Meat quality as influenced by halothane sensitivity and ultimate pH in three porcine breeds

Quantification of the Effects of Electrical and CO2 Stunning on Selected Quality Attributes of Fresh Pork: A Meta-Analysis

Stunning is a statutory pre-slaughter process that may affect the quality of pork. The objective of this study was quantification of the effects of stunning (ES vs. CO2 stunning) on selected quality attributes of pork, using a meta-analytical approach. Data from 18 publications with 46 individual experiments were combined using a random-effect model to estimate the effect size of stunning on the initial and ultimate pH (pH1, pHu); drip loss (DL); colour (lightness—L*, redness—a*, yellowness—b*); and tenderness (expressed as Warner–Bratzler shear force, WBSF) of pork. In overall, loins from ES showed significantly lower pH1 (by 0.08 units); greater DL (by 0.68 p.p.); higher L* (by 1.29 units); and a* (by 0.80 units) as they compared to those from CO2 stunning. In subgroups, a greater-than-overall negative change in pH1, pHu, DL, L* and a* was detected with the application of the head-to-back (HB) stunning method. Additionally, alterations in DL and L* may be magnified with the application of conventional chilling (Conv.) to ES pigs. There was no effect of stunning on WBSF but, due to a low number of research in the database, the reliability of these results may be misleading. These results provide evidence that the differences between these two stunning methods in DL and L* may be diminished by the application of the head-only (HO) or head-to-body (HBO) method, followed by the fast chilling of carcasses.

Effect of gender (barrows vs. females) on carcass traits and meat quality of Celta pig reared outdoors

BACKGROUND

Today, the Celta is the unique indigenous pig breed of Galicia (northwest Spain), included in the Official Catalogue of Breeds of Spain as being in danger of extinction. The objective of this study was to estimate the effect of gender (barrows vs. female) on carcass traits and meat quality of Celta pig reared outdoors. The differences in carcass and meat quality between castrated barrows and gilts (n = 20), reared outdoors and slaughtered at a live weight of 140 kg, were determined.

RESULTS

The mean carcass weight was 108 kg and killing out percentage and chilling losses did not differ (P > 0.05) between genders, with a mean value of 78.2% and 2.68%, respectively. There were no statistical differences in the morphometric parameters between genders except for the leg length (LL) (P < 0.01), and hand length (HL) and ham length (Hml) (P < 0.001), which were greater in barrows. Gender affected significantly pH (5.67 vs. 5.55; P < 0.05) and moisture content (73.2% vs. 72.0%; P < 0.05), while intramuscular fat (IMF) did not differ significantly between genders (2.12% vs. 1.67%, P > 0.05) for barrows and females, respectively. No significant effect (P > 0.05) on parameters measured by Warner-Braztler (WB) test (shear force, firmness and total work of cut) was found, whereas textural profile analysis showed significant differences for all traits determined due to gender effect. Sensory evaluation of longissimus dorsi (LD) samples showed significant differences between genders in odour and taste traits. Finally, there were no significant differences (P > 0.05) in any amino acid concentrations between genders.

CONCLUSION

Values for carcass parameters indicated that Celta pigs produced very similar carcasses to those obtained from other rustic pigs. The percentage of 'noble' cuts relative to carcass weight was higher in barrows than in females. Finally, gender appeared to have little effect on the colour, textural organoleptic traits or amino acid profile of this breed of pig.

Evidence for a new major gene influencing meat quality in pigs

The present investigation primarily deals with the inheritance of a pigmeat quality trait, the Napole technological yield (RTN), a measure of cooked weight to fresh weight. This trait as well as lean percentage at 100 kg liveweight and fattening length from 20 to 100 kg liveweight were recorded on 3459 offspring from 67 sires and 433 dams, and 3052 offspring from 64 sires and 405 dams in Penshire (P66) and Pen Ar Lan (P77) composite lines respectively. The hypothesis of a major 2-allele locus contributing to RTN was tested by use of a segregation analysis method. Highly significant likelihood ratios (mixed vs. polygenic transmission models) lead us to conclude that a major gene RN- exerting an unfavourable effect on RTN is segregating in both lines. Maximum likelihood estimates of the parameters under the hypothesis of mixed (monogenic + polygenic) inheritance show that the difference between the means of the 2 homozygotes amounts to about 3 phenotypic standard deviations of the trait, whereas the complete dominance of RN- cannot be rejected. The frequency of RN- is about 0.6 in both lines. These results are discussed in connection with the previously reported 'Hampshire effect' on pigmeat quality, as the Hampshire breed is a common component of the foundation stock of the 2 composite lines under study.