Genomewide association for a dominant pigmentation gene in sheep.

Most published genomewide association studies (GWAS) in sheep have investigated recessively inherited monogenic traits. The objective here was to assess the feasibility of performing GWAS for a dominant trait for which the genetic basis was already known. A total of 42 Manchega and Rasa Aragonesa sheep that segregate solid black or white coat pigmentation were genotyped using the SNP50 BeadChip. Previous analysis in Manchegas demonstrated a complete association between the pigmentation trait and alleles of the MC1R gene, setting an a priori expectation for GWAS. Multiple methods were used to identify and quantify the strength of population substructure between black and white animals, before allelic association testing was performed for 49,034 SNPs. Following correction for substructure, GWAS identified the most strongly associated SNP (s26449) was also the closest to the MC1R gene. The finding was strongly supported by the permutation tree-based random forest (RF) analysis. Importantly, GWAS identified unlinked SNP with only slightly lower p-values than for s26449. Random forest analysis indicated these were false positives, suggesting interpretation based on both approaches was beneficial. The results indicate that a combined analytical approach can be successful in studies where a modest number of animals are available and substantial population stratification exists.

Genome-wide analysis reveals that the cytochrome P450 family 7 subfamily B member 1 gene is implicated in growth traits in Rasa Aragonesa ewes.

Sheep are very well adapted to changing environments and are able to produce and reproduce with low inputs in feed and water better than other domestic ruminants. Indeed, the ewe body condition score (BCS) and live weight (LW) play a significant role in productive and reproductive performance. This work conducts a genome-wide association study (GWAS) to detect genetic variants associated with growth traits in 225 adult ewes of the Rasa Aragonesa breed by using the genotypes from 50 k and HD Illumina Ovine BeadChip. These ewes were measured for LW, BCS and growth rate (GR) for 2 years, from January to September. Corrected phenotypes for BCS, LW and GR were estimated and used as input for the GWAS. Only one single nucleotide polymorphism (SNP) rs425509273 in chromosome 9 (OAR9), associated with the GR, overcame the genome-wise significance level. One, three and nine SNPs were associated at the chromosome-wise level (FDR 10%) for traits BCS, LW and GR, respectively. The cytochrome P450 family 7 subfamily B member 1 (CYP7B1) candidate gene, located 83 kb upstream from SNP rs425509273 in OAR9, was partially isolated and Sanger-sequenced. Fifteen polymorphisms comprising 12 SNPs, two indels and one polyC, were detected in promoter, exon 1, 3, 5, and intron 1-3 region. The SNP association analysis of the polymorphisms located close to the transcription start site (TSS) showed that a 22 bp insertion located at -58 nucleotides from the TSS (indel (-58)), a polyC (-25), and two A/G SNPs (SNP3 (-114) and SNP5 (-63)) were associated with the GR trait, whereas only the indel (-58) was associated with the BCS trait. The haplotype analysis confirmed these results. The functional characterisation of the polymorphisms at CYP7B1 gene in liver by real-time quantitative PCR analysis confirmed that the mutations in the promoter region affected CYP7B1 gene expression. Our results demonstrated the involvement of the CYP7B1 gene promoter on GR and BCS traits in Rasa Aragonesa. These findings suggest that variations in ovine CYP7B1 may serve as potential genetic markers to be used in breeding programmes to improve growth characteristics that could influence reproductive traits.

Host feeding patterns of Culicoides species (Diptera: Ceratopogonidae) within the Picos de Europa National Park in northern Spain.

Blood meal identification can provide information about the natural host-feeding patterns or preferences of Culicoides species. Such information could indirectly provide data indicating which reservoirs are significant in associated vector-borne diseases. We positively identified the host species through DNA sequencing of the cytochrome b gene in 144 of the 170 (84.7%) blood meal specimens tested. In the remaining samples, identification of the blood-meal source was unsuccessful, possibly due to the post-ingestion time prior to sampling or the availability of the species-specific cytochrome b gene sequences in the database. The majority of identified blood meals were derived from mammalian blood (95.8%), and only six contained chicken blood. We identified five species as mammalian hosts for Culicoides spp.: sheep (87.7%), human (6.5%), cattle (3.7%) and Savi's Pine Vole (Micrototus savii) (2.1%). The results suggested that large mammals, specifically ruminants, were most frequently fed upon by biting midges (Culicoides spp.), but evidence of opportunistic feeding behaviour was also found. Host feeding behaviour of Culicoides species may also be influenced by the relative abundance of a particular host species in the area being studied. In this sense, Savi's Pine Vole, a wild species, was found to be a locally relevant host and a putative reservoir for viruses transmitted by species of biting midges belonging to the Culicoides genus. Finally, feeding on multiple potential host species was observed. One midge acquired blood meals from human and chicken hosts, while four other midges fed on two different sheep.

Experimental Study of the Mechanical Transmission of Rabbit Hemorrhagic Disease Virus (RHDV2/b) by Aedes albopictus (Diptera: Culicidae) and Phlebotomus papatasi (Diptera: Psychodidae).

Rabbit hemorrhagic disease (RHD) is caused by a lagovirus mainly affecting European rabbits (Oryctolagus cuniculus), although other European and North American lagomorph species are also susceptible to fatal infection by the new viral variant RHDV2/b. In the present work, direct mechanical transmission of the rabbit hemorrhagic disease virus (RHDV2/b variant) by the hematophagous Diptera Aedes albopictus (Skuse) (Diptera: Culicidae) and the sand fly Phlebotomus papatasi (Scopoli) (Diptera: Psychodidae) was tested. For each species, six and three laboratory rabbits were exposed to bites of dipterous females partially fed on RHDV2/b viral suspension 2 h and 24 h prior to exposure, respectively. The rabbits were then monitored for clinical changes and mortality for 35 d, and seroconversion was assessed by indirect ELISA. No rabbit died or showed clinical signs of disease, and seroconversion was recorded in two rabbits challenged with P. papatasi females fed the viral suspension 2 h prior to exposure. The number of RHDV2/b RNA copies/female was higher in Ae. albopictus than in P. papatasi but the decrease over time of RNA load in Ae. albopictus was greater than that in P. papatasi. The results of this study suggest the inability of Ae. albopictus to serve as a direct mechanical vector of RHDV2/b, but sand flies could play a role in the local transmission of RHD.

A suitable duplex PCR for ovine embryo sex and genotype of PrnP gene determination for MOET-based selection programmes.

The objective of this study was to test the suitability of a duplex PCR assay for sex and scrapie resistance genotype determination in fresh embryos. Duplex PCR amplified a repetitive and specific fragment of Y chromosome, used for sex diagnosis, and a PrnP fragment. PrnP codons 134 and 156, and codon 171 were genotyped by restriction fragment length polymorphisms and allele-specific PCR, respectively, after re-amplification of PrnP fragment. The specificity of the method was first assessed by testing 359 blood samples from Rasa Aragonesa sheep breed (161 males and 198 females). No amplification failures and total agreement between genotypic and phenotypic sex were found. In the same way, PrnP genotype determination by duplex PCR assay was in agreement with the PrnP animal's genotype established by sequencing. Finally, 73 samples of 1-10 cells from compact morulae were aspirated through the zona pellucida and genotyped for sex and PrnP. The efficiency was 96% when three or more cells were sampled. These results confirm that the duplex PCR assay reported in this work can be used for rapid sex determination in ovine embryos, with a high efficiency and accuracy (96%) when three or more cells are sampled, allowing sexed fresh embryos of known PrnP genotype to be transferred in multiple ovulation and embryo transfer programmes.

Genome-wide association studies for sperm traits in Assaf sheep breed.

Sperm quality traits routinely collected by artificial insemination (AI) center for rams progeny test are related with the capacity to produce sperm doses for AI and, in more or less grade, with males' fertility. Low-quality ejaculates are unuseful to perform AI sperm doses, which suppose high economic loses for the AI center. Moreover, sperm quality traits have low heritability values which make traditional genetic selection little efficient to its improvement. In this work, a genome-wide association study (GWAS) was conducted by using sperm quality traits data and 50 K Affymetrix custom chip genotypes of 429 rams of Assaf breed from OVIGEN AI centre. Furthermore, 47 of these rams were also genotyped with the Illumina HD Ovine BeadChip, and therefore HD genotypes were imputed for all rams with phenotype data. Previous to the GWAS, a linear regression model was fitted including sperm traits as dependent variables; the flock of origin, date of sperm collection, and jump number as fixed effects; rams age at collection in months as covariate; and ram permanent effect as random. Pseudo-phenotypes obtained from this model were used as input for GWAS. Associations at the chromosome-wise level (FDR 10%) of 76 single-nucleotide polymorphisms (SNPs) in 4 chromosomes for ejaculate concentration (CON), 20 SNPs in 3 chromosomes for ejaculate volume (VOL), 32 SNPs in 1 chromosome for ejaculate number of spermatozoa (SPZ), and 23 SNPs for spermatozoa mass motility (MOT) in 17 chromosomes were found. Only SNPs associated with MOT overcame the genome-wide significance level. Some candidate genes for sperm traits variability were SLC9C1 (OAR1), TSN (OAR2), and FUT10 (OAR26) for MOT;. DOCK2, CPLANE1, SPEF2, and RAI14 (OAR16) for CON; SCAPER and PSMA4 (OAR18) for VOL; and PARM1 and LOC101110593 (OAR6) for SPZ. SNPs associated with sperm traits were not found to be correlated with milk production genetic variation; however, the high frequencies of some SNPs with negative effect over sperm traits found in animals at the top milk yield estimated breeding values (EBVs) ranking would allow to exert some selective presure to improve rams sperm performances. Effects and frequencies of some of the SNPs detected over sperm quality traits make these variants good candidates to be used in marker-assisted selection to improve sperm characteristics of Assaf rams and AI center efficiency to produce sperm doses.

Variations in the mitochondrial cytochrome c oxidase subunit I gene indicate northward expanding populations of Culicoides imicola in Spain.

Culicoides imicola is the main vector for bluetongue (BT) and African horse sickness (AHS) viruses in the Mediterranean basin and in southern Europe. In this study, we analysed partial mitochondrial cytochrome c oxidase subunit I (COI) gene to characterize and confirm population expansion of Culicoides imicola across Spain. The data were analysed at two hierarchical levels to test the relationship between C. imicola haplotypes in Spain (n = 215 from 58 different locations) and worldwide (n = 277). We found nineteen different haplotypes within the Spanish population, including 11 new haplotypes. No matrilineal subdivision was found within the Spanish population, while western and eastern Mediterranean C. imicola populations were very structured. These findings were further supported by median networks and mismatch haplotype distributions. Median networks demonstrated that the haplotypes we observed in the western Mediterranean region were closely related with one another, creating a clear star-like phylogeny separated only by a single mutation from eastern haplotypes. The two, genetically distinct, sources of C. imicola in the Mediterranean basin, thus, were confirmed. This type of star-like population structure centred around the most frequent haplotype is best explained by rapid expansion. Furthermore, the proposed northern expansion was also supported by the statistically negative Tajima's D and Fu's Fs values, as well as predicted mismatch distributions of sudden and spatially expanding populations. Our results thus indicated that C. imicola population expansion was a rapid and recent phenomenon.

A deletion in the bone morphogenetic protein 15 gene causes sterility and increased prolificacy in Rasa Aragonesa sheep.

Bone morphogenetic protein 15 (BMP15) is a member of the transforming growth factor beta superfamily, is specifically expressed in oocytes and is essential for sheep prolificacy. Reported mutations in this gene cause increased ovulation rate and infertility in a dosage-sensitive manner. In this work, a new naturally occurring mutation in the BMP15 gene from the ovine Rasa Aragonesa breed is described. This mutation is a deletion of 17 bp that leads to an altered amino acid sequence and introduces a premature stop codon in the protein. Highly significant associations (P < 0.0001) were found between the estimated breeding value for prolificacy and the genotype of BMP15 in Rasa Aragonesa animals with high and low breeding values for this trait. As for other mutations in BMP15, this new mutation is associated with increased prolificacy and sterility in heterozygous and homozygous ewes respectively.

Reliability of sex determination in ovine embryos using amelogenin gene (AMEL).

Sex specific sequence variability of the amelogenin gene has been used for sex determination in the family of Bovidae. In our study, suitability and reliability of the amelogenin gene for ovine sex determination in embryos was studied. The specificity of the method was previously demonstrated by testing 579 blood samples from several Spanish sheep breeds (161 males and 198 females). No amplification failures and very high agreement between genotypic and phenotypic sex was found (578/579), in contrast to humans, where errors in sex determination has been reported because of mutations in AMELX or AMELY genes. However, one female animal showed a male genotypic sex, being the most plausible explanation that a recombination event has happened during the meiosis. In our study only 0.17% (1/579) of the samples tested has been misdiagnosed using the amelogenin gene. Finally, 1-10 cells from each of 67 compact morulae were aspirated through the zona pellucida, and genotyped for sex determination. The efficiency in sex determination was 95 and 98% when more than two and more than three cells were sampled, respectively. The total time required for the genetic test, was less than 4h. These results confirm that the amelogenin gene can be used for rapid sex determination in ovine embryos, with a high efficiency and accuracy (100%) when three or more cells are sampled, allowing transferring sexed fresh embryos in MOET programmes. To our knowledge, this was the first time that sex determination using the amelogenin gene was performed in ovine embryos.

SNP rs403212791 in exon 2 of the MTNR1A gene is associated with reproductive seasonality in the Rasa aragonesa sheep breed.

The aim of this study was to characterize and identify causative SNPs in the MTNR1A gene responsible for the reproductive seasonality traits in the Rasa aragonesa sheep breed. A total of 290 ewes (155, 84 and 51 mature, young and ewe lambs, respectively) from one flock were controlled from January to August. The following three reproductive seasonality traits were considered: the total days of anoestrus (TDA) and the progesterone cycling months (P4CM); both ovarian function seasonality traits based on blood progesterone levels; and the oestrus cycling months (OCM) based on oestrous detection, which indicate behavioural signs of oestrous. We have sequenced the total coding region plus 733 and 251 bp from the promoter and 3'-UTR regions, respectively, from the gene in 268 ewes. We found 9 and 4 SNPs associated with seasonality traits in the promoter (for TDA and P4CM) and exon 2 (for the three traits), respectively. The SNPs located in the gene promoter modify the putative binding sites for various trans-acting factors. In exon 2, two synonymous SNPs affect RFLP sites, rs406779174/RsaI (for the three traits) and rs430181568/MnlI (for OCM), and they have been related with seasonal reproductive activity in previous association studies with other breeds. SNP rs400830807, which is located in the 3'-UTR, was associated with the three traits, but this did not modify the putative target sites for ovine miRNAs according to in silico predictions. Finally, the SNP rs403212791 (NW_014639035.1: g.15099004G > A), which is also associated with the three seasonality phenotypes, was the most significant SNP detected in this study and was a non-synonymous polymorphism, leading a change from an Arginine to a Cysteine (R336C). Haplotype analyses confirmed the association results and showed that the effects found for the seasonality traits were caused by the SNPs located in exon 2. We have demonstrated that the T allele in the SNP rs403212791 in the MNTR1A gene is associated with a lower TDA and higher P4CM and OCM values in the Rasa Aragonesa breed.

Milk yield and genomewide expression profiling in the mammary gland of beef primiparous cows in response to the dietary management during the pre- and postweaning periods.

Accelerated growth programs during prepubertal periods have been promoted to advance the first calving of beef heifers. The objectives of the present study were to evaluate nutrition-induced changes on first lactation milk yield and composition and on gene expression of the mammary gland in Parda de Montaña primiparous cows. Female calves ( = 16) were involved in a 2 × 2 factorial experiment. In the preweaning period (PRE-W; 0-6 mo), female calves were either fed a creep feed supplement (Creep) or fed only their dam's milk (Control). In the postweaning period (POST-W; 6-15 mo), heifers received either a high-energy diet (91.7 MJ/d) or a moderate-energy diet (79.3 MJ/d). All the heifers were managed together from breeding (15 mo) to the end of their first lactation (32 mo). Animal performance; milk production and quantity during the first lactation; plasma glucose, IGF-I, and leptin concentrations; and RNA samples from the mammary gland at the end of the first lactation of the primiparous cows (32 mo) were analyzed. The BW and ADG of the primiparous cow during its first lactation were not different among treatments; however, creep feeding during PRE-W reduced milk production ( < 0.01), milk CP, crude fat, lactose, nonfat solids, and casein content throughout lactation and increased somatic cell count in the third ( < 0.05) and fourth month of lactation ( < 0.10). The energy level during the POST-W had no effect on milk production and quality. Gene expression in the mammary gland was affected by the diet in the PRE-W and POST-W, with the PRE-W diet having the greatest impact. During the PRE-W, creep feeding resulted in upregulation of genes related to immune response and chemokine activity, suggesting that these animals might be in a compromised immune status. Therefore, this strategy would not be recommendable; meanwhile, increasing the energy level in the diet during the POST-W would be recommendable, because it had no deleterious effects on milk yield and composition.

Isolation, mapping and identification of SNPs for four genes (ACP6, CGN, ANXA9, SLC27A3) from a bovine QTL region on BTA3.

On the basis of fine mapping of a quantitative trait loci region of BTA3 for milk fat content, an examination of the comparative map between cattle and human indicates that the annexin 9 protein gene (ANXA9) and the fatty acid transport protein type 3 gene (SLC27A3) are two strong candidate genes. The objective of the present study is to isolate, map and characterize these genes and identify polymorphisms that could be further utilized in linkage or association studies. Furthermore, two new genes which are in the same region, cingulin protein gene (CGN) and lysophosphatidic acid phosphatase protein gene (ACP6) were studied. DNA fragments (869, 1778, 1933 and 2618 bp) corresponding to partial sequences of ACP6,CGN,ANXA9 and SLC27A3 genes were isolated. Direct sequencing of PCR products amplified from different cattle breeds revealed 1, 4, 4 and 2 SNPs for ACP6, CGN,ANXA9 and SLC27A3, respectively. For ANXA9 one SNP was located in exon 5 (A-->G 951) resulting in an amino acid change from histidine to arginine. Finally, ACP6,CGN,ANXA9 and SLC27A3 genes were located on chromosome 3 between ILSTS096 and BMS819 markers, in a region in which quantitative trait loci (QTL) for several milk traits have been described.

Population structure of eleven Spanish ovine breeds and detection of selective sweeps with BayeScan and hapFLK.

The goals of the current work were to analyse the population structure of 11 Spanish ovine breeds and to detect genomic regions that may have been targeted by selection. A total of 141 individuals were genotyped with the Infinium 50 K Ovine SNP BeadChip (Illumina). We combined this dataset with Spanish ovine data previously reported by the International Sheep Genomics Consortium (N = 229). Multidimensional scaling and Admixture analyses revealed that Canaria de Pelo and, to a lesser extent, Roja Mallorquina, Latxa and Churra are clearly differentiated populations, while the remaining seven breeds (Ojalada, Castellana, Gallega, Xisqueta, Ripollesa, Rasa Aragonesa and Segureña) share a similar genetic background. Performance of a genome scan with BayeScan and hapFLK allowed us identifying three genomic regions that are consistently detected with both methods i.e. Oar3 (150-154 Mb), Oar6 (4-49 Mb) and Oar13 (68-74 Mb). Neighbor-joining trees based on polymorphisms mapping to these three selective sweeps did not show a clustering of breeds according to their predominant productive specialization (except the local tree based on Oar13 SNPs). Such cryptic signatures of selection have been also found in the bovine genome, posing a considerable challenge to understand the biological consequences of artificial selection.

Effect of vitamin E supplementation or alfalfa grazing on fatty acid composition and expression of genes related to lipid metabolism in lambs.

The aim of this study was to investigate the effects of vitamin E (VE) supplementation and alfalfa grazing during fattening on fatty acid composition and mRNA expression of genes related to lipid metabolism in the LM of Rasa Aragonesa light lambs. After weaning, 48 lambs were kept indoors and fed a commercial concentrate and a VE supplemented concentrate (480 mg DL-α-tocopheryl acetate/kg DM) for 0 (control [CON]), 10 (VE10d), 20 (VE20d), and 30 d (VE30d) before slaughtering at 22 to 24 kg. Simultaneously, 8 unweaned lambs grazed in alfalfa (154 mg α-tocopherol/kg DM) paddocks with their dams and supplemented with the commercial concentrate (ALF). Immediately after slaughter, LM was sampled to determine gene expression. After 24 h of cooling at 4°C, LM was extracted to determine intramuscular fat (IMF) content and fatty acid composition. The IMF content did not differ with the dietary treatment ( = 0.212). Unweaned grazing alfalfa lambs had greater concentration of rumenic acid (C18:2 c9,t11; P < 0.001) and lower oleic acid (C18:1 c9; = 0.001) content and PUFA n-6:n-3 ratio (P < 0.001) but similar expression of genes implicated in lipid metabolism compared to the concentrate-fed lambs. Vitamin E supplementation did not modify muscle fatty acid composition; however, it increased the expression of FADS2 and ELOVL6, which are involved in desaturation of long-chain fatty acid and the elongation of SFA and MUFA. The results showed that a short period of VE supplementation, especially 10 (VE10d) and 20 d (VE20d), modified gene expression. Overall, the results showed that VE may be acting as a regulatory factor for transcriptional control of genes related to lipid metabolism in the muscle of Rasa Aragonesa light lambs (22-24 kg live weight and younger than 90 d old).

Technical note: A quick and more sensitive method to identify pork in processed and unprocessed food by PCR amplification of a new specific DNA fragment.

We developed and evaluated a PCR procedure to detect pork in heated and unheated meat, sausages, canned food, cured products, and pâtés using a faster, more specific, and more sensitive method than others previously described. Isolation of a new DNA-specific porcine repetitive element was performed by nonspecific PCR amplification. After analyzing this repetitive sequence, a pair of primers were synthesized. To confirm the effectiveness and specificity of this fragment, 55 pig blood DNA samples (from differents breeds) were tested and positive results were obtained. With 200 samples tested from other species, the specific pork amplification was not detected. Using this method, we can partially quantify degree of contamination, depending on the PCR amplification cycles, detecting up to 0.005% pork in beef and 1% pork in duck pâté using 30 and 20 PCR amplification cycles, respectively. The amount of porcine DNA detected in cattle DNA was 1.25 and 250 pg when using 30 and 20 amplification cycles, respectively. Pork has been identified in both heated and unheated meat products, sausages, canned food, hamburgers, and pâtés. In conclusion, specific PCR amplification of a repetitive DNA element seems to be a powerful technique for the identification of pork in processed and unprocessed food, because of its simplicity, specificity, and sensitivity (with 30 amplification cycles we can detect 0.005% pork). Furthermore, it is a very fast method, because 1% pork contamination can be detected with 20 PCR cycles. The procedure is also much cheaper than other methods based on RFLP-PCR, immunodiffusion, or other techniques that need expensive equipment.

Effect of transport time on welfare and meat quality in pigs.

The purpose of this study was to determine the effects of transport duration on some welfare and meat quality parameters. For the study 144 pigs were used. One group of 72 animals was subjected to 15 min and the others to 3 h transport time. Blood from all animals was analysed in order to detect stress-susceptible pigs and assess pre-slaughter stress. Meat quality parameters were analysed from Longissimus thoracis and Semimembranosus muscles. It was concluded that under normal Spanish commercial conditions, pigs subjected to short transport showed a more intense stress response and poorer meat quality than pigs subjected to moderately long transport when they were immediately slaughtered on arrival at the slaughterhouse. Transport of 3 h might have allowed the animals to adapt to transport conditions and then could act as a resting period like a lairage time. The effect of transport time on welfare and meat quality parameters was more important than genotype and sex. Nevertheless, from the point of view of blood enzyme activities, genetically stress susceptible females transported for 3 h were more sensitive to muscle damage.

Random amplified polymorphic DNA fingerprints for identification of species in poultry pâté.

Because some fraudulent or unintentional mislabeling occurs that can be undetected, resulting in lower quality pâté, and because some population groups, for philosophical or religious reasons, do not wish to eat meat from certain species, a new procedure was developed and evaluated to detect pâté species composition by randomly amplified polymorphic DNA (RAPD). The RAPD method was used to generate fingerprint patterns for pork, chicken, duck, turkey, and goose meats. Ten DNA samples from pork, chicken, turkey, and duck meats were tested to confirm the effectiveness and specificity. Specific results for each species were obtained by the RAPD method. Sensitivity of the method was studied by DNA dilution in each species, detecting as little as 250 pg of DNA. Isolations of DNA from 30 pâtés (tinned and untinned) were carried out, and an optimal DNA was obtained for using as template DNA in polymerase chain reaction (PCR). The RAPD-PCR pattern was useful to identify species composition of pork, duck, duck-pork, goose, and poultry pâtés. This study demonstrates the usefulness of RAPD fingerprinting to distinguish between species in pâtés.

Effect of finishing period length with α-tocopherol supplementation on the expression of vitamin E-related genes in the muscle and subcutaneous fat of light lambs.

The aim of this study was to investigate how different finishing period lengths with α-tocopherol supplementation or alfalfa grazing affect mRNA expression levels of genes related to vitamin E metabolism in L. thoracis (LT) muscle and subcutaneous fat (SF) from lambs of the Rasa Aragonesa breed. Indoors, concentrate-fed light lambs (n=48) were supplemented with 500 dl-α-tocopheryl acetate/kg concentrate for an average finishing period length of 0 (C), 10.7 (VE10d), 21.2 (VE20d) and, 32.3 (VE30d) days before slaughtering. Simultaneously, 8 lambs with their dams were alfalfa-grazed. The α-tocopherol affected in a short-term the expression of genes in LT muscle (ABCA1, LPL, APOE, and SREBP1) and SF (ABCA1, SCARB1, LPL, and PPARG). On the contrary, PPARA gene expression showed a long-term α-tocopherol effect because the highest levels of PPARA mRNA were found in the VE30d.

A new single nucleotide polymorphism in the calpastatin (CAST) gene associated with beef tenderness.

First we looked for putative causative mutations in the CAST and CAPN1 genes associated with meat tenderness and found a total of 31 and 7 polymorphisms, respectively, in the Parda de Montaña and Pirenaica breeds. Tenderness was not affected by mutations in CAPN1. However, three SNPs located at intron 5 (BTA7: g.98533962C>G on UMD 3.0), exon 7 (g.98535683A>G) and intron 12 (g.98545188T>A) of the CAST gene were significantly associated with meat tenderness at 7 days post-mortem in the Parda de Montaña breed. The haplotypes h2 and h5 showed significant associations with meat toughness being consistent with the SNP association results, which showed that the g.98535683A>G SNP in CAST might be the causative mutation of the effect found in this study. This mutation changes the amino acid sequence at position p.Thr182Ala (NM_174003). This amino acid substitution could affect the interacting regions between the calpastatin L-domain and calpain, and then could generate a more stable union between calpain and calpastatin.