Fine mapping of porcine SSC14 QTL and SCD gene effects on fatty acid composition and melting point of fat in a Duroc purebred population

The stearoyl-CoA desaturase (delta-9-desaturase; SCD) gene is a candidate gene for fatty acid composition. It is located on pig SSC14 in a region where quantitative trait loci (QTL) for fatty acid composition were previously detected in a Duroc purebred population. The objective of the present study was to fine map the QTL, to identify polymorphisms of the pig SCD gene and to examine the effects of SCD polymorphisms on fatty acid composition and melting point of fat in the population. The pigs were examined for fatty acid composition and melting point of inner and outer subcutaneous fat and inter- and intramuscular fat; the number of pigs examined was 479-521. Two SNPs (g.-353C>T and g.-233T>C) were identified in the promoter region of the SCD gene and were completely linked in the pigs from the base generation. In all pigs, 19 microsatellite markers and SCD haplotypes were then genotyped. Different statistical models were applied to evaluate the effects of QTL and the possible causality of the SCD gene variants with respect to the QTL. The results show that all significant QTL for C14:0, C18:0, C18:1 and melting point of fat were detected in the same region, located near the SCD gene. The results also show a significant association between SCD haplotypes and fatty acid composition and fat melting point in this population. These results indicate that the haplotype of the SCD gene has a strong effect on fatty acid composition and melting point of fat.     

Whole‐genome association study for fatty acid composition of oleic acid in Japanese Black cattle

Fatty acid composition, especially oleic acid (C18:1), plays an important role in the eating quality of meat in Japanese Black cattle. Therefore, the objective of this study was to identify loci associated with C18:1 in the intramuscular fat of the trapezius muscles in Japanese Black cattle using the Illumina BovineSNP50 BeadChip whole genome single nucleotide polymorphism (SNP) assay. We also evaluated the relationship between C18:1 and three fatty acid synthesis genes, fatty acid synthase (FASN), stearoyl‐CoA desaturase and sterol regulatory element‐binding protein‐1. In this experiment, we applied a mixed model and Genomic Control approach using selective genotyping to perform a genome‐wide association study. A total of 160 animals (80 animals with higher values and 80 animals with lower values), selected from 3356 animals based on corrected phenotype, were genotyped using the Illumina BovineSNP50 BeadChip and three fatty acid synthesis genes, and the quality of these SNPs was assessed. In this study, a total of 38 955 SNPs, which included SNPs in the three fatty acid synthesis genes, were used, and the estimated inflation factor was 1.06. In the studied population, a total of 32 SNPs, including the FASN gene, had significant effects, and in particular 30 SNPs of all significant SNPs were located between 49 and 55 Mbp on chromosome 19. This study is one of the first genome‐wide association studies for fatty acid composition in a cattle population using the recently released Illumina BovineSNP50 BeadChip.     

The SNPs in the ACACA gene are effective on fatty acid composition in holstein milk

Fatty acid composition is an important economic trait for both dairy and beef cattle and controlled by genetic factors. Candidate genes controlling fatty acid composition may be found in fat synthesis and metabolism pathways. Acetyl-CoA carboxylase is the flux-determining enzyme in the regulation of fatty acid synthesis in animal tissues. One of two isozymes of this enzyme, acetyl-CoA carboxylase-α (ACACA), catalyses the first committed step of fatty acid synthesis in mammalian cytosol, leading to the biosynthesis of long-chain fatty acids. In the current study, the sequence comparison of the coding sequence (CDS) and two promoter regions (PIA and PIII) in bovine ACACA gene was performed between Japanese Black and Holstein cattle to detect nucleotide polymorphisms influencing fatty acid composition in milk and beef. Five single nucleotide polymorphisms (SNPs) were identified in the CDS region, 28 SNPs in the PIA region and three SNPs in the PIII region. Association study revealed that CCT/CCT type of PIII_#1, #2/PIA_#26 indicated a higher percentage of C14:0 in the milk of the Holstein cattle than CCT/GTC type (p = 0.050) and that a difference of the percentage of C16:0 was observed between CCT/CCT and GTC/GTC type (p = 0.023). CDS_#2 T/T type indicated a higher percentage of C18:0 than T/C type (p = 0.008). In addition, the Japanese Black cattle with CC/GT type of PIII_#1, #2 showed a higher percentage of C18:2 in the meat than those with GT/GT type (p = 0.025). Since PIII is the promoter specific to mammary gland during lactation, the altered expression of the ACACA gene owing to the SNPs in the PIII region may influence the fatty acid composition in the milk.     

Genome-wide mapping for fatty acid composition and melting point of fat in a purebred Duroc pig population

The fatty acid composition and melting point of fatty tissue are among the most important economic traits in pig breeding because of their influence on the eating quality of meat. Identifying the quantitative trait locus (QTL) of these traits may help reveal the genetic structure of fatty acid composition and the melting point of fatty tissue and improve meat-quality traits by marker-assisted selection. We conducted whole-genome QTL analysis for fatty acid composition and melting point of inner and outer subcutaneous fat and inter- and intramuscular fat in a purebred Duroc population. A total of 129 markers were genotyped and used for QTL analysis. For fatty acid compositions of inner and outer subcutaneous fat, three significant QTL and 17 suggestive QTL were detected on SSC2, 4, 6, 8, 9, 10, 11, 12, 14 and 18. For the melting point of inner and outer subcutaneous fat, two significant QTL were detected on the same region of SSC14. For fatty acid compositions of inter- and intramuscular fat, five significant QTL and 13 suggestive QTL were detected on SSC2, 4, 6, 8, 9, 10, 14 and 15. On SSC14, significant QTL for C18:0 and C18:1 of outer subcutaneous fat and intramuscular fat, and melting point of subcutaneous fat, which had high likelihood of odds (LOD) scores (2.67-5.78), were detected in the same region. This study determined QTL affecting fatty acid composition and melting point of different fat tissues in purebred Duroc pigs.     

Contributions of FASN and SCD gene polymorphisms on fatty acid composition in muscle from Japanese Black cattle

The fatty acid synthase (FASN) and stearoyl‐CoA desaturase (delta‐9‐desaturase) (SCD) genes affect fatty acid composition. This study evaluated the contributions of polymorphisms of these genes on fatty acid composition in muscle in two different populations: 1189 and 1058 Japanese Black cattle from the Miyagi and the Yamagata populations respectively. We sampled intramuscular fat from the longissimus thoracis muscle in the Miyagi population and from the trapezius muscle in the Yamagata population. The collective contributions of FASN and SCD polymorphisms to total additive genetic variance for oleic acid were 13.46% in the Miyagi population and 16.29% in the Yamagata population and to phenotypic variance were 5.45% and 6.54% respectively. Although the individual effects of FASN and SCD polymorphisms on fatty acid composition were small, overall gene substitution may effectively improve fatty acid composition. In addition, we found that gene polymorphism contributions of fatty acids varied by population even in the same breed.     

Effect of diets rich in N-3 polyunsatured fatty acids on muscle lipids and fatty acids in Belgian Blue double-muscled young bulls

The present study was aimed at investigating the effect of duration and time of feeding n-3 fatty acids on the fatty acid composition of intramuscular fat and adipose tissue of bulls at slaughter. Four groups of bulls were given during three periods different diets, mainly differing in the presence of linseed as the predominant n-3 fatty acid source in the concentrate either or not in combination with grass (silage) as the roughage. The results show that the fatty acid composition of the feed during the earlier periods of life of the animal were important and influenced the final intramuscular fatty acid composition. Feeding n-3 PUFA during the phases before the finishing diet increased the long chain n-3 PUFA (C20:5n-3, C22:5n-3 and C22:6n-3) compared to animals which were fed only a C 18:3n-3 rich concentrate in the finishing period. The cis-9,trans-11CLA content was increased by feeding linseed in the fattening period and was mainly deposited in the triacylglycerol fraction of the intramuscular fat.     

Genetic parameters for fatty acid composition and feed efficiency traits in Japanese Black cattle

We estimated the genetic parameters related to feed intake (FI), feed efficiency traits (including feed conversion ratio (FCR) and residual feed intake (RFI) of digestible crude protein (DCP) and total digestible nutrients (TDN)), beef marbling score (BMS), melting point of fat (MP) and fatty acid composition. Fat and meat (Musculus trapezius) samples were taken from the carcasses of 863 Japanese Black steers derived from 65 sires, for determination of the MP and fatty acid composition of the total lipid in intramuscular adipose tissue. Genetic parameters were estimated using uni- and bivariate animal models. In addition, pedigree information for 4841 animals was used. Heritability estimates for BMS, MP, individual fatty acids, monounsaturated fatty acids (MUFA), the ratio of saturated fatty acids to MUFA (MUS) and the ratio of elongation (ELONG) were generally high. The FI values of TDN and DCP were also high, but FCRs and RFIs of those were low (0.09 to 0.22). Genetic correlation of BMS with MP was -0.34 (favorable) and with C18:1, MUFA, MUS and ELONG values were 0.40, 0.28, 0.29 and 0.37, respectively (favorable). Genetic correlations of MP with C18:1, MUFA, MUS and ELONG were negative (also favorable) and high (-0.85, -0.98, -1.00 (-0.996) and -0.66, respectively). The correlation estimates for feed efficiency traits of DCP were quite similar to those of TDN. Genetic correlations of BMS with FCRs and RFIs of TDN and DCP were all positive (unfavorable; 0.21 to 0.51), and in particular, the correlations with RFIs of those were high. The correlations of C18:1, MUFA, MUS and ELONG with RFIs of TDN and DCP were positive (unfavorable) but low (0.06 to 0.17), whereas the corresponding correlations with FCRs of those were all negative (favorable; -0.38 to -0.10). These results suggest that the quantity and quality of beef fat can be simultaneously improved and that the quality of beef fat (fatty acid composition) can be improved directly or indirectly with MP. Furthermore, selecting MP or fatty acid traits does not significantly affect feed efficiency.     

The SNP in the promoter region of the bovine ELOVL5 gene influences economic traits including subcutaneous fat thickness

Genetic analyses have contributed to improvements of economically important traits derived from adipose tissue such as fatty acid composition in beef. Elongation of very long chain fatty acids (ELOVL) genes encode for the enzymes that play an important role in elongation of long-chain fatty acids. In this study, we aimed to discover genetic polymorphisms of ELOVL gene family in cattle populations to develop genetic markers. As a result, five synonymous mutations were detected in the coding regions of the ELOVL1, ELOVL2, ELOVL3 and ELOVL5 genes. In addition, six mutations were identified in promoter region of the ELOVL5. Two of five mutations in the promoter region of ELOVL5 were expected to alter the ELOVL5 expression and influence the economic traits, because of the high synteny of the region which was essential for activation of Elovl5 in mouse. Therefore, we performed association analysis between the genotypes and traits and our result revealed that T allele of g.-110T>C in ELOVL5 gene promoter indicated significantly thinner subcutaneous fat thickness (TT, 2.39 cm; CT, 2.35 cm) than that of C allele (CC, 2.68 cm) in a Japanese Black population. Our results suggest that the g.-110T>C is a useful genetic marker for the breeding in beef cattle.     

Feeding vegetable oils to lactating ewes modifies the fatty acid profile of suckling lambs

The objective of this study was to evaluate the effects of vegetable oil supplementation of ewe diets on the performance and fatty acid (FA) composition of their suckling lambs. Forty-eight pregnant Churra ewes (mean BW 64.3±0.92 kg) with their 72 newborn lambs (prolificacy=1.5) were assigned to one of four experimental diets, supplemented with 3% of hydrogenated palm (PALM), olive (OLI), soya (SOY) or linseed (LIN) oil. Lambs were nourished exclusively by suckling from their respective mothers. Ewes were milked once daily, and milk samples were taken once a week. When lambs reached 11 kg, they were slaughtered and samples were taken from musculus longissimus dorsi (intramuscular fat) and subcutaneous fat tissue. No changes were observed in milk yield, proximal composition or lamb performance (P>0.10). Milk and lamb subcutaneous and intramuscular fat samples from the PALM diet had the highest saturated fatty acid concentration, whereas those of the OLI, SOY and LIN diets had the lowest (P<0.05). The greatest monounsaturated fatty acid concentration was observed in milk from ewes fed OLI, and the least in milk and in lamb subcutaneous and intramuscular fat samples from LIN and PALM diets. Milk and lamb fat from ewes fed PALM displayed the highest 16:0 proportion and the lowest 18:0 (P<0.05). There were higher concentrations of cis-9 18:1 in OLI samples (P<0.05), more 18:2n-6 in SOY lambs and milk fat (P<0.001) and the highest levels of 18:3n-3 and 20:5n-3 in LIN samples (P<0.01). Milk and lamb subcutaneous and intramuscular samples from SOY and LIN diets contained the most cis-9, trans-11 conjugated linoleic acid, whereas PALM samples had the least (P<0.01). Sheep diet supplementation with different oils, constituting up to 3% of their diets, resulted in changes in the FA composition of milk and the subcutaneous and intramuscular fat of suckling lambs, but did not affect either milk production or lamb performance.     

Fatty acid composition of lipid A in Pseudomonas fluorescens

The fatty acid composition of lipid A was studied using gas-liquid chromatography (GLC) and GLC-mass spectrometry in Pseudomonas fluorescens strains of biovars A, B, C, i, F and G, the type strain ATCC 13525 (biovar A) inclusive. The following fatty acids were identified as predominant in the composition of lipid A in the strains representing biovars A, B, C, i, F and G: 3-hydroxydecanoic (3-OH C10:0), 2-hydroxydodecanoic (2-OH C12:0), 3-hydroxydodecanoic (3-OH C12:0), dodecanoic (C12:0), hexadecanoic (C16:0), octadecanoic (C18:0), hexadecenoic (C16:1) and octadecenoic (C18:1) acids. Lipid A of a biovar G strain differed noticeably from other strains in its fatty acid composition. Its main components were as follows: 3-hydroxytetradecanoic (3-OH C14:0), 3-hydroxypentadecanoic (3-OH C15:0) and dodecanoic (C12:0) fatty acids. The coefficients of similarity were determined for lipid A specimens isolated from the studied strains of P. fluorescens by calculating their fatty acid composition with a computer.     

Changes in fatty acid composition,cholesterol and fat‐soluble vitamins during development of eggs and larvae in shabbout (Barbus grypus,Heckel 1843)

Changes in fatty acid composition, cholesterol and fat‐soluble vitamins were studied during development (fertilized eggs, yolk‐sac larvae, and after yolk resorption of shabbout, Barbus grypus). Significant differences were found in the monounsaturated fatty acids (MUFAs), polyunsaturated fatty acids (PUFA), PUFA/saturated fatty acids (SFA), ∑n‐3 and eicosapentaenoic acid (EPA)/docosahexaenoic acid (DHA) ratios between eggs and larvae (P < 0.05). Significant differences were also observed in the C14:0, C16:1n‐7, C18:1n‐9, C18:3n‐6, C20:0, C20:4n‐6, C24:0, C24:1, C22:6n‐3 fatty acids between eggs and larvae after yolk‐sac resorption (P < 0.05). Vitamin α‐ Tocopherol and retinol content increased during embryogenesis, but changes were insignificant in retinol acetate, δ‐Tocopherol, K1, K2 and cholesterol content between eggs and larvae after yolk resorption (P > 0.05).     

Association of the leptin gene E2-169T > C and E3-299T > A mutations with carcass and meat quality traits of the Chinese Simmental-cross steers

Leptin is a hormone affecting the regulation of body composition, energy balance, and meat quality in mammals. The objective of this study was to evaluate the association of novel single nucleotide polymorphisms in coding region for leptin gene with carcass and meat quality traits of Chinese Simmental-cross steers. Two SNPs (E2-169 T > C and E3-299 T > A) were genotyped on 135 crossbred bulls. The 45 traits being measured included dressing percentage, dressed weight, marbling score, muscle color score, backfat thickness, fatty acid content, etc. Statistical analysis revealed that two SNPs in the exon of leptin gene were associated with the carcass and meat quality traits. The C-bearing genotypes (CC or TC) of E2-169 T > C (C57R) showed higher dressed weight, thickness of loin, MCS, FCS, intramuscular fat content, and polyunsaturated fatty acid content (P < 0.05). E3-299  > A(S100T) also showed a significant association with the carcass traits (dressing percentage, living QIB) and fatty acid content in Simmental-cross steers(P < 0.05). Our findings suggested that polymorphisms in leptin might be one of the important genetic factors that influence carcass yield and meat quality in beef cattle, and it may be a useful marker for meat quality traits in future marker-assisted selection programs in beef cattle breeding and production.     

Estimates of genetic parameters for fatty acid compositions in the longissimus dorsi muscle of Hanwoo cattle

We estimated the heritabilities (h²) and genetic and phenotypic correlations among individual and groups of fatty acids, as well as their correlations with six important carcass and meat-quality traits in Korean Hanwoo cattle. Meat samples were collected from the longissimus dorsi muscles of 1000 Hanwoo steers that were 30-month-old (progeny of 85 proven Hanwoo bulls) to determine intramuscular fatty acid profiles. Phenotypic data on carcass weight (CWT), eye muscle area (EMA), back fat thickness (BFT), marbling score (MS), Warner–Bratzler shear force (WBSF) and intramuscular fat content (IMF) were also investigated using this half-sib population. Variance and covari.ance components were estimated using restricted maximum likelihood procedures under univariate and pairwise bivariate animal models. Oleic acid (C18:1n-9) was the most abundant fatty acid, accounting for 50.69% of all investigated fatty acids, followed by palmitic (C16:0; 27.33%) and stearic acid (C18:0; 10.96%). The contents of saturated fatty acids (SFAs), monounsaturated fatty acids (MUFAs) and polyunsaturated fatty acids (PUFAs) were 41.64%, 56.24% and 2.10%, respectively, and the MUFA/SFA ratio, PUFA/SFA ratio, desaturation index (DI) and elongation index (EI) were 1.36, 0.05, 0.59 and 0.66, respectively. The h² estimates for individual fatty acids ranged from very low to high (0.03±0.14 to 0.63±0.14). The h² estimates for SFAs, MUFAs, PUFAs, DI and EI were 0.53±0.14, 0.49±0.14, 0.23±0.10, 0.51±0.13 and 0.53±0.13, respectively. The genetic and phenotypic correlations among individual fatty acids and fatty acid classes varied widely (−0.99 to 0.99). Notably, C18:1n-9 had favourable (negative) genetic correlations with two detrimental fatty acids, C14:0 (−0.76) and C16:0 (−0.92). Genetic correlations of individual and group fatty acids with CWT, EMA, BFT, MS, WBSF and IMF ranged from low to moderate (both positive and negative) with the exception of low-concentration PUFAs. Low or near-zero phenotypic correlations reflected potential non-genetic contributions. This study provides insights on genetic variability and correlations among intramuscular fatty acids as well as correlations between fatty acids and carcass and meat-quality traits, which could be used in Hanwoo breeding programmes to improve fatty acid compositions in meat.     

Effect of grazing pastures with different botanical composition by lambs on rumen fatty acid metabolism and fatty acid pattern of longissimus muscle and subcutaneous fat

In order to study the effect of grazing pastures with a different botanical composition on rumen and intramuscular fatty acid metabolism, 21 male lambs were assigned to three botanically different pastures: botanically diverse (BD) (consisting for 65% of a variety of grass species); Leguminosa rich (L) (consisting for 61% of Leguminosae) and intensive English ryegrass (IR) (with 69% Lolium perenne). Pastures were sampled weekly for 12 weeks for analysis of their fatty acid content and composition and on nine occasions to determine the botanical composition. Ruminal and abomasal contents were sampled at slaughter and muscle and subcutaneous fat 24 h after slaughter. All samples were prepared and analysed for fatty acid composition. The L pasture showed a higher fatty acid content (29.8 mg/g dry matter (DM) v. 18.5 and 25.5 mg/g DM, for BD and IR pastures, respectively), but the sum of the proportions of the major polyunsaturated fatty acids, C18:2 n-6 and C18:3 n-3, were similar for the three pastures (69.9, 69.4 and 71.1% of fatty acids methyl esters (FAME) for BD, L and IR pastures, respectively). The BD pasture was richer in C18:2 n-6 (18.2% of FAME), while IR pasture had a higher C18:3 n-3 content (57.2% of FAME). Rumen data showed that animals grazing the BD pasture presented higher proportions of biohydrogenation intermediates, mainly C18:1 t11, C18:2 t11c15 and CLA c9t11, suggesting an inhibition of biohydrogenation. These changes were associated with shifts in the rumen microbial population as indicated by differences in the rumen pattern of volatile fatty acids, microbial odd- and branched-chain fatty acids. In L pasture animals, the content of C18:2 n-6 and C18:3 n-3 in the abomasum and subcutaneous fat was higher. Finally, higher proportions of C20:4 n-6, C20:5 n-3 and C22:5 n-3 and higher indices for elongation and desaturation activity in the intramuscular fat of BD grazing animals suggest some stimulation of elongation and desaturation of long-chain fatty acids, although this also might have been provoked partially by reduced fat deposition (due to a lower growth rate of the animals).     

Dietary fats and body lipid composition in relation to hibernation in free-ranging echidnas

Laboratory studies have shown that high levels of dietary unsaturated fatty acids prolong torpor and lower body temperatures in hibernating herbivorous rodents, which may in turn improve winter survival. The importance of nutritional ecology in relation to hibernation in insectivorous hibernators is unknown. We therefore studied fatty acid composition of dietary insects and the depot fat of echidnas Tachyglossus aculeatus (Monotremata) during the pre-hibernation season and compared depot fat fatty acid composition before and after hibernation. Echidna depot fat fatty acid composition during the pre-hibernation season was almost identical to that of the most abundant prey species, the ant Iridomyrmex sp. Oleic acid (C18:1) was by far the most common fatty acid in both Iridomyrmex sp. (60%) and echidna depot fat (62%). After about 5 months of hibernation and an 18% loss of body mass, echidna fatty acid composition had changed significantly. The percentage of the monounsaturated oleic acid (C18:1) and palmitoleic acid (C16:1) had declined, whereas that of the saturated fatty acids (C12:0, C16:0, C18:0) and the polyunsaturated linoleic acid (C18:2) had increased. Our study suggests that, unlike herbivorous rodent hibernators, echidnas rely to a large extent on monounsaturated fatty acids as fuel for hibernation, reflecting the most common fatty acid in their food. Moreover, it appears that the high concentration of monounsaturated fatty acids compensates for the moderate availability of polyunsaturates and enables them to hibernate at low body temperatures.     

Muscle fat composition of pheasants (<Emphasis Type="Italic">Phasianus colchicus)</Emphasis>, wild ducks (<Emphasis Type="Italic">Anas platyrhynchos</Emphasis>) and black coots (<Emphasis Type="Italic">Fulica atra</Emphasis>)

The aim of this investigation was to characterise the fatty acid composition within intramuscular fat (IMF) of two muscles (breast and thigh) from 28 pheasants, ten wild ducks and 27 black coots from Slovakia. A high variability for all single fatty acids (FA) and the total fat concentration in muscles of wild birds was identified. Black coots deposited the highest fat in breast muscle whereas wild ducks and pheasants accumulated more lipids in thigh muscle. In general, the content of polyunsaturated fatty acids (PUFA) of the IMF in wild bird muscles was high, and the saturated FA concentration was lower compared with muscles of domestic farm animals. The ratio between PUFA and saturated fatty acids (PSQ) ranked between 0.6 and 1.2, and the ratio of n-6/n-3 fatty acid was favourably low in black coot and wild pheasants (3.2 and 2.9, respectively). Farmed pheasants had increased IMF and more saturated and n-6 fatty acids deposited in thigh muscle but not in breast muscle.