Efeito do gene do estresse suíno sobre características de quantidade e qualidade de carcaça

Abstract

RESUMO -O gene do estresse suíno (gene hal), em homozigose recessiva (nn), está associado com a ocorrência da Síndrome do Estresse Porcino (PSS) e com a ocorrência da carne pálida, mole e exudativa (PSE). Em heterozigose (Nn), está relacionado com diminuição na qualidade da carne porém, com maior peso de carcaça. Neste estudo, foi caracterizado o genótipo do gene hal de 160 suínos por meio de análise do DNA extraído de um único folículo piloso. Estes animais foram abatidos e, após, mensuradas características de carcaça de cada um. Entre os 160 animais analisados, 82 (52,58%) foram caracterizados como NN, 67 (41,80%) como Nn e nove (5,62%) como nn. A variação das características de carcaça entre os genótipos foi avaliada por análise de variância, usando o SAS. Os animais dos três genótipos não diferiram quanto ao peso da carcaça quente, à espessura de toucinho, profundidade de músculo, porcentagem de carne magra e cor do músculo longissimus dorsi. Entretanto, a variação da cor ao longo da carcaça foi menor em animais NN (40,82%) do que em Nn (49,77%) e nn (53,83%). Estes resultados indicam que a presença do gene hal tanto em heterozigose como em homozigose recessiva não está associada ao maior peso de carcaça e a utilização destes animais pode acarretar em perda na qualidade da carne. Devido a isto, o uso intencional de animais homozigotos recessivos ou heterozigotos em programas de cruzamento deve ser desestimulado. Palavras-chave: carcaça suína, gene halotano, PCR, PSE, PSS Effect of Swine Stress Gene on Quality and Quantity of CarcassABSTRACT -The swine stress gene (hal gene) in recessive homozygosis (nn) is associated with the occurrence of the Porcine Stress Syndrome (PSS) and with the occurrence of pale, soft and exudative pork (PSE). In heterozygosis (Nn) it is related to low quality of carcass, but higher carcass weight. This study has characterized the genotype of hal gene by DNA-testing, obtained by alkaline extraction from a single hair root, in a sample of 160 swines. These animals were slaughtered and carcass traits for each animal were measured. Among the 160 animals, 82 (52.58%) were identified as NN, 67 (41.80%) as Nn, and 9 (5.62%) as nn. Variation in carcass traits across genotypes was evaluated by analysis of variance, using SAS. The NN, Nn and nn animals did not differ for: hot carcass weight, backfat thickness, muscle depth, lean meat percentage, and longissimus dorsi muscle color. However, variation in carcass color was lower for NN (40.82%) than for Nn (49.77%) and nn (53.83%) animals. These results indicate that the presence of hal gene in heterozygosis or recessive homozigosis was not associated with better carcass weight and the utilization of these animals may lead to lower carcass quality. Therefore, the intentional use of heterozygous and recessive homozygous animals should not be encouraged.

Relationship between the Porcine Stress Syndrome gene and pork quality traits of F2 pigs resulting from divergent crosses

“…The lack of a significant difference in objective color indices and tenderness between the Nn and NN genotypes has also been observed by others (Bastos et al, 2001;Fernandez et al, 2002;Miller et al, 1999;Jeremiah et al, 1999). However, discrepancies in pork quality traits have also been reported.…”

Relationship between the Porcine Stress Syndrome gene and carcass and performance traits in F2 pigs resulting from divergent crosses

“…However, Bastos et al (2001) did not find significant differences in hot carcass weight, backfat thickness, loin depth or lean meat content among the three genotypes (NN, Nn and nn) when studying animals of the Large White, Landrace, Duroc and Pietrain breeds. The results of the present study differ from those described by those authors in terms of hot carcass weight and loin depth, which were higher in Nn than in NN animals (p < 0.05).…”

“…The Hal gene, in recessive homozygosis (nn), is associated with the development of PSS, and is related to mortality during transportation as well as occurrence of pale, soft and exudative (PSE) meat. When in heterozygosis (Nn), the Hal gene continues to be related to poor meat quality, but recessive homozygous (nn) animals gain more weight when compared to normal homozygous (NN) ones (Bastos et al, 2001;Santana et al, 1998). Zhang et al (1992), studying Pietran x Yorkshire crossed animals, attributed 1 to 10% of the phenotypic variation in meat yield and growth traits to the PSS gene locus.…”

An improved method for characterization of the mutation associated to porcine stress syndrome by PCR amplification followed by restriction analysis

“…In recessive homozygotes (nn) the RYR1 gene leads to PSS and the post-mortem manifestation of pale, soft and exudative pork (PSE). In heterozygosis (Nn) the hal gene produces lower carcass quality (BAND et al, 2005a;BASTOS et al, 2001;POMMIER & HOUDE, 1993), but possibly higher carcass weight (BAND et al, 2005b;LEACH et al, 1996). The polymorphism at nucleotide 1843 of the hal gene has been characterized by PCR amplification associated to restriction endonuclease assay (PCR-REA) using blood or muscle biopsy as the source of genomic DNA KAMINSKI et al, 2002).…”