L. Nanni Costa

Combined effects of pre-slaughter treatments and lairage time on carcass and meat quality in pigs of different halothane genotype

The effect of two different lairage times on meat quality was investigated in pigs with different halothane genotype previously submitted to controlled pre-slaughter treatments. One hundred and ninety nine Italian heavy pigs were loaded by ramp or lift and transported unmixed for 1 h to the abattoir at a stocking density of either <0.4 or >0.6 m(2) per 100 kg pigs. After unloading, an equal number of animals within each previous treatment was held in lairage for 2 h or overnight (22 h) before slaughter. Carcass and meat quality and incidence of skin damage were evaluated. Longer lairage did not negatively affect carcass traits and reduced the incidence of PSE meat without increased DFD occurrence. It also seriously increased the amount of skin damage due to fighting, resulting in long fasting. Pre-slaughter treatments and halothane genotype showed a negligible effect on the response to the resting time.

An analysis of data relating to pig carcass quality and indices of stress collected in the European Union

Information from about 5500 pigs killed in five European countries was used to examine the relation of different measures of carcass and meat quality to one another and their relation to biochemical indices of stress in blood collected at slaughter. There were large differences in the prevalence of potentially PSE meat in pigs from the five countries and evidence of a wide range of stress encountered at slaughter. Relationships between the same measurements made in different muscles were generally good and consistent between countries. There were no apparent relationships between indices of stress and characteristics associated with PSE meat. In contrast, greater stress tended to be reflected in more DFD meat. Based on the association between the level of skin blemish and increased muscle ultimate pH values a probable factor contributing to this was fighting between mixed groups of unfamiliar animals.

Study of candidate genes for glycolytic potential of porcine skeletal muscle: identification and analysis of mutations, linkage and physical mapping and association with meat quality traits in pigs

Several genes (PRKAA2, PRKAB1, PRKAB2, PRKAG3, GAA, GYS1, PYGM, ALDOA, GPI, LDHA, PGAM2 and PKM2), chosen according to their role in the regulation of the energy balance and in the glycogen metabolism and glycolysis of the skeletal muscle, were studied. Eleven single nucleotide polymorphisms (SNPs) were identified in six of these genes (PRKAB1, GAA, PYGM, LDHA, PGAM2 and PKM2). Allele frequencies were analyzed in seven different pig breeds for these loci and for a polymorphism already described for GPI and for three polymorphic sites already reported at the PRKAG3 locus (T30N, G52S and I199V). Linkage mapping assigned PYGM and LDHA to porcine chromosome (SSC) 2, PKM2 to SSC7, GAA to SSC12, PRKAB1 to SSC14 and PGAM2 to SSC18. Physical mapping, obtained by somatic cell hybrid panel analysis, confirmed the linkage assignments of PRKAB1 and GAA and localized ALDOA, PRKAB2 and GYS1 to SSC3, SSC4 and SSC6, respectively. Pigs selected for the association study, for which several meat quality traits were measured, were first genotyped at the PRKAG3 R200Q polymorphic site (RN locus), in order to exclude carriers of the 200Q allele, and then were genotyped for all the mutations considered in this work. Significant associations (P ≤ 0.001) were observed for the PRKAG3 T30N and G52S polymorphic sites with meat colour (L* at 24 h post mortem). PGAM2 and PKM2 were significantly associated (P = 0.01) with drip loss percentage and glycogen content at one hour post mortem, respectively.

Investigation of candidate genes for glycolytic potential of porcine skeletal muscle: Association with meat quality and production traits in Italian Large White pigs

The objective of this study was to investigate the association of DNA markers in candidate genes for glycolytic potential on meat quality parameters (pH(1), pH(u), glycogen and lactate content and glycolytic potential of semimembranosus muscle) and estimated breeding values (EBVs) for average daily gain, lean cuts, back fat thickness, ham weight, and feed:gain ratio in 272 Italian Large White pigs. Three mutations in the PRKAG3 gene (T30N, G52S and I199V) were investigated as well as single nucleotide polymorphisms in two other skeletal muscle genes (PGAM2 and PKM2) involved in the glycolytic pathway. Association analysis with the PRKAG3 markers showed significant results (P<0.05) only for pH(1) (I199V, with significant additive effect) and lactate content (T30N), confirming, at least in part, the effects of this gene on meat quality traits. Significant association (P<0.05) was also observed for PGAM2 and ham weight EBV with significant additive and dominance effects. PKM2 was associated with average daily gain, lean cuts (P<0.001), back fat thickness and feed:gain ratio (P<0.05), with significant additive and/or dominance effects on these traits. PKM2 encodes for a key enzyme of the muscle glycolytic pathway and maps on porcine chromosome 7 where other studies have reported important QTL for the same traits. These data might suggest an important function of this gene in the mechanisms that produce the observed effects. The results will be important to evaluate the inclusion of some of these DNA polymorphisms in marker assisted selection programs.

Analysis of raw meat to predict proteolysis in Parma ham

Four hundred and thirty-seven pigs (223 purebred Italian Large White, 97 Italian Landrace, and 117 Duroc), were studied to examine the effect of breed on meat quality and assess the possibility of relating proteolysis of dry-cured hams to raw meat quality. The Duroc pigs had intramuscular fat contents and water holding capacities (M. Semimembranosus) significantly higher than those of the Large White and Landrace. The latter had a significantly higher pH(24h) and cathepsin B activities significantly lower than the Duroc breed. The dry-cured hams (M. Biceps femoris) from the three breeds were significantly different in proximate composition, proteolysis and weight loss at the end of ageing. Data for green hams (including salt content) were used to compute a model to fit the proteolysis of the corresponding dry-cured hams. The variables included in the model (R(2)=0.53 and P<0.01) were cathepsin B activity of raw ham, pH(24h), weight loss after the first salting step, and the salt content of the dry-cured ham. The raw hams with the highest cathepsin B activities, the lowest pH(24h), and the highest weight loss after the first salting were those in which greatest proteolysis occured.

Single nucleotide polymorphisms in several porcine cathepsin genes are associated with growth, carcass, and production traits in Italian Large White pigs

To identify DNA markers associated with performance, carcass, and meat production traits including muscle postmortem cathepsin activity, several porcine genes encoding for lysosomal proteinases (cathepsin B, CTSB; cathepsin D, CTSD; cathepsin F, CTSF; cathepsin H, CTSH; cathepsin L, CTSL; and cathepsin Z, CTSZ) and for a cathepsin inhibitor (cystatin B) were investigated. Single nucleotide polymorphisms were identified in CTSD, CTSH, CTSL, and CTSZ genes with a combination of in silico expressed sequence tag database mining and single-strand conformation polymorphism analysis. Sequencing and PCR-RFLP protocols were used to validate the identified polymorphisms. Allele frequencies at these loci were investigated in Italian Large White, Landrace, Duroc, Piétrain, Belgian Landrace, Hampshire, and Meishan breeds. Genotyping CTSD and CTSH markers made it possible to genetically map these genes to SSC 2 and 7, respectively. Markers in CTSD, CTSH, CTSL, and CTSZ genes, together with mutations we previously reported in cystatin B, CTSB, and CTSF genes, were genotyped in an Italian Large White sib-tested population (272 or 482 animals). For these animals, meat quality traits (cathepsin B activity, pH measured at 2 h postmortem, pH measured at 24 h postmortem, glycogen, lactate, and glycolytic potential of semimembranosus muscle) and EBV for ADG, lean cuts (LC), backfat thickness (BFT), ham weight (HW), and feed:gain ratio (FGR) were determined. Analyzed markers did not show any association with muscle cathepsin B activity. Thus, it could be possible that different genes, other than these investigated candidates, affect this trait, which is correlated with the excessive softness defect of dry-cured hams. The results of association analysis confirmed the effects we already reported in another study for CTSF on ADG (P = 0.008), LC (P = 0.001), and BFT (P = 0.02). Moreover, CTSD was associated with ADG, LC (P < 0.0001), BFT, HW, and FGR (P < 0.001); CTSH was associated with FGR (P = 0.026); and CTSZ was associated with ADG (P = 0.006), LC (P = 0.01), HW (P = 0.024), and FGR (P = 0.029). The biochemical and physiological functions of the lysosomal proteinases, together with the results obtained in our investigation, suggest that the cathepsin gene family might play important roles affecting economic traits in pigs.

Influence of loading method and stocking density during transport on meat and dry-cured ham quality in pigs with different halothane genotypes

The effect of loading method and stocking density in transit on meat and dry-cured ham quality was investigated in pigs with different halothane genotypes. A total of 507 Italian heavy pigs, supplied by two farms, were loaded by ramp or lift and transported unmixed for 35-55 min to the abattoir at a stocking density of either <0.4 or >0.6m(2) per 100 kg pigs. After overnight lairage in separate pens with free access to water, the pigs were slaughtered. Halothane genotype was assessed post mortem. Four hundred and thirty-nine pigs had a homozygous dominant (NN) genotype and 68 pigs were heterozygous (Nn). Carcass skin damage, meat quality traits and ham curing parameters were evaluated. Loading method and stocking density showed a negligible effect on meat and dry-cured ham quality while the predominant factor affecting these was the halothane genotype. Nn pigs produced meat with a faster rate of pH fall and lower water holding capacity as well as ham with higher weight losses in salting and greater incidence of defects in the dry-cured product. There were insignificant interactions between halothane genotype and loading method or stocking density. Overall, irrespective of pre-slaughter treatment, the Nn pigs were less suitable for the production of high quality products such as dry-cured ham.

Investigation on CAST, CAPN1 and CAPN3 porcine gene polymorphisms and expression in relation to post-mortem calpain activity in muscle and meat quality

This study aimed to detect variability in CAST, CAPN1 and CAPN3 porcine genes and to investigate the effect of CAST and CAPN1 polymorphisms on the activity of native and autolyzed μ-calpain and m-calpain, measured from 1 to 72 h post-mortem in Longissimus dorsi (LD) muscle of 30 pigs. Effects of polymorphisms on meat quality parameter such as pH, color and drip loss were also evaluated. Samples carrying CAST EU137105:g.76,872AA genotype showed higher autolyzed μ-calpain activity 24 and 72 h post-mortem, as well as lower drip loss values. Expression of CAST, CAPN1 and CAPN3 was assessed in LD muscles divergent for shear force. Higher CAST and CAPN3 expression was found in LD with high shear force (P<0.2), confirming a direct role for calpastatin but not for calpain 3 in meat tenderization. In conclusion, CAST gene affected post-mortem activation time of calpain and drip loss.

The relationship between carcass bruising in bulls and behaviour observed during pre-slaughter phases

The bruises often observable on bull carcasses after skinning are due to rupture of the vascular supply and accumulation of blood in tissues. They are produced by impact against the handling facilities and/or other bulls, or by violent contact with prods or sticks used improperly by handlers. Bruises reflect poor handling practices during the pre-slaughter operations and result in economic damage due to loss of edible parts, labour cost for trimming and general carcass value depreciation. The aim of this work was to evaluate the possible relationship between some behaviour observed during handling before slaughter and the presence of bruises on bull carcasses.

Fibre optic probe measurements in landrace pigs of different halothane phenotypes

Fibre Optic Probe (FOP) measurements were made in the longissimus dorsi muscle of 70 halothane-positive (HP) and 70 halothane negative (HN) pigs of a synthetic Landrace strain at 45 min (FOP(1)), 3 h (FOP(3)) and 17h (FOP(17)) post mortem. Measurements of pH, rigor and temperature were also made in the slaughterline. Carcasses were sampled (longissimus dorsi, 2-4 lumbar vertebrae) at 18h post mortem and meat quality objectively assessed. The incidence of slight PSE (visual score) was 49% in HP and 10% in HN pigs, while the incidence of serious PSE was 20% and 4%, respectively. Yet, the percentage drip loss during 48 h storage in HN/PSE pigs was higher than in HP/PSE pigs (10·2 vs 7·5%), which was associated with a lower ultimate pH (5·25 vs 5·44). Therefore, it is suggested that the remaining PSE problem in HN Landrace pigs, although less in frequency, might be more serious. In the whole population, of all FOP measurements taken correlations with colour (Hunter L(∗)-value) and percentage drip loss were highest for the FOP(17) measurements (r = 0·82 and 0·69, respectively). FOP(1) was better related than pH(1) to colour, while the relationships with drip loss were of a similar magnitude. Differences in FOP values between HP and HN pigs were larger for FOP(1) (148 vs 108) than for FOP(3) (148 vs 125) or FOP(17) (153 vs 130). The relationship between FOP1 and ultimate meat colour (L(∗)-value) appeared to be higher in HP (0·60) than in HN (0·48) pigs, while for the relationship between FOP(1) and percentage drip loss the reverse was true (0·48 and 0·60, respectively). The effect of halothane phenotype on the relationships found, may partially explain the different results of reflectance measurements reported in the literature as to their predictive value for ultimate meat quality. The results suggest that the measurement of reflectance in the slaughterline offers opportunities for identifying (potential) PSE carcasses. The large genetic influence of halothane phenotype on this parameter, may eventually justify its use as a base for payment for meat quality to the producer.