Effects of limited and excess protein intakes of pregnant gilts on carcass quality and cellular properties of skeletal muscle and subcutaneous adipose tissue in fattening pigs

Nutritional regulation of skeletal muscle energy metabolism, lipid accumulation and meat quality in pigs

The quality of pork determines consumers' purchase intention, which directly affects the economic value of pork. Minimizing the proportion of inferior pork and producing high quality pork are the ultimate goals of the pig industry. Muscle energy metabolism, serving as a regulative hub in organism energy expenditure and storage as a fat deposit, is compatible with myofiber type composition, affecting meat color, intramuscular fat content, tenderness, pH values and drip loss. Increasing data illustrate that dietary nutrients and bioactive ingredients affect muscle energy metabolism, white adipose browning and fat distribution, and myofiber type composition in humans, and rodents. Recently, some studies have shown that modulating muscle energy metabolism and lipid accumulation through nutritional approaches could effectively improve meat quality. This article reviews the progress and development in this field, and specifically discusses the impacts of dietary supply of amino acids, lipids, and gut microbiota as well as maternal nutrition on skeletal muscle energy metabolism, lipid accumulation and meat quality of pigs, so as to provide comprehensive overview with respect to effective avenues for improving meat quality.

Bayesian analysis reveals the influence of maternal effect on pre-weaning body weights in Landlly piglets

The present study was undertaken to estimate the (co)variance components and genetic parameters of body weights recorded in Landlly piglets from birth to weaning at weekly intervals (w0 to w6). The data pertained to body weights of 2462 piglets, born to 91 sires and 159 dams across different generations during a 7-year period from 2014 to 2020. Five animal models (I-V), differentiated by inclusion or exclusion of maternal effects with or without covariance between maternal and direct genetic effects, were fitted on the data using the Bayesian algorithm. The analyses were implemented by Gibbs sampling in the BLUPF90 program and Markov chain Monte Carlo (MCMC) methodology was used to draw samples of posterior distribution pertaining to (co)variance components. Based on deviance information criteria (DIC), model V with inclusion of direct additive genetic, direct maternal genetic and permanent environmental effect of dam as random factors along with covariance between direct additive and maternal effects best fitted the data on pre-weaning traits (w0 to w5). Whereas, model I incorporating only the direct additive genetic effect best fitted the weaning weight (w6) data in Landlly piglets. The posterior mean estimates of direct heritability under the best models for W0 to W6 were 0.13, 0.19, 0.29, 0.13, 0.26, 0.32 and 0.46, respectively. Inclusion of the maternal component helped in better partitioning of variance for different body weights in Landlly piglets. The maternal heritability ranged from 0.06 to 0.14, while the litter heritability ranged from 0.11 to 0.15 for pre-weaning weights (W0 to W5) under the best-fit models. The influence of maternal environment was greater than maternal genetic effect from birth to 4th week of age. The results implied that variations in body weight of Landlly pigs were genetically controlled to moderate levels (especially w2 and w4) with contributions from direct additive and maternal genotype that can be exploited by designing efficient breeding programmes.

Genes Related to Fat Metabolism in Pigs and Intramuscular Fat Content of Pork: A Focus on Nutrigenetics and Nutrigenomics

Simple Summary

The intramuscular fat (IMF) or marbling is an essential pork sensory quality that influences the preference of the consumers and premiums for pork. IMF is the streak of visible fat intermixed with the lean within a muscle fibre and determines sensorial qualities of pork such as flavour, tenderness and juiciness. Fat metabolism and IMF development are controlled by dietary nutrients, genes, and their metabolic pathways in the pig. Nutrigenetics explains how the genetic make-up of an individual pig influences the pig’s response to dietary nutrient intake. Differently, nutrigenomics is the analysis of how the entire genome of an individual pig is affected by dietary nutrient intake. The knowledge of nutrigenetics and nutrigenomics, when harmonized, is a powerful tool in estimating nutrient requirements for swine and programming dietary nutrient supply according to an individual pig’s genetic make-up. The current paper aimed to highlight the roles of nutrigenetics and nutrigenomics in elucidating the underlying mechanisms of fat metabolism and IMF deposition in pigs. This knowledge is essential in redefining nutritional intervention for swine production and the improvement of some economically important traits such as growth performance, backfat thickness, IMF accretion, disease resistance etc., in animals.

Abstract

Fat metabolism and intramuscular fat (IMF) are qualitative traits in pigs whose development are influenced by several genes and metabolic pathways. Nutrigenetics and nutrigenomics offer prospects in estimating nutrients required by a pig. Application of these emerging fields in nutritional science provides an opportunity for matching nutrients based on the genetic make-up of the pig for trait improvements. Today, integration of high throughput “omics” technologies into nutritional genomic research has revealed many quantitative trait loci (QTLs) and single nucleotide polymorphisms (SNPs) for the mutation(s) of key genes directly or indirectly involved in fat metabolism and IMF deposition in pigs. Nutrient–gene interaction and the underlying molecular mechanisms involved in fatty acid synthesis and marbling in pigs is difficult to unravel. While existing knowledge on QTLs and SNPs of genes related to fat metabolism and IMF development is yet to be harmonized, the scientific explanations behind the nature of the existing correlation between the nutrients, the genes and the environment remain unclear, being inconclusive or lacking precision. This paper aimed to: (1) discuss nutrigenetics, nutrigenomics and epigenetic mechanisms controlling fat metabolism and IMF accretion in pigs; (2) highlight the potentials of these concepts in pig nutritional programming and research.

Hydroxy Selenomethionine Improves Meat Quality through Optimal Skeletal Metabolism and Functions of Selenoproteins of Pigs under Chronic Heat Stress

Chronic heat stress (CHS) induces metabolic changes in skeletal muscle from growth to maintenance that jeopardizes growth performance, carcass traits, and meat quality of pigs. We investigated the protective effect of dietary organic selenium (hydroxy-4-methylselenobutanoic acid, OH-SeMet) on CHS-induced skeletal muscle damages of growing pigs, and the corresponding responses of selenoproteins. A total of 40 ((Landrace ×Yorkshire) × Duroc) pigs with an average live weight of 49.64 ± 2.48 kg were used in this 4-week trial. Pigs were randomly allotted to 5 groups: The control group was raised on a basal diet in a thermoneutral environment (22 ± 2 °C); and four CHS groups were raised on a basal diet and supplemented with Se 0.0, 0.2, 0.4, and 0.6 mg/kg as OH-SeMet, respectively, in hyperthermal condition (33 ± 2 °C). CHS resulted in significant decrease of growth performance, carcass traits, and meat quality, which were associated with reduced (p < 0.05) serum alkaline phosphatase (ALP) and total superoxide dismutase (T-SOD) and increased (p < 0.05) serum creatine (CK), sarcous heat shock protein 70 (HSP70), glucokinase (GCK), phosphoenolpyruvate carboxykinase (PEPCK), and malondialdehyde (MDA) contents. Meanwhile, four metabolism-related genes and seven selenoprotein encoding genes were abnormally expressed in skeletal muscle. Dietary OH-SeMet addition partially alleviated the negative impact of CHS on carcass traits and improved meat quality. These improvements were accompanied by the increase in Se deposition, the anti-oxidative capacity of serum and muscle, and protein abundance of GPX1, GPX3, GPX4, and SELENOP. Supplementation with 0.6 mg Se/kg (OH-SeMet) restored the sarcous PEPCK, and 0.4 and 0.6 mg Se/kg (OH-SeMet) restored all abnormally expressed metabolism-related and selenoprotein encoding genes. In summary, dietary supplementation with OH-SeMet beyond Se requirement mitigated CHS-induced depression of carcass traits and meat quality of pigs associated with optimal skeletal metabolism, enhanced antioxidant capacity, and regulation of selenoproteins in skeletal muscle of pigs.

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.

How Does Protein Nutrition Affect the Epigenetic Changes in Pig? A Review

Simple Summary

Epigenetic mechanisms regulate gene expression and depend of nutrition. In farm animals, and concretely, in pigs, some papers on protein nutrition have been realized to improve several productive traits. Changes in protein diet influence on epigenetic mechanisms that could affect productive and reproductive traits in individuals and their offspring. The purpose of this review was to update the current knowledge about the effects of these nutritional changes on epigenetic mechanisms in pigs.

Abstract

Epigenetic changes regulate gene expression and depend of external factors, such as environment and nutrition. In pigs, several studies on protein nutrition have been performed to improve productive and reproductive traits. Indeed, these studies aimed not only to determine broad protein requirements but also pigs’ essential amino acids requirements. Moreover, recent studies tried to determine these nutritional requirements for each individual, which is known as protein precision nutrition. However, nutritional changes could affect different epigenetic mechanisms, modifying metabolic pathways both in a given individual and its offspring. Modifications in protein nutrition, such as change in the amino acid profile, increase or decrease in protein levels, or the addition of metabolites that condition protein requirements, could affect the regulation of some genes, such as myostatin, insulin growth factor, or genes controlling cholesterol and glucose metabolism pathways. This review summarizes the impact of most common protein nutritional strategies on epigenetic changes and describes their effects on regulation of gene expression in pigs. In a context where animal nutrition is shifting towards precision protein nutrition (PPN), further studies evaluating the effects of PPN on animal epigenetic are necessary.

The Effects of Maternal Metformin Treatment on Late Prenatal and Early Postnatal Development of the Offspring Are Modulated by Sex

Metformin is currently used to improve pregnancy outcome in women affected by polycystic ovary syndrome (PCOS) or diabetes. However, metformin may also be useful in pregnancies at risk of intrauterine growth restriction (IUGR) since it improves placental efficiency and the fetuses' developmental competence. There is no data on the duration of the effect of this treatment from the prenatal up to the postnatal stages. Therefore, the present trial aimed at determining the impact of metformin treatment on the offspring neonatal traits and early postnatal development (i.e., during lactation) using an in vivo swine model. The results support that maternal metformin treatment during pregnancy induces protective changes in body shape and composition of the progeny (i.e., larger head size and body length at birth and higher total viscera weight at weaning). However, there were also major effects of the offspring sex (smaller corpulence in females and lower relative weight of main viscerae in males), which should be considered for further preclinical studies and when even the current clinical application in women affected by PCOS or diabetes is implemented.

Maternal Supplementation with Polyphenols and Omega-3 Fatty Acids during Pregnancy: Effects on Growth, Metabolism, and Body Composition of the Offspring

Simple Summary

The present study aimed to determine benefits and risks of a dietary supplementation combining hydroxytyrosol and n3 polyunsaturated fatty acids (PUFA) on developmental patterns and metabolic traits of offspring in swine, a model of intrauterine growth restricted (IUGR) pregnancies. There were no deleterious effects on the reproductive traits of the sows and the postnatal features of the piglets. Piglets from the supplemented sows, in spite of a lower mean weight and corpulence at birth, showed higher average daily weight gain and fractional growth rate afterwards. Consequently, they reached higher weight and corpulence with increased muscle development and better lipidemic and fatty acids profiles than control offspring at juvenile stages.

Abstract

Maternal supplementation with antioxidants and n3 PUFAs may be a promising strategy to reduce the risk of intrauterine growth restriction and preterm delivery, which may diminish the appearance of low-birth-weight neonates. The present study aimed to determine benefits and risks of a dietary supplementation combining hydroxytyrosol, a polyphenol from olive leaves and fruits, and n3 PUFAs, from linseed oil, on developmental patterns and metabolic traits of offspring in swine, a model of IUGR pregnancies. The results obtained indicate that maternal supplementation with hydroxytyrosol and n-3 fatty acids during pregnancy has no deleterious effects on the reproductive traits of the sows (prolificacy, homogeneity of the litter, and percentage of stillborns and low-birth-weight, LBW, piglets) and the postnatal features of the piglets (growth patterns, adiposity, and metabolic traits). Conversely, in spite of a lower mean weight and corpulence at birth, piglets from the supplemented sows showed higher average daily weight gain and fractional growth rate. Thus, at juvenile stages afterwards, the offspring from the treated group reached higher weight and corpulence, with increased muscle development and better lipidemic and fatty acid profiles, in spite of similar adiposity, than offspring in the control group. However, much caution and more research are still needed before practical recommendation and use in human pregnancies.

Microbial Mechanistic Insights into the Role of Sweet Potato Vine on Improving Health in Chinese Meishan Gilt Model

Simple Summary

Sweet potato vine as a source of fiber had been used in China for many years. We investigated the effects of fresh sweet potato vine on intestinal and plasma metabolites as well as colon microbial composition in Chinese Meishan gilts. Results suggest that sweet potato vine promoted intestinal muscle development, decreased gut permeability, endotoxin and pro-inflammatory cytokines concentrations, and increased butyrate production as well as beneficial flora, thus improving gut health.

Abstract

This study explored the impact of fresh sweet potato vine on the growth as well as the metabolites and colon microbial composition in Chinese Meishan gilt. Twenty Meishan gilts (body weight 30 ± 0.18 kg, n = 10 per treatment) were randomly assigned to a control (CON) or sweet potato vine (SPV) supplementation diet treatment. Gilts were housed in individual stalls. In the SPV treatment, 2 kg fresh sweet potato vine was used instead of 0.18 kg basal diet which provided the same amount of digestive energy and crude protein with the exception of crude fiber (CON, 51.00 g/d vs. SPV, 73.94 g/d) in terms of dry matter intake. Gilts were slaughtered and samples were collected on day 19 after the third estrus cycle. The SPV treatment tended to increase slaughter weight of gilts (p = 0.07); it also increased (p < 0.05) gastrointestinal tract weight and intestinal muscle layer thickness. SPV treatment also decreased (p < 0.05) carcass yield and subcutaneous adipose tissue. The concentration of zonulin and endotoxin in plasma was decreased (p < 0.05) as the gilt consumed the SPV diet. Colonic fecal concentrations of endotoxin, lipocalin-2, and tumor necrosis factor-α (TNF-α) were decreased (p < 0.05), and interleukin-10 (IL-10) was increased (p < 0.05) in the SPV treatment. Butyric acid and acetate concentration in colonic content as well as acetate concentration in caecal content were increased (p < 0.05) in the SPV treatment. Furthermore, the expression of carnitine palmityl transferase (CPT-1) and peroxisome proliferator-activated receptor-α (PPAR-α) in gilt liver in SPV treatment was increased (p < 0.05) in comparison with CON treatment. Meanwhile, the composition of the colon microbes was also altered by SPV; representative changes included an increase in Lactobacillus, Bacteroides, Roseburia, and Lachnospira. These results indicate that gilt fed with sweet potato vine had decreased gut permeability, endotoxin and pro-inflammatory cytokines concentrations; colonic fecal microbiota was also changed, which may be further beneficial to the intestinal health of Chinese Meishan gilt.

Energy and protein dilution in broiler breeder pullet diets reduced offspring body weight and yield

The objective of the current research was to evaluate transgenerational effects of maternal dietary energy and protein on growth, efficiency, and yield of broiler offspring. A factorial arrangement of treatments consisting of high and low ME and CP levels fed during the rearing and laying phases was used. The study was a final 2 × 2 × 2 × 2 factorial arrangement of treatments, including broiler sex. Ross 708 broiler breeder pullets (n = 933) were fed diets containing 2,736 (HE_REAR) or 2,528 kcal/kg ME (LE_REAR) with either 15.3% (HP_REAR) or 13.7% CP (LP_REAR). From 25 wk, dams were fed a 15% CP laying diet containing 2,900 (HE_LAY) or 2,800 kcal/kg ME (LE_LAY). Following artificial insemination of the dams at 35 wk, eggs were collected for 1 wk, incubated, and pedigree hatched to preserve maternal identity. Broiler offspring were placed sex-separately into 32 pens, according to laying phase maternal treatments, with rearing maternal treatments nested within pens. Individual BW and pen level feed intake were recorded weekly. Broilers were processed at 40 d of age to evaluate yield. Maternal diet effects on offspring BW were sex dependent and transient. Female LP_REAR × LE_LAY broilers had lower pectoralis major and carcass yield than HP_REAR × LE_LAY females. Male HP_REAR × HE_LAY broilers had increased breast yield (19.8%) compared with 18.4% in HP_REAR × LE_LAY broilers. Carcass yield was lower in LE_REAR × HP_REAR broilers (63.7%) compared with HE_REAR × HP_REAR broilers (64.9%). LE_REAR × HP_REAR dams had the lowest ME to CP ratio (E: P) diets and highest rearing phase CP intake. Maternal diet did not influence offspring FCR. The most consistent contributor to increased BW was higher maternal dietary CP and ME during rearing. Low ME maternal laying phase diets increased BW of male offspring more consistently than of female offspring. Maternal nutrition also influenced broiler yield, and is thus economically important. Energy and protein dilution in broiler breeder pullet diets may have detrimental effects on offspring performance.

Supplementation of sows with L-Arginine during gestating and lactation affects muscle traits of offspring related with postnatal growth and meat quality: From conception to consumption

This study investigated the effect of dietary inclusion of 25 g/day of _L-Arginine (n = 7) or iso‑nitrogenous amounts of alanine (n = 6) from d 30 of gestation to d 28 of lactation of sows on performance, muscle traits and meat quality in offspring. From each litter, heaviest and smallest littermate of both sexes were reared from d 28 and slaughtered at d 140 in accordance with a 2³factorial design. A response to _L-Arginine were obtained on small females where _L-Arginine increased birth weight, however this effect disappeared at weaning. _L-Arginine increased daily gain by 7% and increased the cross-sectional area of the M. semitendinosus in small females by 14%, suggesting an increased lean ratio. Mechanistic studies showed firstly, that small female littermates had increased number of muscle fibres (myogenesis) after _L-Arginine treatment (11%) and secondly increased total DNA (12%) as a consequence of satellite cell proliferation. Traits describing tenderness seem to be affected by _L-Arginine but further studies are needed.

Role of Maternal Dietary Protein and Amino Acids on Fetal Programming, Early Neonatal Development, and Lactation in Swine

Simple Summary

Dietary protein is an important nutrient source for sows, necessary for not only growth and production, but also other physiological functions. Protein limitations in maternal diets have the potential to impair fetal myogenesis, while excess maternal dietary protein appears to only have minor effects on early fetal muscle formation. Effects of maternal protein deficiency on increased fat deposition in porcine neonates is inconsistent with gene expressions in the neonates. Sufficient maternal dietary protein can enhance porcine milk protein and fat concentration. Understanding the function of protein and amino acids in sows and the effects on their offspring can provide rational approaches for the regulation of piglet growth and further improvements in meat quality in the future.

Abstract

Maternal nutrition plays a vital role in fetal development, early development of neonates, and lactation and regulates the lifetime productivity of offspring. During pregnancy, maternal nutrition alters expression of the fetal genome and the development of tissues and organs via fetal programming. After parturition, maternal nutrition continues to regulate growth and development of piglets through maternal milk, which contains carbohydrates, lipids, proteins and oligosaccharides. Thus, deficiencies in maternal nutrition are detrimental to development of piglets, which can lead to inefficient growth and decreased carcass merit. Protein is an important nutritional component for sows, which not only functions in muscle development, but also plays a vital role in embryonic and neonatal development and lactation. Although effects of maternal undernutrition on neonatal development have been widely studied in sows, the function of different maternal dietary protein levels on fetal development, neonatal growth and lactation performance of sows is largely unknown. Determination of the effects and underlying mechanisms of maternal dietary protein levels on development of piglets is vital to the pork industry. Therefore, we summarized recent reports regarding mechanisms of effects of maternal protein levels on regulation of conceptus growth and early postnatal development though uterine fetal programming and lactation in swine.

Impacts of maternal dietary protein intake on fetal survival, growth, and development

Maternal nutrition during gestation, especially dietary protein intake, is a key determinant in embryonic survival, growth, and development. Low maternal dietary protein intake can cause embryonic losses, intra-uterine growth restriction, and reduced postnatal growth due to a deficiency in specific amino acids that are important for cell metabolism and function. Of note, high maternal dietary protein intake can also result in intra-uterine growth restriction and embryonic death, due to amino acid excesses, as well as the toxicity of ammonia, homocysteine, and H2S that are generated from amino acid catabolism. Maternal protein nutrition has a pronounced impact on fetal programming and alters the expression of genes in the fetal genome. As a precursor to the synthesis of molecules (e.g. nitric oxide, polyamines, and creatine) with cell signaling and metabolic functions, L-arginine (Arg) is essential during pregnancy for growth and development of the conceptus. With inadequate maternal dietary protein intake, Arg and other important amino acids are deficient in mother and fetus. Dietary supplementation of Arg during gestation has been effective in improving embryonic survival and development of the conceptus in many species, including humans, pigs, sheep, mice, and rats. Both the balance among amino acids and their quantity are critical for healthy pregnancies and offspring. Impact statement This review aims at: highlighting adverse effects of elevated levels of ammonia in mother or fetus on embryonic/fetal survival, growth, and development; helping nutritionists and practitioners to understand the mechanisms whereby elevated levels of ammonia in mother or fetus results in embryonic/fetal death, growth restriction, and developmental abnormalities; and bringing, into the attention of nutritionists and practitioners, the problems of excess or inadequate dietary intake of protein or amino acids on pregnancy outcomes in animals and humans. The article provides new, effective means to improve embryonic/fetal survival and growth in mammals.

Voluntary locomotor activity promotes myogenic growth potential in domestic pigs

Self-determined physical activity is an essential behavioural need and can vary considerably between individuals of a given species. Although locomotion is suggested as a prerequisite for adequate function of skeletal muscle, domestic pigs are usually reared under limited space allowance. The aim of our study was to investigate if a different voluntary locomotor activity leads to altered properties in the muscle structure, biochemistry and mRNA expression of selected genes involved in myogenesis and skeletal muscle metabolism. Based on a video tracking method, we assigned pigs to three categories according to their total distances walked over five observed time points: long distance, medium distance, and short distance. The microstructure and biochemistry parameters of the M. semitendinosus were unaffected by the distance categories. However, we found distance-dependent differences in the mRNA expression of the genes encoding growth (IGF2, EGF, MSTN) and transcription factors (MRF4, MYOD). In particular, the IGF2/MSTN ratio appears to be a sensitive indicator, at the molecular level, for the locomotor activity of individuals. Our results indicate that the myogenic growth potential of pigs under standard rearing conditions is triggered by their displayed voluntary locomotor activity, but the covered distances are insufficient to induce adaptive changes at the tissue level.

Maternal Macronutrient Consumption and the Developmental Origins of Metabolic Disease in the Offspring

Recent research aimed at understanding the rise in obesity and cardiometabolic disease in children suggests that suboptimal maternal nutrition conditions organ systems and physiological responses in the offspring contributing to disease development. Understanding the mechanisms by which the macronutrient composition of the maternal diet during pregnancy or lactation affects health outcomes in the offspring may lead to new maternal nutrition recommendations, disease prevention strategies and therapies that reduce the increasing incidence of cardiometabolic disease in children. Recent mechanistic animal model research has identified how excess fats and sugars in the maternal diet alter offspring glucose tolerance, insulin signaling and metabolism. Maternal nutrition appears to influence epigenetic alterations in the offspring and the programming of gene expression in key metabolic pathways. This review is focused on experimental studies in animal models that have investigated mechanisms of how maternal consumption of macronutrients affects cardiometabolic disease development in the offspring. Future research using "-omic" technologies is essential to elucidate the mechanisms of how altered maternal macronutrient consumption influences the development of disease in the offspring.

Polyphenols and IUGR pregnancies: Maternal hydroxytyrosol supplementation improves prenatal and early-postnatal growth and metabolism of the offspring

Hydroxytyrosol is a polyphenol with antioxidant, metabolism-regulatory, anti-inflammatory and immuno-modulatory properties. The present study aimed to determine whether supplementing the maternal diet with hydroxytyrosol during pregnancy can improve pre- and early post-natal developmental patterns and metabolic traits of the offspring. Experiment was performed in Iberian sows fed a restricted diet in order to increase the risk of IUGR. Ten sows were treated daily with 1.5 mg of hydroxytyrosol per kg of feed between Day 35 of pregnancy (30% of total gestational period) until delivery whilst 10 animals were left untreated as controls. Number and weight of offspring were assessed at birth, on post-natal Day 15 and at weaning (25 days-old). At weaning, body composition and plasma indexes of glucose and lipids were measured. Treatment with hydroxytyrosol was associated with higher mean birth weight, lower incidence of piglets with low birth weight. Afterwards, during the lactation period, piglets in the treated group showed a higher body-weight than control piglets; such effects were even stronger in the most prolific litters. These results suggest that maternal supplementation with hydroxytyrosol may improve pre- and early post-natal development of offspring in pregnancies at risk of IUGR.

Variation in the ovine MYF5 gene and its effect on carcass lean meat yield in New Zealand Romney sheep

Myogenic factor 5 (MYF5) plays an important role in regulating skeletal muscle, but to date there have been no reports on whether the gene is variable and whether this variation is associated with meat yield in sheep. In this study, four variants (A to D) of ovine MYF5 containing two Single Nucleotide Polymorphisms (SNPs) and one basepair (bp) insertion/deletion were detected by Polymerase Chain Reaction - Single Stranded Conformational Polymorphism (PCR-SSCP) analysis. Breed differences in variant frequencies were observed. The effect of variation in ovine MYF5 on lean meat yield, predicted using VIAScan® technology, was investigated in 388 male NZ Romney lambs. Only genotypes AA and AB were found in these lambs. Lambs with genotype AA had a higher leg yield (P=0.044), loin yield (P=0.002) and total yield (P=0.012) than those with genotype AB. No association with shoulder yield was detected. These results suggest that ovine MYF5 may be a valuable genetic marker for improved lean meat yield.

Amino acid starvation-induced autophagy is involved in reduced subcutaneous fat deposition in weaning piglets derived from sows fed low-protein diet during gestation and lactation : Autophagy is involved in reduced fat deposition in maternal low-protein piglets

PURPOSE

The study aimed to determine the effects of maternal low-protein (LP) diet on subcutaneous fat deposition of weaning piglets and the potential mechanism.

METHODS

Sows were fed either a standard protein (SP, 15 and 18% crude protein) or a LP diet (50% protein levels of SP) throughout pregnancy and lactation. Subcutaneous fat and blood were sampled from male piglets at 28 days of age. Serum biochemical metabolites and hormone concentrations were detected with the enzymatic colorimetric methods. Serum-free amino acid (FAA) levels were measured by amino acid auto-analyzer. The mRNA and protein were measured by qRT-PCR and Western blot.

RESULTS

Body weight, back fat thickness, triglycerides concentrations in subcutaneous fat tissue, and serum, as well as FFA concentrations were significantly reduced in LP piglets when compared with SP piglets. Further studies showed that mRNA and protein expression of acetyl-CoA carboxylase and fatty acid synthetase, two key enzymes of de novo lipogenesis, were significantly reduced in LP piglets, while mRNA expression and the lipolytic enzymes activities of lipolysis genes, adipose triglyceride lipase and hormone-sensitive lipase, were significantly increased. Furthermore, expression of autophagy-related gene 7 and autophagy maker gene microtubule-associated protein 1A/1B-light chain 3 (LC 3) as well as the conversion of LC3I to LC3II were significantly elevated, along with the expression of activating transcription factor-4 and eukaryotic translation initiation factor-2a.

CONCLUSION

These results indicate that amino acid starvation-induced autophagy is involved in reduced subcutaneous fat deposition in maternal LP weaning piglets, demonstrating links between maternal protein restriction and offspring fat deposition.

Invited review: Pre- and postnatal adipose tissue development in farm animals: from stem cells to adipocyte physiology

Both white and brown adipose tissues are recognized to be differently involved in energy metabolism and are also able to secrete a variety of factors called adipokines that are involved in a wide range of physiological and metabolic functions. Brown adipose tissue is predominant around birth, except in pigs. Irrespective of species, white adipose tissue has a large capacity to expand postnatally and is able to adapt to a variety of factors. The aim of this review is to update the cellular and molecular mechanisms associated with pre- and postnatal adipose tissue development with a special focus on pigs and ruminants. In contrast to other tissues, the embryonic origin of adipose cells remains the subject of debate. Adipose cells arise from the recruitment of specific multipotent stem cells/progenitors named adipose tissue-derived stromal cells. Recent studies have highlighted the existence of a variety of those cells being able to differentiate into white, brown or brown-like/beige adipocytes. After commitment to the adipocyte lineage, progenitors undergo large changes in the expression of many genes involved in cell cycle arrest, lipid accumulation and secretory functions. Early nutrition can affect these processes during fetal and perinatal periods and can also influence or pre-determinate later growth of adipose tissue. How these changes may be related to adipose tissue functional maturity around birth and can influence newborn survival is discussed. Altogether, a better knowledge of fetal and postnatal adipose tissue development is important for various aspects of animal production, including neonatal survival, postnatal growth efficiency and health.

Transfer of β-hydroxy-β-methylbutyrate from sows to their offspring and its impact on muscle fiber type transformation and performance in pigs

Background

Previous studies suggested that supplementation of lactating sows with β-hydroxy-β-methylbutyrate (HMB) could improve the performance of weaning pigs, but there were little information in the muscle fiber type transformation of the offspring and the subsequent performance in pigs from weaning through finishing in response to maternal HMB consumption. The purpose of this study was to determine the effect of supplementing lactating sows with HMB on skeletal muscle fiber type transformation and growth of the offspring during d 28 and 180 after birth. A total of 20 sows according to their body weight were divided into the control (CON, n = 10) or HMB groups (HMB, n = 10). Sows in the HMB group were supplemented with β-hydroxy-β-methylbutyrate calcium (HMB-Ca) 2 g /kg feed during d 1 to 27 of lactation. After weaning, 48 mixed sex piglets were blocked by sow treatment and fed standard diets for post-weaning, growing, finishing periods. Growth performance was recorded during d 28 to 180 after birth. Pigs were slaughtered on d 28 (n = 6/treatment) and 180 (n = 6/treatment) postnatal, and the longissimus dorsi (LD) was collected, respectively.

Results

The HMB-fed sows during lactation showed increased HMB concentration (P < 0.05) in milk and LD of weaning piglets (P < 0.05). In addition, offsprings in HMB group had a higher finishing BW and lean percentage than did pigs in CON group (P < 0.05), meanwhile, compared with pigs from sows fed the CON diet, pigs from sows fed HMB diet showed higher type II muscle fiber cross-sectional area (CSA), elevated myosin heavy chain (MyHC) IIb and Sox6 mRNA, and fast-MyHC protein levels in LD (P < 0.05).

Conclusions

HMB supplemented to sow diets throughout lactation increases the levels of HMB in maternal milk and skeletal muscle of pigs during d 28 after birth and promotes subsequent performance of pigs between d 28 and 180 of age by enhancing glycolytic muscle fiber transformation.

Breeding animals for quality products: not only genetics

The effect of the Developmental Origins of Health and Disease on the spread of non-communicable diseases is recognised by world agencies such as the United Nations and the World Health Organization. Early environmental effects on offspring phenotype also apply to domestic animals and their production traits. Herein, we show that maternal nutrition not only throughout pregnancy, but also in the periconception period can affect offspring phenotype through modifications of gametes, embryos and placental function. Because epigenetic mechanisms are key processes in mediating these effects, we propose that the study of epigenetic marks in gametes may provide additional information for domestic animal selection.

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.

Genome-Wide Detection of CNVs and Their Association with Meat Tenderness in Nelore Cattle

Brazil is one of the largest beef producers and exporters in the world with the Nelore breed representing the vast majority of Brazilian cattle (Bos taurus indicus). Despite the great adaptability of the Nelore breed to tropical climate, meat tenderness (MT) remains to be improved. Several factors including genetic composition can influence MT. In this article, we report a genome-wide analysis of copy number variation (CNV) inferred from Illumina® High Density SNP-chip data for a Nelore population of 723 males. We detected >2,600 CNV regions (CNVRs) representing ≈6.5% of the genome. Comparing our results with previous studies revealed an overlap in ≈1400 CNVRs (>50%). A total of 1,155 CNVRs (43.6%) overlapped 2,750 genes. They were enriched for processes involving guanosine triphosphate (GTP), previously reported to influence skeletal muscle physiology and morphology. Nelore CNVRs also overlapped QTLs for MT reported in other breeds (8.9%, 236 CNVRs) and from a previous study with this population (4.1%, 109 CNVRs). Two CNVRs were also proximal to glutathione metabolism genes that were previously associated with MT. Genome-wide association study of CN state with estimated breeding values derived from meat shear force identified 6 regions, including a region on BTA3 that contains genes of the cAMP and cGMP pathway. Ten CNVRs that overlapped regions associated with MT were successfully validated by qPCR. Our results represent the first comprehensive CNV study in Bos taurus indicus cattle and identify regions in which copy number changes are potentially of importance for the MT phenotype.

Diet before and during Pregnancy and Offspring Health: The Importance of Animal Models and What Can Be Learned from Them

This review article outlines epidemiologic studies that support the hypothesis that maternal environment (including early nutrition) plays a seminal role in determining the offspring’s long-term health and metabolism, known as the concept of Developmental Origins of Health and Diseases (DOHaD). In this context, current concerns are particularly focused on the increased incidence of obesity and diabetes, particularly in youth and women of child-bearing age. We summarize key similarities, differences and limitations of various animal models used to study fetal programming, with a particular focus on placentation, which is critical for translating animal findings to humans. This review will assist researchers and their scientific audience in recognizing the pros and cons of various rodent and non-rodent animal models used to understand mechanisms involved in fetal programming. Knowledge gained will lead to improved translation of proposed interventional therapies before they can be implemented in humans. Although rodents are essential for fundamental exploration of biological processes, other species such as rabbits and other domestic animals offer more tissue-specific physiological (rabbit placenta) or physical (ovine maternal and lamb birth weight) resemblances to humans. We highlight the important maternal, placental, and fetal/neonatal characteristics that contribute to developmentally programmed diseases, specifically in offspring that were affected in utero by undernutrition, overnutrition or maternal diabetes. Selected interventions aimed at prevention are summarized with a specific focus on the 1000 days initiative in humans, and maternal exercise or modification of the n-3/n-6 polyunsaturated fatty acid (PUFA) balance in the diet, which are currently being successfully tested in animal models to correct or reduce adverse prenatal programming. Animal models are essential to understand mechanisms involved in fetal programming and in order to propose interventional therapies before they can be implemented in humans. Non-rodent animals are particularly important and should not be neglected, as they are often more physiologically-appropriate models to mimic the human situation.

Maternal high-protein diet during pregnancy, but not during suckling, induced altered expression of an increasing number of hepatic genes in adult mouse offspring

PURPOSE

Indirect effects of a high-protein maternal diet are not well understood. In this study, we analyzed short-term and sustainable effects of a prenatal versus early postnatal maternal high-protein diet on growth and hepatic gene expression in mouse offspring.

METHODS

Dams were exposed to an isoenergetic high-protein (HP, 40 % w/w) diet during pregnancy or lactation. Growth and hepatic expression profiles of male offspring were evaluated directly after weaning and 150 days after birth. Offspring from two dietary groups, high-protein diet during pregnancy and control diet during lactation (HPC), and control diet during pregnancy and high-protein diet during lactation (CHP), were compared with offspring (CC) from control-fed dams.

RESULTS

Maternal CHP treatment was associated with sustained offspring growth retardation, but decreased numbers of affected hepatic genes in adults compared to weanlings. In contrast, offspring of the HPC group did not show persistent effects on growth parameters, but the number of affected hepatic genes was even increased at adult age. In both dietary groups, however, only a small subset of genes was affected in weanlings as well as in adults.

CONCLUSIONS

We conclude that (1) prenatal and early postnatal maternal HP diet caused persistent, but (2) different effects and partially complementary trends on growth characteristics and on the hepatic transcriptome and associated pathways and that (3) only a small number of genes and associated upstream regulators might be involved in passing early diet-induced imprints to adulthood.

Offspring subcutaneous adipose markers are sensitive to the timing of maternal gestational weight gain

BACKGROUND

Excessive maternal weight gain during pregnancy impacts on offspring health. This study focused on the timing of maternal gestational weight gain, using a porcine model with mothers of normal pre-pregnancy weight.

METHODS

Trial design ensured the trajectory of maternal gestational weight gain differed across treatments in early, mid and late gestation. Diet composition did not differ. On day 25 gestation, sows were assigned to one of five treatments: Control sows received a standard gestation diet of 2.3 kg/day (30 MJ DE/day) from early to late gestation (day 25-110 gestation). E sows received 4.6 kg food/day in early gestation (day 25-50 gestation). M sows doubled their food intake in mid gestation (day 50-80 gestation). EM sows doubled their food intake during both early and mid gestation (day 25-80 gestation). L sows consumed 3.5 kg food/day in late gestation (day 80-110 gestation). Offspring body weight and food intake levels were measured from birth to adolescence. Markers of lipid metabolism, hypertrophy and inflammation were investigated in subcutaneous adipose tissue of adolescent offspring.

RESULTS

The trajectory of gestational weight gain differed across treatments. However total gestational weight gain did not differ except for EM sows who were the heaviest and fattest mothers at parturition. Offspring birth weight did not differ across treatments. Subcutaneous adipose tissue from EM offspring differed significantly from controls, with elevated mRNA levels of lipogenic (CD36, ACACB and LPL), nutrient transporters (FABP4 and GLUT4), lipolysis (HSL and ATGL), adipocyte size (MEST) and inflammation (PAI-1) indicators. The subcutaneous adipose depot from L offspring exhibited elevated levels of CD36, ACACB, LPL, GLUT4 and FABP4 mRNA transcripts compared to control offspring.

CONCLUSIONS

Increasing gestational weight gain in early gestation had the greatest impact on offspring postnatal growth rate. Increasing maternal food allowance in late gestation appeared to shift the offspring adipocyte focus towards accumulation of fat. Mothers who gained the most weight during gestation (EM mothers) gave birth to offspring whose subcutaneous adipose tissue, at adolescence, appeared hyperactive compared to controls. This study concluded that mothers, who gained more than the recommended weight gain in mid and late gestation, put their offspring adipose tissue at risk of dysfunction.

Maternal nutrition induces gene expression changes in fetal muscle and adipose tissues in sheep

Background

Maternal nutrition during different stages of pregnancy can induce significant changes in the structure, physiology, and metabolism of the offspring. These changes could have important implications on food animal production especially if these perturbations impact muscle and adipose tissue development. Here, we evaluated the impact of different maternal isoenergetic diets, alfalfa haylage (HY; fiber), corn (CN; starch), and dried corn distillers grains (DG; fiber plus protein plus fat), on the transcriptome of fetal muscle and adipose tissues in sheep.

Results

Prepartum diets were associated with notable gene expression changes in fetal tissues. In longissimus dorsi muscle, a total of 224 and 823 genes showed differential expression (FDR ≤0.05) in fetuses derived from DG vs. CN and HY vs. CN maternal diets, respectively. Several of these significant genes affected myogenesis and muscle differentiation. In subcutaneous and perirenal adipose tissues, 745 and 208 genes were differentially expressed (FDR ≤0.05), respectively, between CN and DG diets. Many of these genes are involved in adipogenesis, lipogenesis, and adipose tissue development. Pathway analysis revealed that several GO terms and KEGG pathways were enriched (FDR ≤0.05) with differentially expressed genes associated with tissue and organ development, chromatin biology, and different metabolic processes.

Conclusions

These findings provide evidence that maternal nutrition during pregnancy can alter the programming of fetal muscle and fat tissues in sheep. The ramifications of the observed gene expression changes, in terms of postnatal growth, body composition, and meat quality of the offspring, warrant future investigation.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2164-15-1034) contains supplementary material, which is available to authorized users.

High- and low-protein gestation diets do not provoke common transcriptional responses representing universal target-pathways in muscle and liver of porcine progeny

AIM

Maternal diets introduce transcriptional changes in the offspring, highlighting the concept of genetic and physiological plasticity. Our previous analyses investigated stage-dependent transcriptional responses to either maternal high or low protein/carbohydrate ratios in either muscle or liver. Foetal programming is proposed to be mediated by a small number of gatekeeper processes, such as cytoskeleton remodelling and cell-cycle regulation. Here, we conducted an overall analysis of a three-dimensional data set aiming to elucidate, whether there are universally targeted pathways of adaptive transcriptional response to different protein/carbohydrate ratios.

METHODS

Microarray analyses were performed on liver and skeletal muscle tissue sampled at 94 days post-conception and 1, 28 and 188 days post-natum from offspring (n = 253) of German Landrace gilts that were fed isoenergetic diets containing low, high or adequate protein.

RESULTS

Cluster analyses revealed a hierarchical influence of tissue, ontogenetic stage and diet on transcript levels. Considering results cumulatively over stages, liver showed only marginal transcriptional differences between the dietary groups, whereas considerable differences appeared in muscle. Considering results cumulatively over tissues, nutrition-responsive transcriptions were observed along ontogenesis. Pathway analyses revealed transcript differences in genes related to tissue remodelling, cell-cycle regulation and mitochondrial function.

CONCLUSION

The factors tissue, stage and diet impact gene expression in a hierarchical order. Porcine liver appeared to be a tissue that was more resilient to nutritional modulation compared with skeletal muscle tissue. Differential modulation between tissues and dietary groups reveal that there are no universal target-pathways of adaptive transcriptional response to different protein diets.

Predicted high-performing piglets exhibit more and larger skeletal muscle fibers

Postnatal (muscle) growth potential in pigs depends on the total number and hypertrophy of myofibers in skeletal muscle tissue. In a previous study an algorithm was developed to predict piglet BW at the end of the nursery period (10 wk of age) on the basis of BW at birth, at weaning, and at 6 wk of age. The objective of this study was to determine whether the differences in growth performance between poor (PP) and high (HP) performing piglets could be the result of different skeletal muscle properties. Therefore, from a total of 368 piglets (offspring from Hypor sows bred to TOPIGS sires) 2 groups with a divergent growth performance were selected at 6 wk of age: HP (n = 20, predicted BW at 10 wk of age 26.8-30.9 kg) and PP (n = 20, predicted BW at 10 wk of age 16.0-22.9 kg). Piglets were euthanized at 10 wk of age, and samples of the semitendinosus muscle (STN) were collected for histochemistry and gene expression analysis using quantitative PCR (qPCR). At 10 wk of age, realized BW did not differ from predicted BW in either group (P > 0.880). The HP piglets exhibited greater ADG and ADFI from 6 to 10 wk and greater BW at birth and 6 and 10 wk of age (P ≤ 0.002) compared with the PP piglets, whereas G:F ratio was similar (P = 0.417). Superior growth performance of HP piglets was associated with a 1.27-fold higher IGF1 plasma concentration at 10 wk compared with the PP piglets (P = 0.044). The greater weight and muscle cross-sectional area of STN in HP piglets was due to a 1.20-fold increase in total muscle fiber number (TFN; P = 0.009) and 1.34-fold increase in fiber cross-sectional area (FCSA; P = 0.004) compared with the PP piglets. The number of myonuclei per red and intermediate fiber was greater in HP piglets (P ≤ 0.097), but the nucleus-to-cytoplasm ratio was unaffected by the performance group (P = 0.861). The mRNA expression of proliferating cell nuclear antigen (PCNA), paired box 7 (PAX7), myogenic factor 5 (MYF5), and myogenic differentiation factor (MYOD) did not differ between groups (P ≥ 0.327). However, IGF2-specific mRNA expression was numerically higher in the HP piglets (P = 0.101). The greater myofiber number, the higher degree of myofiber hypertrophy, and the increased muscular mRNA expression of IGF2 indicate that HP piglets exhibit a greater capacity for lean accretion and may grow faster until market weight. In summary, pigs that were selected for predicted high BW at 10 wk of age using a complex selection model had a superior muscularity in terms of greater TFN and FCSA, which may be of advantage for lean mass accretion in later life and for meat quality.

Effects of L-carnitine supplementation to suckling piglets on carcass and meat quality at market age

In a previous study, carnitine supplementation to piglets during the suckling period resulted in an increased total muscle fibre number at weaning in piglets of low birth weight. The objective of the present study was to investigate whether this effect is maintained until market age and whether this would attenuate the negative consequences of low birth weight on carcass and meat quality. Using a split-plot design with litter as block, sex as whole plot and treatment as subplot, the effects of early-postnatal l-carnitine supplementation on female and castrated male piglets of low birth weight were investigated on a total of 56 German Landrace piglets from 14 litters. From days 7 to 27 of age piglets were orally supplemented once daily with 400 mg of l-carnitine dissolved in 1 ml of water or received an equal volume of water without carnitine. From weaning (day 28) until slaughter (day 166 of age) all pigs were fed standard diets. At weaning, carnitine-supplemented piglets had a twofold increased concentration of free carnitine (P < 0.001) and a lower concentration of non-esterified fatty acids (P < 0.05) in blood plasma indicating that carnitine became bioavailable and increased fatty acid utilization during the period of supplementation. Growth performance was not influenced by treatment in any growth period. Dual-energy X-ray absorptiometry revealed no differences in body composition between groups in weeks 12, 16 and 20 of age. LW at slaughter, carcass weight, measures of meat yield and fat accretion, as well as body composition by chemical analyses and dissection of primal cuts did not differ between treatments. No differences between control and carnitine-treated pigs in total fibre number (P = 0.85) and fibre cross-sectional area (P = 0.68) in m. semitendinosus (ST) measured at slaughter could be observed. The carnitine group tended to exhibit a smaller proportion of slow-twitch oxidative fibres (P = 0.08), a greater proportion of fast-twitch glycolytic fibres (P = 0.11), and increased specific lactate dehydrogenase activity (P = 0.09) in ST indicating a more glycolytic muscle metabolism. Compared with the controls, a lower pH24 value was observed (P = 0.05) in ST muscle of carnitine-supplemented pigs, which - in castrates only - was associated with an increased drip loss (P < 0.01). Meat quality traits in m. longissimus were not influenced by treatment. In conclusion, our hypothesis that early-postnatal carnitine supplementation to piglets of low birth weight permanently increases myofibre number and improves later carcass and meat quality could not be confirmed by this experiment.

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.

Influence of maternal low protein diet during pregnancy on hepatic gene expression signature in juvenile female porcine offspring

SCOPE

Epidemiological and experimental evidence indicates that maternal nutrition status contributes to long-term changes in the metabolic phenotype of the offspring, a process known as fetal programming.

METHODS AND RESULTS

We have used a swine model (Sus scrofa) to analyze consequences of a maternal low protein diet (about 50% of control) during pregnancy on hepatic lipid metabolism and genome-wide hepatic gene expression profile of juvenile female offspring (mean age 85 days). We found 318 S. scrofa genes to be differentially expressed in the liver at age 85 days. In the low protein offspring group key genes of fatty acid de novo synthesis were downregulated whereas several genes of lipolysis and phospholipid biosynthesis were upregulated. qRT-PCR analysis of selected genes verified microarray data and revealed linear correlations between gene expression levels and slaughter weight. Hepatic cholesterol 7α hydroxylase protein expression tended to be lower in the low protein group. Total lipid and triglyceride content and fatty acid composition of total lipids were not different between groups.

CONCLUSION

A maternal low protein diet during pregnancy induces a distinct hepatic gene expression signature in juvenile female pigs which was not translated into phenotypical changes of liver lipid metabolism.

In utero programming of later adiposity: the role of fetal growth restriction

Intrauterine growth restriction (IUGR) is strongly associated with obesity in adult life. The mechanisms contributing to the onset of IUGR-associated adult obesity have been studied in animal models and humans, where changes in fetal adipose tissue development, hormone levels and epigenome have been identified as principal areas of alteration leading to later life obesity. Following an adverse in utero development, IUGR fetuses display increased lipogenic and adipogenic capacity in adipocytes, hypoleptinemia, altered glucocorticoid signalling, and chromatin remodelling, which subsequently all contribute to an increased later life obesity risk. Data suggest that many of these changes result from an enhanced activity of the adipose master transcription factor regulator, peroxisome proliferator-activated receptor-γ (PPARγ) and its coregulators, increased lipogenic fatty acid synthase (FAS) expression and activity, and upregulation of glycolysis in fetal adipose tissue. Increased expression of fetal hypothalamic neuropeptide Y (NPY), altered hypothalamic leptin receptor expression and partitioning, reduced adipose noradrenergic sympathetic innervations, enhanced adipose glucocorticoid action, and modifications in methylation status in the promoter of hepatic and adipose adipogenic and lipogenic genes in the fetus also contribute to obesity following IUGR. Therefore, interventions that inhibit these fetal developmental changes will be beneficial for modulation of adult body fat accumulation.

Transcriptional response of skeletal muscle to a low-protein gestation diet in porcine offspring accumulates in growth- and cell cycle-regulating pathways

Inadequate maternal protein supply during gestation represents an environmental factor that affects physiological signaling pathways with long-term consequences for growth, function, and structure of various tissues. Hypothesizing that the offspring's transcriptome is persistently altered by maternal diets, we used a porcine model to monitor the longitudinal expression changes in muscle to identify pathways relevant to fetal initiation of postnatal growth and development. German Landrace gilts were fed isoenergetic gestational diets containing 6.5% (LP) or 12.1% protein. The longissimus dorsi samples were collected from offspring at 94 days postconception (dpc) and 1, 28, and 188 days postnatum (dpn) for expression profiling. At 94 dpc, 1 dpn, and 28 dpn relatively few transcripts (<130) showed an altered abundance between the dietary groups. In fact, at 94 dpc genes of G2/M checkpoint regulation and mitotic roles of Polo-like kinases showed lowered transcript abundance in LP. At 188 dpn 677 transcripts were altered including those related to oxidative phosphorylation, citrate cycle, fatty acid metabolism (higher abundance in LP) and cell cycle regulation (lower abundance in LP). Correspondingly, transcriptional alterations during pre and postnatal development differed considerably among dietary groups, particularly for genes related to cell cycle regulation (G1/S and G2/M checkpoint regulation; cyclines), growth factor signaling (GH, IGF1, mTOR, RAN, VEGF, INSR), lipid metabolism, energy metabolism, and nucleic acid metabolism. In skeletal muscle, fetal programming related to maternal LP diets disturbed gene expression in growth-related pathways into adulthood. Diet-dependent gene expression may hamper proper development, thereby affecting signaling pathways related to energy utilization.

A gestational high protein diet affects the abundance of muscle transcripts related to cell cycle regulation throughout development in porcine progeny

BACKGROUND

In various animal models pregnancy diets have been shown to affect offspring phenotype. Indeed, the underlying programming of development is associated with modulations in birth weight, body composition, and continual diet-dependent modifications of offspring metabolism until adulthood, producing the hypothesis that the offspring's transcriptome is permanently altered depending on maternal diet.

METHODOLOGY/PRINCIPAL FINDINGS

To assess alterations of the offspring's transcriptome due to gestational protein supply, German Landrace sows were fed isoenergetic diets containing protein levels of either 30% (high protein--HP) or 12% (adequate protein--AP) throughout their pregnancy. Offspring muscle tissue (M. longissimus dorsi) was collected at 94 days post conception (dpc), and 1, 28, and 188 days post natum (dpn) for use with Affymetrix GeneChip Porcine Genome Arrays and subsequent statistical and Ingenuity pathway analyses. Numerous transcripts were found to have altered abundance at 94 dpc and 1 dpn; at 28 dpn no transcripts were altered, and at 188 dpn only a few transcripts showed a different abundance between diet groups. However, when assessing transcriptional changes across developmental time points, marked differences were obvious among the dietary groups. Depending on the gestational dietary exposure, short- and long-term effects were observed for mRNA expression of genes related to cell cycle regulation, energy metabolism, growth factor signaling pathways, and nucleic acid metabolism. In particular, the abundance of transcripts related to cell cycle remained divergent among the groups during development.

CONCLUSION

Expression analysis indicates that maternal protein supply induced programming of the offspring's genome; early postnatal compensation of the slight growth retardation obvious at birth in HP piglets resulted, as did a permanently different developmental alteration and responsiveness to the common environment of the transcriptome. The transcriptome modulations are interpreted as the molecular equivalent of developmental plasticity of the offspring that necessitates adaptation and maintenance of the organismal phenotype.

A low protein diet during pregnancy provokes a lasting shift of hepatic expression of genes related to cell cycle throughout ontogenesis in a porcine model

Background

In rodent models and in humans the impact of gestational diets on the offspring's phenotype was shown experimentally and epidemiologically. Adverse environmental conditions during fetal development provoke an intrauterine adaptive response termed 'fetal programming', which may lead to both persistently biased responsiveness to extrinsic factors and permanent consequences for the organismal phenotype. This leads to the hypothesis that the offspring's transcriptome exhibits short-term and long-term changes, depending on the maternal diet. In order to contribute to a comprehensive inventory of genes and functional networks that are targets of nutritional programming initiated during fetal life, we applied whole-genome microarrays for expression profiling in a longitudinal experimental design covering prenatal, perinatal, juvenile, and adult ontogenetic stages in a porcine model. Pregnant sows were fed either a gestational low protein diet (LP, 6% CP) or an adequate protein diet (AP, 12% CP). All offspring was nursed by foster sows receiving standard diets. After weaning, all offspring was fed standard diets ad libitum.

Results

Analyses of the hepatic gene expression of the offspring at prenatal (94 dies post conceptionem, dpc) and postnatal stages (1, 28, 188 dies post natum, dpn) included comparisons between dietary groups within stages as well as comparisons between ontogenetic stages within diets to separate diet-specific transcriptional changes and maturation processes. We observed differential expression of genes related to lipid metabolism (e.g. Fatty acid metabolism, Biosynthesis of steroids, Synthesis and degradation of ketone bodies, FA elongation in mitochondria, Bile acid synthesis) and cell cycle regulation (e.g. Mitotic roles of PLK, G1/S checkpoint regulation, G2/M DNA damage checkpoint regulation). Notably, at stage 1 dpn no regulation of a distinct pathway was found in LP offspring.

Conclusions

The transcriptomic modulations point to persistent functional demand on the liver towards cell proliferation in the LP group but not in the AP group at identical nutritional conditions during postnatal life due to divergent 'programming' of the genome. Together with the observation that the offspring of both groups did not differ in body weight but in body composition and fat content, the data indicate that the activity of various genes led to diverse partitioning of nutrients among peripheral and visceral organs and tissues.