Meat quality and carcass traits in relation to HGD-BstXI and HGD-HaeIII PCR–RFLP polymorphism in Chinese red cattle

We investigated the effect of homogentisate 1, 2 dioxygenase (HGD) gene on meat quality and carcass traits in 287 Chinese red cattle. The PCR–SSCP method was used to identify polymorphism of the HGD gene in the exon 1 and intron 1. Two polymorphisms were detected in intron 1 and two restriction sites for endonuclease HGD-BstXI and HGD-HaeIII have also been found. The HGD-BstXI genotypes showed significant effects on cooking loss, drip loss, net meat weight, carcass weight, and eye muscle area (P < 0.05). The HGD-HaeIII genotypes significant affected cooking loss, muscle fibre diameter, shear force, drip loss, and carcass yield ratio (P < 0.05). Moreover, we found significant effects of diplotypes on cooking loss, muscle fibre diameter, shear force, drip loss, net meat weight, carcass weight, and eye muscle area (P < 0.05).     

Investigation on interferon alpha-inducible protein 6 (IFI6) gene as a candidate for meat and carcass quality in pig

The aim of this research was to screen for polymorphism and to perform an association study of IFI6 with meat and carcass quality traits. A SNP (g.370A>G) was detected which was associated (P<0.05) with meat colour, pH 24h post mortem (p.m.) in ham, conductivity 45 min p.m. in loin and conductivity 24 h p.m. in ham, drip loss and carcass length in Duroc x Pietrain and with meat colour, muscle area and ham percentage in the Pietrain population. Highest expression of IFI6 mRNA was detected in skeletal muscle (longissimus dorsi) by qRT-PCR comparing different tissues. Both qRT-PCR and western blot revealed that the IFI6 gene and protein expressions were significantly (P<0.05) higher in skeletal muscle with low drip loss compared to that of high drip loss. IFI6 protein was localized in the myocytes membrane. Results suggested that IFI6 might play roles in meat and carcass quality and is a potential positional, physiological and functional candidate gene for improving meat quality traits in pigs.     

Polymorphism and expression of the porcine Tenascin C gene associated with meat and carcass quality

The research aimed to screen for polymorphism, expression of Tenascin C (TNC) and association with meat and carcass quality traits. Three single nucleotide polymorphisms were detected. In a Duroc×Pietrain F2 cross (DuPi) population, g.44488C>T was associated with meat color and ham weight; g.68794A>G was associated with pH at 24h post mortem in ham (pH24(H)) and muscle area but g.68841C>T was not statistically associated. Genotyping in a commercial Pietrain (Pi) population showed that g.44488C>T was associated with pH24(H), whereas g.68794A>G was associated with conductivity at 45 min post mortem in loin and backfat thickness. Diplotypes showed significant effects on pH24(H) in both populations. The expression was associated with pH at 45 min post mortem in loin and cooking loss. TNC was significantly higher in animals with higher muscle pH. Linkage analysis revealed four trans-regulated eQTL on four autosomes. These results suggest that TNC could be a potential candidate gene for meat quality traits in pigs.     

Effects on performance and carcass and meat quality attributes following immunocastration with the gonadotropin releasing factor vaccine Bopriva or surgical castration of Bos indicus bulls raised on pasture in Brazil

Bos indicus bulls 20 months of age grazed on pasture in Minas Gerais, Brazil either received 2 doses of the GnRF vaccine Bopriva at d0 and d91 (group IC, n = 144) or were surgically castrated on d91 (group SC, n = 144). Slaughter on d280, was 27 weeks after castration. Adverse safety issues in 8% of group SC bulls following surgery contrasted with 0% in group IC bulls. At d105 testosterone levels were suppressed to similar levels in both groups. Importantly, group IC bulls had higher live weight, hot carcass weight, ADG (P < 0.005) and dressing percentage (P < 0.0001) compared to group SC animals. There were no negative effects on carcass or meat quality traits, thus immunocastration was concluded to offer a safe and effective method that provides production gains, and improves animal welfare in Bos indicus beef bulls without impacting meat and carcass quality.     

Association of polymorphisms at DGAT1, leptin, SCD1, CAPN1 and CAST genes with color,marbling and water holding capacity in meat from beef cattle populations in Sweden

The objective of this study was to investigate the associations of single nucleotide polymorphisms (SNPs) at five candidate genes with meat pH, color, marbling and water holding capacity (WHC) in young bulls from five beef breeds (n = 243) in Sweden. The UASMS2 polymorphism at the leptin gene and the SNPs at the Stearoyl-CoA desaturase 1 gene (SCD1.878) and μ-calpain gene (CAPN1:c.947) were associated with variation in meat color traits after 6 days of exposure to air. The K232A polymorphism at the diacylglycerol O-acyltransferase 1 (DGAT1) gene and the CAPN1:c.947 SNP were associated with level of beef marbling. There was no association between the SNP at the calpastatin gene (CAST:c.155) and meat quality traits, nor was there any association of the tested SNPs with WHC traits and pH value.     

The effects of the myostatin g+6723G>A mutation on carcass and meat quality of lamb

This study evaluated the effects of the myostatin g + 6723G > A mutation on carcass and meat quality traits of lamb (AA: n = 5; AG: n = 8; GG: n = 9). Dressing percentage was positively affected by the mutation with homozygotes for the mutation having the highest yield. Regarding carcass composition, there was a significant increase in the proportional weights of the loin and hindquarter muscles. Objective meat quality traits of the M. longissimus lumborum (LL) and M. semimembranosus (SM) were not significantly affected. For the SM, toughness (shear force and compression) tended to be lowest for homozygotes for the mutation. The myostatin g + 6723G > A mutation did not affect sensory meat quality traits of grilled steaks for the LL, but resulted in a significant improvement in eating quality for the SM. Given the number of animals in this study, the robustness of the outcome of this study with regard to the effects on meat quality and its causes requires further investigation.     

The porcine tribbles homolog 3 (TRIB3) gene: Identification of a missense mutation and association analysis with meat quality and production traits in Italian heavy pigs

TRIB3 plays an important role in energy metabolism. This work aimed to study the porcine tribbles homolog 3 (TRIB3) gene and to evaluate its association with meat quality and carcass traits in pigs. By sequencing a portion of the porcine TRIB3 gene two single nucleotide polymorphisms (SNPs) in the first coding exon (one synonymous SNP: c.132 T > C; and one missense mutation: c.146C > T, p.P49L) were identified. The two polymorphisms were in complete linkage disequilibrium. In silico analysis of the p.P49L mutation suggested that it could have functional effects. Association studies in four groups of pigs (651 animals in total) indicated that this gene marker was associated with back fat thickness in Italian Large White and Italian Duroc pigs in two different experimental designs (P < 0.1 and P < 0.05). This polymorphism tended to be associated with lactate content of the semimembranosus muscle (P < 0.1). Among several other tissues, TRIB3 is expressed in fat and skeletal muscle.     

Identification of genetic markers associated with residual feed intake and meat quality traits in the pig

Residual feed intake (RFI) has become increasingly important and is being considered as a more reasonable approach to evaluate feed efficiency in livestock. However, the cost and technical difficulties in measuring this trait restrict the extensive adoption of RFI selection, and this makes marker assisted selection (MAS) a feasible tool. In addition, the effects on meat quality caused by low RFI selection have yet to be clarified. In this study, 11 SNPs from eight candidate genes were evaluated in a Yorkshire pig experimental population (n = 169) consisting of a low RFI selection line and a randomly selected control line. Associations of these SNPs with RFI, growth rate, carcass composition, and meat quality measures including water holding capacity, pH at 2 d postmortem, meat color and sensory traits were analyzed. The SNPs FTO p.Ala198Ala and TCF7L2 c.646+514A > G showed significant (P < 0.05) and suggestively significant (P < 0.1) associations with RFI, respectively. The MC4R SNP p.Asp298Asn was associated with backfat but it was not with ADG and meat quality attributes. Both SNPs within HNF1A were associated with intramuscular lipid content and sensory juiciness. The SNPs ACC1 c^∗384C > T and TCF7L2 c.646+514A > G were significantly (P < 0.05) associated with ADG. The SNPs CTSZ p.Arg64Lys and TCF7L2 c.646+514A > G were associated with both visual scoring of meat color and the objective L-value measure of meat color. This study has identified potential genetic markers suitable for MAS in improving RFI, ADG, and meat color traits, but these associations need to be validated in other larger populations.     

Mitochondrial respiratory activity in porcine longissimus muscle fibers of different pig genetics in relation to their meat quality

The pig genetics of Duroc, Pietrain (MHS homozygote negative, PiNN), Pietrain (MHS homozygote positive, PiPP) and a F2-Duroc-Pietrain cross-breed were analyzed. The animals had comparable (P > 0.05) carcass weights, but the PiPP pigs had higher carcass yield and lean meat values (P < 0.05). Considering the meat quality characteristics, the PiPP showed a faster pH drop and higher electrical conductivity, drip loss, shear force as well as lightness and redness values (P < 0.05). The PiPP animals had less slow-twitch-oxidative (STO) and more fast-twitch-glycolytic (FTG) muscle fibers, whereas the results of the Duroc animals were converse (P < 0.05). The STO and FTG fibers of the PiPP animals were larger than those of the other genetics (P < 0.05). The analysis of the mitochondrial respiratory activity (MRA) using permeabilized longissimus muscle fibers resulted in no differences between the pig genetics before and immediately after slaughter. During chilling the MRA decreased in all pigs but to a higher extent in the PiPP pigs (P < 0.05).     

Association of the melanocortin-4 receptor (MC4R) with feed intake,growth, fatness and carcass composition in pigs raised in Poland

The melanocortin-4 receptor (MC4R) is involved in feed intake regulation. A missense mutation G/A in position 1426, which causes Asp-Asn substitution at position 298 in the MC4R gene has been associated with feed intake, fatness and growth, however published results of its effect are inconsistent. In our study we evaluated an effect of missense mutations on carcass composition, growth traits and meat quality in 1191 gilts of five breeds: Polish Large White, Polish Landrace, Pu?awska, Pietrain and Duroc. G/A 1426 MC4R mutations were genotyped using a 7500 Real-Time PCR System (Applied Biosystem). Our observations confirm that the G allele is frequent in breeds selected for lean meat content (Pietrain – 92.4%) and rare in breed with a fat carcass (Duroc – 31.5%), which has been previously reported. Our study revealed that the A allele was associated with increased daily feed intake (AA – 2.51 kg; GG – 2.31 kg in the Pu?awska breed, P < 0.05), daily gain and backfat thickness (AA – 1.67 cm, GG – 1.52 cm in PL, P < 0.01) and decreased lean meat content (total weight of ham was 0.5 kg greater in G/G than in A/A Pu?awska animals). We obtained an unexpected result for IMF: higher percentage of IMF was observed in the G/G genotype.     

Verocytotoxigenic Escherichia coli O157 in beef and sheep abattoirs in Ireland and characterisation of isolates by Pulsed-Field Gel Electrophoresis and Multi-Locus Variable Number of Tandem Repeat Analysis

This study aimed to investigate verocytotoxigenic Escherichia coli O157 in the largest beef and sheep slaughter plants in Ireland over a one-year period. Samples consisted of pooled rectal swabs (n = 407) and pooled carcass swabs (n = 407) from 5 animals belonging to the same herd or flock and minced meat (n = 91) from the same sampling date. E. coli O157 isolates were characterised using PCR for a range of genes, i.e. 16S, rfbE, fliC, vtx1, vtx2, eaeA and confirmed VTEC O157 isolates were tested for antimicrobial susceptibility and typed using Pulsed-Field Gel Electrophoresis (PFGE) and Multi-Locus Variable Number of Tandem Repeat Analysis (MLVA). VTEC O157 was isolated from 7.6% and 3.9% of bovine rectal and carcass swab samples and from 5.8% and 2.9% of ovine rectal and carcass swab samples respectively. None of the bovine minced meat samples (n = 77) and only one of the 14 ovine minced meat samples was positive for VTEC O157. Following PFGE and MLVA, cross contamination from faeces to carcasses was identified. While PFGE and MLVA identified the same clusters for highly related strains, MLVA discriminated better than PFGE in addition to being more rapid and less labour intensive. Results showed that cattle and sheep presented for slaughter in Ireland harbour VTEC O157, and although the levels entering the food chain are low, this should not be overlooked as possible sources of zoonotic infection; molecular typing was able to demonstrate relationships among strains and could be used to elucidate the sources of human infection.     

Effects of stress by unfamiliar sounds on carcass and meat traits in bulls from three continental beef cattle breeds at different ageing times

One-hundred-and-twenty-four young bulls of three Continental beef cattle breeds were used to study the effect of pre-slaughter stress by unfamiliar sounds on carcass traits and quality characteristics of beef aged for three different periods. Stress due to unfamiliar noises had a moderately negative effect on carcass and meat quality. Carcasses from group Stressed had higher (P < 0.05) values of pH₀, pH₂₄, a*, and Warner-Bratzler shear force, and lower (P < 0.05) values of L*, b* and pressure losses than from Unstressed animals. There were significant differences (P < 0.05) among breeds in L*, a* and pressure losses. The ageing time had a significant effect on chromatic variables, WBSF and pressure losses. The cooking losses were not significantly affected by any of the three factors discussed. These results emphasize the importance of implementing appropriate management practices during pre-slaughter handling of cattle in order to reduce any possible risk factor for stress, as well as the different sensitivity of the breeds to similar stimuli.     

Association mapping of quantitative trait loci for carcass and meat quality traits at the central part of chromosome 2 in Italian Large White pigs

Association mapping of the central part of porcine chromosome 2 harboring QTLs for carcass and meat quality traits was performed with 17 gene-tagged SNPs located between 44.0 and 77.5 Mb on a physical map (Sscrofa10.2) in Italian Large White pigs. For the analyzed animals records of estimated breeding values for average daily gain, back fat thickness, lean cuts, ham weight, feed conversion ratio, pH₁, pH_u, CIE L*, CIE a*, CIE b* and drip loss were available. A significant QTL for fat deposition (adjusted P = 0.0081) and pH₁ (adjusted P = 0.0972) to MYOD1 at position 44.4 Mb and a QTL for growth and meatiness (adjusted P = 0.0238–0.0601) to UBL5 at position 68.9 Mb were mapped. These results from association mapping are much more accurate than those from linkage mapping and facilitate further search for position candidate genes and causative mutations needed for application of markers through marker assisted selection.     

Effects of pregnancy and feeding level on carcass and meat quality traits of Nellore cows

Carcass and meat quality traits of 16 pregnant and 5 non-pregnant cows fed at 1.2 times maintenance and 16 pregnant and 6 non-pregnant fed ad libitum were evaluated. Pregnancy did not affect final body weight (FBW; P = 0.0923), cold carcass yield (CCY; P = 0.0513), longissimus muscle area (LMA; P = 0.8260), rib fat thickness (RFT; P = 0.1873) and shear force (WBSF; P = 0.9707). A lower FBW (P = 0.0028), LMA (P = 0.0048) and RFT (P = 0.0001) were observed in feed restricted cows. However, no differences were found for CCY (P = 0.7243) and WBSF (P = 0.0759) among feeding level groups. These data suggests that carcass and meat quality traits are not affected by pregnancy status in Nellore cows. Moreover, although cows experiencing feed restriction did have reduced deposition of subcutaneous fat and lean tissue, there were no major impacts on meat quality traits.     

Variation in exon 10 of the ovine calpain 3 gene (CAPN3) and its association with meat yield in New Zealand Romney sheep

Variation in the ovine CAPN3 gene was analysed using PCR-single strand conformational polymorphism, and its effect on growth and carcass traits was assessed in 513 New Zealand Romney lambs produced by 17 unrelated rams. Among the four allelic variants detected, the presence of variant *02 was found to be associated with an increased proportion of shoulder yield (absent: 32.6 ± 0.01%; present: 33.4 ± 0.03%; P = 0.016), and tended to be associated with increased shoulder yield (lean meat yield of the shoulder expressed as a percentage of the hot carcass weight) (absent: 16.6 ± 0.06%; present: 17.02 ± 0.20%; P = 0.067). No association was detected with growth traits or other carcass traits.     

Fatty acid profile,carcass and meat quality traits of young Nellore bulls fed crude glycerin replacing energy sources in the concentrate

Carcass and meat quality traits of 60 Nellore young bulls fed diets without crude glycerin (CG); with CG replacing corn (CGc; 10% of dry matter — DM) in the concentrate; and with CG replacing soybean hull (CGsh; 10% of DM) in the concentrate were evaluated. Diets were evaluated at two concentrate levels (CLs). The CL did not affect cold carcass weight (CCW; P = 0.6074), cold carcass dressing (CCD; P = 0.9636), rib fat thickness (RFT; P = 0.8696) and longissimus muscle area (LMA; P = 0.7524). Animals fed diets with CGc or CGsh showed meat with greater deposition of monounsaturated fatty acid (MUFA; P = 0.0022) and CLA (18:2 cis-9, trans-11) contents (P = 0.0001) than animals fed diets without CG. The inclusion of 10% of CG in diets CGc or CGsh does not affect the carcass and meat quality traits; however, it increases the MUFA and CLA contents in beef, although these changes are very small in nutritional terms.     

Effect of a supplementation of Euphorbia heterophylla on nutritional meat quality of Guinea pig (Cavia porcellus L.)

The aim of the present work was to study the effect of dietary supplementation of Euphorbia heterophylla on the quality of the Guinea pig meat. Forty guinea pigs were divided into two groups fed ad libitum during 46 days a Panicum maximum diet (Panicum diet) or a mixed diet (75% Panicum maximum + 25% Euphorbia heterophylla) (Paneuphorbia diet) to compare their effects on performances and on the composition of guinea pig tissues and carcass. Daily weight gain, liver weight, carcass yield, and the lipid content of both the carcass and the perirenal fat were significantly increased by the Paneuphorbia diet. Feeding Paneuphorbia diet increased (P < 0.05) the n-3 PUFA content in perirenal fat, muscle, liver and in the carcass and decreased (P < 0.05) the n-6/n-3 ratios in all these tissues and the carcass. In conclusion, this study shows that Euphorbia heterophylla is a source of n-3 fatty acids which can improve significantly the n-3 PUFA content of Guinea pig meat and carcass.     

Association between cathepsin L (CTSL) and cathepsin S (CTSS) polymorphisms and meat production and carcass traits in Italian Large White pigs

The aim of this work was to identify and analyse DNA markers in two cathepsin genes, cathepsin L (CTSL) and cathepsin S (CTSS), and study their association with meat quality parameters (including cathepsin activity of post mortem muscle) and several production traits in Italian Large White pigs. In silico analysis of the porcine CTSL and CTSS genes identified two new single nucleotide polymorphisms (SNPs), one located in exon 5 (CTSL) and one positioned in the 5′-untranslated region (CTSS). Allele frequencies of these two SNPs were evaluated in 7 different pig breeds. In addition, radiation hybrid mapping localized the CTSS gene on porcine chromosome 4, in an important QTL region for meat and fat deposition. Association analysis with meat quality traits, carried out in 268 Italian Large White pigs, indicated association of the CTSL polymorphism with average daily gain (ADG), weight of lean cuts (LC) and back fat thickness (BFT) estimated breeding values (P < 0.05). Results for LC and BFT were also confirmed using a selective genotyping approach in other Italian Large White pigs (P < 0.01). In the 268 Italian Large White pigs, the CTSS polymorphism was associated with feed:gain ratio and ADG (P < 0.05). No association was observed between the analysed markers and meat quality parameters (pH₁, pH_u, lactate, glycogen, glycolytic potential and cathepsin activity, all measured on Musculus semimembranosus). Overall these results, together with those previously reported for other genes of this family, suggest that cathepsin genes play a role in defining economically important traits in pigs.     

Spoilage characteristics of Brochothrix thermosphacta and campestris in chilled vacuum packaged lamb,and their detection and identification by real time PCR

The spoilage potential of Brochothrix campestris and Brochothrix thermosphacta was investigated in vacuum-packed lamb. Striploins (n = 338) were inoculated and stored for twelve weeks at temperatures − 1.5, 0, 2 and 7 °C. Growth around 5–6 log₁₀ CFU/cm² was recorded after six weeks at 0, 2 and 7 °C, and ~ 3 log₁₀ CFU/cm² after nine weeks at − 1.5 °C. B. campestris was shown to cause spoilage by nine weeks at temperatures above 0 °C by the presence of green drip and unacceptable odours. Molecular based assays for the detection and differentiation of B. thermosphacta and B. campestris were developed and validated. A TaqMan assay was designed to target a unique single-nucleotide polymorphism in the Brochothrix 16 s rRNA gene with a sensitivity of < 7 CFU per reaction. Secondly a specific PCR was designed for B. campestris targeting the structural genes, brcA and brcB. These testing regimes offer a rapid and cost effective method for the detection and screening of Brochothrix species in meat products and processing environments.     

Enhancing pork loin quality attributes through genotype,chilling method and ageing time

The experiment was conducted to examine opportunities for enhancing pork quality through the use of post-mortem ageing when combined with different chilling regimes. Large White (LW, n = 24) and Duroc × Large White (Duroc, n = 24) barrows were slaughtered and alternate carcass sides were either conventionally or blast-chilled. The longissimus thoracis et lumborum muscle was dissected from the carcass sides (24 h post-mortem) and trimmed of cover fat. Three sections (15 cm length) were vacuum packaged and assigned to 2, 7 or 14 days of ageing (2 °C) randomized within muscle location. Blast-chilled meat had lower purge (P = 0.009) and drip (P = 0.0009) losses and higher hue (P = 0.02) than conventionally chilled meat. However chilling by conventional or blast-chilling methods had no effect on sensory characteristics (P > 0.1). When breeds were compared, meat from Duroc barrows had lower moisture (P < 0.0001) and higher intramuscular fat content (P < 0.0001), L∗ (P = 0.0003) and hue (P = 0.007) values than LW. Overall tenderness (P = 0.005), juiciness (P = 0.0007) and palatability (P < 0.0001), as well as flavour intensity (P < 0.0001) and desirability (P < 0.0001) values were higher and undesirable flavours were lower (P < 0.0001) for meat from Duroc pigs, when compared with LW. Ageing increased purge loss (P < 0.0001), L∗ (P < 0.0001), hue (P < 0.0001), chroma (P < 0.0001) and content of protein (P = 0.002), with corresponding decreases (P < 0.0001) in drip loss and moisture content. Instrumental (P < 0.0001) and sensory (initial, P < 0.0001 and overall, P < 0.0001) tenderness increased from day 2 to 14. Therefore independent of chilling method, ageing improved quality of pork loins. Moreover ageing had greater effect on tenderness, while breed had greater effect on flavour which may be related to differences in intramuscular fat content.