Improve Pork Quality Research Articles

Multivariate genome-wide association studies on tenderness of Berkshire and Duroc pig breeds.

Genome-wide association studies (GWAS) have been steadily used for identification of genomic links to disease and various economical traits. Of those traits, a tenderness of pork is one of the most important factors in quality evaluation of consumers. In this study, we use two pig breed populations; Berkshire is known for its excellent meat quality and Duroc which is known for its high intramuscular fat content in meat. Multivariate genome-wide association studies (MV-GWAS) was executed to compare SNPs of two pigs to find out what genetic variants occur the tenderness of pork. Through MV-GWAS, we have identified candidate genes and the association of biological pathways involved in the tenderness of pork. From these direct and indirect associations, we displayed the usefulness of simple statistical models and their potential contribution to improving the meat quality of pork. We identified a candidate gene related to the tenderness in only Berkshire. Furthermore, several of the biological pathways involved in tenderness in both Berkshire and Duroc were found. The candidate genes identified in this study will be helpful to use them in breeding programs for improving pork quality.

Identification of single nucleotide polymorphisms in carnosine-related genes and effects of genotypes on pork meat quality attributes

Carnosine has pH-buffering and antioxidant properties that may bring advantages in terms of meat quality attributes. This study aimed at identifying polymorphisms in carnosine-related genes (CARNS1, SLC6A6, SLC15A3, SLC15A4) that might associate with muscle carnosine content and meat quality traits in pigs (Duroc, Landrace, Yorkshire). Twenty seven SNPs were identified and association analyses performed for SLC15A3 c.*35C>T and c.*52C>T (3′ UTR region), and SLC15A4 c.658A>G (Ile220Val) and c.818G>A (Ser273Asn) SNPs. Associations were observed for SNP c.658A>G with carnosine content, color b* and L*, drip and cooking losses, pH24h and glycolytic potential values (P≤0.05). The same associations were observed for SNP c.818G>A, but they were not significant after FDR correction. Results suggest that specific SLC15A4 gene variants might increase muscle carnosine content and improve meat quality. With a minor allele frequency of 0.17 for SNP c.658A>G in Yorkshire pigs, selection in favor of the c.658A allele may be considered as a mean to improve pork quality attributes.

Effect of meat enhancement solutions with hydroxypropyl methylcellulose and konjac flour on texture and quality attributes of pale, soft, and exudative pork.

Meat processors could use KHCO with HPMC or KF as ingredients to improve color, texture, and pH of PSE meat. The reduction of variation between PSE and normal pork muscle would improve pork quality and add value to PSE meat products.

Effect of advancing the supply of finisher diet on growth performances and carcass and pork quality of heavy barrows and gilts

A total of 120 Duroc×(Large White×Landrace) pigs, 50% barrows and 50% gilts, with 54.1±0.14 kg BW and 103±3 days of age, were used to study the effect of advancing the shift to a standard finisher feed from 100 to 90 and 80 kg BW on production performances and carcass and pork quality. Each of the six treatments (two sexes×three BWs at time of feeding shift) was replicated four times and the experimental unit was the pen (with five pigs for growth performance and carcass variables and three pigs for pork and fat traits). The grower (163 g CP and 9.5 g total Lys/kg) and the finisher diets (152 g CP and 7.9 g total Lys/kg) were based on maize, barley and vegetal protein concentrates, contained 13.39 MJ metabolizable energy/kg and were offered ad libitum through the trial. Pigs intended for dry-cured product elaboration were slaughtered at 170±3 days of age as average (124 and 115 kg BW for barrows and gilts, respectively). For the overall period, barrows ate more feed (P<0.001) and grew faster (P=0.03) than gilts. No effect of feed shift was observed on growth performances, although the average daily CP intake (P=0.01) and feeding costs (P=0.04) were reduced by advancing the transition to the finisher feed. Carcasses from barrows were heavier (P<0.001) and had wider backfat depth (P<0.001) than those from gilts but no significant differences were observed in the meat chemical composition. The feed change schedule did not modify carcass or meat traits. It is concluded that an early shift to the finisher feed (at 80 kg BW instead of 100 kg BW) might be an interesting strategy in pigs intended for dry-cured products because, although it neither increased body fatness nor improved pork quality, CP intake and feeding costs were reduced without impairment of growth performances. Results were similar for barrows and gilts.

The AMPK V199i Mutation in Berkshire Pigs Decreases the Rate of Postmortem pH Decline in Skeletal Muscle

ObjectivesAMP-activated protein kinase (AMPK) is a heterotrimeric enzyme that participates in the regulation of cellular energy homeostasis and is comprised of an ɑ, β, and γ subunit. In pigs, two known genetic mutations in the skeletal muscle specific γ3 regulatory subunit alter fresh pork quality. The first mutation, AMPKγ3R200Q (Rendement Napole mutation), arises from an arginine to glutamine substitution and makes AMPK constitutively active. Animals with this mutation produce meat with an abnormally low ultimate pH known as acid meat. The second mutation, AMPKγ3V199I, arises from a valine to isoleucine substitution making AMPK unresponsive to AMP. While the AMPKγ3V199I mutation has been associated with improved pork quality, little information is available elucidating the biochemical mechanism responsible. Therefore, our objective was to investigate the role of the AMPKγ3V199I mutation in determining fresh meat quality during the conversion of muscle to meat.Materials and MethodsWe investigated this mutation using Berkshire pigs, a breed known to carry the AMPKg3V199I mutation with a high frequency (80 to 90% homozygous mutants). Homozygous mutant (n = 12) and heterozygous Berkshire pigs (n = 9) were harvested at The Ohio State University’s Meat Laboratory. Muscle samples were collected from the longissimus lumborum et thoracis at 0, 30, 60, 120, 240, and 1440 min postmortem and frozen in liquid nitrogen to measure pH decline. To determine the rate of pH decline, a single exponential decay curve was fit to the data to derive a rate constant for each pig. After 1440 min, carcass data were measured for dressing percentage, backfat thickness, loin eye area, and Minolta color (L*, a*, and b*). Data were analyzed with a mixed model in JMP. The LSMeans were compared using a Student’s t test and considered significant at P ≤ 0.05.ResultsNo differences were detected in any carcass measurements. The homozygous mutant pigs exhibited a decreased rate of postmortem pH decline (P = 0.0325). This difference primarily arose from the elevated muscle pH of homozygous mutant muscle at 30 min (P = 0.0036) and 60 min (P = 0.0391) postmortem compared to the heterozygous pigs. The slower postmortem pH decline may explain the superior meat quality associated with Berkshire pigs and may be due to a decreased glycolytic capacity in the homozygous pigs.ConclusionThe AMPKγ3V199I mutation results in a slower pH decline in homozygous mutants compared to heterozygotes. The data also suggest that the AMPKγ3V199I mutation may be a recessive mutation compared to the dominant AMPKγ3R200Q mutation.

Effects of cell death-inducing DFF45-like effector B on meat quality traits in Berkshire pigs.

Cell death-inducing DFF45-like effector (CIDE) B is a member of the CIDE family of apoptosis-inducing factors. In the present study, we detected a single nucleotide polymorphism (SNP), c.414G>A, which corresponds to the synonymous SNP 414Arg, in CIDE-B in the Berkshire pigs. We also analyzed the relationships between the CIDE-B SNP and various meat quality traits. The SNP was significantly associated with post-mortem pH24h, water-holding capacity (WHC), fat content, protein content, drip loss, post-mortem temperature at 12 h (T12) and 24 h (T24) in a co-dominant model (P < 0.05). A significant association was detected between the SNP and post-mortem pH24h, fat content, protein content, drip loss, shear force, and T24 in gilts; and color parameter b*, WHC, and T24 in barrows (P < 0.05). The SNP was significantly correlated with the fat content, and CIDE-B mRNA expression was significantly upregulated during the early stage of adipogenesis, suggesting that CIDE-B may contribute towards initiation of adipogenesis (P < 0.05). Furthermore, CIDE-B mRNA was strongly expressed in the liver, kidney, large intestine, and small intestine, and weakly expressed in the stomach, lung, spleen, and white adipose tissue. These results indicate that the CIDE-B SNP is closely associated with meat quality traits and may be a useful DNA marker for improving pork quality.

Effects of the ratio of unsaturated fatty acid to saturated fatty acid on the growth performance, carcass and meat quality of finishing pigs.

The effects on finishing pigs (80–100 kg BW) fed diets supplemented with oil sources containing different ratios of unsaturated to saturated fatty acids (UFA:SFA ratio) were evaluated in 15 barrows and 15 gilts (Duroc × Large White × Landrace). Three experimental diets were evaluated using a randomized complete block design, with broken rice, soybean meal and rice bran as the main feedstuffs in the control diet. Diets 2 and 3 consisted of the control diet supplemented with 3% oil, with UFA:SFA ratios of 2.5:1 and 5:1, respectively. Overall, there was no significant difference (P > 0.05) found in the average daily gain (ADG) of the pigs fed the treatment diets; however, the pigs fed the control diet and diet 3 had better (P < 0.05) feed conversion ratios (FCR) than the pigs fed diet 2. The pigs fed diets 2 and 3, which were supplemented with oil at UFA:SFA ratios of 2.5:1 and 5:1, had greater (P < 0.05) average daily feed intakes (ADFI) than the pigs in the control group. Additionally, it was found that the gender of the pigs had an effect (P < 0.05) on the FCR. Interaction effects between the experimental diets and the gender of the pigs (P < 0.05) were found in the ADFI and FCR. There were no significance differences (P > 0.05) among the treatment groups with regard to the carcass quality of the pigs; however, it was found that the gilts had greater (P < 0.01) loin eye areas than the barrows fed diets 2 and 3 and the loin eye area of pig fed diet 2 was the largest (P < 0.05). In the case of the meat quality parameters, it was clearly found that the pigs fed the control diet had a greater (P < 0.05) lightness (L∗) in the meat colour, and the lowest cooking loss was found in the pigs fed the diet supplemented with fat containing the UFA:SFA ratio of 5:1. Overall, the dietary treatment did not significantly affect the drip loss, thawing loss and shear force of the pork. In conclusion, the supplementation of oil with UFA:SFA ratios of 2.5:1 and 5:1 has the potential to improve pork quality.

Over-Expression of Porcine Myostatin Missense Mutant Leads to A Gender Difference in Skeletal Muscle Growth between Transgenic Male and Female Mice.

Myostatin, a transforming growth factor-β family member, is a negative regulator of skeletal muscle development and growth. Piedmontese cattle breeds have a missense mutation, which results in a cysteine to tyrosine substitution in the mature myostatin protein (C313Y). This loss-of-function mutation in myostatin results in a double-muscled phenotype in cattle. Myostatin propeptide is an inhibitor of myostatin activity and is considered a potential agent to stimulate muscle growth in livestock. In this study, we generated transgenic mice overexpressing porcine myostatin missense mutant (pmMS), C313Y, and wild-type porcine myostatin propeptide (ppMS), respectively, to examine their effects on muscle growth in mice. Enhanced muscle growth was observed in both pmMS and ppMS transgenic female mice and also in ppMS transgenic male mice. However, there was no enhanced muscle growth observed in pmMS transgenic male mice. To explore why there is such a big difference in muscle growth between pmMS and ppMS transgenic male mice, the expression level of androgen receptor (AR) mutant AR45 was measured by Western blot. Results indicated that AR45 expression significantly increased in pmMS transgenic male mice while it decreased dramatically in ppMS transgenic male mice. Our data demonstrate that both pmMS and ppMS act as myostatin inhibitors in the regulation of muscle growth, but the effect of pmMS in male mice is reversed by an increased AR45 expression. These results provide useful insight and basic theory to future studies on improving pork quality by genetically manipulating myostatin expression or by regulating myostatin activity.

Dynamic transcriptome profiles of skeletal muscle tissue across 11 developmental stages for both Tongcheng and Yorkshire pigs.

BackgroundThe growth and development of skeletal muscle directly impacts the quantity and quality of pork production. Chinese indigenous pig breeds and exotic species vary greatly in terms of muscle production and performance traits. We present transcriptome profiles of 110 skeletal muscle samples from Tongcheng (TC) and Yorkshire (YK) pigs at 11 developmental periods (30, 40, 55, 63, 70, 90, and 105 days of gestation, and 0, 1, 3, and 5 weeks of age) using digital gene expression on Solexa/Illumina’s Genome Analyzer platform to investigate the differences in prenatal and postnatal skeletal muscle between the two breeds.ResultsMuscle morphological changes indicate the importance of primary fiber formation from 30 to 40 dpc (days post coitus), and secondary fiber formation from 55 to 70 dpc. We screened 4,331 differentially expressed genes in TC and 2,259 in YK (log2 ratio >1 and probability >0.7). Cluster analysis showed different gene expression patterns between TC and YK pigs. The transcripts were annotated in terms of Gene Ontology related to muscle development. We found that the genes CXCL10, EIF2B5, PSMA6, FBXO32, and LOC100622249 played vital roles in the muscle regulatory networks in the TC breed, whereas the genes SGCD, ENG, THBD, AQP4, and BTG2 played dominant roles in the YK breed. These genes showed breed-specific and development-dependent differential expression patterns. Furthermore, 984 genes were identified in myogenesis. A heat map showed that significantly enriched pathways (FDR <0.05) had stage-specific functional regulatory mechanisms. Finally, the differentially expressed genes from our sequencing results were confirmed by real-time quantitative polymerase chain reaction.ConclusionsThis study detected many functional genes and showed differences in the molecular mechanisms of skeletal muscle development between TC and YK pigs. TC pigs showed slower muscle growth and more complicated genetic regulation than YK pigs. Many differentially expressed genes showed breed-specific expression patterns. Our data provide a better understanding of skeletal muscle developmental differences and valuable information for improving pork quality.Electronic supplementary materialThe online version of this article (doi:10.1186/s12864-015-1580-7) contains supplementary material, which is available to authorized users.

Genome-wide association analyses for meat quality traits in Chinese Erhualian pigs and a Western Duroc × (Landrace × Yorkshire) commercial population.

BackgroundUnderstanding the genetic mechanisms that underlie meat quality traits is essential to improve pork quality. To date, most quantitative trait loci (QTL) analyses have been performed on F2 crosses between outbred pig strains and have led to the identification of numerous QTL. However, because linkage disequilibrium is high in such crosses, QTL mapping precision is unsatisfactory and only a few QTL have been found to segregate within outbred strains, which limits their use to improve animal performance. To detect QTL in outbred pig populations of Chinese and Western origins, we performed genome-wide association studies (GWAS) for meat quality traits in Chinese purebred Erhualian pigs and a Western Duroc × (Landrace × Yorkshire) (DLY) commercial population.MethodsThree hundred and thirty six Chinese Erhualian and 610 DLY pigs were genotyped using the Illumina PorcineSNP60K Beadchip and evaluated for 20 meat quality traits. After quality control, 35 985 and 56 216 single nucleotide polymorphisms (SNPs) were available for the Chinese Erhualian and DLY datasets, respectively, and were used to perform two separate GWAS. We also performed a meta-analysis that combined P-values and effects of 29 516 SNPs that were common to Erhualian, DLY, F2 and Sutai pig populations.ResultsWe detected 28 and nine suggestive SNPs that surpassed the significance level for meat quality in Erhualian and DLY pigs, respectively. Among these SNPs, ss131261254 on pig chromosome 4 (SSC4) was the most significant (P = 7.97E-09) and was associated with drip loss in Erhualian pigs. Our results suggested that at least two QTL on SSC12 and on SSC15 may have pleiotropic effects on several related traits. All the QTL that were detected by GWAS were population-specific, including 12 novel regions. However, the meta-analysis revealed seven novel QTL for meat characteristics, which suggests the existence of common underlying variants that may differ in frequency across populations. These QTL regions contain several relevant candidate genes.ConclusionsThese findings provide valuable insights into the molecular basis of convergent evolution of meat quality traits in Chinese and Western breeds that show divergent phenotypes. They may contribute to genetic improvement of purebreds for crossbred performance.Electronic supplementary materialThe online version of this article (doi:10.1186/s12711-015-0120-x) contains supplementary material, which is available to authorized users.

Genomic Selection, a New Era for Pork Quality Improvement

Traditional breeding approaches apply sophisticated statistical tools such as best linear unbiased prediction (BLUP) to evaluate the genetic potential of animals for economically important traits using phenotype and pedigree information observed on the animal. However, the genetic gain achieved is relatively slow for traits with low-to-moderate heritability, or expensive to measure traits, such as those determined post-mortem e.g., pork quality. Nowadays, the availability of dense panels of DNA markers covering the whole genome along with powerful statistical tools has made genomic selection (GS) feasible in pigs. The large number of single nucleotide polymorphisms generated by high-throughput technologies can be used in GS to select superior animals with better meat quality. Many quantitative trait loci (QTL) affecting meat quality traits have been detected in pigs demonstrating the potential for this improvement. Genomic selection uses genome-wide markers so that all QTL are likely to be in linkage disequilibrium with at least one marker. Genomic selection sums the effects of markers covering the whole genome so that potentially all the genetic variance associated with the traits and explained by the markers are considered. This can greatly improve selection accuracy to accelerate genetic gain for pork quality traits. In this review, we discuss the genetic component underlying pork quality variation, statistical approaches for pork quality genomic prediction, and present recent highlights for their application in swine breeding programs. Firstly, we review how pork quality is integrated into breeding objectives. Secondly, we present approaches for application of molecular genetics in meat quality improvement. Additionally, we discuss the statistical methods for genomic prediction including ridge regression, Bayesian approaches, GBLUP, and combining genomic and traditional information using single-step BLUP. Finally, we review the strategies for their use in swine genetic improvement and management. In particular, we review the strategy for implementing GS in swine breeding programs to improve pork quality.

Studies on Intramuscular Fat Percentage in Live Swine Using Real-time Ultrasound to Determine Pork Quality.

In the modern pork industry, selection of high intramuscular fat (IMF) in pigs is necessary to improve pork quality. Ultrasound has been used previously to predict subcutaneous fat thickness and IMF in the longissimus muscles of line pigs and Real-time ultrasound has also been reported as a reliable method for estimating IMF in live pigs. So we estimate the correlation between meat quality traits and IMF percentage to investigate the possibility of utilizing real-time ultrasound technology for predicting IMF percentage in line pigs to improve pork quality. The genetic and phenotypic correlations for chemical intramuscular fat (CIMF) and ultrasound intramuscular fat (UIMF) were estimated to be 0.75 and 0.76, respectively. These results suggest that genetic factors strongly influence meat quality. The genetic and phenotypic correlation between UIMF and CIMF were 0.75, 0.76, respectively. The heritability of UIMF and CIMF were 0.48 and 0.50, respectively. So we concluded that CIMF can be replaced with UIMF and Ultrasound machines can be used to test IMF in live swine. In future, UIMF can be utilized to improve pork quality as an alternative to CIMF.

Effects of Duroc Breeding Lines on Carcass Composition and Meat Quality.

This study was performed to investigate the carcass composition and pork quality of Duroc breeding lines in Korea. A total of 200 Duroc pigs were used, and those were originated from four different great-grandparent (GGP) breeding stock farms (L1: N farm, L2: W farm, L3: S farm, L4: R farm). The carcasses of pigs from these farms were collected, and meat quality traits were evaluated. L1 and L2 had smaller carcass weights and thin backfat, whereas L3 and L4 had heavy carcass weights and thick backfat. L3 and L4 had higher contents of fat and protein than L1 and L2. For the meat quality characteristics, L1, L2, and L4 had higher pH values than L3. In addition, L4 had higher water holding capacity than the other lines. L4 had the highest sensory evaluation scores with regard to both juiciness and flavor. Consequently, the study results indicate that pork quality information from domestic Duroc breeding stock lines could be used to effectively improve pork quality in Korea.

Immunocastration of Male Pigs – Situation Today

Immunological castration of male pigs is an attractive alternative to surgical castration and nowadays is increasingly used in many countries to reduce boar taint and improve pork quality. Moreover, immunocastrated pigs showed reduced sexual and aggressive behaviour compared to entire male pigs, thus improving animal welfare. Carcass and meat quality parameters generally do not differ between immunocastrated and surgically castrated male pigs.

Dietary resveratrol supplementation improves meat quality of finishing pigs through changing muscle fiber characteristics and antioxidative status

This study investigated the effects of resveratrol (0, 300, 600mg/kg) on meat quality, muscle fiber characteristics and antioxidative capacity of finishing pigs. The results showed that resveratrol not only increased m. longissimus dorsi (LM) pH24h, a*, crude protein and myoglobin content but also decreased L*24h, shear force, drip loss, glycolytic potential, as well as backfat depth, LM lactate dehydrogenase activity and mRNA level. Meanwhile, LM total antioxidative capacity, glutathione peroxidase activity and its mRNA level were increased by resveratrol, while malonaldehyde content was decreased. In addition, resveratrol increased myosin heavy chain (MyHC)IIa mRNA level and decreased MyHCIIb mRNA level, along with decreased myofiber cross-sectional area. In conclusion, these results suggest that resveratrol is an effective feed additive to improve pork quality, and the underlying mechanism may be partly due to the changed muscle fiber characteristics and antioxidative capacity induced by resveratrol.

Swine PPAR-γ2 expression upregulated in skeletal muscle of transgenic mice via the swine Myozenin-1 gene promoter.

Myozenin-1 (Myoz1) gene-encoded calsarcin-2 protein was expressed exclusively in fast-twitch muscles. Peroxisome proliferator-activated receptor γ2 (PPAR-γ2) is a key regulator of adipocyte differentiation, fatty acid uptake and storage in mammals. In this study, transgenic (TG) mice were generated by injecting linearized DNA that contained mouse creatine kinase M-type enhancer, Myoz1 core promoter, swine PPAR-γ2 (sPPAR-γ2) and SV40 polyadenylation sequences into pronuclei of fertilized FVB/NJ mouse embryos using microinjection technology. Then, the TG mice were used to identify whether swine Myoz1 (sMyoz1) promoter could upregulate sPPAR-γ2 expression in skeletal muscle in a TG mouse model. The results showed that the sMyoz1 promoter indeed upregulated sPPAR-γ2 expression on both the RNA and protein levels. The target genes of PPAR-γ in fat formation pathways, such as fatty acid-binding protein 4 (FABP4) and lipoprotein lipase (LPL), were also overexpressed on the RNA level. Meanwhile, the level of skeletal muscle triacylglycerol in TG mice was increased (P < 0.05), and the result of Oil Red-O staining in the skeletal muscle sections also showed that the number of lipid droplets was significantly increased in TG mice compared to wild-type mice, which might improve the intramuscular fat (IMF) content. For pork, the quality was mostly influenced by the IMF; the identification of swine muscle-specific promoter, sMyoz1, could further serve to develop transgenic pigs with higher intramuscular fat contents and improve pork quality.

Advances in porcine miRNAome

MicroRNA (miRNA), a class of non-coding RNA (about 22 nt), widely exists in different organisms and plays an important role in growth, development, and apoptosis. Recently, many studies have shown that miRNAs serve as a regulatory mechanism in mediating the development of pig muscle, fat, reproductive and immunity traits. The next-generation of high-throughput sequencing technology plays a critical role on finding new miRNAs and identifying their different expressions in pig. In this review, we summarize the application of the next-generation of high-throughput sequencing technology in the study of pig miRNAs as well as the regulatory roles of several important miRNAs in fat metabolism, muscle development, oocyte maturation and development of B cells and T cells. This review will provide insight into the research on pig miRNAs, and some ideas on how to improve pork quality, growth, reproductive and immunity performance.

Improvement in the carcass traits and meat quality of growing-finishing Rongchang pigs by conjugated linoleic acid through altered gene expression of muscle fiber types.

A total of 160 Rongchang pigs (26.76±1.78 kg) were randomly assigned to 5 dietary treatment groups until their body weight (BW) reached 90 kg. The diets were supplemented with 0, 0.5, 1.0, 1.5, and 2.0% conjugated linoleic acid (CLA). Our results showed that the 1.0 to 2.0% CLA-fed pigs had less back fat deposition when their BW reached 90 kg than the pigs that received less than 1% CLA. During the 30 to 60 kg growing period, 1.0, 1.5, and 2.0% CLA treatments improved pork quality by significantly reducing the pork pH (P<0.01) and color value (P<0.05), but they increased marble scaling (P<0.01). Similarly, the 1.5 and 2.0% CLA-fed pigs had more marble than other pigs when their BW reached 90 kg. Furthermore, CLA significantly affected the expression of muscle fiber-type genes. The 1.5% CLA-fed pigs exhibited the highest mRNA expression of MyHC1 and MyHC2a (P<0.05) at 60 kg BW. At 90 kg BW, the highest expression of MyHC1 and MyHC2a (P<0.05) was found in the 2.0% CLA group. However, MyHC2x was downregulated in the CLA-fed pigs at this time. In addition, CLA supplements did not evidently alter mRNA expression of MyHC2b at all times. These results demonstrate that CLA could affect carcass traits and improve the meat quality of growing-finishing pigs by altering the expression of genes related to muscle growth and development; 1-1.5% CLA was the most appropriate CLA dose.

Water sprinkling market pigs in a stationary trailer. 2. Effects on selected exsanguination blood parameters and carcass and meat quality variation

In each of 12 weeks between May and September, 2011, two identical pot-belly trailers were loaded with 208 pigs each and transported to the slaughter plant (2h trip). One of the two trailers was equipped with a water sprinkling system (WS) installed inside the truck compartments whereas the other one transported pigs under standard commercial conditions (control, CONT). The water sprinkling system was activated for 5min in the stationary truck, both at the farm (at the end of loading) and at the plant (immediately before unloading). Blood lactate levels at exsanguination, carcass and meat quality traits were assessed on a sub-sample of randomly selected pigs (n=384/576). Exsanguination lactate levels were lower (P=0.02) in WS pigs compared to CONT, regardless of ambient temperature. Concurrently, the pH value of the Longissimus dorsi (LD) muscle at 1h post-mortem (pH1) was greater (P=0.009) in WS pigs compared to CONT, regardless of ambient temperature. The effect of water sprinkling interacted with location inside the truck and ambient temperature. Water sprinkling reduced exsanguination lactate levels in pigs transported in compartments 5 and 8 (which are located at the front and at the rear of the middle deck, respectively) such that lower lactate was observed in compartment 5 at 15°C (P=0.03) and 18°C (P=0.009), and in compartment 8 at 22°C (P=0.03) and 25°C (P=0.04). In compartment 5, the pH1 value in the LD muscle of WS pigs was higher than in the CONT group at 18°C (P=0.002), 22°C (P<0.001) and 25°C (P=0.005); pH1 in the SM muscle of WS pigs was lower at 18°C (P=0.01) and 22°C (P=0.02); and drip loss in the WS group was lower than in the CONT group at 22°C (P=0.01), and at 25°C (P=0.02). No significant effect was detected in compartment 4 (which is located at the rear of the top floor), or in compartment 9 (which is located at the front to the bottom deck). The results of this study showed that the sprinkling protocol applied was effective, particularly in some trailer compartments, in reducing stress response and improving pork quality of pigs transported in pot-bellied trailers.

2011 AND 2012 EARLY CAREERS ACHIEVEMENT AWARDS: Farm and pig factors affecting welfare during the marketing process1,2

The objective of this paper is to review the scientific literature to identify on-farm factors that contribute to market weight pig transportation losses. Transportation of market weight pigs is an essential element to the multisite pork production model used in the United States. In 2011 alone, approximately 111 million market weight pigs were transported from the finishing site to the abattoir. For pigs, the marketing process can present a combination of potentially novel, physical, and/or unfamiliar experiences that can be stressful. If the pig cannot cope with these sequential and additive stressors, then an increased rate of transportation losses could occur with a detrimental effect on pork carcass value. Current yearly estimates for transport losses are 1 million pigs (1%). A variety of market weight pig and farm factors have been reported to detrimentally affect transportation losses. By understanding how pigs interact with their environment during marketing, researchers, producers, and personnel at the abattoir may begin to identify, prioritize, and attempt to minimize or eliminate these stressors. This process will ultimately decrease transportation losses, improve pork quality, and increase profitability.