H-FABP and LEPR gene expression profile in skeletal muscles and liver during ontogenesis in various breeds of pigs

Integrative proteome and metabolome analyses reveal molecular basis underlying growth and nutrient composition in the Pacific oyster, Crassostrea gigas

In order to comprehend the molecular basis of growth, nutrient composition, and color pigmentation in oysters, comparative proteome and metabolome analyses of two selectively bred oyster strains with contrasting growth rate and shell color were used in this study. A total of 289 proteins and 224 metabolites were identified differentially expressed between the two strains. We identified a series of specifically enriched functional clusters implicated in protein biosynthesis (RPL4, MRPS7, and CARS), fatty acid metabolism (ACSL5, PEX3, ACOXI, CPTIA, FABP6, and HSD17B12), energy metabolism (FH, PPP1R7, CLAM2, and RGN), cell proliferation (MYB, NFYC, DOHH, TOP2a, SMARCA5, and SMARCC2), material transport (ABCB1, ABCB8, VPS16, and VPS33a), and pigmentation (RDH7, RDH13, Retsat, COX15, and Cyp3a9). Integrated proteome and metabolome analyses indicate that fast-growing strain utilize energy-efficient mechanisms of ATP generation while promoting protein and polyunsaturated fatty acid synthesis, activating the cell cycle to increase cell proliferation and thus promoting their biomass increase. These results uncovered molecular mechanisms underlying growth regulation, nutrition quality, and pigmentation and provided candidate biomarkers for molecular breeding in oysters. SIGNIFICANCE: Rapid growth has always been the primary breeding objective to increase the production profits of Pacific oyster (Crassostrea gigas), while favorable nutritional quality and beautiful color add commercial value. In recent years, proteomic and metabolomic techniques have been widely used in marine organisms, although these techniques are seldom utilized to study oyster growth and development. In this study, two C. gigas strains with contrasted phenotypes in growth and shell color provided an ideal model for unraveling the molecular basis of growth and nutrient composition through a comparison of the proteome and metabolome. Since proteins and metabolites are the critical undertakers and the end products of cellular regulatory processes, identifying the differentially expressed proteins and metabolites would allow for discovering biomarkers and pathways that were implicated in cell growth, proliferation, and other critical functions. This work provides valuable resources in assistance with molecular breeding of oyster strains with superior production traits of fast-growth and high-quality nutrient value.

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.

Distribution characteristics and regulation of amino acids and fatty acids in muscle and adipose tissues of sheep grown in natural grazing environment

The composition of amino acid and fatty acid has a vital function on meat quality and animal health. However, the underlying mechanism of amino acid and fatty acid metabolism in sheep during different grazing periods is still unclear. In this study, a total of 12 sheep were employed in different grazing periods. Our results showed that the composition of amino acids and fatty acids in muscle and adipose tissues was significantly altered between dry grass (DG) period and green grass (GG) period. Changes in the activities of the metabolism-related enzymes including BCKD, BCAT2, ACC, SCD, HSL, GSK3β, p-GSK3β, and FABP4 were observed in muscle and adipose during different grazing periods. In addition, the mRNA expression levels of ACC, FAS, SCD, HSL, LPL, and DGAT1 in muscle and adipose tissue were changed markedly in different grazing periods. Furthermore, the expression levels of mTOR and β-catenin/PPARγ/C/EBPα pathway-related proteins were predominantly altered in muscle and adipose among DG and GG. Taken together, all investigations simplified the process of amino acid and fatty acid metabolism disorders caused by different grazing periods, and the mTOR and β-catenin/PPARγ/C/EBPα play the essential role in this process, which provided an underlying mechanism of metabolism and meat quality.

Single-nucleotide polymorphisms in FABP4 gene associated with growth traits in Egyptian sheep

Aim:

The present study was performed to assess the association of single-nucleotide polymorphisms (SNPs) in the fatty acid-binding protein 4 (FABP4) gene with birth weight (BW), final weight (FW), and average daily gain (ADG) in three Egyptian sheep breeds.

Materials and Methods:

Genomic DNA was extracted from the blood samples of 50 male and female individuals representing Ossimi, Rahmani, and Barki sheep breeds. A 407 bp nucleotide (nt) segment from the first intron of FABP4 was amplified by polymerase chain reaction, sequenced, and analyzed in the different samples.

Results:

Sequence analysis of the determined segment (407 bp) revealed four SNPs (all transition types) at nt position 372 (CP011894.1:g.57605471) A>G, nt position 211 (CP011894.1:g.57605632) A>G, nt position 143 (CP011894.1:g.57605700) T>C, and nt position 111 (CP011894.1:g.57605732) T>C. The allelic and genotypic frequencies for the identified SNPs in the sheep breeds were calculated. At nt positions 372 and 211, two alleles were identified (A and G). Only two genotypes were present at nt position 372 (AA and AG), while three genotypes were present at nt position 211 (AA, AG, and GG). Two alleles (T and C) and three identified genotypes (TT, TC, and CC) were detected at nt positions 143 and 111. Analysis of the results revealed that AA genotype at nt position 372 is associated with higher estimates for BW, FW, and ADG when compared to all the other genotypes. Very high correlation coefficients were found between the genotypes 143-TT and 111-TT and also between 143-TC and 111-TC. The genotypes 372-AG, 211-GG, 211-AA, 143-TT, 143-CC, 111-TT, 111-TC, and 111-CC were associated with negative effects on BW, FW, and ADG.

Conclusion:

The detection of four SNPs in a partial sequence of the Egyptian ovine FABP4 gene intron 1 reflected that this gene harbors substantial diversity. In addition, a novel SNP at nt position 372 (CP011894.1:g.57605471) A>G was associated with higher estimates for BW, FW, and ADG.

The temporal-spatial patterns, polymorphisms and association analysis with meat quality traits of FABP1 gene in domestic pigeons (Columba livia)

1. Fatty acid-binding proteins (FABP) are members of lipid-binding proteins, which participate in the metabolism and intracellular transportation of lipids. This study was designed to investigate the expression patterns, polymorphisms and associations with meat quality traits of the FABP1 gene in pigeons. 2. The temporal-spatial expression patterns showed FABP1 was widely expressed in all eleven tissues from 0-4 weeks of age, the expression level in the liver was the highest, followed by the small intestine and subcutaneous fat. 3. Five novel SNPs were found; all of them were synonymous and in Hardy-Weinberg equilibrium. Association analysis revealed that for the SNP of G161C, the AB and BB genotypes had higher (P ≤ 0.01) inosinic acid concentrations in breast muscle than the AA genotype. The BB genotype showed the highest (P < 0.01) intramuscular fat among the three genotypes, and significantly greater FABP1 mRNA levels were observed in the breast muscle of the BB genotype than in the AA and AB genotypes (P < 0.01). In the SNP C1376T, the AB and BB genotypes showed higher (P < 0.01) intramuscular fat than the AA genotype, and the relative mRNA expression level of the BB (P < 0.01) and AB (P < 0.05) genotypes was higher than that of the AA genotype in breast muscle. Correlation analysis implied that the FABP1 mRNA expression level was closely related to the inosinic acid (P < 0.05) and intramuscular fat content (P < 0.01). Oil red O staining of frozen sections of breast muscle on d 28 for SNPs G161C and C1376T also indicated that the BB genotype had the highest intramuscular fat content in both SNPs. In addition, correlation analysis implied the FABP1 mRNA expression level was closely related to inosinic acid (P < 0.05) and intramuscular fat content (P < 0.01). 4. The results suggested that FABP1 could be a potential candidate gene in marker-assisted selection for breeding pigeons with high-quality meat.

Relationship among porcine lncRNA TCONS_00010987, miR-323, and leptin receptor based on dual luciferase reporter gene assays and expression patterns

Objective

Considering the physiological and clinical importance of leptin receptor (LEPR) in regulating obesity and the fact that porcine LEPR expression is not known to be controlled by lncRNAs and miRNAs, we aim to characterize this gene as a potential target of SSC-miR-323 and the lncRNA TCONS_00010987.

Methods

Bioinformatics analyses revealed that lncRNA TCONS_00010987 and LEPR have SSC-miR-323-binding sites and that LEPR might be a target of lncRNA TCONS_00010987 based on cis prediction. Wild-type and mutant TCONS_00010987-target sequence fragments and wild-type and mutant LEPR 3′-UTR fragments were generated and cloned into pmiR-RB-REPORT^TM-Control vectors to construct respective recombinant plasmids. HEK293T cells were co-transfected with the SSC-miR-323 mimics or a negative control with constructs harboring the corresponding binding sites and relative luciferase activities were determined. Tissue expression patterns of lncRNA TCONS_00010987, SSC-miR-323, and LEPR in Anqing six-end-white (AQ, the obese breed) and Large White (LW, the lean breed) pigs were detected by real-time quantitative polymerase chain reaction; backfat expression of LEPR protein was detected by western blotting.

Results

Target gene fragments were successfully cloned, and the four recombinant vectors were constructed. Compared to the negative control, SSC-miR-323 mimics significantly inhibited luciferase activity from the wild-type TCONS_00010987-target sequence and wild-type LEPR-3′-UTR (p<0.01 for both) but not from the mutant TCONS_00010987-target sequence and mutant LEPR-3′-UTR (p>0.05 for both). Backfat expression levels of TCONS_ 00010987 and LEPR in AQ pigs were significantly higher than those in LW pigs (p<0.01), whereas levels of SSC-miR-323 in AQ pigs were significantly lower than those in LW pigs (p<0.05). LEPR protein levels in the backfat tissues of AQ pigs were markedly higher than those in LW pigs (p<0.01).

Conclusion

LEPR is a potential target of SSC-miR-323, and TCONS_00010987 might act as a sponge for SSC-miR-323 to regulate LEPR expression.

Association of H-FABP gene polymorphisms with intramuscular fat content in Three-yellow chickens and Hetian-black chickens

BACKGROUND

To explore the relationship between the heart-type fatty acid binding protein (H-FABP) gene and intramuscular fat (IMF), a polymorphism of the second exon of the H-FABP gene was investigated in 60 Three-yellow chickens (TYCs) and 60 Hetian-black chickens (HTBCs).

RESULTS

The IMF contents of the cardiac, chest and leg muscles in HTBC were increased compared with TYC. Both TYC and HTBC populations exhibited Hardy-Weinberg Equilibrium (HWE) according to the χ(2) test. Three variations of the two birds were detected, namely, G939A, G982A and C1014T. HTBCs with the TT genotypes exhibit increased IMF content in the chest muscles compared with the TC genotype. Thus, the G982A site could be considered a genetic marker for selecting increased IMF content in the chest muscles of HTBC. The correlation coefficients revealed that H-FABP mRNA expression was negatively correlated with the IMF content in the cardiac, chest and leg muscles of HTBC and in the cardiac and chest muscles of TYC. The relative mRNA expression of H-FABP was reduced in the cardiac and leg muscles of HTBC compared with TYC, but this difference was not observed at the protein level, as assessed by Western blot analysis.

CONCLUSIONS

These findings offer essential data that can be useful in the breeding program of HTBC and future research exploring the role of H-FABP in IMF deposition and regulation in chickens.

Correlation between Heart-type Fatty Acid-binding Protein Gene Polymorphism and mRNA Expression with Intramuscular Fat in Baicheng-oil Chicken

This study aims to determine the polymorphism and mRNA expression pattern of the heart-type fatty acid-binding protein (H-FABP) gene and their association with intramuscular fat (IMF) content in the breast and leg muscles of Baicheng oil chicken (BOC). A total of 720 chickens, including 240 black Baicheng oil chicken (BBOC), 240 silky Baicheng oil chicken (SBOC), and 240 white Baicheng oil chicken (WBOC) were raised. Three genotypes of H-FABP gene second extron following AA, AB, and BB were detected by polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) strategy. The G939A site created AA genotype and G956A site created BB genotype. The content of IMF in AA genotype in breast muscle of BBOC was significantly higher than that of AB (p = 0.0176) and the genotype in leg muscle of WBOC was significantly higher than that of AB (p = 0.0145). The G939A site could be taken as genetic marker for higher IMF content selecting for breast muscle of BBOC and leg muscle of WBOC. The relative mRNA expression of H-FABP was measured by real-time PCR at 30, 60, 90, and 120 d. The IMF content significantly increased with age in both muscles. The mRNA expression level of H-FABP significantly decreased with age in both muscles of the three types of chickens. Moreover, a significant negative correlation between H-FABP abundance and IMF content in the leg muscles of WBOC (p = 0.035) was observed. The mRNA expression of H-FABP negatively correlated with the IMF content in both breast and leg muscles of BOC sat slaughter time.

Molecular characterization and different expression patterns of the FABP gene family during goat skeletal muscle development

The FABP (adipocyte fatty acid-binding protein) genes play an important role in intracellular fatty acid transport and considered to be candidate genes for fatness traits in domestic animal. In this study, we cloned the cDNA sequences of goat FABP family genes and their expression patterns were detected by semi-quantitative RT-PCR and quantitative real time RT-PCR. Expression analysis showed that goat FABP1 gene was predominantly expressed in liver, kidney and large intestine. While FABP4 was widely expressed in many tissues with a high expression level was observed in the fat, skeletal muscle, stomach and lung. Notably, FABP2 gene was expressed specifically in small intestine. Moreover, goat FABP3 was expressed at 60 day with the highest level, then significantly (p < 0.01) decreased at the 90 day. No significant expression differences were observed in longissimus dorsi muscles among 3 day, 30 day and 60 day. Goat FABP4 was expressed at 3 day with the lowest level, then significantly (p < 0.01) increased to a peak at the 60 day. In addition, a significant relationship between FABP3 mRNA expression levels and intramuscular fat (IMF) content was observed. These results suggest that the FABP3 and FABP4 may be important genes for meat quality and provides useful information for further studies on their roles in skeletal muscle IMF deposit.

Transcriptional Characterization of Porcine Leptin and Leptin Receptor Genes

The leptin (LEP) and its receptor (LEPR) regulate food intake and energy balance through hypothalamic signaling. However, the LEP-LEPR axis seems to be more complex and its expression regulation has not been well described. In pigs, LEP and LEPR genes have been widely studied due to their relevance. Previous studies reported significant effects of SNPs located in both genes on growth and fatness traits. The aim of this study was to determine the expression profiles of LEP and LEPR across hypothalamic, adipose, hepatic and muscle tissues in Iberian x Landrace backcrossed pigs and to analyze the effects of gene variants on transcript abundance. To our knowledge, non porcine LEPR isoforms have been described rather than LEPRb. A short porcine LEPR isoform (LEPRa), that encodes a protein lacking the intracellular residues responsible of signal transduction, has been identified for the first time. The LEPRb isoform was only quantifiable in hypothalamus while LEPRa appeared widely expressed across tissues, but at higher levels in liver, suggesting that both isoforms would develop different roles. The unique LEP transcript showed expression in backfat and muscle. The effects of gene variants on transcript expression revealed interesting results. The LEPRc.1987C>T polymorphism showed opposite effects on LEPRb and LEPRa hypothalamic expression. In addition, one out of the 16 polymorphisms identified in the LEPR promoter region revealed high differential expression in hepatic LEPRa. These results suggest a LEPR isoform-specific regulation at tissue level. Conversely, non-differential expression of LEP conditional on the analyzed polymorphisms could be detected, indicating that its regulation is likely affected by other mechanisms rather than gene sequence variants. The present study has allowed a transcriptional characterization of LEP and LEPR isoforms on a range of tissues. Their expression patterns seem to indicate that both molecules develop peripheral roles apart from their known hypothalamic signal transduction function.

Association between subcutaneous and intramuscular fat content in porcine ham and loin depending on age, breed and FABP3 and LEPR genes transcript abundance

The objective of the present study was to analyze the level of intramuscular fat (IMF) in loin (musculus longissimus dorsi) and ham (musculus semimembranosus) and the level of subcutaneous fat in these cuts depending on breed, age and the expression level of FABP3 and LEPR genes. The results obtained showed that only the breed influenced on the level of both intramuscular and subcutaneous fat to the same extent (P ≤ 0.001). The age of animals had an effect on fat content of the cuts (P ≤ 0.001) and to a lower extent on the level of IMF in both muscles (P ≤ 0.05). We confirmed highly significant effect of breed and age on the LEPR mRNA abundance—the expression of the this gene increased significantly (P ≤ 0.01) with age and the highest expression was found for the Puławska breed in m. longissimus dorsi and for the Polish Landrace breed in m. semimembranosus. We observed the high correlations between the transcript level of the LEPR gene and the fat content of individual cuts (P ≤ 0.01). The expression level of FABP3 gene influenced the level of IMF (P ≤ 0.01), but not the level of subcutaneous fat in loin and ham.

Expression levels of candidate genes for intramuscular fat deposition in two Banna mini-pig inbred lines divergently selected for fatness traits

Intramuscular fat (IMF) content plays an important role in meat quality. Many genes involved in lipid and energy metabolism were identified as candidate genes for IMF deposition, since genetic polymorphisms within these genes were associated with IMF content. However, there is less information on the expression levels of these genes in the muscle tissue. This study aimed at investigating the expression levels of sterol regulating element binding protein-1c (SREBP-1c), diacylglycerol acyltransferase (DGAT-1), heart-fatty acids binding protein (H-FABP), leptin receptor (LEPR) and melanocortin 4 receptor (MC4R) genes and proteins in two divergent Banna mini-pig inbred lines (BMIL). A similar growth performance was found in both the fat and the lean BMIL. The fat meat and IMF content in the fat BMIL were significantly higher than in the lean BMIL, but the lean meat content was lower. The serum triacylglycerol (TAG) and free fatty acid (FFA) contents were significantly higher in the fat than in the lean BMIL. The expression levels of SREBP-1c, DGAT-1 and H-FABP genes and proteins in fat BMIL were increased compared to the lean BMIL. However, the expression levels of LEPR and MC4R genes and proteins were lower.

Fatty acid composition and lipogenic enzyme protein expression in subcutaneous adipose tissue of male pigs vaccinated against boar taint, barrows, and entire boars

Objectives of this study were to compare fatty acid composition of subcutaneous adipose tissue of entire boars, barrows, and male pigs vaccinated against boar taint with a vaccine containing a GnRH analogue-protein conjugate (Improvac, Pfizer Animal Health) and to investigate the association between fatty acid composition and protein expression of key lipogenic enzymes in entire boars, barrows, and vaccinated pigs. Differences between groups were observed in the content of total SFA (P≤0.001), MUFA (P=0.035), and n-6 PUFA (P≤0.001) but not n-3 PUFA (P=0.373). Total SFA were greater (P<0.001) in barrows and vaccinated pigs compared with entire animals. This was accompanied by an increase (P<0.05) in the protein expression of the lipogenic enzyme fatty acid synthase in barrows and vaccinated pigs. Total MUFA content was increased (P<0.001) in barrows compared with entire and vaccinated pigs. This was not accompanied (P>0.05) by an increase in expression of stearoyl-CoA desaturase protein, the enzyme catalyzing MUFA biosyntheses. Total n-6 PUFA content did not differ (P<0.001) between entire and vaccinated pigs but was lower in barrows. Expression of Δ6-desaturase protein, one of the key enzymes of PUFA biosynthesis, was greater (P<0.05) in vaccinated pigs than in barrows but did not differ significantly between vaccinated and entire animals. We conclude that fatty acid profile of animals vaccinated against boar taint is similar to that of entire male pigs and that the effect of physical castration and vaccination on fatty acid composition involves changes in lipogenic enzyme protein expression.

Expression of genes involved in energy homeostasis in the duodenum and liver of Holstein-Friesian and Jersey cows and their F1 hybrid

Differences in feed intake and production efficiency in lactating Holstein-Friesian (HF), Jersey (JE), and JE × HF (F1) dairy cows have been reported. The liver-gut axis is important in the regulation of energy homeostasis, appetite behaviour, and production efficiency. The objectives of this study were to determine: 1) the effect of dairy cow genotype on the expression profiles of genes involved in energy homeostasis in duodenal and hepatic tissue, and 2) the association between the expression of these genes across both tissues and with economically important production efficiency traits. The expression of 27 candidate genes involved in energy homeostasis, feed intake, and energy storage was measured by qPCR. Duodenal expression of the pro-opiomelanocortin ( POMC), glucagon-like peptide 1 receptor ( GLP1R), and insulin-like growth factor 1 ( IGF1) genes was highest in HF. In contrast, hepatic expression of the leptin receptor ( LEPR), insulin-like growth factor 1 receptor ( IGF1R), protein kinase, AMP-activated, beta 1 ( AMPKB1), and POMC genes was highest in the F1 cross. In the duodenum, positive correlations were observed between mRNA expression of anorectic peptides ( POMC and GLP1R), whereas a negative correlation was detected between orexigenic (ghrelin) and anorectic (peptide YY) gene expression. A negative correlation was observed between duodenal POMC gene expression and both residual feed intake and milk production efficiency traits, while GLP1R gene expression was negatively correlated with milk production efficiency traits. A heterotic effect was observed in hepatic expression of AMKPB1, IGF1R, LEPR, POMC in the F1 genotype, possibly mediating improved feed efficiency in cross-bred cows. In conclusion, key genes involved in energy homeostasis and appetite behaviour are differentially expressed due to cow genotype in a tissue-dependent fashion. POMC and GLP1R are potential candidate genes for the identification of single nucleotide polymorphisms regulating energetic efficiency in the dairy cow, which may be incorporated into future breeding programmes.

Genetic determinants for intramuscular fat content and water-holding capacity in mice selected for high muscle mass

Intramuscular fat content and water-holding capacity are important traits in livestock as they influence meat quality, nutritive value of the muscle, and animal health. As a model for livestock, two inbred lines of the Berlin Muscle Mouse population, which had been long-term selected for high muscle mass, were used to identify genomic regions affecting intramuscular fat content and water-holding capacity. The intramuscular fat content of the Musculus longissimus was on average 1.4 times higher in BMMI806 than in BMMI816 mice. This was accompanied by a 1.5 times lower water-holding capacity of the Musculus quadriceps in BMMI816 mice. Linkage analyses with 332 G(3) animals of reciprocal crosses between these two lines revealed quantitative trait loci for intramuscular fat content on chromosome 7 and for water-holding capacity on chromosome 2. In part, the identified loci coincide with syntenic regions in pigs in which genetic effects for the same traits were found. Therefore, these muscle-weight-selected mouse lines and the produced intercross populations are valuable genetic resources to identify genes that could also contribute to meat quality in other species.