Ana Maria Bridi

Efeito do genótipo halotano, da ractopamina e do sexo do animal na qualidade da carne suína

Este trabalho foi realizado com o objetivo de avaliar o efeito da adicao de ractopamina na racao sobre a qualidade da carne de suinos dos genotipos halotano homozigoto dominante (HalNN) e heterozigoto (HalNn). Durante o experimento (21 dias), 24 suinos machos castrados e 12 femeas (metade de cada genotipo) com peso medio inicial de 72,6 kg de PV foram avaliados segundo delineamento experimental em blocos casualizados, em arranjo fatorial 2 x 2 x 2 (dois genotipos halotano; duas racoes: controle e com adicao de 10 ppm de ractopamina; e dois sexos: machos castrados e femeas). A analise do DNA genomico foi realizada por intermedio das tecnicas de PCR-RLPC. A avaliacao da qualidade da carne foi realizada no musculo Longissimus dorsi e o pH da carne foi medido 45 minutos (pH inicial) e 24 horas apos o abate (pH final). Avaliaram-se a perda de agua por gotejamento durante o degelo e a coccao, a cor da carne, o grau de marmoreio e a maciez objetiva. Nao houve interacao genotipo ´ ractopamina para as caracteristicas de qualidade da carne avaliadas. Nenhum animal do genotipo homozigoto dominante apresentou carne PSE (textura mole, cor palida e com pouca agua), ao passo que os suinos do genotipo heterozigoto apresentaram carne com 33,3% de PSE. O uso de 10 ppm de ractopamina na racao nao afetou os parâmetros de qualidade da carne. Os animais do genotipo HalNn apresentaram carne com qualidade inferior a dos suinos HalNN. O pH final foi menor e a incidencia de carne PSE foi maior nos suinos machos castrados que nas femeas.

Efeito do genótipo halotano e de diferentes sistemas de produção na qualidade da carne suína

The effect of halothane genotypes (heterozygous and dominant homozygous) and intensive rearing systems (indoor, wood shavings bedding and outdoor) on pork quality were determinated. Ninety six castrated male pigs were used for the trial. Identification of the halothane genotype was determined in blood samples using the DNA-test, based on the polymerase chain reaction (PCR) amplification of the critical region of the ryanodine receptor and subsequent restricion of the amplifield fragment by the restriction fragment lengh polymorfism (RFLP) technique. The pH at 45 minutes and 24 hours after slaughter was measured on the Longissimus dorsi and Semimembranosus muscles. At the laboratory, the Longissimus dorsi muscle was used for the evaluation of the color, marbling, drip loss, defrosting loss and cooking loss and shear force. The muscle of heterozygous pigs for the halothane gene had lower pH and higher drip loss and the incidence of the PSE condition in this genotype was three times higher. The rearing system did not affect the initial and ultimate pH or water holding capacity. Indoor reared pigs had greater frequency of PSE carcass. The interaction between halothane genotypes and rearing systems had no significant effect on any trait studied.

Efeito do genótipo halotano e de diferentes sistemas de produção no desempenho produtivo e na qualidade da carcaça suína

The objective of this study was to evaluate the effect of the halothane genotypes (heterozygous and dominant homozygous) and intensive rearing systems (indoor, wood shavings bedding and outdoor) on growth performance, carcass and meat yield. Ninety six castrated male pigs were used for the trial. Identification of the halothane genotype was determined in blood samples using the DNA-test, based on the polymerase chain reaction (PCR) for amplification of the critical region of the ryanodine receptor and subsequent restriction of the amplified fragment by restriction fragment lengh polymorfism technique (RFLP). Growth and finishing performance were evaluated by weight gain, feed intake and feed efficiency. Carcass quality was evaluated by backfat and muscle depth, meat percentage through Hennessy Grading Probe and carcass weight. Twenty four hours after slaugther, ham and loin weight were recorded and the loin eye area was evaluated. The growth performance was similar for the two genotypes. The heterozygous pigs for the halothane gene had higher percentage of fat-free lean and less fat in the carcass. Outdoor reared pigs showed lower average daily gain and worst efficiency than pigs reared indoor. Carcasses of pigs reared under wood shavings bed had less fat-free lean and greater backfat thickeness. The interaction between halothane genotypes and rearing systems had no significant effect on any trait studied.