Performance Traits Of Pigs Research Articles

Genetic parameters for mesenteric torsion in a pig maternal line

Mesenteric torsion (MT) is a condition characterized by the twisting of intestinal loops, leading to a disruption in blood flow and abdominal distension. Several factors can predispose animals to this condition, which primarily affects healthy, fast-growing pigs and often results in fatal outcomes. Given the absence of studies on the genetic factors associated with this condition, our research aimed to estimate the heritability coefficient for MT and explore the genetic correlations between MT and performance traits in pigs. Our dataset comprised of 43,384 records of pigs from a maternal line from a nucleus farm. These pigs were born between 2010 and 2022 and had recorded information regarding MT status (0 for healthy and 1 for affected animals), weaning weight (WW), as well as pedigree, genotypes, and genomic estimated breeding values (GEBVs) for the following traits: MT status, days to reach 110 kg (D110), feed conversion adjusted to 110 kg (FC110), and backfat thickness adjusted to 110 kg (BT110). In our statistical model, the effects of contemporary group (CG: sex, year, and week of weaning) and the linear covariate WW were considered fixed effects, while the direct additive genetic effect was accounted as random. On average, pigs affected by MT had an age of 104.35 ± 37.75 days, and the condition had an overall herd frequency of 2.46 %. Mesenteric torsion occurred more frequently in female pigs raised in collective pens compared to non-castrated males raised in individual pens. Heritability estimates for MT, using both pedigree (0.13 ± 0.02) and genomic (0.12 ± 0.02) data, were of low magnitude. This suggests that while there is genetic variability associated with MT, a significant portion of this variation is due to environmental variance. The correlation between MT and BT110 GEBVs was of low magnitude (0.05). In contrast, the correlations between GEBVs for MT and both D110 and FC110 were moderate in magnitude (0.22 for both traits). This implies that pigs taking longer to reach 110 kg and those with poorer feed conversion are more likely to develop MT. There is genetic variability for mesenteric torsion in pigs. Selection aimed at improving feed conversion and reducing the age at which pigs reach 110 kg could lead to a decrease in the occurrence of MT within pig populations.

Searching threshold temperature for farrowing performance traits of pigs in Japan using public meteorological data

暑熱負荷の頑健なモデリングを目指し，2007年から2022年の間に得られたブタランドレース種10,320頭の分娩成績52,668件を対象に，気象庁気温データを用いたプラトー線形折れ線回帰分析を行い，分割点である閾値気温を探索した．対象形質は，分娩時の一腹総産子数（TNB），生存産子数（NBA），死産子豚数（NSB），総産子体重（LWB），平均産子体重（MWB）および産子生存率（SVB）である．TNB，NBA，LWBは種付日，NSB，MWBおよびSVBは分娩日最高気温を用いた．10.0°Cから25.0°Cまで0.1°C刻みで閾値気温を変えたとき，モデルの決定係数が最大となったのは，TNB，NBA，NSB，LWB，MWB，SVBでそれぞれ17.7°C，16.6°C，22.9°C，17.1°C，10.0°C，22.9°Cであった．本結果は，気象データを活用したブタ育種価評価法の開発において有用と期待される．

Microbiability and microbiome-wide association analyses of feed efficiency and performance traits in pigs

BackgroundThe objective of the present study was to investigate how variation in the faecal microbial composition is associated with variation in average daily gain (ADG), backfat thickness (BFT), daily feed intake (DFI), feed conversion ratio (FCR), and residual feed intake (RFI), using data from two experimental pig lines that were divergent for feed efficiency. Estimates of microbiability were obtained by a Bayesian approach using animal mixed models. Microbiome-wide association analyses (MWAS) were conducted by single-operational taxonomic units (OTU) regression and by back-solving solutions of best linear unbiased prediction using a microbiome covariance matrix. In addition, accuracy of microbiome predictions of phenotypes using the microbiome covariance matrix was evaluated.ResultsEstimates of heritability ranged from 0.31 ± 0.13 for FCR to 0.51 ± 0.10 for BFT. Estimates of microbiability were lower than those of heritability for all traits and were 0.11 ± 0.09 for RFI, 0.20 ± 0.11 for FCR, 0.04 ± 0.03 for DFI, 0.03 ± 0.03 for ADG, and 0.02 ± 0.03 for BFT. Bivariate analyses showed a high microbial correlation of 0.70 ± 0.34 between RFI and FCR. The two approaches used for MWAS showed similar results. Overall, eight OTU with significant or suggestive effects on the five traits were identified. They belonged to the genera and families that are mainly involved in producing short-chain fatty acids and digestive enzymes. Prediction accuracy of phenotypes using a full model including the genetic and microbiota components ranged from 0.60 ± 0.19 to 0.78 ± 0.05. Similar accuracies of predictions of the microbial component were observed using models that did or did not include an additive animal effect, suggesting no interaction with the genetic effect.ConclusionsOur results showed substantial associations of the faecal microbiome with feed efficiency related traits but negligible effects with growth traits. Microbiome data incorporated as a covariance matrix can be used to predict phenotypes of animals that do not (yet) have phenotypic information. Connecting breeding environment between training sets and predicted populations could be necessary to obtain reliable microbiome predictions.

57. Microbial biomarkers for pig performance traits under different social stress challenges

57. Microbial biomarkers for pig performance traits under different social stress challenges

GENETIC ANALYSIS OF UKRAINIAN LARGE WHITE PIG BREED BY POLYMORPHISMS IN RYR1, ESR1 AND PRLR GENES

Marker-Assisted Selection is getting increasing attention in Ukrainian animal breeding as an effective tool for choosing animals with desirable traits. Identification of molecular markers which are related to major genes is a promising approach for improving economic traits and has to be checked for further gene-trait associations. Single nucleotide polymorphisms are genetic markers that can be associated with production traits. SNP genotyping has to be done additionally for each breed to see if they are polymorphic and have significant associations with certain traits. Among the candidate genes that influence the expression of productive traits, special attention is drawn to RYR1, ESR1 and PRLR genes. Gene RYR1 is associated with muscle hypertrophy and other meat quality defects in pigs. ESR1 and PRLR genes influence reproduction and affect the litter size in pigs. SNPs RYR1 g.1843 C>T, ESR1 SNP c.1227 C>T and PRLR g. 1789 G>A have been receiving increasing attention as potential markers for improving quality and pig performance traits. This study investigated the allele variants in three genes (RYR1, ESR1 and PRLR) in Ukrainian Large White pigs of different inside breed types (ULW-1 and ULW-2). The study was performed on 200 pigs. Genotyping was performed using PCR–RFLP method. SNP RYR1 g.1843 C>T was not polymorphic in ULW-1 and ULW-2 inside breed types, when ESR1 SNP c.1227 C> T and PRLR g. 1789 G>A were highly polymorphic. SNPs in ESR1 and PRLR genes had high PIC and χ2 values which indicates the relevance of further associative studies in ULW-1 and ULW-2. Informativeness of the genetic markers in ESR1 and PRLR genes was optimal for associative studies in Ukrainian Large White pig breed of first and second inside breed type.

Genome-wide analyses reveal the regions involved in the phenotypic diversity in Sicilian pigs.

Nero Siciliano (Sicilian Black, SB) is a local pig breed generally of uniform black color. In addition to this officially recognized breed, there are animals showing morphological characteristics resembling the SB but with gray hair (Sicilian Grey, SG). The SG, compared with the SB, also shows a more compact structure with greater transverse diameters, higher average daily gains and lower thickness of the back fat. In this study, using the Illumina PorcineSNP60 BeadChip, we run genome-wide analyses to identify regions that may explain the phenotypic differences between SB (n=21) and SG (n=27) individuals. Combining the results of the two case-control approaches (GWAS and FST ), we identified two significant regions, one on SSC5 (95 401 083 bp) and one on SSC15 (55 051 435 bp), which contains several candidate genes related to growth traits in pig. The results of the Bayesian population differentiation approach identified a marker near the MGAT4C, a gene associated with average daily gain in pigs. Finally, scanning the genome for runs of homozygosity islands, we found that the two groups have different runs of homozygosity islands, with several candidate genes involved in coat color (in SG) or related to different pig performance traits (in SB). In summary, the two analyzed groups differed for several phenotypic traits, and genes involved in these traits (growth, meat traits and coat color) were detected. This study provided another contribution to the identification of genomic regions involved in phenotypic variability in local pig populations.

Analysis of Genetic Parameters of Carcass Traits and Daily Gain of Native Breed Pigs Raised in Poland

Abstract The aim of the study was to determine genetic parameters of live performance traits in pigs of three native breeds maintained in Poland. As part of the conservation programmes, the Puławska (Puł), Złotnicka White (ZW) and Złotnicka Spotted (ZS) breeds are monitored for productivity based on performance test results of these breeds. The study included 6042 gilts and 2406 boars of the Puławska breed, 866 Złotnicka White gilts, and 903 Złotnicka Spotted gilts. The genetic parameters were estimated separately for each breed, and also separately for sexes in the case of the Puławska breed. The components (co)variance and genetic parameters were estimated using the REML method for the animal model taking into account different combination of fixed and random effects. Convergence of the iterative process was achieved by the selection of AIREML algorithm. The coefficients of genetic and phenotypic correlations between measurements of slaughter traits and daily gain were low for all breed groups. In turn, the relationships between backfat thickness measurements and carcass meat percentage were estimated as high. Only the correlations of slaughter traits with loin eye height were not uniform for the analysed breed groups. The coefficients of heritability (h2) were high and intermediate for all breeds and sexes. The highest heritability coefficients were obtained for daily gain (0.58 in ZW to 0.80 in Puł gilts), followed by backfat thickness (0.37 in Puł gilts to 0.64 in ZW) and carcass meat percentage (0.40 in ZS to 0.56 in ZW). The lowest coefficients were obtained for loin eye height (0.24 in Puł boars to 0.40 in ZW). The estimated genetic parameters could be used to verify selection indices of the breeds included in the genetic resources conservation programmes.

English

Data from fifty-four pigs: twenty-five Duroc, twenty-one Large White and eight crosses of Duroc and Large White (Hybrid) were used to quantify and mathematically describe the performance traits of pigs. The aim of this study was to investigate the effects of genotype, sex and their interaction on the performance characteristics of three pig genotypes. The pigs were 30 kg of body weight and 70 days of age at the beginning of the study. Records for body weight (BW), body length (BL), feed intake (FI), feed conversion ratio (FCR), rump and back fat thickness, trunk length(TRL), height at withers (HW), chest girth (CG),tail length (TL), shoulder to tail length (STL) were used for the analysis. The results of the least squares means analysis on the performance traits showed that genotype and sex were important sources of variation for traits such as feed intake (FI), feed conversion ratio (FCR), rump and back fat thickness. Also, the linear body traits namely; body weight (BW), body length (BL), trunk length (TRL), height at withers (HW), chest girth (CG), tail length(TL) and shoulder to tail length (STL) were significantly (P<0.05) influenced by genotype and sex. The male sex and the hybrid had better performance traits at various stages. Key words: Pig, genotype, sex, hybrid, duroc, Large White. &nbsp

Polymorphisms of the porcine cathepsins, growth hormone-releasing hormone and leptin receptor genes and their association with meat quality traits in Ukrainian Large White breed.

Cathepsins, growth hormone-releasing hormone (GHRH) and leptin receptor (LEPR) genes have been receiving increasing attention as potential markers for meat quality and pig performance traits. This study investigated the allele variants in four cathepsin genes (CTSB, CTSK, CTSL, CTSS), GHRH and LEPR in pure-bred Ukrainian Large White pigs and evaluated effects of the allele variants on meat quality characteristics. The study was conducted on 72 pigs. Genotyping was performed using PCR–RFLP technique. Meat quality characteristics analysed were intramuscular fat content, tenderness, total water content, ultimate pH, crude protein and ashes. A medium level of heterozygosity values was established for GHRH and LEPR genes which corresponded to very high levels of informativeness indexes. Cathepsins CTSL, CTSB and CTSK had a low level of heterozygosity, and CTSS did not segregate in this breed. Association studies established that intramuscular fat content and tenderness were affected by the allele variance in GHRH and LEPR but not by CTSB and CTSL genes. The GHRH results could be particularly relevant for the production of lean prime cuts as the A allele is associated with both, a lower meat fat content and better tenderness values, which are two attributes highly regarded by consumers. Results of this study suggest that selective breeding towards GHRH/AA genotype would be particularly useful for improving meat quality characteristics in the production systems involving lean Large White lines, which typically have less than 2 % intramuscular fat content.

A genome-wide linkage analysis for reproductive traits in F2 Large White × Meishan cross gilts.

Female reproductive performance traits in pigs have low heritabilities thus limiting improvement through traditional selective breeding programmes. However, there is substantial genetic variation found between pig breeds with the Chinese Meishan being one of the most prolific pig breeds known. In this study, three cohorts of Large White × Meishan F2 cross-bred pigs were analysed to identify quantitative trait loci (QTL) with effects on reproductive traits, including ovulation rate, teat number, litter size, total born alive and prenatal survival. A total of 307 individuals were genotyped for 174 genetic markers across the genome. The genome-wide analysis of the trait-recorded F2 gilts in their first parity/litter revealed one QTL for teat number significant at the genome level and a total of 12 QTL, which are significant at the chromosome-wide level, for: litter size (three QTL), total born alive (two QTL), ovulation rate (four QTL), prenatal survival (one QTL) and teat number (two QTL). Further support for eight of these QTL is provided by results from other studies. Four of these 12 QTL were mapped for the first time in this study: on SSC15 for ovulation rate and on SSC18 for teat number, ovulation rate and litter size.

Parent-of-origin effects cause genetic variation in pig performance traits

In order to assess the relative importance of genomic imprinting for the genetic variation of traits economically relevant for pork production, a data set containing 21 209 records from Large White pigs was analysed. A total of 33 traits for growth, carcass composition and meat quality were investigated. All traits were recorded between 1997 and 2006 at a test station in Switzerland and the pedigree included 15 747 ancestors. A model with two genetic effects for each animal was applied: the first corresponds to a paternal and the second to a maternal expression pattern of imprinted genes. The imprinting variance was estimated as the sum of both corresponding genetic variances per animal minus twice the covariance. The null hypothesis of no imprinting was tested by a restricted maximum likelihood ratio test with two degrees of freedom. Genomic imprinting significantly contributed to the genetic variance of 19 traits. The proportion of the total additive genetic variance that could be attributed to genomic imprinting was of the order between 5% and 19%.

Pharmacological analyses of two naturally occurring porcine melanocortin-4 receptor mutations in domestic pigs

The melanocortin-4 receptor (MC4R) is critical in regulating mammalian food intake and energy expenditure. Numerous mutations in the MC4R gene have been identified from obese humans. So far two naturally occurring porcine MC4R (pMC4R) mutations, D298N and R236H, have been identified from various strains of pigs and D298N is being utilized as a genetic marker to screen performance traits of pigs. In this study, we performed functional analyses of pMC4R D298N and R236H, including their ligand binding and signaling properties in transiently transfected HEK293T cells. Ligand binding assays showed that both D298N and R236H pMC4Rs had similar binding capacities and affinities for the natural agonist α-MSH and the natural antagonist Agouti-related protein as wild-type pMC4R. In signaling assays, both mutants had normal EC50 and maximal signaling to α-MSH. In summary, pMC4R mutants D298N and R236H do not have any overt functional defects; therefore we suggest caution using these mutations as selection markers in breeding programs.

The novel polymorphism of the beta 3‐adrenergic receptor gene and its distribution in domestic pigs and wild boars in Asia

ABSTRACTThe beta 3‐adrenergic receptor (ADRB3) is a G protein‐coupled receptor that is involved in regulating energy homeostasis. We have studied DNA sequences of porcine ADRB3 to find candidate genetic polymorphisms for economically important growth and performance traits in pigs. Five novel haplotypes derived from the three In/dels and 44 SNPs were identified among domestic pigs and wild boars. Three of them encode non‐synonymous amino acid sequences by five missense polymorphisms and a frameshift by a thymine insertion. The amino acid polymorphic sites were distributed as follows: one substitution was in extracellular loop 1, three substitutions were in intracellular loop3 and one substitution and the deletion of two amino acids were at the carboxyl‐terminal. There was no polymorphism in the transmembrane domains. In addition, we surveyed the allelic frequency of the thymine insertion that cause frameshift in South‐east Asian local pigs, including some commercial breeds and wild boars. This thymine insertion was distributed widely in the domestic pigs and wild boars. The frequencies of this allele were relatively low in Western improved breeds, while they were very common in Asian breeds and wild boars in Asia. This result indicates that this insertion originally occurred in ancient Asian wild boars and then circulated among Asian domestic pigs. This allele also spread over Western breeds, probably through the introgression of Asian pigs into European stocks during the 18th and 19th centuries.

SNaPshot Minisequencing and a Panel of Candidate Genes for Complex Routine Testing of Meat Performance Traits in Pigs

The aim of the study was to introduce a convenient method for identification of differences among individual animals in genes supposed to influence meat performance in pigs. The set of seven candidate genes (IGF2, FOS, MC4R, DGAT1, MYF4, MYF, and MC3R) was used. To determine the genotypes, multiplex polymerase chain reaction (PCR) and minisequencing using SNaPshot system (Applied Biosystems; Forster City, CA, USA) were applied. The efficiency of this gene panel for routine testing in pigs was verified in the Black Pied Přeštice pig breed by the statistical general linear model. The results showed that both the method and the gene panel are convenient for meat quality testing and offer reproducible results.

Heat and social rank impact behavior and physiology of PRRS-virus-infected pigs

Changes in thermal environment can invoke a stress response in pigs, which in turn can potentially impact their immune system and disease susceptibility. We investigated effects of heat stress and social rank on behavior, immune responsiveness, and performance of pigs challenged with porcine reproductive and respiratory syndrome (PRRS) virus. Sixty-four 7-week-old PRRS-naïve pigs were assigned to each of four experimental treatments consisting of a 2 × 2 factorial design: PRRS (PRRS− or PRRS+) and environmental temperature (24 °C or 32 °C). Blood samples were taken prior to and at days 7 and 14 post-inoculation, and alveolar macrophages were collected via bronchoalveolar lavage at day 14. Total white blood cell counts, natural killer cytotoxicity, macrophage numbers, macrophage subpopulations, and performance measures were all significantly affected by social rank, heat stress, and/or infection status of the pig. Heat stress and PRRS status also significantly influenced the amount of time pigs spent lying with or without contacting another animal. Cortisol and various immune measures were also affected by PRRS status. These results show not only that intranasal inoculation with PRRS virus affects physiological, behavioral, and performance measures in growing pigs, but that social rank influences pigs' immune responsiveness to PRRS as well. Moreover, heat stress does not have additive negative impact on physiological or performance traits in pigs challenged with PRRS virus.

Polymorphism of Insulin-like Growth Factor 1 Receptor Gene in 12 Pig Breeds and Its Relationship with Pig Performance Traits

The polymorphism of insulin-like growth factor I receptor (IGFIR) gene in 12 pig breeds (total n = 593) was detected by PCR-SacII-restriction fragment length polymorphism and allele A (379 bp) or allele B (235 bp and 144 bp) observed. In the studied breeds, it was found that European pigs principally carried allele A, while Chinese native pig breeds principally carried allele B. In addition, the role of pig IGFIR was investigated in 156 Wanbai pigs and 212 Large Yorkshire pigs. Growth related variables including body weight at birth, 2-, 4- and 6-mo of age and backfat thickness and lean percentage estimated by ultrasonography at 6-mo of age were recorded in analyzing the association between IGFIR gene polymorphism and growth traits. AA-genotype pigs exhibited greater (p<0.05) body weights (BW) at birth, 2- and 6- mo of age, but not at 4-mo of age, than those of the BB-genotype in Wanbai and Yorkshire breeds. Moreover, in the Yorkshire breed, AA-genotype pigs had less backfat thickness (p<0.05) and greater lean percentage (p<0.01) than the BB genotyped Based on these results, it is necessary to do more studies on IGFIR before introducing the IGFIR locus into breeding programs.

A QTL affecting daily feed intake maps to Chromosome 2 in pigs

Our understanding of the molecular genetic basis of several key performance traits in pigs has been significantly advanced through the quantitative trait loci (QTL) mapping approach. However, in contrast to growth and fatness traits, the genetic basis of feed intake traits has rarely been investigated through QTL mapping. Since feed intake is an important component of efficient pig production, the identification of QTL affecting feed intake may lead to the identification of genetic markers that can be used in selection programs. In this study a QTL analysis for feed intake, feeding behavior, and growth traits was performed in an F2 population derived from a cross between Chinese Meishan and European Large White pigs. A QTL with a significant effect on daily feed intake (DFI) was identified on Sus scrofa Chromosome 2 (SSC2). A number of suggestive QTL with effects on daily gain, feed conversion, and feeding behavior traits were also located. The significant QTL lies close to a previously identified mutation in the insulin-like growth factor 2 gene (IGF2) that affects carcass composition traits, although the IGF2 mutation is not segregating in the populations analyzed in the current study. Therefore, a distinct causal variant may exist on the P arm of SSC2 with an effect on feed intake.

Glufosinate herbicide-tolerant (LibertyLink) rice vs. conventional rice in diets for growing-finishing swine1,2

Genetically modified (GM) rice (LibertyLink, event LLRICE62) that is tolerant to glufosinate ammonium (Liberty) herbicide was compared with a near-isogenic (NI) conventional medium-grain brown rice (cultivar, Bengal) and a commercially milled long-grain brown rice in diets for growing-finishing pigs. The GM and NI rice were grown in 2000. The GM rice was from fields treated (GM+) or not treated (GM-) with glufosinate herbicide. The GM- and NI rice were grown using herbicide regimens typical of southern United States rice production practices. The four rice grains were similar in composition. Growing-finishing pigs (n = 96) were fed fortified rice-soybean meal diets containing the four different rice grains from 25 to 106 kg BW. Diets contained 0.99% lysine initially (growing phase), with lysine decreased to 0.80% (early finishing phase) and 0.65% (late finishing phase), when pigs reached 51 and 77 kg, respectively. The percentage of rice in the four diets was constant during each of the three phases (72.8, 80.0, and 85.8% for the growing, early-finishing, and late-finishing phases, respectively). There were six pen replicates (three pens of barrows and three pens of gilts) and four pigs per pen for each dietary treatment. All pigs were slaughtered at the termination of the study to collect carcass data. At the end of the 98-d experiment, BW gain, feed intake (as-fed basis), and feed:gain ratio did not differ (P > 0.05) for pigs fed the GM+ vs. conventional rice diets, but growth performance traits of pigs fed the GM+ rice diets were superior (P < 0.05) to those of pigs fed the GM- rice diet (ADG = 0.86, 0.79, 0.81, and 0.85 kg/d; ADFI = 2.41, 2.49, 2.37, and 2.45 kg/d; feed:gain = 2.80, 3.17, 2.95, and 2.89 for GM+, GM-, NI, and commercially milled rice, respectively). Carcass traits (adjusted for final BW) did not differ (P = 0.10) among treatments (hot carcass yield = 73.5, 72.6, 72.6, and 73.2%; 10th-rib backfat = 23.0, 22.7, 21.3, and 23.8 mm; LM area = 38.6, 38.0, 38.2, and 38.1 cm(2); carcass fat-free lean = 50.5, 50.5, 51.2, and 50.0%). Gilts grew slower (P < 0.05) and were leaner (P < 0.05) than barrows. Responses to type of rice did not differ between barrows and gilts, with no evidence of a diet x gender interaction (P = 0.50) for any trait. The results indicate that the glufosinate herbicide-tolerant rice was similar in composition and nutritional value to conventional rice for growing-finishing pigs.

Growth hormone gene polymorphisms and growth performance traits in duroc, Landrace and Tao-Yuan Pigs

This study investigated the restriction fragment length polymorphism (RFLP) of the porcine growth hormone (pGH) gene in Duroc, Landrace, and Tao-Yuan pigs and its effects on growth performance and levels of plasma growth hormone in peripheral circulation. Genomic DNA extracted from 81 Tao-Yuan, 60 Landrace and 48 Duroc pigs were subjected to Southern blot hybridization with a pGH cDNA probe. Polymorphism was detected with the restriction enzymes TaqI and DraI. A comparison of these three breeds showed significant differences in allelic frequencies. Blood samples for radioimmunoassay (RIA) of GH were collected biweekly during the experimental period from pigs 12 to 40 weeks of age. Tao-Yuan pigs showed a mean plasma GH level (2.51 ± 1.23 ng/mL) that was much lower than that of the Landrace (3.80 ± 1.52 ng/mL) and Duroc (4.20 ± 1.03 ng/mL) pigs (P< 0.05). Moreover, the Tao-Yuan pigs also showed poorer growth performance than the Landrace and the Duroc pigs both in the daily weight gain (0.37 ± 0.06 vs 0.67 ± 0.05 and 0.70 ± 0.05 kg/day, P< 0.01) and feed efficiency (3.12 ± 0.28 vs. 2.60 ± 0.14 and 2.52 ± 0.12, P< 0.05). These results suggest that the growth performance trait in these pigs is highly correlated with their growth hormone genotype.

Effect of genetic variants of the heart fatty acid-binding protein gene on intramuscular fat and performance traits in pigs.

In order to find genetic markers to improve the meat quality of pigs by breeding we studied the relationship between variation in the heart fatty acid-binding protein (H-FABP) gene (FABP3) and intramuscular fat (IMF) content. To estimate the effect of H-FABP, pigs from two Duroc populations were selectively mated in such a way that at least two genotypes were present in each litter. In total, data from 983 pigs and pedigree information from three preceding generations were analyzed. Offspring were tested for IMF content as well as backfat thickness (BFT), BW, and drip loss of the meat (DRIP). All pigs were assigned to H-FABP RFLP genotype classes either by the assessed genotype (75%) or based on a probability score determined according to genotypic information of their relatives (25%). Contrasts were detected between homozygous H-FABP RFLP genotype classes for IMF content (.4%, P < .05), BFT (.6 mm, P < .01), and BW (2.4 kg, P < .10). No significant contrasts were detected for DRIP. Results for IMF content, BFT, and BW were confirmed when only genotyped animals were analyzed. Variation in BFT partially explained the effect on IMF content. Although other closely linked genes on porcine chromosome 6 might be responsible for the observed effect, interference of the halothane gene was excluded because all parental animals were noncarriers. In conclusion, H-FABP RFLP can be used as markers to select for increased IMF content and growth in breeding programs.