The objective of this study was to evaluate the effects of ractopamine supplementation, castration method, and their interaction on the behavioral and physiological response to preslaughter stress and carcass and meat quality of 2 Piétrain genotypes. A total of 1,488 male pigs (115 ± 5 kg BW) were distributed according to a 2 × 2 × 2 factorial arrangement of treatments. The first factor was ractopamine supplementation with 2 groups of pigs (376 and 380 pigs each) receiving 7.5 mg/kg of ractopamine (RAC) or not (NRAC) in their diet during the last 28 d of the finishing period. The second factor was castration method, with 744 surgical castrates (SC) and 744 immunized males (IM), and the third factor was the genotype with 2 crossbreeds containing 50% (genotype A, GA; n = 744) or 25% (genotype B, GB; n = 744) Piétrain genetics. Surgical castration took place at 2 d of age, whereas immunization against gonadotropin-releasing factor (GnRF) was performed through 2 subcutaneous injections of GnRF analog (Improvest, 2 mL) at 10 and 4 wk before slaughter. At loading more vocal stimulation was needed by the handler to drive GB pigs forward through the farm alley (P = 0.01) and RAC-fed GB pigs through the ramp (P = 0.02). Feeding RAC to IM increased the number of fights in lairage compared with SC (P = 0.03). Feeding RAC shortened fighting bouts compared with NRAC pigs (P = 0.05). The SC-GA pigs showed a greater gastrointestinal tract temperature during unloading (P = 0.05) and lairage time (P = 0.03). Blood creatine kinase (CK) concentrations were greater (P = 0.04) in SC compared with IM, and no difference was found in the concentrations of stress hormones in urine collected postmortem. Dressing yield was greater (P = 0.01) in RAC and SC-GB pigs. Carcasses from RAC pigs and IM were leaner than those from NRAC and SC pigs (P < 0.001 and P = 0.002, respectively). Feeding RAC to IM increased drip loss in the LM (P = 0.05). Warner-Bratzler shear force values were slightly greater in the LM from RAC-GB pigs and from IM compared with SC (P = 0.01 and P < 0.001, respectively) and in the semimembranosus muscle of RAC pigs (P = 0.006). In conclusion, immunization against GnRF more than the use of Piétrain genotypes appears to be a viable alternative to the use of ractopamine, as it seems to promote production of lean carcasses without compromising animal welfare and pork quality.
resumoSuínos provenientes de três linhagens genéticas A, B e C comercializadas no Brasil, com peso vivo de 100 a 120 kg foram submetidos ao insensibilizador elétrico manual (45)(46)(47)(48)(49)(50)(51)(52)(53)(54)(55)(56)(57)(58)(59)(60) Hz e 1,4 -1,5 A) e ao sistema gasoso coletivo (COMBI-BUTINA 90% CO 2 ). Alíquotas sanguíneas, para determinação dos níveis de creatina fosfoquinase (CPK), lactato e cortisol, assim como amostras do músculo semimembranosus (10 g) para a determinação do gene halotano, foram coletadas. Comparando-se os sistemas de insensibilização elétrico e gasoso (CO 2 ), o elétrico demonstrou ser mais estressante, proporcionando maiores concentrações plasmáticas de cortisol (p ≤ 0,001) e lactato (p ≤ 0,001) para as linhagens genéticas A e C, nas condições estudadas, porém não se observou diferenças significativas para os indicadores sanguíneos e sistemas de insensibilização em questão quando a linhagem B foi considerada. Diferenças significativas entre as linhagens genéticas A, B e C foram obtidas comparando-se os valores plasmáticos de creatina fosfoquinase (p ≤ 0,001), lactato (p ≤ 0,001) e cortisol (p ≤ 0,001) quando atordoados com o sistema gasoso, entretanto, quando o sistema elétrico foi utilizado, somente os valores de cortisol apresentaram diferenças significativas (p ≤ 0,001). A presença do gene halotano (Nn) foi observada somente na linhagem B. PAlAvrAs-chAve: insensibilização, bem-estar animal, suínos, estresse. summArY EVALUATION OF PIG HYBRIDS STUNNED WITH ELECTRICAL AND GASEOUS (CO 2 ) SYSTEMS. PART 1 -BLOOD STRESS INDICATORS.Pigs of three genetics lineages A, B and C marketed in Brazil, with alive weight from 100 to 120 kg were submitted to the manual electric stunning (Karl Schermer 220-230/250 volts, 45-60 Hz and 1.4 -1.5 A) and to the collective gaseous system (COMBI-BUTINA 90% CO 2 ). Blood samples, for levels determination of creatine phosphokinase (CPK), lactate and cortisol, as well as samples of the semimembranosus muscle (10 g) for the determination of the gene halothane, were collected. Being compared the electric and gaseous stunning systems, the electric stunning did demonstrate to be more stressful providing larger plasmatic concentrations of cortisol ( p ≤ 0.001) and lactate ( p ≤ 0.001) for the genetic lineages A and C, in the studied conditions. However it didn't observe significant differences beween the sanguine indicators and stunning systems in subject when the lineage B was considered. Significant differences among the genetic lineages A, B and C were obtained being compared the plasmatic values of creatine phosphokinase (p ≤ 0.001), lactate (p ≤ 0.001) and cortisol (p ≤ 0.001) when stunned with the gaseous system, however when the electric system was used only the cortisol values presented significant differences (p ≤ 0.001). The presence of the gene halothane (Nn) was only observed in the lineage B.
II Efic ácia do sistema de contenção (automatizado e mecânico) no atordoamento de bovinosEffectiveness of the restraining system (automated and mechanical) in the cattle stunning
O desenvolvimento das anomalias PSE e DFD na carne suína é fruto de interação entre o genótipo e o ambiente. Portanto, os procedimentos de abate por si constituem fatores estressantes muito fortes para os animais. Embora a insensibilização elétrica tenha sido muito difundida desde o final da década de 1920, o aspecto humanitário da insensibilização com CO 2 ainda é um assunto muito controvertido dentro da comunidade científica. Esta técnica de insensibilização vem ganhando muita popularidade na comunidade européia. Entretanto, aspectos relativos ao bem-estar proporcionado por esta técnica são muito questionados [50]. AVALIAÇÃO DE DIFERENTES HÍBRIDOS SUÍNOS SUBMETIDOS RESUMOSuínos provenientes de três linhagens genética (A, B e C) comercializados no Brasil, com peso vivo de 100 a 120 kg foram submetidos ao insensibilizador elétrico manual (Karl Schermer 220-230/250 volts, 45-60 Hz e 1,4-1,5A) e ao gasoso coletivo (Combi-Butina 90% CO 2 ) no mesmo abatedouro. O sistema gasoso proporcionou aos híbridos valores (b*) superiores (p≤0,001) quando comparados ao sistema elétrico, assim como diferenças nos valores médios de refletância luminosa interna (Hennessy-gp4) aos 45 min. pm e 24ª h pm (p≤0,05). Quando submetidos ao sistema gasoso, diferenças entre os híbridos nos valores médios de luminosidade superficial (L) 24ª h pm (p≤0,0001), pH 24ª h pm (SM) (p≤0,0001), valores (b*) 24ª h pm (p≤0,05), reflectância luminosa interna aos 45 min e 24ª h (LD) (p≤0,001) foram observadas. Utilizando-se o sistema manual elétrico verificaram-se diferenças significativas nos valores médios de refletância luminosa interna (LD) aos 45 min. e 24ª h pm (p≤0,001), assim como nos valores médios de pH 24ª h pm (SM) e (SC) (p≤0,05). Entretanto as diferenças obtidas entre os sistemas de insensibilização e híbridos estudados não foram suficientes para proporcionar diferenças significativas nos valores de capacidade de retenção de água, perda por exsudação e "umidade exprimível". Palavras-chave: insensibilização, bem-estar animal, qualidade de carne. SUMMARY EVALUATION OF DIFFERENT SWINE BREEDS SUBMITTED TO THE ELECTRIC AND GASEOUS(CO 2 ) STUNNING SYSTEMS.PART 2 -QUALITY OBJECTIVE MENSURATIONS. Pigs of three genetic lineages A, B and C commercialized in Brazil, with weight from 100 to 120 kg, were submitted to the manual electric stunning (Karl Schermer 220-230/250 Volts, 45-60 Hz and 1,4 -1,5A) and to the collective gaseous system (COMBI-BUTINA 90% CO 2 ) at the same slaughterhouse. The gaseous system provided to the hybrids an increase in the values (b*) (p≤0,001), when compared to the electric system, as well as differences in the average values of light scattering (Hennessy-gp4) to the 45 min. pm and 24ª h pm (p≤0,05). When submitted to the gaseous system, differences among the hybrid in the average values of superficial brightness (L) 24ª h pm (p≤0,0001) pH 24ª h pm (SM) (p≤0,0001), values (b*) 24ª h pm (p≤0,05), light scattering 45 min e 24ª h (LD) (p≤0,001) were observed. By using the manual electric system, significant differences were v...
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