemented with 1% Gln from d 85 of gestation until farrowing. One normal body weight piglet and one IUGR piglet were obtained from six litters in each group. Reproductive performance, plasma concentrations of free amino acids and related metabolites as well as piglet growth and tissue indexes were determined. Maternal Gln supplementation during late gestation increased the average birth weight, while decreasing the within-litter variation of newborn piglets. The concentrations of Gln in plasma were lower in IUGR piglets than in normal piglets. Glutamine supplementation enhanced Gln concentrations in maternal and piglet plasma and the piglet jejunum, compared with the Control group. Supplementing Gln suppressed intestinal miR-29a levels, and increased the abundance of extracellular matrix (ECM) and tight junction (TJ) proteins, resulting in increased intestinal weight and improved morphologies of the piglets. Collectively, Gln supplementation to the sow's diet increased fetal growth, decreased the within-litter variation of newborn piglets, and alleviated the IUGR-induced intestinal impairment. These findings suggest the possibility of maternal glutamine supplementation in the prevention and treatment of IUGR in animal production and human medicine.

Higher Maternal Protein Intake during Pregnancy Is Associated with Lower Cord Blood Concentrations of Insulin-like Growth Factor (IGF)-II, IGF Binding Protein 3, and Insulin, but Not IGF-I, in a Cohort of Women with High Protein Intake

Background: Prenatal exposure to dietary protein may program growth-regulating hormones, consequently influencing early-life growth patterns and later risk of associated chronic diseases. The insulin-like growth factor (IGF) axis is of particular interest in this context given its influence on pre- and postnatal growth and its sensitivity to the early nutritional environment.Objective: Our objective was to examine associations of maternal protein intake during pregnancy with cord blood concentrations of IGF-I, IGF-II, IGF binding protein-3 (IGFBP-3), and insulin.Methods: We studied 938 mother-child pairs from early pregnancy through delivery in the Project Viva cohort. Using multivariable linear regression models adjusted for maternal race/ethnicity, education, income, smoking, parity, height, and gestational weight gain and for child sex, we examined associations of second-trimester maternal protein intake [grams per kilogram (weight before pregnancy) per day], as reported on a food frequency questionnaire, with IGF-I, IGF-II, IGFBP-3, and insulin concentrations in cord blood. We also examined how these associations may differ by child sex and parity.Results: Mothers were predominantly white (71%), college-educated (64%), and nonsmokers (67%). Mean ± SD protein intake was 1.35 ± 0.35 g ⋅ kg^-1 ⋅ d^-1 Each 1-SD increment in second-trimester protein intake corresponded to a change of -0.50 ng/mL (95% CI: -2.26, 1.26 ng/mL) in IGF-I and -0.91 μU/mL (95% CI: -1.45, -0.37 μU/mL) in insulin. Child sex and parity modified associations of maternal protein intake with IGF-II and IGFBP-3: protein intake was inversely associated with IGF-II in girls (P-interaction = 0.04) and multiparous mothers (P-interaction = 0.05), and with IGFBP-3 in multiparous mothers (P-interaction = 0.04).Conclusions: In a cohort of pregnant women with relatively high mean protein intakes, higher intake was associated with lower concentrations of growth-promoting hormones in cord blood, suggesting a pathway that may link higher protein intake to lower fetal growth. This trial was registered at clinicaltrials.gov as NCT02820402.

Moderate high or low maternal protein diets change gene expression but not the phenotype of skeletal muscle from porcine fetuses

The aim of our study was to characterize the immediate phenotypic and adaptive regulatory responses of fetuses to different in utero conditions reflecting inadequate maternal protein supply during gestation. The gilts fed high- (250% above control) or low- (50% under control) protein diets isoenergetically adjusted at the expense of carbohydrates from the day of insemination until the fetuses were collected at day 64 or 94 of gestation. We analyzed body composition, histomorphology, biochemistry, and messenger RNA (mRNA) expression of fetal skeletal muscle. Both diets had only marginal effects on body composition and muscular cellularity of fetuses including an unchanged total number of myofibers. However, mRNA expression of myogenic regulatory factors (MYOG, MRF4, P ≤ 0.1), IGF system (IGF1, IGF1R, P ≤ 0.05) and myostatin antagonist FST (P = 0.6, in males only) was reduced in the fetal muscle exposed to a maternal low-protein diet. As a result of excess protein, MYOD, MYOG, IGF1R, and IGFBP5 mRNA expression (P ≤ 0.05) was upregulated in fetal muscle. Differences in muscular mRNA expression indicate in utero regulatory adaptive responses to maternal diet. Modulation of gene expression immediately contributes to the maintenance of an appropriate fetal phenotype that would be similar to that observed in the control fetuses. Moreover, we suggest that the modified gene expression in fetal skeletal muscle can be viewed as the origin of developmental muscular plasticity involved in the concept of fetal programming.

Weight-loss diets and 2-y changes in circulating amino acids in 2 randomized intervention trials

BACKGROUND

Circulating amino acids, such as branched-chain amino acids (BCAAs) and aromatic amino acids (AAAs), have been associated with diabetes risk; however, little is known about how a long-term dietary intervention for weight loss affects circulating amino acids.

OBJECTIVES

We examined the effects of weight-loss diets on long-term changes in plasma amino acids and the associations of these changes with weight loss and the improvement of insulin resistance.

DESIGN

We repeatedly measured plasma amino acid profiles over 2 y in overweight or obese participants from 2 randomized, dietary intervention, weight-loss trials [774 subjects from the POUNDS LOST (Preventing Overweight Using Novel Dietary Strategies Trial) and 318 subjects from the DIRECT (Dietary Intervention Randomized Controlled Trial)].

RESULTS

Intervention diets consistently lowered most of the amino acid concentrations, including BCAAs and AAAs, in both trials. In the POUNDS LOST, average-protein diets (15% of daily energy) showed stronger effects than did high-protein diets (25% of daily energy) on reducing concentrations of the diabetes-associated BCAA valine at 6 mo independent of the weight change. In both trials, weight loss was directly related to the concurrent reduction of the BCAAs leucine and isoleucine, the AAAs tyrosine and phenylalanine, and 4 other amino acids. For example, per kilogram of weight loss, there was a 0.04-SD decrease in log tyrosine (∼0.6 μmol/L) in both trials. In addition, we showed that reductions in alanine and the AAA tyrosine were significantly related to improved insulin resistance (measured with the use of the homeostasis model assessment of insulin resistance), independent of weight loss, in both trials (both P < 0.05). For example, per 1-SD decrease in log tyrosine (∼17 μmol/L), there was a 0.04-SD (∼3%) improvement in insulin resistance in the POUNDS LOST and a 0.13-SD (∼8%) improvement in insulin resistance in the DIRECT.

CONCLUSION

Our findings underscore the potential importance of dietary interventions in improving amino acid profiles (i.e., reducing diabetes risk-enhancing amino acid concentrations) along with and beyond weight loss. The POUNDS LOST and the DIRECT were registered at clinicaltrials.gov as NCT00072995 and NCT00160108, respectively.

Impacts of Maternal Nutrition on Vascularity of Nutrient Transferring Tissues during Gestation and Lactation

As the demand for food increases with exponential growth in the world population, it is imperative that we understand how to make livestock production as efficient as possible in the face of decreasing available natural resources. Moreover, it is important that livestock are able to meet their metabolic demands and supply adequate nutrition to developing offspring both during pregnancy and lactation. Specific nutrient supplementation programs that are designed to offset deficiencies, enhance efficiency, and improve nutrient supply during pregnancy can alter tissue vascular responses, fetal growth, and postnatal offspring outcomes. This review outlines how vascularity in nutrient transferring tissues, namely the maternal gastrointestinal tract, the utero-placental tissue, and the mammary gland, respond to differing nutritional planes and other specific nutrient supplementation regimes.

Low and high dietary protein:carbohydrate ratios during pregnancy affect materno-fetal glucose metabolism in pigs

Inadequate dietary protein during pregnancy causes intrauterine growth retardation. Whether this is related to altered maternal and fetal glucose metabolism was examined in pregnant sows comparing a high-protein:low-carbohydrate diet (HP-LC; 30% protein, 39% carbohydrates) with a moderately low-protein:high-carbohydrate diet (LP-HC; 6.5% protein, 68% carbohydrates) and the isoenergetic standard diet (ST; 12.1% protein, 60% carbohydrates). During late pregnancy, maternal and umbilical glucose metabolism and fetal hepatic mRNA expression of gluconeogenic enzymes were examined. During an i.v. glucose tolerance test (IVGTT), the LP-HC-fed sows had lower insulin concentrations and area under the curve (AUC), and higher glucose:insulin ratios than the ST- and the HP-LC-fed sows (P < 0.05). Insulin sensitivity and glucose clearance were higher in the LP-HC sows compared with ST sows (P < 0.05). Glucagon concentrations during postabsorptive conditions and IVGTT, and glucose AUC during IVGTT, were higher in the HP-LC group compared with the other groups (P < 0.001). (13)C glucose oxidation was lower in the HP-LC sows than in the ST and LP-HC sows (P < 0.05). The HP-LC fetuses were lighter and had a higher brain:liver ratio than the ST group (P < 0.05). The umbilical arterial inositol concentration was greater in the HP-LC group (P < 0.05) and overall small fetuses (230-572 g) had higher values than medium and heavy fetuses (≥573 g) (P < 0.05). Placental lactate release was lower in the LP-HC group than in the ST group (P < 0.05). Fetal glucose extraction tended to be lower in the LP-HC group than in the ST group (P = 0.07). In the HP-LC and LP-HC fetuses, hepatic mRNA expression of cytosolic phosphoenolpyruvate carboxykinase (PCK1) and glucose-6-phosphatase (G6PC) was higher than in the ST fetuses (P < 0.05). In conclusion, the HP-LC and LP-HC sows adapted by reducing glucose turnover and oxidation and having higher glucose utilization, respectively. The HP-LC and LP-HC fetuses adapted via prematurely expressed hepatic gluconeogenic enzymes.

Intrauterine growth retarded piglet as a model for humans--studies on the perinatal development of the gut structure and function

The overall acceptance of pig models for human biomedical studies is steadily growing. Results of rodent studies are usually confirmed in pigs before extrapolating them to humans. This applies particularly to gastrointestinal and metabolism research due to similarities between pig and human physiology. In this context, intrauterine growth retarded (IUGR) pig neonate can be regarded as a good model for the better understanding of the IUGR syndrome in humans. In pigs, the induction of IUGR syndrome may include maternal diet intervention, dexamethasone treatment or temporary reduction of blood supply. However, in pigs, like in humans, circa 8% of neonates develop IUGR syndrome spontaneously. Studies on the pig model have shown changes in gut structure, namely a reduced thickness of mucosa and muscle layers, and delayed kinetic of disappearance of vacuolated enterocytes were found in IUGR individuals in comparison with healthy ones. Functional changes include reduced dynamic of gut mucosa rebuilding, decreased activities of main brush border enzymes, and changes in the expression of proteins important for carbohydrate, amino acids, lipid, mineral and vitamin metabolism. Moreover, profiles of intestinal hormones are different in IUGR and non-IUGR piglets. It is suggested that supplementation of the mothers during the gestation and/or the IUGR offspring after birth can help in restoring the development of the gastrointestinal tract. The pig provides presumably the optimal animal model for humans to study gastrointestinal tract structure and function development in IUGR syndrome.

Effects of low and high protein:carbohydrate ratios in the diet of pregnant gilts on maternal cortisol concentrations and the adrenocortical and sympathoadrenal reactivity in their offspring

Inadequate maternal nutrition during gestation may cause an adverse environment for the fetus leading to alterations of the hypothalamic-pituitary-adrenal (HPA) and sympatho-adrenomedullary (SAM) systems later in life. In the present study, we investigated the effects of diets with low and high protein:carbohydrate ratios on cortisol concentrations of pregnant gilts as well as the long-term effects on the function of the HPA and SAM axes in their offspring. Throughout gestation, 33 German Landrace gilts were fed high (HP, 30%), low (LP, 6.5%), or adequate (AP, 12.1%) protein diets, which were made isocaloric by adjusting the carbohydrate content. The salivary cortisol concentrations of the sows were measured in the course of the gestation period. The offspring were cross-fostered, and the plasma cortisol and catecholamine concentrations of the offspring were determined on postnatal d (PND) 1 and 27 and under specific challenging conditions: after weaning (PND 29) and after ACTH and insulin challenges (PND 68 and 70, respectively). Glucocorticoid receptor (GR) binding and neurotransmitter concentrations were measured in stress-related brain regions, and histological analyses of the adrenal were performed. Maternal salivary cortisol concentrations increased throughout gestation (P < 0.001) and the LP gilts had greater salivary cortisol compared with the AP and HP gilts (P < 0.05). No differences between diets were found for cortisol, corticosteroid-binding globulin, and catecholamine concentrations in plasma and for GR binding in hippocampus and hypothalamus in piglets at PND 1 and 27. However, the cortisol response to weaning was increased in LP piglets (P < 0.05), and in HP offspring the basal plasma noradrenaline concentrations were increased (P < 0.05). The cortisol response to the ACTH and the insulin challenge did not differ between diets. On PND 81, an increased adrenal medulla area was observed in LP offspring compared with the AP offspring (P < 0.05). Our results show that maternal diets with aberrant protein:carbohydrate ratios during gestation have moderate long-term effects on the function of the HPA and SAM system in the offspring, which indicates that pigs show a considerable plasticity to cope with maternal malnutrition.

High and low protein∶ carbohydrate dietary ratios during gestation alter maternal-fetal cortisol regulation in pigs

Imbalanced maternal nutrition during gestation can cause alterations of the hypothalamic-pituitary-adrenal (HPA) system in offspring. The present study investigated the effects of maternal low- and high-protein diets during gestation in pigs on the maternal-fetal HPA regulation and expression of the glucocorticoid receptor (GR), mineralocorticoid receptor (MR), 11β-hydroxysteroid dehydrogenase 1 and 2 (11β-HSD1 and 11β-HSD2) and c-fos mRNAs in the placenta and fetal brain. Twenty-seven German Landrace sows were fed diets with high (HP, 30%), low (LP, 6.5%) or adequate (AP, 12.1%) protein levels made isoenergetic by varying the carbohydrate levels. On gestational day 94, fetuses were recovered under general anesthesia for the collection of blood, brain and placenta samples. The LP diet in sows increased salivary cortisol levels during gestation compared to the HP and AP sows and caused an increase of placental GR and c-fos mRNA expression. However, the diurnal rhythm of plasma cortisol was disturbed in both LP and HP sows. Total plasma cortisol concentrations in the umbilical cord vessels were elevated in fetuses from HP sows, whereas corticosteroid-binding globulin levels were decreased in LP fetuses. In the hypothalamus, LP fetuses displayed an enhanced mRNA expression of 11β-HSD1 and a reduced expression of c-fos. Additionally, the 11β-HSD2 mRNA expression was decreased in both LP and HP fetuses. The present results suggest that both low and high protein∶carbohydrate dietary ratios during gestation may alter the expression of genes encoding key determinants of glucocorticoid hormone action in the fetus with potential long-lasting consequences for stress adaptation and health.

The association between the macronutrient content of maternal diet and the adequacy of micronutrients during pregnancy in the Women and Their Children’s Health (WATCH) study

Nutrition during pregnancy can induce alterations in offspring phenotype. Maternal ratio of protein to non-protein (P:NP) energy has been linked to variations in offspring body composition and adult risk of metabolic disease. This study describes the dietary patterns of pregnant women by tertiles of the P:NP ratio and compares diet to Australian recommendations. Data are from 179 Australian women enrolled in the Women and Their Children's Health Study. Diet was assessed using a validated 74-item food frequency questionnaire. Food group servings and nutrient intakes were compared to the Australian Guide to Healthy Eating and Australian Nutrient Reference Values. Higher maternal P:NP tertile was positively associated with calcium (P = 0.003), zinc (P = 0.001) and servings of dairy (P = 0.001) and meat (P = 0.001) food groups, and inversely associated with the energy dense, nutrient poor non-core (P = 0.003) food group. Micronutrient intakes were optimized with intermediate protein (18%E-20%E), intermediate fat (28%E-30%E) and intermediate carbohydrate (50%E-54%E) intakes, as indicated in tertile two. Results suggest a moderate protein intake may support pregnant women to consume the largest variety of nutrients across all food groups.