Intramuscular Fatty Acid Composition Research Articles

Gene co-expression network analysis for porcine intramuscular fatty acid composition

In pigs, meat quality depends markedly on the fatty acid (FA) content and composition of the intramuscular fat, which is partly determined by the gene expression in this tissue. The aim of this work was to identify the link between muscle gene expression and its FA composition. In an (Iberian × Duroc) × Duroc backcrossed pig population, we identified modules of co-expressed genes, and correlation analyses were performed for each of them versus the phenotypes, finding four relevant modules. Two of the modules were positively correlated with saturated FAs (SFAs) and monounsaturated FAs (MUFAs), while negatively correlated with polyunsaturated FAs (PUFAs) and the omega-6/omega-3 ratio. The gene-enrichment analysis showed that these modules had over-representation of pathways related with the biosynthesis of unsaturated FAs, the Peroxisome proliferator-activated receptor signalling pathway and FA elongation. The two other relevant modules were positively correlated with PUFA and the n-6/n-3 ratio, but negatively correlated with SFA and MUFA. In this case, they had an over-representation of pathways related with fatty and amino acid degradation, and with oxidative phosphorylation. Using a graphical Gaussian model, we inferred a network of connections between the genes within each module. The first module had 52 genes with 87 connections, and the most connected genes were ADIPOQ, which is related with FA oxidation, and ELOVL6 and FABP4, both involved in FA metabolism. The second module showed 196 genes connected by 263 edges, being FN1 and MAP3K11 the most connected genes. On the other hand, the third module had 161 genes connected by 251 edges and ATG13 was the top neighbouring gene, while the fourth module had 224 genes and 655 connections, and its most connected genes were related with mitochondrial pathways. Overall, this work successfully identified relevant muscle gene networks and modules linked with FA composition, providing further insights on how the physiology of the pigs influences FA composition.

Identification of candidate regulatory genes for intramuscular fatty acid composition in pigs by transcriptome analysis

BackgroundIntramuscular fat (IMF) content and its fatty acid (FA) composition are typically controlled by several genes, each with a small effect. In the current study, to pinpoint candidate genes and putative regulators involved in FA composition, we performed a multivariate integrative analysis between intramuscular FA and transcriptome profiles of porcine longissimus dorsi (LD) muscle. We also carried out a combination of network, regulatory impact factor (RIF), in silico prediction of putative target genes, and functional analyses to better support the biological relevance of our findings.ResultsFor this purpose, we used LD RNA-Seq and intramuscular FA composition profiles of 129 Iberian × Duroc backcrossed pigs. We identified 378 correlated variables (13 FA and 365 genes), including six FA (C20:4n-6, C18:2n-6, C20:3n-6, C18:1n-9, C18:0, and C16:1n-7) that were among the most interconnected variables in the predicted network. The detected FA-correlated genes include genes involved in lipid and/or carbohydrate metabolism or in regulation of IMF deposition (e.g., ADIPOQ, CHUK, CYCS, CYP4B1, DLD, ELOVL6, FBP1, G0S2, GCLC, HMGCR, IDH3A, LEP, LGALS12, LPIN1, PLIN1, PNPLA8, PPP1R1B, SDR16C5, SFRP5, SOD3, SNW1, and TFRC), meat quality (GALNT15, GOT1, MDH1, NEU3, PDHA1, SDHD, and UNC93A), and transport (e.g., EXOC7 and SLC44A2). Functional analysis highlighted 54 over-represented gene ontology terms, including well-known biological processes and pathways that regulate lipid and carbohydrate metabolism. RIF analysis suggested a pivotal role for six transcription factors (CARHSP1, LBX1, MAFA, PAX7, SIX5, and TADA2A) as putative regulators of gene expression and intramuscular FA composition. Based on in silico prediction, we identified putative target genes for these six regulators. Among these, TADA2A and CARHSP1 had extreme RIF scores and present novel regulators in pigs. In addition, the expression of TADA2A correlated (either positively or negatively) with C20:4n-6, C18:2n-6, C20:3n-6, C18:1n-9, and that of CARHSP1 correlated (positively) with the C16:1n-7 lipokine. We also found that these two transcription factors share target genes that are involved in lipid metabolism (e.g., GOT1, PLIN1, and TFRC).ConclusionsThis integrative analysis of muscle transcriptome and intramuscular FA profile revealed valuable information about key candidate genes and potential regulators for FA and lipid metabolism in pigs, among which some transcription factors are proposed to control gene expression and modulate FA composition differences.

STC2 Inhibits Hepatic Lipid Synthesis and Correlates with Intramuscular Fatty Acid Composition, Body Weight and Carcass Traits in Chickens

Stanniocalcin 2 (STC2) is a secreted glycoprotein involved in multiple biological processes. To systemically study the biological role of STC2 in chickens, phylogenetic tree analysis and conservation analysis were conducted. Association analysis between variations in the STC2 gene and the economic traits of Gushi-Anka F2 was conducted. The tissue expression patterns of STC2 expression in different chicken tissues and liver at different stages were detected. The biological role of STC2 in chicken liver was investigated through overexpression and interfering methods in the LMH cell line. Correlation analyses between STC2 expression and lipid components were conducted. (1) The phylogenetic tree displayed that chicken STC2 is most closely related with Japanese quail and most distantly related with Xenopus tropicalis. STC2 has the same identical conserved motifs as other species. (2) rs9949205 (T > C) found in STC2 intron was highly significantly correlated with chicken body weight at 0, 2, 4, 6, 8, 10 and 12 weeks (p < 0.01). Extremely significant correlations of rs9949205 with semi-evisceration weight (SEW), evisceration weight (EW), breast muscle weight (BMW), leg muscle weight (LMW), liver weight and abdominal fat weight (AFW) were revealed (p < 0.01). Significant associations between rs9949205 and abdominal fat percentage, liver weight rate, breast muscle weight rate and leg muscle weight rate were also found (p < 0.05). Individuals with TT or TC genotypes had significantly lower abdominal fat percentage and liver weight rate compared to those with the CC genotype, while their body weight and other carcass traits were higher. (3) STC2 showed a high expression level in chicken liver tissue, which significantly increased with the progression of age (p < 0.05). STC2 was observed to inhibit the content of lipid droplets, triglycerides (TG) and cholesterol (TC), as well the expression level of genes related to lipid metabolism in LMH cells. (4) Correlation analysis showed that the STC2 gene was significantly correlated with 176 lipids in the breast muscle (p < 0.05) and mainly enriched in omega-3 and omega-6 unsaturated fatty acids. In conclusion, the STC2 gene in chicken might potentially play a crucial role in chicken growth and development, as well as liver lipid metabolism and muscle lipid deposition. This study provides a scientific foundation for further investigation into the regulatory mechanism of the STC2 gene on lipid metabolism and deposition in chicken liver.

ELOVL gene family plays a virtual role in response to breeding selection and lipid deposition in different tissues in chicken (Gallus gallus)

BackgroundElongases of very long chain fatty acids (ELOVLs), a family of first rate-limiting enzymes in the synthesis of long-chain fatty acids, play an essential role in the biosynthesis of complex lipids. Disrupting any of ELOVLs affects normal growth and development in mammals. Genetic variations in ELOVLs are associated with backfat or intramuscular fatty acid composition in livestock. However, the effects of ELOVL gene family on breeding selection and lipid deposition in different tissues are still unknown in chickens.ResultsGenetic variation patterns and genetic associations analysis showed that the genetic variations of ELOVL genes were contributed to breeding selection of commercial varieties in chicken, and 14 SNPs in ELOVL2-6 were associated with body weight, carcass or fat deposition traits. Especially, one SNP rs17631638T > C in the promoter of ELOVL3 was associated with intramuscular fat content (IMF), and its allele frequency was significantly higher in native and layer breeds compared to that in commercial broiler breeds. Quantitative real-time PCR (qRT-PCR) determined that the ELOVL3 expressions in pectoralis were affected by the genotypes of rs17631638T > C. In addition, the transcription levels of ELOVL genes except ELOVL5 were regulated by estrogen in chicken liver and hypothalamus with different regulatory pathways. The expression levels of ELOVL1-6 in hypothalamus, liver, abdominal fat and pectoralis were correlated with abdominal fat weight, abdominal fat percentage, liver lipid content and IMF. Noteworthily, expression of ELOVL3 in pectoralis was highly positively correlated with IMF and glycerophospholipid molecules, including phosphatidyl choline, phosphatidyl ethanolamine, phosphatidyl glycerol and phospholipids inositol, rich in ω-3 and ω-6 long-chain unsaturated fatty acids, suggesting ELOVL3 could contribute to intramuscular fat deposition by increasing the proportion of long-chain unsaturated glycerophospholipid molecules in pectoralis.ConclusionsIn summary, we demonstrated the genetic contribution of ELOVL gene family to breeding selection for specialized varieties, and revealed the expression regulation of ELOVL genes and their potential roles in regulating lipid deposition in different tissues. This study provides new insights into understanding the functions of ELOVL family on avian growth and lipid deposition in different tissues and the genetic variation in ELOVL3 may aid the marker-assisted selection of meat quality in chicken.

Influence of Dietary Algae Meal on Lipid Oxidation and Volatile Profile of Meat from Lambs with Competent Reticular Groove Reflex.

Dietary lipid sources influence intramuscular fatty acid composition, which in turn may affect the volatile profile of meat. The aim of this work was to investigate the effects of marine algae supplementation (Aurantiochytrium limacinum) on volatile compounds of cooked lamb meat. Forty-eight lambs with 42 days of age were divided into three groups: lambs fed a conventional diet without algae meal supplementation (NOALG), lambs with competent reticular groove reflex (RGR) fed the same diet supplemented with 2.5% marine algae meal mixed in the concentrate (ALGCON), and lambs with competent RGR, receiving the same diet and fed with 2.5% marine algae meal in a milk replacer to bypass the rumen (ALGMILK). Lipid and protein oxidation in raw meat was assessed and volatile compounds in grilled meat were determined. The highest and lowest lipid oxidations were observed in the ALGMILK and NOALG groups, respectively. Protein oxidation was unaffected. Out of 56 identified compounds, 12 volatiles significantly increased in both algae groups and 6 of them exclusively in the ALGCON treatment. Algae meal supplementation and its form of administration, either protected or not from rumen degradation, are important factors to consider in lipid oxidation and the aromatic profile of lamb meat.

Association of IFNA16 and TNFRSF19 Polymorphisms with Intramuscular Fat Content and Fatty Acid Composition in Pigs.

Simple SummaryInterferon-alpha-16 (IFNA16) and tumor necrosis factor receptor superfamily member 19 (TNFRSF19) are cytokines that may play a role in adipogenesis, lipid accumulation and fatty acid metabolism in the muscle tissue of mammals. However, no association study of the porcine IFNA16 and TNFRSF19 genes with the fatty acid composition of intramuscular fat has been reported in pigs. Therefore, the current study was performed to verify single nucleotide polymorphisms of the porcine IFNA16 and TNFRSF19 genes and to analyze how they affect intramuscular fat content and fatty acid composition in commercial crossbred pigs. The porcine IFNA16 c.413G > A polymorphism was associated with stearic acid, total saturated fatty acids and the ratio of monounsaturated fatty acids to saturated fatty acids. Moreover, the TNFRSF19 c.860G > C polymorphism was associated with intramuscular fat content and arachidic acid levels. The results revealed that the porcine IFNA16 and TNFRSF19 polymorphisms are related to lipid deposition and/or fatty acid composition in the muscle tissue of pigs. These findings suggest that the porcine IFNA16 and TNFRSF19 gene variants may contribute to lipid accumulation and fatty acid deposition in the muscle tissue of pigs.Interferon-alpha-16 (IFNA16) and tumor necrosis factor receptor superfamily member 19 (TNFRSF19) are cytokines that may play a role in adipogenesis and fatness. Single nucleotide polymorphisms (SNPs) of the porcine IFNA16 and TNFRSF19 genes were verified and their association with intramuscular fat (IMF) content and fatty acid (FA) composition were evaluated in commercial crossbred pigs. Two non-synonymous SNPs of the porcine IFNA16 c.413G > A and TNFRSF19 c.860G > C loci were detected in commercial crossbred pigs. The porcine IFNA16 c.413G >A polymorphism was significantly associated with stearic acid, total saturated FAs (SFAs), and the ratio of monounsaturated FAs (MUFAs) to SFAs (p < 0.05). Furthermore, the porcine TNFRSF19 c.860G > C polymorphism was found to be significantly associated with IMF content and arachidic acid levels (p < 0.05). The results revealed that porcine IFNA16 and TNFRSF19 polymorphisms are related to IMF content and/or FA composition and affirmed the importance of these cytokine genes as potential candidate genes for lipid deposition and FA composition in the muscle tissue of pigs.

Transcriptome shifts triggered by vitamin A and SCD genotype interaction in Duroc pigs

BackgroundThe composition of intramuscular fat depends on genetic and environmental factors, including the diet. In pigs, we identified a haplotype of three SNP mutations in the stearoyl-coA desaturase (SCD) gene promoter associated with higher content of monounsaturated fatty acids in intramuscular fat. The second of these three SNPs (rs80912566, C > T) affected a putative retinol response element in the SCD promoter. The effect of dietary vitamin A restriction over intramuscular fat content is controversial as it depends on the pig genetic line and the duration of the restriction. This study aims to investigate changes in the muscle transcriptome in SCD rs80912566 TT and CC pigs fed with and without a vitamin A supplement during the fattening period.ResultsVitamin A did not affect carcass traits or intramuscular fat content and fatty acid composition, but we observed an interaction between vitamin A and SCD genotype on the desaturation of fatty acids in muscle. As reported before, the SCD-TT pigs had more monounsaturated fat than the SCD-CC animals. The diet lacking the vitamin A supplement enlarged fatty acid compositional differences between SCD genotypes, partly because vitamin A had a bigger effect on fatty acid desaturation in SCD-CC pigs (positive) than in SCD-TT and SCD-TC animals (negative). The interaction between diet and genotype was also evident at the transcriptome level; the highest number of differentially expressed genes were detected between SCD-TT pigs fed with the two diets. The genes modulated by the diet with the vitamin A supplement belonged to metabolic and signalling pathways related to immunity and inflammation, transport through membrane-bounded vesicles, fat metabolism and transport, reflecting the impact of retinol on a wide range of metabolic processes.ConclusionsRestricting dietary vitamin A during the fattening period did not improve intramuscular fat content despite relevant changes in muscle gene expression, both in coding and non-coding genes. Vitamin A activated general pathways of retinol response in a SCD genotype-dependant manner, which affected the monounsaturated fatty acid content, particularly in SCD-CC pigs.

Effects of increasing dietary oil inclusion from different sources on growth performance, carcass and meat quality traits, and fatty acid profile in genetically lean immunocastrated male pigs

A total of 96 genetically lean immunocastrated male pigs were used in a 98-day study to evaluate the effects of including 3% soybean oil (SO), canola oil (CO), or fish oil (FO) in the diets vs. feeding a standard commercial diet with 1.5% SO (control) on growth performance, carcass and meat quality traits, consumer acceptability, and intramuscular fatty acid composition of the longissimus lumborum (LL) muscle. Pigs were blocked by initial body weight (BW; 28.44 ± 2.95 kg) and assigned to one of four treatments, with six replicate pens per treatment and four pigs per pen. Pig BW and pen feed disappearance were recorded weekly. At the conclusion of the study, pigs were slaughtered, carcass characteristics were measured, and a sample of the LL was removed for meat quality assessment, fatty acid composition analysis, and overall liking evaluation. Dietary treatments had no effect on overall growth performance and pig carcasses. Although loins from pigs fed diets containing either 3% SO or CO had decreased (P = 0.05) Warner-Bratzler shear force, only the addition of 3% SO to pig diets resulted in loin chops that were rated higher (P < 0.001) for consumer overall liking. Adding either 3% SO or CO increased (P < 0.01) the percentages of oleic acid and total monounsaturated fatty acids in the LL intramuscular fat compared to control- or FO-fed pigs. However, intramuscular fat from 3% SO- or CO-fed pigs had the lowest (P < 0.01) proportion of total omega (n)-3 polyunsaturated fatty acids (PUFA) than control- or FO-fed pigs. Including 3% oil, regardless of source, reduced (P < 0.01) total PUFA, total n-6 PUFA, and PUFA:saturated fatty acid (SFA) ratio than control-fed pigs. Dietary FO inclusion decreased (P < 0.01) n-6:n-3 PUFA ratio, but also increased total SFA (P < 0.01) and atherogenic index (P = 0.02) in the LL intramuscular fat. These results indicate that feeding genetically lean immunocastrated male pigs with diets containing 3% FO provided a healthier fatty acid profile in the loins, with the highest content of n-3 PUFA and the lowest n-6:n-3 PUFA ratio; however, pork quality that resulted in greater consumer acceptability was achieved when immunocastrated male pigs were fed 3% SO.

The effect of substitution of mixed grass hay with Urtica cannabina hay and/or Leymus chinensis hay on blood biochemical profile, carcass traits, and intramuscular fatty acid composition in finishing lambs

In this study, the effects of substitution of mixed grass hay with Urtica cannabina hay and/or Leymus chinensis hay on blood metabolites, carcass traits, and intramuscular fatty acid composition of finishing lambs were assessed. Thirty-two male Ujumuqin × small-tailed Han lambs were randomly allocated into four dietary treatment groups (n = 8): (1) 500 g/kg mixed grass hay + 500 g/kg concentrate (control, G50); (2) 500 g/kg Leymus chinensis hay + 500 g/kg concentrate (L50); (3) 500 g/kg flowering U. cannabina hay + 500 g/kg concentrate (U50); and (4) 250 g/kg L. chinensis hay + 250 g/kg flowering U. cannabina hay + 500 g/kg concentrate (L25-U25). Diets were provided in a pellet form and animals were individually fed during the 57-day experimental period. All lambs were slaughtered after the feeding trial. Compared to the control diet, the U50 and L25-U25 diets increased (P = 0.001) glucose concentration and decreased total cholesterol and triglyceride concentrations in lamb’s blood (P = 0.022 and 0.015, respectively). The U50 and L25-U25 groups had greater (P = 0.001) total antioxidant capacity and lower (P = 0.019) malondialdehyde value; and the U50 group had greater (P = 0.003) catalase activity, compared to the control group. Carcass traits were unaffected by dietary treatment, but meat of the U50 and L25-U25 lambs contained lower levels of saturated and monounsaturated fatty acids (P = 0.031 and 0.048, respectively), and greater (P < 0.001) level of polyunsaturated fatty acids than the meat of control lambs. In particular, the highest (P = 0.021) c9,t11-conjugated linoleic acid was in meat from lambs fed the U50 diet versus L50 and control diets. Use of 250 g/kg U. cannabina plus 250 g/kg L. chinensis or 500 g/kg U. cannabina as a basic feedstuff was more effective at improving blood biochemical profiles and increasing the health-promoting fatty acids of meat of fattening lambs.

Effect of production system on fatty acid composition in subcutaneous adipose tissue of Ile de France lambs

Effect of production system on fatty acid composition in subcutaneous adipose tissue of Ile de France lambs

The effect of genotype and sex on growth and carcass traits of lambs

Submitted 2020-07-24 | Accepted 2020-08-31 | Available 2020-12-01 https://doi.org/10.15414/afz.2020.23.mi-fpap.276-281 The objective of the present study was to investigate the effect of genotype and sex on growth and carcass traits of grazing lambs. A total of 32 lambs (16 Improved Jezersko-Solcava - JSR and 16 crossbreds with Texel - JSRT, 8 males and 8 females within each genotype) were included in the study. The lambs were grazed together with their dams from the beginning of the grazing period and had free access to commercial concentrate from the age of 10 days. Lambs were weaned at the average body weight of 22.9 kg. Feeding with a concentrate was finished when lambs achieved 35 kg of body weight and were slaughtered. Daily gains from birth to slaughter and from weaning to slaughter were calculated. Several carcass traits were determined. JSRT lambs had significantly higher daily gain from birth to slaughter, hot and cold carcass weights, and dressing percentages compared to JSR lambs. Carcass conformation was higher in JSRT than JSR carcasses. Also, carcasses of JSRT were shorter and wider than JSR carcasses. Rib eye muscle areas of JSRT lambs were significantly larger, and the colour was significantly lighter. Males had significantly higher average daily gain from birth to slaughter and from weaning to slaughter than females. Females had higher dressing percentages and subcutaneous and internal fatness scores than males. Females had significantly higher amount of kidney fat. The colour of males’ meat was significantly lighter than that of females. Crossbreeding with Texel rams improved growth and carcass traits of lambs, and males had better growth performance and several carcass traits than females. Keywords: lambs, commercial crossbreeding, sex, growth, carcass trait References Blasco, M. et al. (2019). Effect of Texel crossbreeding on productive traits, carcass and meat quality of Segurena lambs. Journal of the Science of Food and Agriculture, 99, 3335-3342. https://doi.org/10.1002/jsfa.9549 Cardoso, M. T. M. et al. (2013). Performance and carcass quality in three genetic groups of sheep in Brazil. Revista Brasileira de Zootecnia, 42(10), 734-742. https://doi.org/10.1590/S1516-35982013001000007 Claffey, N. A. et al. (2018). Effect of breed and castration on production and carcass traits of male lambs following an intensive finishing period. Translational Animal Science, 2, 407-418. https://doi.org/10.1093/tas/txy070 Do Prado Paim, T. et al. (2013). Performance, survivability and carcass traits of crossbred lambs from five paternal breeds with local hair breed Santa Ines ewes. Small Ruminant Research, 112, 28-34. https://doi.org/10.1016/j.smallrumres.2012.12.024 Facciolongo, A. M. et al. (2018). Effect of diet lipid source (linseed vs. soybean) and gender on performance, meat quality and intramuscular fatty acid composition in fattening lambs. Small Ruminant Research, 159, 11-17. https://doi.org/10.1016/j.smallrumres.2017.11.015 Freitas-de-Melo, A. et al. (2019). Behavioral pattern in Texel x Corriedale terminal crossbreeding: Maternal behavior score at birth, lambs’ feeding behaviors, and behavioral responses of lambs to abrupt weaning. Journal of Veterinary Behavior, 30, 9-15. https://doi.org/10.1016/j.jveb.2018.10.007 Nunes, I. A. et al. (2019). Performance, carcass characteristics, and centesimal composition of meat from Santa Ines lambs and Texel crossbred lambs (Santa Ines × Texel). Canadian Journal of Animal Science, 99(2), 228-236. https://doi.org/10.1139/cjas-2016-0231 Perez, P. et al. (2007). Gender and slaughter weight effects on carcass quality traits of suckling lambs from four different genotypes. Small Ruminant Research, 70, 124-130. https://doi.org/10.1016/j.smallrumres.2006.01.013 SAS. (2014). SAS/STAT® 13.2 User’s Guide. SAS Institute Inc., Cary, NC, USA. Scales, G. H. et al. (2000). Effect of sire breed on growth, carcass, and wool characteristics of lambs born to Merino ewes in New Zealand. New Zealand Journal of Agricultural Research, 43(1), 93-100. https://doi.org/10.1080/00288233.2000.9513412

Novel Genomic Regions Associated with Intramuscular Fatty Acid Composition in Rabbits.

Simple SummaryA divergent selection experiment on intramuscular fat (IMF) content was carried out during nine generations in rabbits. The IMF content was successfully improved through generations. Besides, selection for IMF content generated a correlated response on its composition. Association analyses were performed to understand the genetic background of IMF composition using two rabbit lines divergently selected for IMF content. Several genomic regions and genes were identified, revealing the polygenic nature of the intramuscular fatty acid composition in rabbits.Intramuscular fat (IMF) content and its composition affect the quality of meat. Selection for IMF generated a correlated response on its fatty acid composition. The increase of IMF content is associated with an increase of its saturated (SFA) and monounsaturated (MUFA) fatty acids, and consequently a decrease of polyunsaturated fatty acids (PUFA). We carried out a genome wide association study (GWAS) for IMF composition on two rabbit lines divergently selected for IMF content, using a Bayes B procedure. Association analyses were performed using 475 individuals and 90,235 Single Nucleotide Polymorphisms (SNPs). The main objectives were to identify genomic regions associated with the IMF composition and to generate a list of candidate genes. Genomic regions associated with the intramuscular fatty acid composition were spread across different rabbit chromosomes (OCU). An important region at 34.0–37.9 Mb on OCU1 was associated with C14:0, C16:0, SFA, and C18:2n6, explaining 3.5%, 11.2%, 11.3%, and 3.2% of the genomic variance, respectively. Another relevant genomic region was found to be associated at 46.0–48.9 Mb on OCU18, explaining up to 8% of the genomic variance of MUFA/SFA. The associated regions harbor several genes related to lipid metabolism, such as SCD, PLIN2, and ERLIN1. The main genomic regions associated with the fatty acids were not previously associated with IMF content in rabbits. Nonetheless, MTMR2 is the only gene that was associated with both the IMF content and composition in rabbits. Our study highlighted the polygenic nature of the fatty acids in rabbits and elucidated its genetic background.

Identification of strong candidate genes for backfat and intramuscular fatty acid composition in three crosses based on the Iberian pig

Meat quality has an important genetic component and can be modified by the fatty acid (FA) composition and the amount of fat contained in adipose tissue and muscle. The present study aimed to find genomic regions associated with the FA composition in backfat and muscle (longissimus dorsi) in 439 pigs with three different genetic backgrounds but having the Iberian breed in common. Genome-wide association studies (GWAS) were performed between 38,424 single-nucleotide polymorphisms (SNPs) covering the pig genome and 60 phenotypic traits related to backfat and muscle FA composition. Nine significant associated regions were found in backfat on the Sus scrofa chromosomes (SSC): SSC1, SSC2, SSC4, SSC6, SSC8, SSC10, SSC12, and SSC16. For the intramuscular fat, six significant associated regions were identified on SSC4, SSC13, SSC14, and SSC17. A total of 52 candidate genes were proposed to explain the variation in backfat and muscle FA composition traits. GWAS were also reanalysed including SNPs on five candidate genes (ELOVL6, ELOVL7, FADS2, FASN, and SCD). Regions and molecular markers described in our study may be useful for meat quality selection of commercial pig breeds, although several polymorphisms were breed-specific, and further analysis would be needed to evaluate possible causal mutations.

A large-scale comparison of meat quality and intramuscular fatty acid composition among three Chinese indigenous pig breeds

Derived from the long historical natural and artificial selection, Chinese indigenous pigs have formed their own special meat characteristics. We herein systematically evaluated 14 meat characteristics and 15 fatty acid composition traits on three Chinese local pig breeds. The experimental pigs were produced by crossing design covering all sire genealogy and most of dam genealogy in each of the three breeds’ seed conservation farms. All animals were reared in the same standardized housing and feeding conditions. A Comparison study showed that most of the investigated meat quality traits present significant differences among Bamaxiang, Erhualian and Laiwu breeds. While Erhualian pigs outperformed pH traits, the Laiwu pigs showed extremely high intramuscular fat content, better meat color and lower drip loss (P < .05). The highest contents of total saturated fatty acids and total polyunsaturated fatty acids were found in Laiwu and Erhualian, respectively. These results will benefit the future breeding utilization of these genetic resources for worldwide swine meat quality improvement.

Effect of an extruded linseed diet on meat quality traits in Nero Lucano pigs

The study aimed to evaluate the effect of a diet containing extruded linseed (Linum usitatissimum L.) on growth performances, carcass traits and meat quality in Nero Lucano pigs. Sixteen male piglets were weaned at about 50 days of age and divided into two homogeneous groups fed a control diet (C) or a diet containing 3% extruded linseed (EL). The trial lasted 32 weeks and pigs were slaughtered at 9 months of age. Samples from the Longissimus dorsi (Ld) muscle were analysed to assess physical and chemical parameters and intramuscular fatty acid composition. Average daily gain, feed intake and feed conversion ratio were not affected by the diet. Pigs fed the C diet showed a significantly greater slaughter weight in comparison to the EL group (116.50 vs 108.25 kg) Meat pH and chemical composition were not influenced by the diet. No differences were found for shear force (WBS) in raw meat, while cooked meat of the EL group showed a lower WBS value. The EL diet significantly lowered total SFA and increased total PUFA, of both n-6 and n-3 series. Among the n-6, significant differences between dietary treatments were found for linoleic acid. As for the n-3 series, EL feeding significantly enhanced linolenic acid, EPA, DPA and DHA. Feeding EL also significantly lowered the PUFA/SFA and n-6/n-3 ratios and the AI and TI, with benefits for human health. In conclusion, dietary supplementation with 3% EL didn't affect growth performance while it improved the fatty acid profile of meat.&#x0D; Keywords: fatty acid profile, feeding, flaxseed, pork

Genetic parameters of muscle fatty acid profile in a purebred Large White heavy pig population

Semimembranosus muscle samples from 795 Large White heavy pigs were used to determine their intramuscular fatty acid composition and to estimate the heritability and the genetic correlations of these traits. Muscle fatty acids showed heritability estimates of low-to-moderate magnitude, ranging from 0.157 for total fatty acids to 0.237 for docosahexaenoic acid. Only small differences in heritability appeared among fatty acids based on their chain length, saturation and double bond position. Omega-6 polyunsaturated fatty acids showed positive genetic correlations with carcass lean % (0.563 ± 0.005) and loin thickness (0.438 ± 0.005) while being negatively related to backfat thickness measured both by calibre (−0.225 ± 0.008) and Fat-O-Meat'er (FOM) apparatus (−0.603 ± 0.004). Interestingly, the monounsaturated fatty acid class was not correlated with carcass measures and presented only a weak positive genetic correlation with intramuscular fat (0.145 ± 0.002). This result suggests that in heavy pig breeds monounsaturated fatty acids in muscle could be selected for without interfering with carcass traits.

Intramuscular fatty acid composition of steers finished on oat pastures mixture with vetch or cornmeal supplementation

ABSTRACT: The effects of energetic supplementation and mixture vetch (Vica sativa L.) were studied to evaluate the intramuscular fatty acid profile of steers finished on oat (Avena sativa L.) pastures. Eighteen 21-month-old crossbred steers were evaluated. The experiment was carried out in three treatments and six repetitions: oat pasture (OA), oat pasture + vetch (OA + VET), and oat pasture + supplementation (OA + SUP). Supplementation comprised the addition of corn meal at a daily dose of 1% of the animals’ body weight. Steers receiving supplementation had higher lipid content in Longissimus lumborum than did those fed with OA + VET (1.25 vs 1.02%), whereas those fed with OA (1.15%) showed intermediate values. Conjugated linoleic acid levels were higher in steers fed OA (0.57%) and OA + SUP (0.59%), whereas the highest amount of omega-3 fatty acids was observed in animals fed OA + VET (3.32%). Pasture-finishing without supplementation resulted in a lower ratio of n-6:n-3 (3.14). Steers finished in oat mixture with vetch showed healthier intramuscular fat than did those finished with cornmeal supplementation; importantly, the higher the amount of PUFAs, the better n-6:n-3 ratio.

Effects of dietary extruded linseed (&lt;i&gt;Linum usitatissimum&lt;/i&gt; L.) on performance and meat quality in Podolian young bulls

This study compared effects of a diet containing 3% extruded linseed (EL) (Linum usitatissimum L.) with a control diet (C) on growth, carcass traits, and meat quality in young Podolian bulls. After 208 days on feed, the bulls were slaughtered at 18 months of age. Samples of Longissimus lumborum (Ll) were analysed to assess their physical and chemical parameters and intramuscular fatty acid composition. Average daily gain, feed intake and feed efficiency were not affected by treatments. Bulls fed EL (n = 6) had significantly greater final (612 kg versus 593 kg) and slaughter weights (583 kg versus 563 kg) than those fed C (n = 6). Compared with C, EL significantly increased percentages of lean from the pelvic limb (71.9% versus 69.3%) and of bone from the lumbar region (30.0 versus 27.1%). Meat pH recorded at slaughter was significantly greater for C than EL (6.7 versus 6.4). Diet did not affect meat colour, chemical composition and shear force of either the raw or cooked meat. Total amounts of saturated, monounsaturated and polyunsaturated fatty acids were not influenced by the diets. Concentrations of linoleic acid (C18:2 n-6) (3.30 versus 4.08) and total n-6 fatty acids (3.83 versus 4.73) were reduced by EL, while EL significantly enhanced linolenic acid (C18:3 n-3) (0.45 vs 0.20) and total n-3 fatty acids (1.64 versus 1.18) in the meat compared with C. Thus, dietary supplementation with 3% EL improved the amount of n-3 fatty acids in the meat from young Podolian bulls without affecting their performance.Keywords: carcass traits, fatty acids, feed efficiency, growth, meat colour

Performance and Intramuscular Fatty Acid Composition of Holstein Male Calves Fed Canola Oil Containing Diets

Performance and Intramuscular Fatty Acid Composition of Holstein Male Calves Fed Canola Oil Containing Diets

The effect of carcass weight on fatness and muscle and fat colour of male Ojinegra de Teruel light lambs

This study aimed to evaluate the effects of increases in lamb carcass weight in 1-kg steps from 8 to 11 kg on carcass fatness, muscle colour, subcutaneous and renal fat colour, tissue composition of the thoracic limb, and intramuscular fatty acid composition. Sixty-two carcasses from Ojinegra de Teruel male lambs fed concentrates ad libitum and barley straw were used. Both carcass scores and renal fat weight increased with carcass weight (P = 0.0001), but the percentage increase in renal fat weight was twice that of fat scores. Renal fat was prone to store carotenoids earlier than caudal fat, resulting in increased chroma. With increasing carcass weight, muscle colour became less light (decreased L* (P = 0.0001) and an increased in chroma scores (P = 0.001). Increments of 1 kg of carcass weight led to noticeable changes in the M. rectus abdominis colour, except at the increment from 10 kg to 11 kg. Slaughtering lambs at light weights was found to be advisable because renal fat is not a valuable part of the carcass. The lean percentage of the thoracic limb did not increase with carcass weight, as the increased muscle:bone ratio (P = 0.0001) was offset by an increased fat percentage (especially the intermuscular fat %). Changes with increasing carcass weight in the proportions of the main fatty acids in intramuscular fat were small. Moreover, intramuscular fat did not change in quantity or quality. However, when selling carcasses at heavier weights is preferred, achieving carcasses of 11 kg rather than 10 kg was found to be advisable because the deposition of fat in both was similar. Breeds that deposit fat earlier than the breed used in this study should be fed low-energy diets to improve carcass quality. This feeding strategy could also be considered if fat deposition differs between sexes.