Diarrhea induced by insufficient fat absorption in weaned piglets: Causes and nutrition regulation

Fat is one of the three macronutrients and a significant energy source for piglets. It plays a positive role in maintaining intestinal health and improving production performance. During the weaning period, physiological, stress and diet-related factors influence the absorption of fat in piglets, leading to damage to the intestinal barrier, diarrhea and even death. Signaling pathways, such as fatty acid translocase (CD36), pregnane X receptor (PXR), and AMP-dependent protein kinase (AMPK), are responsible for regulating intestinal fat uptake and maintaining intestinal barrier function. Therefore, this review mainly elaborates on the reasons for diarrhea induced by insufficient fat absorption and related signaling pathways in weaned-piglets, with an emphasis on the intestinal fat absorption disorder. Moreover, we focus on introducing nutritional strategies that can promote intestinal fat absorption in piglets with insufficient fat absorption-related diarrhea, such as lipase, amino acids, and probiotics.

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.

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.

Proteomic analysis of adipose tissue during the last weeks of gestation in pure and crossbred Large White or Meishan fetuses gestated by sows of either breed

Background

The degree of adipose tissue development at birth may influence neonatal survival and subsequent health outcomes. Despite their lower birth weights, piglets from Meishan sows (a fat breed with excellent maternal ability) have a higher survival rate than piglets from Large White sows (a lean breed). To identify the main pathways involved in subcutaneous adipose tissue maturation during the last month of gestation, we compared the proteome and the expression levels of some genes at d 90 and d 110 of gestation in purebred and crossbred Large White or Meishan fetuses gestated by sows of either breed.

Results

A total of 52 proteins in fetal subcutaneous adipose tissue were identified as differentially expressed over the course of gestation. Many proteins involved in energy metabolism were more abundant, whereas some proteins participating in cytoskeleton organization were reduced in abundance on d 110 compared with d 90. Irrespective of age, 24 proteins differed in abundance between fetal genotypes, and an interaction effect between fetal age and genotype was observed for 13 proteins. The abundance levels of proteins known to be responsive to nutrient levels such as aldolase and fatty acid binding proteins, as well as the expression levels of FASN, a key lipogenic enzyme, and MLXIPL, a pivotal transcriptional mediator of glucose-related stimulation of lipogenic genes, were elevated in the adipose tissue of pure and crossbred fetuses from Meishan sows. These data suggested that the adipose tissue of these fetuses had superior metabolic functionality, whatever their paternal genes. Conversely, proteins participating in redox homeostasis and apoptotic cell clearance had a lower abundance in Meishan than in Large White fetuses. Time-course differences in adipose tissue protein abundance were revealed between fetal genotypes for a few secreted proteins participating in responses to organic substances, such as alpha-2-HS-glycoprotein, transferrin and albumin.

Conclusions

These results underline the importance of not only fetal age but also maternal intrauterine environment in the regulation of several proteins in subcutaneous adipose tissue. These proteins may be used to estimate the maturity grade of piglet neonates.

Electronic supplementary material

The online version of this article (10.1186/s40104-018-0244-2) contains supplementary material, which is available to authorized users.

Saturated or unsaturated fat supplemented maternal diets influence omental adipose tissue proteome of suckling goat-kids

The aim of the present study was to investigate how maternal diet can influence the adipose tissue of goat kids. Omental adipose tissue proteomes of goat-kids from mothers fed with diet enriched with stearic acid (ST-kids), fish oil (FO-kids) and standard diets (CTRL) were determined by quantitative iTRAQ 2D-LC-MS/MS analysis. Twenty proteins were found to be differentially expressed in suckling kids' omental adipose tissue. Stearic acid induces changes in a higher number of proteins when compared to fish oil. Eleven proteins, namely AARS, ECl1, PMSC2, CP, HSPA8, GPD1, RPL7, OGDH, RPL24, FGA and RPL5 were decreased in ST-kids only. Four proteins, namely DLST, EEF1G, BCAP31 and RALA were decreased in FO-kids only, and one, NUCKS1, was increased. Four proteins, namely PMSC1, PPIB, TUB5×2 and EIF5A1, were be less abundant in both ST- and FO- kids. Most of the protein whose abundance was decreased in ST kids (10 out of 15) are involved in protein metabolism and catabolism pathways. Qualitative gene expression analysis confirmed that all the proteins identified by mass spectrometry, with the exception of FGA, were produced by adipose tissue. Quantitative gene expression analysis demonstrated that two proteins, namely CP, a minor acute phase protein, and ECl1, involved in fatty acid beta oxidation, were downregulated at mRNA level as well. ECl1 gene expression was downregulated in ST-kids AT as compared to Ctrl-kids and CP was downregulated in both ST- and FO-kids. The present results demonstrate that it is possible to influence adipose goat-kid proteome by modifying the maternal diet.

Effects on pig immunophysiology, PBMC proteome and brain neurotransmitters caused by group mixing stress and human-animal relationship

Peripheral blood mononuclear cells (PBMC) are an interesting sample for searching for biomarkers with proteomic techniques because they are easy to obtain and do not contain highly abundant, potentially masking proteins. Two groups of pigs (n = 56) were subjected to mixing under farm conditions and afterwards subjected to different management treatments: negative handling (NH) and positive handling (PH). Serum and PBMC samples were collected at the beginning of the experiment one week after mixing (t0) and after two months of different handling (t2). Brain areas were collected after slaughter and neurotransmitters quantified by HPLC. Hair cortisol and serum acute phase proteins decreased and serum glutathione peroxidase increased at t2, indicating a lower degree of stress at t2 after adaptation to the farm. Differential gel electrophoresis (DIGE) was applied to study the effects of time and treatment on the PBMC proteome. A total of 54 differentially expressed proteins were identified, which were involved in immune system modulation, cell adhesion and motility, gene expression, splicing and translation, protein degradation and folding, oxidative stress and metabolism. Thirty-seven protein spots were up-regulated at t2 versus t0 whereas 27 were down-regulated. Many of the identified proteins share the characteristic of being potentially up or down-regulated by cortisol, indicating that changes in protein abundance between t0 and t2 are, at least in part, consequence of lower stress upon adaptation to the farm conditions after group mixing. Only slight changes in brain neurotransmitters and PBMC oxidative stress markers were observed. In conclusion, the variation in hair cortisol and serum APPs as well as the careful analysis of the identified proteins indicate that changes in protein composition in PBMC throughout time is mainly due to a decrease in the stress status of the individuals, following accommodation to the farm and the new group.

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.

High-Protein Exposure during Gestation or Lactation or after Weaning Has a Period-Specific Signature on Rat Pup Weight, Adiposity, Food Intake, and Glucose Homeostasis up to 6 Weeks of Age

BACKGROUND

Early-life nutrition has a programming effect on later metabolic health; however, the impact of exposure to a high-protein (HP) diet is still being investigated.

OBJECTIVE

This study evaluated the consequences on pup phenotype of an HP diet during gestation and lactation and after weaning.

METHODS

Wistar rat dams were separated into 2 groups fed an HP (55% protein) or normal protein (NP) (control; 20% protein) isocaloric diet during gestation, and each group subsequently was separated into 2 subgroups that were fed an HP or NP diet during lactation. After weaning, male and female pups from each mother subgroup were separated into 2 groups that were fed either an NP or HP diet until they were 6 wk old. Measurements included weight, food intake, body composition, blood glucose, insulin, glucagon, leptin, insulin-like growth factor I, and lipids.

RESULTS

Feeding mothers the HP diet during gestation or lactation induced lower postweaning pup weight (gestation diet × time, P < 0.0001; lactation diet × time, P < 0.0001). Regardless of dams' diets, pups receiving HP compared with NP diet after weaning had 7% lower weight (NP, 135.0 ± 2.6 g; HP, 124.4 ± 2.5 g; P < 0.0001), 16% lower total energy intake (NP, 777 ± 14 kcal; HP, 649 ± 13 kcal; P < 0.0001) and 31% lower adiposity (P < 0.0001). Pups receiving HP compared with NP diet after weaning had increased blood glucose, insulin, and glucagon when food deprived (P < 0.0001 for all). The HP compared with the NP diet during gestation induced higher blood glucose in food-deprived rats (NP, 83.2 ± 2.1 mg/dL; HP, 91.2 ± 2.1 mg/dL; P = 0.046) and increased plasma insulin in fed pups receiving the postweaning NP diet (gestation diet × postweaning diet, P = 0.02).

CONCLUSION

Increasing the protein concentration of the rat dams' diet during gestation, and to a lesser extent during lactation, and of the pups' diet after weaning influenced pup phenotype, including body weight, fat accumulation, food intake, and glucose tolerance at 6 wk of age.

Gender-specific effects of intrauterine growth restriction on the adipose tissue of adult rats: a proteomic approach

BACKGROUND

Intrauterine growth restriction (IUGR) may program metabolic alterations affecting physiological functions and lead to diseases in later life. The adipose tissue is an important organ influencing energy homeostasis. The present study was aimed at exploring the consequences of IUGR on the retroperitoneal adipose tissue of adult male and female rats, using a proteomic approach.

METHODS AND RESULTS

Pregnant Wistar rats were fed with balanced chow, either ad libitum (control group) or restricted to 50 % of control intake (restricted group) during the whole gestation. The offspring were weaned to ad libitum chow and studied at 4 months of age. Retroperitoneal fat was analyzed by two-dimensional gel electrophoresis followed by mass spectrometry. Both male and female restricted groups had low body weight at birth and at weaning but normal body weight at adulthood. The restricted males had normal fat pads weight and serum glucose levels, with a trend to hyperinsulinemia. The restricted females had increased fat pads weight with normal glucose and insulin levels. The restricted males showed up-regulated levels of proteasome subunit α type 3, branched-chain-amino-acid aminotransferase, elongation 1- alpha 1, fatty acid synthase levels, cytosolic malate dehydrogenase and ATP synthase subunit alpha. These alterations point to increased proteolysis and lipogenesis rates and favoring of ATP generation. The restricted females showed down-regulated levels of L-lactate dehydrogenase perilipin-1, mitochondrial branched-chain alpha-keto acid dehydrogenase E1, and transketolase. These findings suggest impairment of glycemic control, stimulation of lipolysis and inhibition of proteolysis, pentose phosphate pathway and lipogenesis rates. In both genders, several proteins involved in oxidative stress and inflammation were affected, in a pattern compatible with impairment of these responses.

CONCLUSIONS

The proteomic analysis of adipose tissue showed that, although IUGR affected pathways of substrate and energy metabolism in both males and females, important gender differences were evident. While IUGR males displayed alterations pointing to a predisposition to later development of obesity, the alterations observed in IUGR females pointed to a metabolic status of established obesity, in agreement with their increased fat pads mass.

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.

Birth weight alters the response to postnatal high-fat diet-induced changes in meat quality traits and skeletal muscle proteome of pigs

Low birth weight (LBW) exerts persistent effects on the growth and development of offspring. The present study was conducted to test the hypothesis that LBW alters the response of pigs to high-fat (HF) diet-induced changes in meat quality and skeletal muscle proteome. Normal-birth weight (NBW) and LBW piglets were fed a control diet or a HF diet from weaning to slaughter at 110 kg body weight. Most of the meat quality traits were influenced by LBW. Meat quality analysis revealed that LBW piglets had a greater ability to deposit intramuscular lipids than their heavier littermates when fed a HF diet. Increased shear force, lower pH45min and drip loss were observed in the skeletal muscle of LBW piglets compared with NBW piglets. Proteomic analysis revealed forty-six differentially expressed proteins in the skeletal muscle of LBW and NBW piglets fed the control diet or HF diet. These proteins play a central role in cell structure and motility, glucose and energy metabolism, lipid metabolism, and cellular apoptosis, as well as stress response. Of particular interest is the finding that LBW altered the response to HF diet-induced changes in the expression of proteins related to stress response (heat shock protein) and glucose and energy metabolism (pyruvate kinase, phosphoglycerate mutase, enolase and triosephosphate isomerase). Taken together, our findings revealed that the HF diet-induced changes in the expression of glucose and energy metabolism-related proteins varied between NBW and LBW piglets, which provides a possible mechanism to explain higher intramuscular fat store in LBW pigs when fed a HF diet.

Application of proteomics technology in adipocyte biology

Obesity and its associated complications have reached epidemic proportions in Western-type societies. Concomitantly, the obesity incidence in developing countries is increasing. One hallmark of obesity is the differentiation of pre-adipocytes into mature triglyceride-loaded adipocytes present in subcutaneous and visceral adipose tissue depots. This may ultimately lead to dysfunctional adipose tissue together with detrimental changes in the profiles of (pre-)adipocyte-secreted proteins, known as adipokines. Obesity-induced alterations in adipokine profiles contribute to the development of obesity-associated disorders. Consequently, the interest in the molecular events responsible for adipose tissue modifications during weight gain and weight loss as well as in the aetiology of obesity-associated disorders is growing. Molecular mechanisms involved in pre-adipocyte differentiation and alterations in adipokine profiles have been examined at the gene and protein level by high-throughput technologies. Independent proteomics studies have contributed significantly to further insight into adipocyte biology, particularly with respect to adipokine profiling. In this review novel findings obtained with adipo-proteomics studies are highlighted and the relevance of proteomics technologies to further understand molecular aspects of adipocyte biology is discussed.

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.

MicroRNA-130b and microRNA-374b mediate the effect of maternal dietary protein on offspring lipid metabolism in Meishan pigs

To investigate whether the effect of maternal dietary protein on offspring lipid metabolism is mediated by microRNA (miRNA), fourteen Meishan sows were fed either low-protein (LP, half of standard protein (SP) level, n 7) or SP (n 7) diets throughout gestation and lactation periods. PPAR-γ and CCAAT/enhancer-binding protein-β (C/EBP-β) protein expression was evaluated. The expression of miRNA predicted to directly target PPAR-γ and C/EBP-β in the subcutaneous fat of offspring at weaning age was determined, and the functions of these potential miRNA were verified. The results showed that piglet body weight and back fat thickness were significantly decreased in the LP group compared with the SP group (P< 0·05). The protein level of PPAR-γ was significantly decreased and C/EBP-β protein expression was also decreased, though not significantly (P= 0·056), in the subcutaneous fat of the LP group. Furthermore, miRNA expression analysis showed that miR-130b, targeting the PPAR-γ 3′-untranslated region (UTR), and miR-374b, targeting the C/EBP-β 3′-UTR, were significantly increased in the LP group compared with the SP group; other candidate regulatory miRNA were expressed similarly in both groups. Dual luciferase activity assay results indicated that miR-130b directly recognised and bound to the 3′-UTR of PPAR-γ and thereby suppressed PPAR-γ gene expression. Similar results were found for miR-374b and the 3′-UTR of C/EBP-β. The present study showed that miR-130b and miR-374b are involved in the effect of maternal dietary protein on offspring lipid metabolism in pigs. These results shed new light on our understanding of the maternal effect on offspring lipid deposition.

Maternal energy and protein affect subsequent growth performance, carcass yield, and meat color in Chinese Yellow broilers

This experiment was carried out to investigate effects of maternal ME and CP levels on growth performance, carcass traits, and meat quality of broiler offspring. A total of 1,134 thirty-week-old Chinese Yellow broiler breeders was randomly assigned to 3 dietary ME levels (11.09, 11.51, and 11.92 MJ/kg) and 3 CP levels (15.5, 16.5, and 17.5%) in a 3×3 factorial arrangement. Each dietary treatment had 6 replicates with 21 hens per replicate. At 39 wk of age, 30 settable eggs per replicate were selected for hatching. All broiler offspring were fed the same diets. There were significant ME×CP interactions in egg CP and ether extract (EE) contents, BW at d 1, 22 to 42 d ADG, ADFI during 1 to 21 d and 43 to 63 d, shear force, plasma albumin, cholesterol, and triglycerides contents of broiler offspring. Dietary ME at 11.92 MJ/kg increased average egg weight, egg EE content, and broiler 1-d-old BW compared with 11.09 MJ/kg group at 16.5%, 15.5%, and 17.5% CP levels, respectively (P<0.05). Maternal 11.51 and 11.92 MJ/kg of ME increased 1 to 21-d ADFI, and 11.51 MJ/kg of ME decreased lightness (L*) value of broiler offspring compared with 11.09 MJ/kg group at 17.5 and 16.5% CP levels, respectively (P<0.05). Broiler breeder dietary CP at 17.5% decreased egg EE content, increased average egg weight, egg CP content, BW at d 1, and 1 to 21-d ADFI of broiler offspring compared with 15.5% CP group at 11.92 MJ/kg of ME level (P<0.05). Maternal dietary 15.5% CP increased dressing percentage and decreased yellowness (b*) value of broiler offspring compared with 16.5% and 17.5% CP groups at 11.51 MJ/kg of ME level, respectively (P<0.05). Collectively, the results indicate that maternal diets composed of 11.51 to 11.92 MJ/kg of ME and 17.5% CP at 39 wk of age increased growth performance during 1 to 21 d in Chinese Yellow broiler, whereas 11.51 MJ/kg of ME and 15.5% CP improved carcass dressing percentage and meat color of their offspring.

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.

Proteomic characterization of adipose tissue constituents, a necessary step for understanding adipose tissue complexity

The original concept of adipose tissue as an inert storage depot for the excess of energy has evolved over the last years and it is now considered as one of the most important organs regulating body homeostasis. This conceptual change has been supported by the demonstration that adipose tissue serves as a major endocrine organ, producing a wide variety of bioactive molecules, collectively termed adipokines, with endocrine, paracrine and autocrine activities. Adipose tissue is indeed a complex organ wherein mature adipocytes coexist with the various cell types comprising the stromal-vascular fraction (SVF), including preadipocytes, adipose-derived stem cells, perivascular cells, and blood cells. It is known that not only mature adipocytes but also the components of SVF produce adipokines. Furthermore, adipokine production, proliferative and metabolic activities and response to regulatory signals (i.e. insulin, catecholamines) differ between the different fat depots, which have been proposed to underlie their distinct association to specific diseases. Herein, we discuss the recent proteomic studies on adipose tissue focused on the analysis of the separate cellular components and their secretory products, with the aim of identifying the basic features and the contribution of each component to different adipose tissue-associated pathologies.

Adipose tissue proteomes of intrauterine growth-restricted piglets artificially reared on a high-protein neonatal formula

The eventuality that adipose tissues adapt to neonatal nutrition in a way that may program later adiposity or obesity in adulthood is receiving increasing attention in neonatology. This study assessed the immediate effects of a high-protein neonatal formula on proteome profiles of adipose tissues in newborn piglets with intrauterine growth restriction. Piglets (10th percentile) were fed milk replacers formulated to provide an adequate (AP) or a high (HP) protein supply from day 2 to the day prior weaning (day 28, n=5 per group). Adipocytes with small diameters were present in greater proportions in subcutaneous and perirenal adipose tissues from HP piglets compared with AP ones at this age. Two-dimensional gel electrophoresis analysis of adipose tissue depots revealed a total of 32 protein spots being up- or down-regulated (P<.10) for HP piglets compared with AP piglets; 18 of them were unambiguously identified by mass spectrometry. These proteins were notably related to signal transduction (annexin 2), redox status (peroxiredoxin 6, glutathione S-transferase omega 1, cyclophilin-A), carbohydrate metabolism (ribose-5-phosphate dehydrogenase, lactate dehydrogenase), amino acid metabolism (glutamate dehydrogenase 1) and cell cytoskeleton dynamics (dynactin and cofilin-1). Proteomic changes occurred mainly in dorsal subcutaneous adipose tissue, with the notable exception of annexin 1 involved in lipid metabolic process having a lower abundance in HP piglets for perirenal adipose tissue only. Together, modulation in those proteins could represent a novel starting point for elucidating catch-up fat growth observed in later life in growing animals having been fed HP formula.

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

The aim of this study was to investigate whether dietary protein intake of gilts during gestation below (50%) or above (250%) recommendations affects body composition, carcass and meat quality, and properties of skeletal muscle and subcutaneous adipose tissue (SCAT) in offspring at d 83 and 188 of age. German Landrace gilts were fed isoenergetic gestation diets (~13.7 MJ of ME/kg) containing a low (LP, 6.5%; n = 18), an adequate (AP, 12.1%; n = 20), or a high (HP, 30%; n = 16) protein content from mating until farrowing. Within 48 h of birth, offspring were cross-fostered to sows fed a standard diet. On d 83 of age, no effects of the LP diet on BW and body composition were detected, whereas HP pigs showed a slight growth delay (P = 0.06) associated with increased relative weights of small intestine (P < 0.01) and brain (P = 0.08), and reduced relative thymus weight (P < 0.01). On d 188 of age, BW was not different among the dietary groups. However, the carcass of LP pigs contained less (P = 0.01) lean and more (P = 0.07) fat compared with AP and HP pigs, which was only pronounced in pigs originating from large litters (P < 0.05). Like skeletal muscles (P = 0.06), the heart muscle weighed less (P = 0.02) in LP than AP pigs. Compared with AP pigs, LP pigs exhibited a fewer (P = 0.09) total number of myofibers in semitendinosus muscle plus LM both at d 83 and 188 of age, whereas total muscular DNA was less (P = 0.02) at d 188 only. The mRNA abundance of IGF2 measured on d 188 was reduced in SCAT (P = 0.03) and LM (P = 0.07) of LP compared with AP pigs. No changes in muscular fiber type frequency, capillary density, or creatine kinase activity, as well as SCAT adipocyte size and number, were observed at either stages of age. Meat quality characteristics remained unchanged at d 83, whereas Warner-Bratzler shear force value in LM was decreased (P = 0.03) in LP compared with AP pigs on d 188 of age. The results suggest that the maternal LP diet impairs prenatal myofiber formation, reduces the potential of postnatal lean growth related to reduced IGF2 mRNA expression and myonuclear accumulation, and consequently changes carcass quality toward reduced lean proportion and improved tenderness at market weight. In contrast, except for a slight transient growth delay, excess dietary protein during gestation seems to have little effect on the fetal programming of postnatal muscle and adipose tissue phenotype of the progeny.

Somatic cytochrome c (CYCS) gene expression and promoter-specific DNA methylation in a porcine model of prenatal exposure to maternal dietary protein excess and restriction

There is growing evidence that maternal nutrition during gestation has an important effect on offspring development as well as on their gene expression with long-term effects on the metabolic state. A potential mechanism forming long-lasting gene expression patterns is DNA methylation of cytosine in CpG dinucleotides within the promoter region of distinct genes. There has been special focus on mitochondrial dysfunction by prenatal malnourishment over the recent years. To this end, we investigated the gene expression of somatic cytochrome c (CYCS), an important member of the respiratory chain, in a porcine model of gestational protein over- and undersupply at 94 d post-conception and 1, 28 and 188 d of age, and analysed the association with the DNA methylation status within the CYCS promoter. Gene expression on day 1 post natum showed a significant increase in the low protein (LP) group (P = 0·0005) and a slight increase in the high protein (HP) group (P = 0·079) compared with the control (CO) group in the liver. The mean of the methylation level over forty-seven CpG sites from nucleotide (nt) − 417 to − 10 was significantly decreased in the LP (P = 0·007) and HP (P = 0·009) groups compared with that in the CO group. Excess and restricted protein supply during pregnancy led to hypomethylation of a number of CpG sites in the CYCS promoter, including those representing putative transcription factor-binding sites, associated with elevated expression levels. However, the impact of the low-protein gestation diet is more pronounced, indicating that the offspring could better adapt to excess rather than restricted protein supply.

A high protein diet during pregnancy affects hepatic gene expression of energy sensing pathways along ontogenesis in a porcine model

In rodent models and in humans the impact of gestational diets on the offspring's phenotype was shown experimentally and epidemiologically. The underlying programming of fetal development was shown to be associated with an increased risk of degenerative diseases in adulthood, including the metabolic syndrome. There are clues that diet-dependent modifications of the metabolism during fetal life can persist until adulthood. This leads to the hypothesis that the offspring's transcriptomes show short-term and long-term changes depending on the maternal diet. To this end pregnant German landrace gilts were fed either a high protein diet (HP, 30% CP) or an adequate protein diet (AP, 12% CP) throughout pregnancy. Hepatic transcriptome profiles of the offspring were analyzed at prenatal (94 dpc) and postnatal stages (1, 28, 188 dpn). Depending on the gestational dietary exposure, mRNA expression levels of genes related to energy metabolism, N-metabolism, growth factor signaling pathways, lipid metabolism, nucleic acid metabolism and stress/immune response were affected either in a short-term or in a long-term manner. Gene expression profiles at fetal stage 94 dpc were almost unchanged between the diets. The gestational HP diet affected the hepatic expression profiles at prenatal and postnatal stages. The effects encompassed a modulation of the genome in terms of an altered responsiveness of energy and nutrient sensing pathways. Differential expression of genes related to energy production and nutrient utilization contribute to the maintenance of development and growth performance within physiological norms, however the modulation of these pathways may be accompanied by a predisposition for metabolic disturbances up to adult stages.

Limited and excess protein intake of pregnant gilts differently affects body composition and cellularity of skeletal muscle and subcutaneous adipose tissue of newborn and weanling piglets

AIM

This study investigated whether dietary protein intake less (50%) or greater (250%) than requirements throughout gestation differently affects offspring body composition and cellular properties of skeletal muscle and subcutaneous adipose tissue (SCAT).

METHODS

Primiparous gilts were fed iso-energetic diets containing adequate (22 AP), high (21 HP), or low (19 LP) protein contents. Newborn (n = 166) and weanling piglets cross-fostered to sows fed a standard diet (day 28; n = 83) were examined by morphological, biochemical, histological, and molecular analyses of the body, SCAT, and semitendinosus, longissimus, biceps femoris muscles.

RESULTS

Lowered birth weight (BW) in response to the HP and LP diets (p < 0.01) resulted from decreases in all body constituents in LP, and mainly from reduced body fat in HP piglets (p < 0.05). In the light BW class within litters, HP piglets exhibited a greater percentage of muscle tissue (p < 0.05) than LP piglets. Less SCAT mass in HP and LP piglets resulted from reduced (p < 0.05) number, but not the size of adipocytes. The LP diet adversely affected myogenesis and muscular differentiation derived from less (p < 0.01) primary and secondary myofibers, lower creatine kinase activity (p < 0.05), less IGF2 mRNA (p < 0.10), and greater expression of the embryonic myosin heavy chain isoform (p < 0.01). Catch-up growth of LP but not HP pigs until day 28 increased body fat (p = 0.01). Despite compensated muscle growth in LP piglets, the deficit in myofiber number remained.

CONCLUSION

Poor intrauterine environment by limited and excess protein supply retards fetal growth, but only limited protein supply impairs myogenesis, persistently restricts muscle growth potential, and favors obesity at infancy.

Postnatal growth velocity modulates alterations of proteins involved in metabolism and neuronal plasticity in neonatal hypothalamus in rats born with intrauterine growth restriction

Intrauterine growth restriction (IUGR) due to maternal protein restriction is associated in rats with an alteration in hypothalamic centers involved in feeding behaviour. In order to gain insight into the mechanism of perinatal maternal undernutrition in the brain, we used proteomics approach to identify hypothalamic proteins that are altered in their expression following protein restriction in utero. We used an animal model in which restriction of the protein intake of pregnant rats (8% vs. 20%) produces IUGR pups which were randomized to a nursing regimen leading to either rapid or slow catch-up growth. We identified several proteins which allowed, by multivariate analysis, a very good discrimination of the three groups according to their perinatal nutrition. These proteins were related to energy-sensing pathways (Eno 1, E(2)PDH, Acot 1 and Fabp5), redox status (Bcs 1L, PrdX3 and 14-3-3 protein) or amino acid pathway (Acy1) as well as neurodevelopment (DRPs, MAP2, Snca). In addition, the differential expressions of several key proteins suggested possible shunts towards ketone-body metabolism and lipid oxidation, providing the energy and carbon skeletons necessary to lipogenesis. Our results show that maternal protein deprivation during pregnancy only (IUGR with rapid catch-up growth) or pregnancy and lactation (IUGR with slow postnatal growth) modulates numerous metabolic pathways resulting in alterations of hypothalamic energy supply. As several of these pathways are involved in signalling, it remains to be determined whether hypothalamic proteome adaptation of IUGR rats in response to different postnatal growth rates could also interfere with cerebral plasticity or neuronal maturation.