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We genotyped single nucleotide polymorphisms (SNPs) in 5 cathepsin or cystatin genes (cathepsin F, CTSF; cathepsin L, CTSL; cathepsin S, CTSS; cathepsin Z, CTSZ; cystatin B, CSTB) in two groups of Italian Duroc pigs: the first group (n. 100) was chosen using a selective genotyping approach with extreme estimated breeding value (EBV) for visible intermuscular fat (VIF); the second group (n. 218) was made of performance-tested Duroc pigs not selected by any criteria. CTSL marker showed a tendency towards association (P < 0.10) with VIF (first group) and back fat thickness (BFT) and average daily gain (ADG; second group). In the second group, the CTSL polymorphism was associated with weight of lean cuts (LC; P < 0.05). Additive effects for all mentioned traits in the second group was significant (P < 0.05). The results we obtained in the Italian Duroc pigs confirmed the results and the direction of the effects already reported for the Italian Large White breed.

Nero Siciliano is an autochthonous pig breed reared in the internal areas of Sicily region mainly in the Nebrodi mountains. The animals are usually completely black with a dorsal stripe but a few present white portions mainly in the face or in the fore legs. According to the increased requests of the consumers for local and typical products, meat and cured products of Nero Siciliano pigs are sold at a higher price compared to other pig products. Thus there is the need to guarantee both consumers and the whole Nero Siciliano production chain from possible frauds. The identification and/or use of DNA markers that may be breed specific could make it possible to establish breed traceability and authenticity systems for the products obtained with this local pig breed. Mutations in coat colour genes have been already described and utilized for porcine breed traceability. In this trial we analysed mutations identified in two coat colour affecting genes, the melanocortin 1 receptor (MC1R) and the v-kit Hardy-Zuckerman 4 feline sarcoma viral oncogene (KIT), with the aim to characterize the Nero Siciliano pig at these loci and provide useful information to establish authenticity systems for the meat products. Fragment analysis of PCR products and PCRRFLP methods were used to identify the polymorphic sites that can distinguish known alleles at these two loci in 104 Nero Siciliano pigs. Four alleles were identified at the MC1R locus: the two dominant black alleles (ED2, frequency of 0.673; ED1, 0.187), allele EP (0.106) and the recessive e allele (0.034). The results showed that different alleles were observed at this locus, polymorphisms at the MC1R gene cannot be used for product traceability and authentication of this breed. As regards the KIT locus, all the animals were negative for the splice site mutation of exon/intron 17. Thus, meat of Nero Siciliano pigs can be distinguished from meat of white pigs that are positive for this polymorphic site. Moreover, at this locus only 4 pigs showed the 3’-5’ duplication breakpoint suggesting that they carried the Ip allele. Studies are in progress to evaluate the effect of this allele on coat colour phenotypes in Nero Siciliano pig.

Fatty acid synthase (FASN) is a multifunctional enzyme that plays a central role in fatty acid biosynthesis catalysing the conversion of acetyl-CoA and malonyl-CoA into long-chain saturated fatty acids and has an important role in energy homeostasis. Pig FASN gene has been assigned to chromosome 12p1.5 and a T>C polymorphism in the fourth exon was found. Adiponectin (ADN) is a fat-derived hormone involved in insulin sensitivity, in lipid and glucose metabolism. In literature is reported that the gene was mapped on chromosome 13 at 53.6 cM, in a region containing QTL for intramuscolar fat (IMF). In this gene several SNPs were identified and one of these polymorphisms (a G>A missense mutation within the 60th codon) determining the Val-Ile substitution in the protein, has been previously reported.The aim of this work is to analyse the variability of polymorphisms of fatty acid synthase described by Munoz et al., 2003 (Anim. Genet. 34:234) and adiponectin genes, candidates for meat and carcass quality...

TBC1D1 [TBC1 (tre-2/USP6, BUB2, cdc16) domain family, member 1] is a Rab-GTPase-activating related protein implicated in regulating the trafficking of glucose transporter 4 (GLUT4 or SLC2A4) storage vesicles to the cell surface in response to insulin and AMPK-activating stimuli in skeletal muscle. Mutations in the human and mouse TBC1D1 genes confer risk of obesity or leanness. We identified five single nucleotide polymorphisms (SNPs) in the porcine TBC1D1 gene. One of them (FN677935:g.219G>A) was genotyped either by high resolution melting and PCR-RFLP analyses to study allele frequencies in a few pig breeds and evaluate association with meat production and carcass traits in five groups of sib-tested pigs of Italian Large White and Italian Duroc breeds. The g.219G>A SNP was associated (P < 0.05) with ham weight, back fat thickness and lean cuts content in Italian Large White and with visible intermuscular fat in Italian Duroc pigs.

TRIB3 plays an important role in energy metabolism. This work aimed to study the porcine tribbles homolog 3 (TRIB3) gene and to evaluate its association with meat quality and carcass traits in pigs. By sequencing a portion of the porcine TRIB3 gene two single nucleotide polymorphisms (SNPs) in the first coding exon (one synonymous SNP: c.132 T>C; and one missense mutation: c.146C>T, p.P49L) were identified. The two polymorphisms were in complete linkage disequilibrium. In silico analysis of the p.P49L mutation suggested that it could have functional effects. Association studies in four groups of pigs (651 animals in total) indicated that this gene marker was associated with back fat thickness in Italian Large White and Italian Duroc pigs in two different experimental designs (P

The aim of this work was to identify and analyse DNA markers in two cathepsin genes, cathepsin L (CTSL) and cathepsin S (CTSS), and study their association with meat quality parameters (including cathepsin activity of post mortem muscle) and several production traits in Italian Large White pigs. In silico analysis of the porcine CTSL and CTSS genes identified two new single nucleotide polymorphisms (SNPs), one located in exon 5 (CTSL) and one positioned in the 5'-untranslated region (CTSS). Allele frequencies of these two SNPs were evaluated in 7 different pig breeds. In addition, radiation hybrid mapping localized the CTSS gene on porcine chromosome 4, in an important QTL region for meat and fat deposition. Association analysis with meat quality traits, carried out in 268 Italian Large White pigs, indicated association of the CTSL polymorphism with average daily gain (ADG), weight of lean cuts (LC) and back fat thickness (BFT) estimated breeding values (P

Catechol-O-methyltransferase (COMT) gene is a candidate for the variability of several traits including anxiety, stress response and pain sensibility. The aim of this work was to study COMT gene regions in horse samples (Equus caballus) to check for polymorphisms. DNA samples from 12 horses of different breeds were amplified with two primer pairs and then sequenced on both strands. We analysed about 1000 bp of the gene including exon 4, 5, and 6 regions, the intron 4 and part of the 3’UTR. One single nucleotide polymorphism located in the 3’-UTR of COMT gene (c.*111G>A) was identified and a new PCR-RFLP protocol was set up. Preliminary results indicated that the most frequent allele was the c.*111G. The mutation for its localisation in the 3’-UTR region might have an effect on the mRNA stability and on the levels of enzymes.

We recently showed that a polymorphism in the fat mass and obesity associated (FTO) gene (AM931150: g.276T > G) is associated with fat deposition traits in pigs. To confirm this result, we genotyped this polymorphism in an Italian Duroc population made up by 313 performance tested pigs with known estimated breeding values (EBVs) for average daily gain, back fat thickness (BFT), feed:gain ratio, lean cuts (LC), and visible intermuscular fat (VIF, a measure of intermuscular fat in the hams). In addition, we genotyped 148 commercial heavy pigs for which several fat deposition traits and lean meat percentage were measured. The results of the association analyses confirmed the effect of the FTO mutation on obesity-related traits (VIF, BFT and LC) in the Italian Duroc pigs (P < 0.01) and in the commercial pigs (intramuscular fat content of different muscles, P < 0.05 or P < 0.10; lean meat content, P < 0.05; BFT, P < 0.05; intermuscular fat content in the hams, P < 0.05).

Summary The transmembrane glycoprotein encoded by the Toll-like receptor 4 gene (TLR4) acts as the transducing subunit of the lipopolysaccharide receptor complex of mammals, which is a major sensor of infections by Gram-negative bacteria. As variation in TLR4 may alter host immune response to lipopolysaccharide, the association between TLR4 polymorphisms and immune traits of the respiratory and gut systems has important implications for livestock. Here, a sequence dataset from 259 animals belonging to commercial and traditional European pig populations, consisting of 4305 bp of TLR4, including the full transcribed region, a portion of intron 2 and the putative promoter region, was used to explore genetic variation segregating at the TLR4 locus. We identified 34 single nucleotide polymorphisms, 17 in the coding sequence and 17 in the non-coding region. Five non-synonymous mutations clustered within, or in close proximity to, the hypervariable domain of exon 3. In agreement with studies in other mammals, a major exon 3 haplotype segregated at high frequency in the whole sample of 259 pigs, while variants carrying non-synonymous substitutions showed frequencies ranging between 0.6% and 8.7%. Although results on exon 3 provided suggestive evidence for purifying selection occurring at the porcine TLR4 gene, the analysis of both coding and non-coding regions highlighted the fact that demographic factors strongly influence the tests of departure from neutrality. The phylogenetic analysis of TLR4 identified three clusters of variation (ancestral, Asian, European), supporting the evidence of Asian introgression in European main breeds and the well documented history of pig breed domestication previously identified by mtDNA analysis.

Cathepsin K (CTSK) was selected as a candidate gene for fat deposition in pigs because recently, in human and mouse, it was shown that this lysosomal proteinase is an obesity marker. A single nucleotide polymorphism (SNP) was identified in intron 4 of the porcine CTSK gene (g.15G>A; FM209043). Allele frequencies of this polymorphism were analysed in seven pig breeds. Radiation hybrid mapping confirmed the localization of CTSK to porcine chromosome 4, close to the FAT1 QTL region. Three populations of pigs (one Italian Large White and two Italian Duroc groups of pigs) were selected for association analysis. In the Italian Large White breed the g.15G>A SNP was not informative. Association analysis including all Italian Duroc pigs showed that the CTSK marker was associated with back fat thickness and lean cuts (P < 0.01), and average daily gain and feed:gain ratio (P < 0.05) estimated breeding values.

A Total of 2005 first lactation Holstein-Friesian cows with known 305-d lactation yield for milk, fat, and protein were available. For each cow, genotypes for α s1 -casein, β-casein, κ-casein, and β-lactoglobulin were known. It appears that the milk protein variants α s1 -casein, β-casein, and κ-casein may not be segregating independently. Effects of genetic variants of milk proteins on estimated individual Parmesan cheese yields were investigated. The relationships of the genetic variants of milk proteins to total lactation milk yield, fat yield, protein yield, fat percentage, and protein percentage were also investigated. Least squares analysis of the data indicated that α s1 -casein genotype significantly influenced milk yield, fat yield, and protein yield with the highest yields obtained for the genotype BB . Cheese yield on a fixed amount of milk and fat percentage were significantly related to β-lactoglobulin genotype with the highest estimates obtained for BB . Protein percentage was influenced by α s1 -casein and κ-casein, with the genotypes BC and BB , respectively, having the highest percentages. Significantly higher lactation cheese yields were estimated with α s1 -casein genotype BB . Using the prediction equation to estimate cheese yield (on data from another study), it was found that differences in Parmesan cheese yield from milk of either κ-casein genotype AA or BB were greater than expected based on composition. Differences in salted curd yield from another study using milk of either β-lactoglobulin genotype AA or BB were also greater than expected.

This article reviews the advances in molecular genetics that have led to the identification of genes and markers associated with meat quality in pig. The development of a considerable number of annotated livestock genome sequences represents an incredibly rich source of information that can be used to identify candidate genes responsible for complex traits and quantitative trait loci effects. In pig, the huge amount of information emerging from the study of the genome has helped in the acquisition of new knowledge concerning biological systems and it is opening new opportunities for the genetic selection of this specie. Among the new fields of genomics recently developed, functional genomics and proteomics that allow considering many genes and proteins at the same time are very useful tools for a better understanding of the function and regulation of genes, and how these participate in complex networks controlling the phenotypic characteristics of a trait. In particular, global gene expression profiling at the mRNA and protein level can provide a better understanding of gene regulation that underlies biological functions and physiology related to the delivery of a better pig meat quality. Moreover, the possibility to realize an integrated approach of genomics and proteomics with bioinformatics tools is essential to obtain a complete exploitation of the available molecular genetics information. The development of this knowledge will benefit scientists, industry and breeders considering that the efficiency and accuracy of the traditional pig selection schemes will be improved by the implementation of molecular data into breeding programs.

D’Alessandro, E., Fontanesi, L., Liotta, L., Davoli, R., Chiofalo, V., and Russo, V., 2007. Analysis of the MC1R Gene in the Nero Siciliano Pig Breed and Usefulness of this Locus for Breed Traceability. Veterinary Research Communications, 31(Suppl. 1), 389–392

Mammalian coat colour is mainly determined by the distribution of two different types of melanins: pheomelanin (red/yellow pigments) and eumelanin (black pigments). Their synthesis is regulated by the melanocortin 1 receptor (MC1R/Extension locus) that binds the α-melanocyte-stimulating hormone (α-MSH) and the agouti signalling protein (ASIP, coded by the Agouti locus). In mammals, several studies have reported that loss-of-function mutations in MC1R lead to red/yellow pigmentation, while gain-of-function mutations lead to black/dark colours. Mutations at the Agouti locus exert, in general, epistatic interactions on the Extension locus. In goats, classical genetic studies have indicated that variations at the Agouti locus may be the main source of colour variability within and between breeds, while the effect of the Extension locus on this phenotypic trait has been only partially deduced. In order to better understand the role of the Extension locus on coat colour in this species, here we analysed...

Glycolytic Potential (GP) is an important parameter influencing pig meat quality. In order to identify genes and gene networks influencing glycolytic potential we utilized microarray analysis and studied the expression profile of skeletal muscle tissue from Italian Large White pigs with extreme high/low levels of GP. The knowledge of differentially expressed genes in groups of pigs with substantively different GP values could be a first step to understand the metabolic regulatory pathways influencing GP. The genes more expressed in the samples with low GP are mainly associated with energy metabolism while those more expressed in the samples with high GP are involved in intracellular transport. These results can give useful information to identify candidate genes for glycolytic potential level of pig meat.

Beta-lactoglobulin (b-lg) is a globular protein belonging to the lipocalin family. It is the major whey protein in the milk of ruminants. It is also present in the milk of most mammals but is lacking in rodents, lagomorphs and humans. A large number of variants have been reported for cow and sheep milk. Several studies have shown association between b-lg variants and milk production and composition, even if the results are not always concordant. In goat, no b-lg variants related with amino acid change have been characterized at DNA level, but some authors described the presence of polymorphisms in the 3’UTR and in the proximal promoter region. Mutations in the promoter region could be those most likely responsible for different level of gene expression. The aim of this work was to study the genetic polymorphism at DNA level of b-lg gene in Girgentana goat breed. A total of 238 genomic DNA samples of Girgentana breed were genotyped. A fragment of 709 bp, including 588 bp of proximal promoter region and 121 bp of exon 1, was amplified using primers GOAPF3 and GoatE1R2. PCR-RFLP procedure was used for fast detection of two single nucleotide substitutions as described by Graziano et al. (2003). The base substitutions originating the polymorphic sites consist of: 1. a transition T›C at position -341 and 2. a transition C›T at position -60. A FspBI PCR-RFLP protocol was used to detect the mutation -341 (T/C) and a SmaI PCR-RFLP protocol for the mutation -60 (C/T) of the proximal promoter region. The allelic frequencies and the Hardy-Weinberg equilibrium were estimated using the GENEPOP software. Girgentana goat breed shows no significant deviation from Hardy- Weinberg equilibrium for the allele frequencies found in both polymorphic sites considered. The genotypic frequencies for both mutations resulted in 0.65 (T/T), 0.33 (T/C) and 0.02 (C/C) for the position -341, and 0.82 (C/C), 0.17 (C/T) and 0.01 (T/T) for the position -60. These results are in agreement with the previous obtained by Graziano et al. (2003) in the same breed. Further analysis are in progress to investigate the possible effect of these variants on the expression of b-lg gene, on the milk protein composition and on milk production traits.

Una mutazione puntiforme nell’esone 8 del gene del recettore dell’ormone della crescita (GHR), che cambia l’aminoacido fenilalanina in tirosina in posizione 279 (F279Y), è stata indicata avere un effetto positivo sulla percentuale di proteina del latte (allele F) o sulla quantità di latte (allele Y). Fino ad ora nessun dato relativo alla distribuzione di questi due alleli era disponibile in alcuna razza bovina e per questo nel presente studio abbiamo analizzato le frequenze alleliche di questo polimorfismo in alcune razze bovine da latte e a duplice attitudine allevate in Italia. Campioni di latte, peli e seme sono stati collezionati da 679 animali appartenenti a sette razze diverse (Frisona Italiana, n=108; Bruna Italiana, n=104; Pezzata Rossa Italiana, n=104; Jersey, n=104; Reggiana, n=108; Modenese, n=66; Rendena, n=85). Per l’analisi della mutazione F279Y del gene GHR è stato messo a punto un protocollo basato sulla tecnica di PCR-RFLP con un primer forward modificato, che inserisce nel frammento di DNA amplificato un sito di taglio artificiale per l’enzima di restrizione SspI. Per confermare i risultati dell’analisi PCR-RFLP, è stato sequenziato un frammento di del gene di 381 pb ottenuto da bovini con diverso genotipo. In tutte le razze analizzate l’allele F è risultato il più frequente con un valore massimo di circa il 95% nella Bruna Italiana e nella Jersey ed un valore minimo di circa il 73% nella Frisona Italiana. Nelle razze Rendena, Pezzata Rossa Italiana, Reggiana e Modenese la frequenza di questo allele è risultato, rispettivamente dell’82%, 91%, 92% e 92%. I dati ottenuti non hanno rilevato alcun scostamento statisticamente significativo dall’equilibrio di Hardy-Weinberg. Le frequenze alleliche della Frisona Italiana e della Rendena sono risultate essere significativamente (rispettivamente P

DNA markers are commonly used for large-scale evaluation of genetic diversity in farm animals, as a component of the management of animal genetic resources. AFLP markers are useful for such studies as they can be generated relatively simply; however, challenges in analysis arise from their dominant scoring and the low level of polymorphism of some markers. This paper describes the results obtained with a set of AFLP markers in a study of 59 pig breeds. AFLP fingerprints were generated using four primer combinations (PC), yielding a total of 148 marker loci, and average harmonic mean of breed sample size was 37.3. The average proportion of monomorphic populations was 63% (range across loci: 3%-98%). The moment-based method of Hill and Weir (2004, Mol Ecol 13:895-908) was applied to estimate gene frequencies, gene diversity (F(ST)), and Reynolds genetic distances. A highly significant average F(ST) of 0.11 was estimated, together with highly significant PC effects on gene diversity. The variance of F(ST) across loci also significantly exceeded the variance expected under the hypothesis of AFLP neutrality, strongly suggesting the sensitivity of AFLP to selection or other forces. Moment estimates were compared to estimates derived from the square root estimation of gene frequency, as currently applied for dominant markers, and the biases incurred in the latter method were evaluated. The paper discusses the hypotheses underlying the moment estimations and various issues relating to the biallelic, dominant, and lowly polymorphic nature of this set of AFLP markers and to their use as compared to microsatellites for measuring genetic diversity.

An important prerequisite for a conservation programme is a comprehensive description of genetic diversity. The aim of this study was to use anonymous genetic markers to assess the between- and the within-population components of genetic diversity for European pig breeds at the scale of the whole continent using microsatellites. Fifty-eight European pig breeds and lines were analysed including local breeds, national varieties of international breeds and commercial lines. A sample of the Chinese Meishan breed was also included. Eleven additional breeds from a previous project were added for some analyses. Approximately 50 individuals per breed were genotyped for a maximum of 50 microsatellite loci. Substantial within-breed variability was observed, with the average expected heterozygosity and observed number of alleles per locus being 0.56 [range 0.43-0.68] and 4.5 respectively. Genotypic frequencies departed from Hardy-Weinberg expectations (P < 0.01) in 15 European populations, with an excess of homozygotes in 12 of them. The European breeds were on average genetically very distinct, with a Wright F(ST) index value of 0.21. The Neighbour-Joining tree drawn from the Reynolds distances among the breeds showed that the national varieties of major breeds and the commercial lines were mostly clustered around their breeds of reference (Duroc, Hampshire, Landrace, Large White and Pietrain). In contrast, local breeds, with the exception of the Iberian breeds, exhibited a star-like topology. The results are discussed in the light of various forces, which may have driven the recent evolution of European pig breeds. This study has consequences for the interpretation of biodiversity results and will be of importance for future conservation programmes.

Genetic diversity within and between breeds (and lines) of pigs was investigated. The sample comprised 68 European domestic breeds (and lines), including 29 local breeds, 18 varieties of major international breeds, namely Duroc, Hampshire, Landrace, Large White and Pietrain, and 21 commercial lines either purebred or synthetic, to which the Chinese Meishan and a sample of European wild pig were added. On average 46 animals per breed were sampled (range 12–68). The genetic markers were microsatellites (50 loci) and AFLP (amplified fragment length polymorphism, 148 loci). The analysis of diversity showed that the local breeds accounted for 56% of the total European between-breed microsatellite diversity, and slightly less for AFLP, followed by commercial lines and international breeds. Conversely, the group of international breeds contributed most to within-breed diversity, followed by commercial lines and local breeds. Individual breed contributions to the overall European between- and within-breed diversity were estimated. The range in between-breed diversity contributions among the 68 breeds was 0.04–3.94% for microsatellites and 0.24–2.94% for AFLP. The within-breed diversity contributions varied very little for both types of markers, but microsatellite contributions were negatively correlated with the between-breed contributions, so care is needed in balancing the two types of contribution when making conservation decisions. By taking into account the risks of extinction of the 29 local breeds, a cryopreservation potential (priority) was estimated for each of them.

Six batches of four commercial hybrids of heavy pigs, reared for the production of Italian dry-cured hams, were identifiedfor having homogeneous feeding and farm conditions. For a total of 235 pigs, slaughtered in the same slaughterhouse,carcass traits and muscle composition were measured. The pigs were genotyped for single nucleotide polymorphisms(SNPs) of Na+, K+-ATPase subunit alpha 2 (ATPase, Na+/K+ transporting, alpha 2 (+) polypeptide; ATP1A2), cystatinB (CSTB), mitochondrial 2,4-dienoyl-CoA reductase 1 (DECR1), leptin (LEP; 3 SNPs), melanocortin receptor 4(MC4R), melanocortin receptor 5 (MC5R), sarcolipin (SLN) and titin (TTN) genes. All genes showed biallelic polymorphismsand the alleles were differently distributed between the six batches. Pigs were subsequentely clustered in “lean”and “fat” using either carcass traits (lean percentage, backfat thickness, loin muscle thickness, ham weight and hamcover fat thickness: 100 lean and 135 fat) or meat composition data (dry matter, protein, fat and ash of Biceps femorisand Vastus lateralis and pH after 24 hours: 126 lean and 109 fat). The association of gene polymorphisms with leanessand fatness of pigs was thus investigated using a logistic regression. ATP1A2, LEP (HinfI polymorphism) and MC4R,together with sex and ham weight were, included in the model to screen lean and fat pigs classified according to carcasstraits data, yielding a correct classification of 71%. For the lean and fat pigs classified according to muscle composition,sex, CSTB, DECR1, MC5R and LEP (AciI/TaqI polymorphisms) were included in the regression analysis, that yielded a66% of pigs correctly classified.These preliminary results may indicate that some of the selected candidate genes could be associated to production traitsand are worth of further investigations.

Myosin is one of the most important skeletal muscle proteins. It is composed of myosin heavy chains and myosin light chains that exist with different isoforms coded by different genes. We studied the porcine myosin heavy chain 2B (MYH4) and the porcine skeletal muscle myosin regulatory light chain 2 (HUMMLC2B) genes. A single nucleotide polymorphism (SNP), identified for each gene, was used for linkage mapping of MYH4 and HUMMLC2B to porcine chromosome (Sscr) 12 and Sscr 3, respectively. The mapping of these two genes was confirmed by using a porcine-rodent radiation hybrid panel, even if for MYH4 the LOD score and the retention fraction were low. Allele frequencies at the two loci were studied in a sample of 307 unrelated pigs belonging to seven different pig breeds. Moreover the distribution of the alleles at these two loci was analysed in groups of pigs with extreme divergent (positive and negative) estimated breeding values (EBV) for four meat production traits that have undergone selection in Italian heavy pigs.

*Institute of Animal Physiology and Genetics, Academy of Sciences of the Czech Republic, 277 21 Libechov, Czech Republic. Institute of Animal Husbandry and Breeding, Department of Animal Breeding and Biotechnology, University of Hohenheim, Garbenstrasse 17, D-70593 Stuttgart, Germany. Ghent University, Faculty of Veterinary Medicine, Department of Animal Nutrition, Genetics, Breeding and Ethology, Heidestraat 19, 9820 Merelbeke, Belgium. DIPROVAL Sezione di Allevamenti Zootecnici, Faculty of Agriculture, University of Bologna, Via F.lli Rosselli 107, 42100 Reggio Emilia, Italy

The effect of two different lairage times on meat quality was investigated in pigs with different halothane genotype previously submitted to controlled pre-slaughter treatments. One hundred and ninety nine Italian heavy pigs were loaded by ramp or lift and transported unmixed for 1 h to the abattoir at a stocking density of either0.4 or0.6 m(2) per 100 kg pigs. After unloading, an equal number of animals within each previous treatment was held in lairage for 2 h or overnight (22 h) before slaughter. Carcass and meat quality and incidence of skin damage were evaluated. Longer lairage did not negatively affect carcass traits and reduced the incidence of PSE meat without increased DFD occurrence. It also seriously increased the amount of skin damage due to fighting, resulting in long fasting. Pre-slaughter treatments and halothane genotype showed a negligible effect on the response to the resting time.

The porcine ATPase, Ca++ transporting, plasma membrane 1 (ATP2B1) gene maps to chromosome band 5q23

Porcine skeletal muscle genes play a major role in determining muscle growth and meat quality. Therefore, to progress towards a better understanding of the genetic factors influencing these traits, the first step is to characterize the genes expressed in skeletal muscle tissue in pig. To this aim, we constructed a porcine biceps femoris muscle cDNA library and sequenced 111 randomly isolated clones. By FASTA analysis, we identified 72 unique clones: 47 showed homology to previously identified genes in human or other mammals, 20 matched uncharacterized expressed sequence tags (ESTs), two showed no significant matches to sequences already present in DNA databases, and three other clones containing only repetitive elements were excluded from further analysis. Mitochondrial genes (16.2%), myosin heavy chain genes (9%) and the actin α skeletal muscle gene (9%) were the most abundant transcripts. Among the 47 identified genes several muscle-specific or predominant sequences expressed in skeletal muscle were found. The sequences of the clones matching uncharacterized human, mouse or porcine ESTs were tested by GRAIL in order to identify putative coding regions. The results of our analysis allowed the establishment of a first list of genes expressed in porcine skeletal muscle.

The present paper describes the isolation and linkage mapping of two isoforms of skeletal muscle myosin heavy chain in pig. Two partial cDNAs (pAZMY4 and pAZMY7), coding for the porcine myosin heavy chain-2B and -beta respectively, have been isolated from a pig skeletal muscle cDNA library. Four RFLPs were detected with the putative porcine skeletal myosin heavy chain-2B probe (pAZMY4) and one RFLP was identified with the putative myosin heavy chain-beta probe (pAZMY7). Two myosin heavy chain loci were mapped by linkage analysis performed with the five RFLPs against the PiGMaP linkage consortium ResPig database: the MYH1 locus, which identifies the fast skeletal muscle myosin heavy chain gene cluster, was located at the end of the map of porcine chromosome 12, while the MYH7 locus, which identifies the myosin heavy chain-alpha/-beta gene cluster, was assigned to the long arm of porcine chromosome 7.

Sources/description: Expressed sequence tags, European Molecular Biology Laboratory (EMBL) accession numbers AJ301262, AJ301107, and AJ301170, corresponding respectively to portions of the porcine muscle creatine kinase (CKM), peroxisomal enoyl coenzyme A hydratase 1 (ECH1), and skeletal slow troponin T1 (TNNT1) genes were isolated from an adult porcine skeletal muscle cDNA library. Polymerase chain reaction primers for CKM and ECH1 were designed in the 3¢-untranslated region to amplify fragments of 207 bp and 104 bp, respectively. For TNNT1, primers were designed in the coding sequence, each on a different exon, according to the organization of the human and mouse TNNT1 gene. Partial sequencing confirmed that the obtained amplicon of about 490 bp contained portions of exons 8 and 9 and the intervening intron of the porcine TNNT1 gene (EMBL accession number AJ495809).

Description: A recombinant clone was isolated at random from a skeletal muscle cDNA library1. The sequence of the resulting 598 bp insert (EMBL accession number X94253) was compared in EMBL and GenBank databases using BLASTN2. The comparisons showed the highest matches with mouse and human PCBP2 cDNAs3−5 (mouse X75947, mouse X97982, human X78136and mouse L19661; BLASTN probability were 1·9e-182, 1·1e-176, 1·6e-174 and 4·7 e-172, respectively). Excluding two gaps that could be due to alternative splicing, the deduced porcine protein sequence revealed the complete identity with corresponding human ( X78136) and mouse ( L19661) sequences. The mouse sequences X75947and X97982showed only one amino acid difference (Arg instead of Gly) with the deduced amino acid sequence of the porcine cDNA clone isolated.