Loin Eye Muscle Research Articles

Genome-wide mapping and identification of new quantitative trait loci affecting meat production, meat quality, and carcass traits within a Duroc purebred population1

Most QTL detection studies in pigs have been carried out in experimental F(2) populations. However, segregation of a QTL must be confirmed within a purebred population for successful implementation of marker-assisted selection. Previously, QTL for meat quality and carcass traits were detected on SSC 7 in a Duroc purebred population. The objectives of the present study were to carry out a whole-genome QTL analysis (except for SSC 7) for meat production, meat quality, and carcass traits and to confirm the presence of segregating QTL in a Duroc purebred population. One thousand and four Duroc pigs were studied from base to seventh generation; the pigs comprised 1 closed population of a complex multigenerational pedigree such that all individuals were related. The pigs were evaluated for 6 growth traits, 7 body size traits, 8 carcass traits, 2 physiological traits, and 11 meat quality traits, and the number of pigs with phenotypes ranged from 421 to 953. A total of 119 markers were genotyped and then used for QTL analysis. We utilized a pedigree-based, multipoint variance components approach to test for linkage between QTL and the phenotypic values using a maximum likelihood method; the logarithm of odds score and QTL genotypic heritability were estimated. A total of 42 QTL with suggestive linkages and 3 QTL with significant linkages for 26 traits were detected. These included selection traits such as daily BW gain, backfat thickness, loin eye muscle area, and intramuscular fat content as well as correlated traits such as body size and meat quality traits. The present study disclosed QTL affecting growth, body size, and carcass, physiological, and meat quality traits in a Duroc purebred population.

Association of an SNP marker in exon 24 of a class 3 phosphoinositide‐3‐kinase (PIK3C3) gene with production traits in Duroc pigs

A C↔T single nucleotide polymorphism (SNP) on exon 24 of the porcine class 3 phosphoinositide-3-kinase (PIK3C3) gene is considered a possible genetic marker for selecting backfat (BF) thickness and carcass fat, although only one study has published results on its effects by performing experiments on a single resource family. We analyzed the association of this PIK3C3 polymorphism with production traits in 739 Duroc pigs. The C allele frequency was 67.9% in our study population. PIK3C3 polymorphism showed significant effects on average daily weight gain (ADG), BF thickness, intermuscular fat content (IMF), and the size of the loin eye muscle area (EMA). The C alleles increased ADG, BF and IMF, and decreased EMA. The predicted differences in traits between the homozygous pigs of the C and T alleles were 40 g/day for DG, 1.2 mm for BF, 0.44% for IMF, and 1.6 cm(2) for EMA. Furthermore, the statistical models for estimating the breeding values of each trait had lower Akaike's information criterion values when adding PIK3C3 genotype information. We therefore confirmed that the polymorphism in PIK3C3 (C2604T) has the potential to be a genetic marker for production traits in Duroc pigs.

한우보증씨수소 선발지수 개선에 관한 연구

본 연구를 통하여 도체성적에 대한 경제적 가치를 산출하고 이를 토대로 새로운 한우 보증씨수소 선발지수를 제안하였다. 선발지수는 경제적으로 중요한 형질에 필요한 만큼의 가중치를 주어 개체를 효과적으로 선발하는 데 도움을 주는 강력한 도구로써 농장에서 일어나는 수입과 지출을 고려하여 선발지수를 산출할 수 있다. 최근에는 이러한 선발지수를 농장에서 자기 농장에 알맞게 개발할 수있도록 인터넷을 통하여 서비스를 제공하고 있다 (Lazenby 등. 1998). 그러나 우리나라는 조수입의 산출은 가능하지만 경비를 정확히 산출할 수 있는 농가가 드물기 때문에 아직 농가차원에서 적절한 선발지수를 만들어 사용하는 것은 어려운 것으로 보인다. 또한 이러한 이유로 인하여 한우 보증씨수소를 선발함에 있어 비용부분을 고려하지 못하고 조수익에 의존하여 지수를 만들 수밖에 없는 문제를 안고 있다. 아울러 선발에서 고려할 수 있는 갈비생산량, 등심생산량, 안심생산량, 정육율 등 도체에서 얻을 수 있는 다양한 형질의 개발과 측정이 필요하고, 암소선발을 위해서는 농가의 번식기록을 통해 얻을 수 있는 번식형질에 대한 조사가 이루어져야 미국과 같이 다양한 선발지수를 개발하고 활용 (Greiner, 2006)하여 다양화로 나가는 소비시장에 적절히 대응해 나갈 수 있을 것이다. Hanwoo proven bulls have been selected since 1987 and consequently contributed to farmers for the improvement of beef cattle in Korea. The demand for the quality beef production as well as higher production efficiency was erupted after early 2000 as relatively cheap imported beef released. Therefore the pressure on the reformation of selection index for Hanwoo proven bulls have been piled up to furnish with Hanwoo's competitive. A total of 734 progeny test data were analyzed to select traits and their weights in the selection index to meet the beef market requirement. Regression analysis with stepwise selection method was used to select proper trait and its weight for selection index. A series of computer simulation was carried out to compare the currently using selection index with the alternate two selection indices proposed in this study. New selection index using standardized breeding values of Loin eye Muscle Area (LMA), Backfat Thickness (BFT) and Marbling Score (MS) with weight ratio 1:-1:6 was proposed. Results showed higher performance in improving MS and BFT gain by 22% and 31% still holding 86%~89% of genetic gain achieved by current index in Carcass Weight (CW) and LMA when new selection index was fitted. Because, new index has little consideration for production cost, further research should be performed to build selection index including cost and income simultaneously.

Polymorphism of bovine Y-STR UMN0929 and its correlation with carcass traits in five Chinese beef cattle populations

The correlations between Y chromosome polymorphisms and the carcass traits were studied in five Chinese beef cattle populations by PCR, single strand conformation polymorphism and Y-STR sequence analysis. Nine alleles and their frequencies were identified on Y-STR UMN0929 region in Qinchuan (n=116), Luxi (n=112), Jinnan (n=104) pure breeds, Simmental×Qinchuan crossbred (n=80) and Angus×Qinchuan crossbred (n=96). The most popular A-176 and B-178 alleles were presented in all 5 cattle populations in the range of 12% (Jinnan) to 66% (Simmental×Qinchuan). The allele I-194 presented Luxi and Angus×Qinchuan. In Qinchun cattle, G-190 and E-186 alleles had bigger effect on BPI (4.23±0.32 and 4.22±0.48 kg/cm, P<0.01) and CW (325.40±49.42 and 316.73±45.29 kg, P<0.01), respectively. In Luxi cattle, I-194 allele affected higher BPI (4.08±0.35 kg/cm, P<0.01) and CW (302.07±17.55 kg, P<0.01), respectively. In Jinnan cattle breed, H-192 had higher BPI (4.32±0.50 kg/cm, P<0.05) and CW (327.87±59.37 kg, P<0.05), respectively. In Simmental×Qinchuan cross breed, C-180 allele affected largely on BPI (5.16±0.25 kg/cm, P<0.05) and CW (393.16±25.92 kg, P<0.05). In Angus×Qinchuan cross breed, I-194 had higher BPI (4.43±0.33 kg, P<0.05) and CW (346.63±29.77 kg, P<0.05). Correlations between alleles and other carcass traits (net meat weight, top grade weight, slaughter rate, net meat rate, loin-eye muscle area, carcass length, meet tenderness and shear force) were also analyzed using mixed-effect model. Cattle Y-STR UMN0929 loci alleles and its correlation with carcass traits in beef cattle populations could be implemented into the cattle breeding program for choosing beef cattle with better carcass traits.

An insertion/deletion variant of a thymine base in exon 2 of the porcine beta 3‐adrenergic receptor gene associated with loin eye muscle area

An insertion/deletion variant of a thymine base (T5 and T6) in exon 2 of porcine beta 3-adrenergic receptor (ADRB3) gene has been described. In the current study, we made an association study between the ADRB3 polymorphisms and production traits in 735 Duroc pigs. The allele frequencies for the T5 and T6 alleles in our study population were 0.433 and 0.567, respectively. Any associations between ADRB3 genotype and average daily weight gain during test period, or backfat thickness and intramuscular fat content were not detected in either sex. However the size of the loin eye muscle area (EMA) was significantly associated with ADRB3 genotypes in gilts. T6-homozygous gilts had a higher mean of EMA (40.6 +/- 0.6 cm(2)) than T5-homozygous (38.1 +/- 0.4 cm(2), P = 0.002) and heterozygous (38.8 +/- 0.3 cm(2), P = 0.034) gilts. This association was not detected in males. In addition, a multiple traits animal model best linear unbiased predictor (BLUP) analysis revealed that the T6-homozygous genotype had positive effects on breeding value of EMA. Accordingly, we suggest that ADRB3 polymorphism has the potential to be an important genetic marker for prediction of EMA in Duroc pigs.

Sire and growth-path effects on sheep meat production. 3. Fascicular structure of lamb loin muscle (m. longissimus lumborum) and the impact on eating quality

The effects of sire genetics and growth path on the fascicular structure (FS) of lamb loin muscle (m. longissimus lumborum; LL) and the consequences for eating quality were studied in progeny (n = 299) of 20 Poll Dorset sires and Merino ewes. Sires were selected on the basis of their Australian sheep breeding values (ASBV) for post-weaning growth (PWWT), loin eye muscle depth (PEMD) and subcutaneous fat (PFAT). Growth of lambs was varied by time of weaning (early or late) and by feeding level within weaning group, where lambs were either fully fed throughout or were feed restricted for 55 days then re-alimented to achieve liveweight of ~45 kg at slaughter. The FS variables were determined in differentially stained histological sections of LL by using automated image segmentation and circle geometry methodology and were defined as percentage connective tissue, perimysial seam thickness and fascicular width. Sire ASBV was not a significant covariate to measures of FS, despite ASBV-related effects on growth, carcass leanness and fatness. Independent of weaning time, faster growth was induced by re-alimentation of feed-restricted lambs, resulting in LL with less connective tissue as a percentage of cross-sectional area and larger fascicles than for fully fed peers. The direction of the perimysial seam thickness response varied with treatment and time of weaning. Rapid growth of re-alimented early weaned restricted lambs resulted in thinner seams than for fully fed peers, whereas the opposite response was observed in the late-weaned lamb contrast. This suggests that the weight and age of the lamb at the time of nutritional compromise and re-alimentation are important factors in determining the thickness of perimysial connective-tissue seams. Whilst the evidence confirms differential accretion of the myofibrillar and connective tissues and despite reports of positive effects on tenderness brought about by such changes, variation in structural measures was not associated with variation in either objective measures (compression) or sensory scores for tenderness of the loin muscle. The data from the present study support the tenet that rapid growth before slaughter, combined with appropriate sire genetics, will not compromise the physical characteristics and sensory qualities of the meat.

Effects of Lower Dietary Lysine and Energy Content on Carcass Characteristics and Meat Quality in Growing-finishing Pigs

Fifty-four PIC barrows were used to evaluate the effects of lower dietary lysine content and energy level on carcass characteristics and meat quality in slaughter pigs. Pigs were allotted to one of three treatments by body weight with six replicate pens in each treatment. The dietary treatments for body weights of 20-50 kg, 50-80 kg and 80-90 kg were as follows, respectively: control diet (digestible energy 14.22 MJ/kg, lysine/DE 0.67 g/MJ, 0.53 g/MJ and 0.42 g/MJ); a low lysine group (digestible energy 14.22 MJ/kg, lysine/DE 0.49, 0.38 and 0.30 g/MJ); and a low lysine-low energy group or low nutrient group (digestible energy 13.11 MJ/kg, lysine/DE 0.49, 0.38 and 0.30 g/MJ). The daily weight gain, daily feed intake and feed efficiency were calculated in the overall growth period (nearly 12 weeks). Meanwhile, carcass characteristics and meat quality were evaluated at 60 and 90 kg body weight respectively. During the overall growth trial, lowering dietary lysine and nutrient level both decreased weight gain (p<0.05) and feed efficiency (p<0.01). At 60 kg body weight, decreasing dietary lysine and nutrient level noticeably decreased dressing percentage (p<0.01) and back fat depth at last rib of PIC pigs (p<0.01), but enhanced marbling scores (p<0.10), intramuscular fat content (p<0.10) and water loss rate (p<0.01) of the longissimus dorsi muscle. At 90 kg body weight, lean percentage (p<0.01) was evidently reduced by both lowering lysine content and nutrient level in the diet. However, the shoulder back fat depth (p<0.05) and marbling scores of the loin eye muscle (p<0.05) were increased; Lowering dietary nutrient level could improve back fat depth of 10th rib (p<0.01) and last rib (p<0.01), intramuscular fat content (p<0.10), redness (p<0.01) and water loss rate of the loin eye muscle (p<0.05), but decrease loin area (p<0.05). Finally, when comparing the 60 kg and 90 kg slaughter weights, it was found that the shoulder back fat depth (p<0.01, p<0.10), 6th-7th rib (p<0.01, p<0.01), 10th-rib (p<0.01, p<0.01) and last rib back fat depth (p<0.01, p<0.01) of the low lysine and low nutrient group were all obviously increased comparing with the control group. Taken together, the results showed that decreasing dietary lysine content and nutrient level increased intramuscular fat content and water loss rate of longissimus dorsi muscle; On the other hand, both lowering dietary lysine and nutrient level markedly compensated to increase back fat deposition in the later finishing period (body weight from 60

Características de carcaça de suínos de três linhagens genéticas em diferentes idades ao abate

O objetivo deste trabalho foi estudar as características da carcaça de suínos de diferentes linhagens genéticas, em diferentes idades ao abate. Foram utilizados 88 suínos por linhagem, fêmeas e machos castrados, com idade e peso médio iniciais de 74 dias e 30kg, respectivamente, pertencentes a três linhagens genéticas distintas, designadas de AgroceresPic, Dalland e Seghers. A etapa experimental foi dividida em quatro fases (Crescimento I, Crescimento II, Terminação I e Terminação II). Ao final de cada etapa, foram abatidos 60 animais (10 por linhagem/sexo), para as caracterizações: Peso (PCQ) e Rendimento de Carcaça Quente (RCQ), Área de Olho de Lombo (AOL) e Espessura de Toucinho (ET). Na análise dos resultados foi utilizado um delineamento inteiramente casualizado com desdobramento dos graus de liberdade em esquema fatorial 4 x 3 x 2, sendo quatro idades ao abate (90, 119, 150 e 186 dias), três linhagens (AgroceresPic, Dalland e Seghers) e dois sexos (fêmea e macho castrado), com 10 repetições por tratamento, sendo utilizado o pacote PROC MIXED do Softwear SAS. Os valores médios de peso vivo apresentaram diferença entre as linhagens e interação entre fase e linhagem (P&lt;0,05). Os valores médios das demais variáveis estudadas apresentaram diferença e a interação (P&lt;0,05) entre fase, linhagem e sexo, sendo que de maneira geral as principais diferenças ocorreram a partir da fase de Terminação I, em que as fêmeas das linhagens AgroceresPic e Dalland apresentaram melhores resultados (P&lt;0,05) de RCQ (80,4 e 80,7%, respectivamente) em comparação com os machos (78,8 e 78,7%, respectivamente) e além disso as fêmeas Dalland apresentaram valores superiores (P&lt;0,01) de AOL e ET (45,7cm² e 11,4mm x 38,3cm² e 18,3mm). Conclui-se que as linhagens genéticas avaliadas apresentaram características de carcaça muito interessantes para o mercado atual e que as fêmeas suínas podem ser utilizadas em programas que visem o abate de animais mais pesados.

Relationship between myosin heavy chain isoform expression and muscling in several diverse pig breeds1

The objective of this study was to examine the relationship of the relative abundance of transcripts of myosin heavy chain (MyHC) isoforms and muscling in several diverse pig breeds. The animals used were from 3 pure breeds (Pietrain, Duroc, and Mongcai) and 2 crosses [Duroc x Pietrain (DUPI) and Duroc x Berlin Miniature pigs (DUMI)]. Real-time PCR quantification of MyHC isoforms I, IIa, IIx, and IIb showed that the relative expression of MyHC IIb was greater in pigs with large LM areas in both DUPI (69.6 vs. 53.0%) and DUMI (60.5 vs. 47.5%). In DUPI, similar transcript levels of MyHC I were found in both large and small LM (14.7 and 15.2%), whereas in DUMI animals, these values were 18.4 and 33.5% (P < 0.05). The groups of animals with large and small LM area in the DUPI also tended to differ in MyHC IIa and IIx transcripts. The comparison among different breeds confirmed the trend of high MyHC IIb transcript abundance together with high muscularity. In Pietrain, Duroc, DUPI, and DUMI, MyHC IIb accounted for more than half of the MyHC transcripts (65.4, 59.7, 54.0, and 54.0%). Mongcai showed low MyHC IIb (11.4%) but high type I, IIa, and IIx relative RNA levels (24.1, 28.5, and 35.9%). Frequencies of fibers, determined by muscle fiber staining with ATPase, and relative abundance of MyHC isoforms, determined by quantitative reverse transcription-PCR, of corresponding pairs of type I, IIa, and IIx/ IIb were correlated (r = 0.71, 0.67, and 0.52, respectively). The study demonstrates that MyHC IIb fibers are the most prominent in pigs having large LM area and implies that MyHC IIb is the determining fiber contributing to the differentiation of large and small loin eye muscle area in the pig.

Comparing pivotal and REML-based confidence intervals for heritability

Heritability quantifies the extent to which a physical characteristic is passed from one generation to the next. From a statistical perspective, heritability is the proportion of the phenotypic variance attributable to (additive) genetic effects and is equal to a function of variance components in linear mixed models. Relying on normal distribution assumptions, one can compute exact confidence intervals for heritability using a pivotal quantity procedure. Alternatively, large-sample properties of the restricted maximum likelihood (REML) estimator can be used to construct asymptotic confidence intervals for heritability. Exact and asymptotic intervals are compared loineye muscle area measurements and balanced one-way random effects models having groups of correlated responses. In some cases the two interval methods yield vastly different results and the REML-based confidence interval does not maintain the nomiral coverate value even for seemingly large sample sizes. For finite sample size applications, the validity of the REML-based procedure depends on the correlation structure of the data.

RAÇÕES CONTENDO MILHETO OU SORGO E COM SUPLEMENTAÇÃO DE AMINOÁCIDOS PARA SUÍNOS EM TERMINAÇÃO

O experimento foi realizado no Departamento de Zootecnia da Universidade Federal de Lavraspara avaliar a influência de rações contendo milheto ou sorgo, suplementadas com aminoácidos, nodesempenho e características de carcaça de suínos em terminação. Utilizaram-se 27 suínos machoscastrados com peso vivo médio de 69,0 ± 2,8 kg que foram alojados individualmente em baias de concreto. Odelineamento experimental utilizado foi o inteiramente ao acaso com três tratamentos (T1 - Ração controle:formulada à base de milho e farelo de soja; T2 – Ração milheto: formulada com milheto e L-lisina; T3 – Raçãosorgo: formulada com sorgo, L-lisina e L-treonina.). Em todos os tratamentos as rações foram suplementadascom minerais e vitaminas. Os suínos das rações controle apresentaram maior (P&lt;0,05) peso final, consumomédio de ração, ganho médio de peso e melhor conversão alimentar (P&lt;0,05) quando comparados aosanimais que consumiram a ração com sorgo. Não houve diferenças (P&gt;0,05) na área de olho do lombo e pesodo pernil entre os tratamentos. O grupo de animais consumindo a ração contendo sorgo apresentou menor(P&lt;0,05) espessura de toucinho em relação aos animais das rações controle e milheto, que por sua vez foramsemelhantes (P&gt;0,05) entre si. Conclui-se que rações formuladas exclusivamente com milheto ou sorgo esuplementadas com aminoácidos reduzem o desempenho de suínosemterminação, embora a ração contendosorgo, L-lisina e L-treonina pode ser utilizada para reduzir a gordura da carcaça.

Genetic parameters for feed efficiency traits and their relationships with growth and carcass traits in Duroc pigs

Genetic parameters for feed efficiency traits of 380 boars and growth and carcass traits of 1642 pigs (380 boars, 868 gilts and 394 barrows) in seven generations of Duroc population were estimated. Feed efficiency traits included the feed conversion ratio (FCR), and nutritional (RFI(nut)), phenotypic (RFI(phe)) and genetic (RFI(gen)) residual feed intake. Growth and carcass traits were the age to reach 105-kg body weight (A105), loin eye muscle area (EMA), backfat (BF), intra-muscular fat (IMF) and meat tenderness. The mean values for RFI(phe) and RFI(gen) were close to zero and for RFI(nut) was negative. All the measures of feed efficiency were moderately heritable (h(2) = 0.31, 0.38, 0.40 and 0.27 for RFI(nut), RFI(phe), RFI(gen) and FCR respectively). The heritabilities for all growth and carcass traits were moderate (ranged from 0.37 to 0.45), except for BF, which was high (0.72). The genetic correlations of RFI(phe) and RFI(gen) with A105 were positive and high. Measures of RFI were correlated negatively with EMA. BF was more strongly correlated with measures of RFI (r(g) > or = 0.73) than with FCR (r(g) = 0.52). Selection for daily gain, EMA, BF and IMF caused favourable genetic changes in feed efficiency traits. Results of this study indicate that selection against either RFI(phe) or RFI(gen) would give a similar correlated response in carcass traits.

Effects of Heart Fatty Acid-binding Protein Genotype on Intramuscular Fat Content in Duroc Pigs Selected for Meat Production and Meat Quality Traits

Using multi-trait animal model BLUP, selection was conducted over seven generations for growth rate (DG), real-time ultrasound loin-eye muscle area (LEA), backfat thickness (BF), and intramuscular fat content (IMF) to develop a new line of purebred Duroc pigs with enhanced meat production and meat quality. This study was intended to investigate the relationship between restriction fragment length polymorphism (RFLP) of a heart fatty acid-binding protein (H-FABP) gene and intramuscular fat content (IMF) of this Duroc purebred population. The present experiment examined the RFLP of 499 slaughtered pigs. The DNA was separated from the blood or ear tissue of the pigs, which were slaughtered at 105 kg of body weight. Intramuscular fat content of the longissimus muscle was measured using chemical analysis. A significant difference was detected in the breeding value of IMF among the H-FABP PCR RFLP genotypes. The AA genotype has a significantly larger positive effect on the IMF breeding value than do the Aa and aa genotypes for the MspI RFLP. In addition, the DD genotype has a significantly greater positive effect on IMF breeding value than the Dd and dd genotypes for the HaeIII RFLP. For the HinfI RFLP, the hh genotype has a significantly larger positive effect on IMF breeding value than the HH genotype. Multiple regression analysis was performed using the IMF breeding values as the dependent variable and the three H-FABP genotypes as independent variables. Results revealed that the contribution of the genotypes to variation in IMF breeding values was approximately 40%. These results demonstrated that H-FABP RFLPs affect IMF in this Duroc population.

한우의 성장 및 도체형질에 대한 유전모수 추정

ABSTRACT This study was conducted to investigate the genetic correlations among the traits used to select young bulls and proven bulls in Hanwoo Performance and Progeny Test Program in Korea. For the estimation of heritabilities and correlations among the growth traits of bulls and carcass traits of progeny steers, 2,532 records of performance tested bull calves and 1,819 records of progeny tested steers were collected from Livestock Improvement Main Center (LIMC), National Agricultural Cooperative Federation (NACF). Fixed effects of mixed model for each traits were selected by using stepwise regression analysis and prior values of variance components were estimated by MTDFREML. The prior values of variance components were estimated with pairwise 2 traits model followed by single trait analysis. The estimated heritability of backfat thickness(BF), dressing percentage(DP), loin-eye muscle area(LMA), marbling score(MS) and weight at 12 months(WT12) was 0.51, 0.32, 0.27, 0.33, 0.50 and 0.26, respectively. Genetic correlation of WT12 of bull calves with backfat thickness, carcass weight and loin-eye muscle area of steers was positive correlation as 0.05, 0.35 and 0.21, respectively. However genetic correlation of WT12 with DP and MS showed negative correlation as 󰠏0.09 and 󰠏0.27, respectively and these negative genetic correlations implies that bulls that may be superior in carcass traits can be lost at the first step of selection and current selection method should be modified to solve this problem.(

Genetic Parameter Estimation of Carcass Traits of Duroc Predicted Using Ultrasound Scanning Modes

A total of 6,804 records for Duroc breed were collected from three farms registered at the Korean Animal Improvement Association (KAIA) from 1998 to 2004 of which both records from two ultrasound modes (A and B) were analyzed to estimate the variance components of carcass traits. Three carcass traits backfat thickness (bf), loin eye muscle area (Ima) and lean meat percentage (Imp) were measured. These traits were analyzed separately as bfl, Imal and lmp1 for ultrasound mode A and bf2, lma2 and lmp2 for ultrasound mode B with multiple trait animal model by using MTDFREML (Boldman et al., 1993). All the traits revealed medium heritability values. Estimated heritabilities for bfl, bf2, Imal, lma2, lmp1 and lmp2 were 0.45, 0.39, 0.32, 0.25, 0.28 and 0.39, respectively. Estimated genetic correlations for traits bfl and bf2, Imal and lma2, Impi and lmp2 were positive but low. Specifically, genetic correlations between bfl and bf2 was 0.30 while the estimates for lean traits between Imal and lma2 and between Impi and lmp2 were 0.15 and 0.18, respectively. Conversely, high negative genetic correlations existed between bfl and the lean traits lma2, lmp2. Likewise, the estimated genetic correlations between Imal and lma2 and Impi and lmp2 were low.

Cloning and analysis of differentially expressed ESTs in swine muscle tissue

The obvious difference in muscle growth and meat quality traits exists between Chinese indigenous pig and exotic pigs. In order to study the reason of these phenotypic differences and search the potential gene related to growth and meat quality traits, silver-stained mRNA differential display technique was used to detect the difference with mRNA of loin-eye muscle tissue from maturity pigs of Lantang in Guangdong Province and Large Yorkshire. One of the newly discovered expressed sequence tag (ESTsp3) was analyzed by using bioinformatic technique. The results showed: (1) nearly 2000 cDNA fragments were detected with 30 primer pairs, and 6 differentially expressed ESTs in the loin-eye muscle tissues from the two breeds were isolated and obtained. The differential fragments were cloned and sequenced. The all sequences were recorded in the GenBank. (2) The 786 bp fragment of ESTsp3 was obtained with in silico elongation system, the ORF analysis revealed that it existed as an 83 aa complete open reading frame, and the elongation sequences were verified by RT-PCR. The analysis of in silico expression profile showed that ESTsp3 is expressed in various growth stages and in most tissues and organs, such as soft tissue, skin, skeletal muscle and kidney, but with variant expression quantity.

Comparative Feeding Values of Soybean Hulls and Wheat Bran for Growing and Finishing Swine

Feeding values of soybean hulls (SH) were compared to those of wheat bran (WB) for swine diets by chemical compositions, a digestion trial, a preference test by self-selection, and two feeding trials. The SH and the WB appeared to have, on air- dry basis, 11.1 vs. 15.4% CP, 32.5 vs. 8.7% crude fiber (CF), 36.8 vs. 10.7% ADF, 0.6 vs. 0.1% Ca, and 492 vs. 92 ppm Fe, respectively. Lysine and total sulfur-containing amino acids in the SH were 0.66 vs. 0.37%, respectively. Apparent digestibility values of the SH were 71% for dry matter, 50% for CP, and 74% for CF. Apparent digestible energy and MEn values of the SH were 2,420 and 2,370 kcal kg -1 , respectively, which were comparable to those of the WB, 2,420 and 2,275 kcal kg -1 (NRC, 1998), respectively. The first feeding trial was conducted with 72 crossbred growing pigs with an average weight of 29.6 kg. The pigs when fed the diets containing 0, 6 and 10% SH by replacing the WB on a weight basis for 42 days did not show significant differences in body weight gain and feed/gain ratio among the treatments. The same trends were observed in the second trial with 60 crossbred finishing pigs with an average weight of 64.5 kg when fed the diets containing 12% SH or WB for 41 days. Back-fat thickness and adjusted loin eye muscle area of the finisher pigs were also not significantly different between the two groups. When allowed to self-select from two different feed troughs containing 10% SH or WB for two weeks, two groups of 80 pigs with 10 pigs per pen consumed the two diets exactly in equal proportion. In conclusion, the soybean hulls can be included up to 10 and 12% for growing or finishing pig diets, respectively, replacing the wheat bran on a weight basis without any adverse effects on palatability of diets and animal performances. (Asian-Aust. J. Anim. Sci. 2005. Vol 18, No. 6 : 861- 867)

Selection for daily gain, loin-eye area, backfat thickness and intramuscular fat based on desired gains over seven generations of Duroc pigs

To develop an excellent line of Duroc breed in performance traits and meat quality traits, selection of that breed was conducted over seven generations for growth rate (DG), real-time ultrasound loin eye muscle area (EM), backfat thickness (BF), and intramuscular fat content (IMF) based on desired gains. Those performance traits were measured in 1646 pigs. Meat quality traits were measured in 547 pigs. Meat quality traits were IMF and tenderness (TEND) in M. longissimus that was taken two sections above the last rib and measured 24 h after slaughter. Selection was based on a selection index method that included four traits at the first and second generations of selection: DG, EM, BF, and IMF. After the third generation, EBVs for four traits were obtained from analyses of performance and meat quality data. Respective heritability estimates for DG, EM, BF, IMF, and TEND were 0.48, 0.45, 0.72, 0.46, and 0.45. The IMF was correlated positively with DG (genetic correlation r G: 0.23, phenotypic correlation r P: 0.07) and BF ( r G: 0.24, r P: 0.21); it was correlated negatively with EM ( r G: − 0.24, r P: − 0.24). Selection and correlated responses were estimated from predicted breeding values using genetic parameters derived from multivariate REML analysis. Those responses corresponded well with DG and IMF.

Genetic correlation between serum insulin-like growth factor-1 concentration and performance and meat quality traits in Duroc pigs.

This study was intended to examine whether serum IGF-I concentration is appropriate for use as a physiological predictor for genetic improvement of meat production and meat quality traits in pigs. Heritabilities and genetic correlations were estimated for these traits. The Duroc breed used in this study was selected for seven generations for average daily BW gain (DG) from 30 to 105 kg of BW, loin-eye muscle area (EM), backfat thickness (BF), and intramuscular fat (IMF) content. Serum IGF-I concentration of boars and gilts at the fourth generation of selection and that of boars, gilts, and barrows from the fifth to seventh generations of selection were measured at 8 wk (IGFI-8W) for 832 animals and again at the time they reached 105 kg of BW (IGFI-105KG) for 834 animals. A multivariate REML procedure was used to estimate genetic parameters with a model incorporating generation of selection, sex, common environmental effect of litter, and individual additive genetic effects. Heritability estimates for IGFI-8W and IGFI-105KG were 0.23 +/- 0.02 and 0.26 +/- 0.03, respectively. The estimates of common environmental effect for IGFI-8W and IGFI-105KG were 0.20 +/- 0.02 and 0.03 +/- 0.01, respectively. Positive genetic correlations were estimated between IGFI-8W and DG (0.26 +/- 0.08), EM (0.22 +/- 0.10), and IMF (0.32 +/- 0.10). Moreover, the positive genetic correlation between IGFI-105KG and EM was 0.42 +/- 0.08. These results indicate that serum IGF-I concentration at an early stage of growth was effective for prediction of IMF, but it was not a reliable physiological predictor of genetic merit of meat production traits.

Genetic correlation between serum insulin-like growth factor-1 concentration and performance and meat quality traits in Duroc pigs1

This study was intended to examine whether serum IGF-I concentration is appropriate for use as a physiological predictor for genetic improvement of meat production and meat quality traits in pigs. Heritabilities and genetic correlations were estimated for these traits. The Duroc breed used in this study was selected for seven generations for average daily BW gain (DG) from 30 to 105 kg of BW, loin-eye muscle area (EM), backfat thickness (BF), and intramuscular fat (IMF) content. Serum IGF-I concentration of boars and gilts at the fourth generation of selection and that of boars, gilts, and barrows from the fifth to seventh generations of selection were measured at 8 wk (IGFI-8W) for 832 animals and again at the time they reached 105 kg of BW (IGFI-105KG) for 834 animals. A multivariate REML procedure was used to estimate genetic parameters with a model incorporating generation of selection, sex, common environmental effect of litter, and individual additive genetic effects. Heritability estimates for IGFI-8W and IGFI-105KG were 0.23 ± 0.02 and 0.26 ± 0.03, respectively. The estimates of common environmental effect for IGFI-8W and IGFI-105KG were 0.20 ± 0.02 and 0.03 ± 0.01, respectively. Positive genetic correlations were estimated between IGFI-8W and DG (0.26 ± 0.08), EM (0.22 ± 0.10), and IMF (0.32 ± 0.10). Moreover, the positive genetic correlation between IGFI-105KG and EM was 0.42 ± 0.08. These results indicate that serum IGF-I concentration at an early stage of growth was effective for prediction of IMF, but it was not a reliable physiological predictor of genetic merit of meat production traits.