RESUMEN

Enhancing stress resilience through the early life period in pigs could potentially improve pork quality. It was hypothesised that pigs receiving maternal contact or positive human contact during lactation would have improved carcass and pork quality. Seventy-nine mixed-sex pigs were selected from a 2 × 2 factorial randomised block design for treatments maternal contact (MC+) / reduced maternal contact (MC-); and positive human contact (HC+) / control (HC-). Modified farrowing crates were utilised to reduce maternal contact (MC-). Litters in the HC+ treatment received five minutes of daily positive human interaction (stroking). Treatments ceased at 22 days of age (weaning) and pigs were slaughtered after 21 weeks of age. The m. longissimus thoracis et lumborum pH was higher in HC+ than HC- pigs (P < 0.05) during chilling, from 90 min post slaughter. No HC effects (P > 0.05) were observed for cortisol or haptoglobin concentration, hot carcass weight, P2 backfat, carcass scratches, colour, drip loss, cook loss and shear force. MC+ tended (P < 0.086) to increase carcass weight, P2 and carcass scratch score compared to MC-, but no further impacts were observed. The impact of positive human contact during early life was observed 20+ weeks after treatment with reduced pH decline, potentially indicating a reduction in pre-slaughter stress, however there were no further impacts on pork quality. There is evidence that maternal contact is important for lifetime growth performance of pigs but the impacts on stress resilience are less apparent.

RESUMEN

In this study, pigs from 3 supply chains were slaughtered in an Australian summer and winter (n = 20 for each supply chain). The pigs were from 2 sexes (female and castrated male) and 2 carcass weight groups (high: 95.0 to 100.0 kg and low: 75.0 to 80.0 kg). From each carcass, the Biceps femoris (BF), Longissimus thoracis et lumborum (LTL), and Triceps brachii (TB) were excised at 24 h postmortem, vacuum packed, frozen at 24-48 h and transported to the lab. Cooking loss, Warner-Bratzler shear force (WBSF) and texture profile analysis (adhesiveness, chewiness, cohesiveness, hardness, resilience, and springiness) were measured in LTL and BF. pH, collagen content, and solubility and intramuscular fat (IMF) content were determined for all muscles. Results showed that BF was tougher than LTL, and winter samples were tougher than summer ones (P < 0.05). The TB had higher pH, collagen, and IMF content than BF and LTL (P < 0.05). Collagen solubility was higher in castrated male and winter samples. pH, collagen solubility, and IMF content were significantly (P < 0.05) related to chewiness and hardness in pork BF and LTL. pH and IMF were also related to cooking loss, while collagen solubility and IMF were related to WBSF (P < 0.05). The relationships of pH and IMF with pork texture were predominantly driven by the LTL, while the relationships between collagen solubility and texture were predominantly driven by the BF. Collagen solubility and IMF of pork BF and TB were related to those of LTL, but the correlations were not strong enough for prediction. Pork texture and chemical components were affected by muscle, seasons, sex and carcass weight. pH, collagen solubility, and IMF-affected pork texture.

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Pork quality was affected by the season, sex, and weight of the pigs and muscle type. In this study, we determined how season, sex, weight, and muscle affected pork chemical components and texture and, how pH, collagen and intramuscular fat affected pork texture. The results showed that pork silverside was tougher than the loin, while pork collected during winter was tougher than that collected during summer. The pork shoulder had higher pH, intramuscular fat, and collagen content than silverside and loin. Pork with higher pH, collagen solubility, and intramuscular fat content would be the tenderest.

Asunto(s)

Tejido Adiposo , Colágeno , Músculo Esquelético , Estaciones del Año , Animales , Masculino , Femenino , Colágeno/química , Colágeno/metabolismo , Músculo Esquelético/química , Músculo Esquelético/fisiología , Porcinos/fisiología , Peso Corporal , Factores Sexuales , Carne/análisis , Carne/normas , Culinaria

RESUMEN

Pork eating quality is affected by various factors. In this study, Longissimus thoracis et lumborum (LTL) and Semimembranosus (SM) muscles from seven genetic lines (PM-LR - Pure maternal, Landrace-type; PM-LW - Pure maternal, Large White-type; PM-D - Pure maternal, Duroc-type; PT-D - Pure terminal, Duroc-type; PT-LW - Pure terminal, Large White-type; PT-LR - Pure Terminal, Landrace-type; Comp-P × LW × D - Composite Terminal - Pietran × Large white × Duroc) were analyzed for pH, intramuscular fat (IMF) content, and collagen content and solubility. A consumer sensory test using check-all-that-apply (CATA) and biometric approaches was also conducted. The results showed that the IMF content of line PM-D was the highest (P = 0.004), while line PT-LW received the highest score in tenderness, liking of flavor, purchase intent, and quality grading (P < 0.05). Line PM-LR and PT-LR showed the lowest IMF content and were least preferred by consumers. Compared to LTL, SM showed higher pH, collagen solubility, and sensory scores in tenderness, juiciness, liking of flavor, and overall liking (P < 0.05). Different muscles and lines were associated with different CATA terms but not with differences in consumer emotional responses. pH positively influenced tenderness, juiciness, and overall liking (P < 0.05), but IMF and collagen had little effect. The flavor was the most important sensory attribute contributing to overall liking, followed by tenderness. Genetic line and muscle affected pork chemical properties and eating quality. The findings are important for the Australian pork industry to improve the eating quality of their products.

Asunto(s)

Colágeno , Comportamiento del Consumidor , Músculo Esquelético , Carne de Cerdo , Gusto , Animales , Humanos , Músculo Esquelético/química , Concentración de Iones de Hidrógeno , Femenino , Masculino , Adulto , Carne de Cerdo/análisis , Tejido Adiposo/química , Persona de Mediana Edad , Porcinos , Sus scrofa , Adulto Joven

RESUMEN

BACKGROUND: This experiment was conducted to test the hypothesis that vitamin E (Vit E) and acetylsalicylic acid (ASA), a cyclooxygenase-2 (COX-2) inhibitor, will additively reduce the production of the immunosuppressive molecule prostaglandin E2 (PGE2) and hence reduce inflammatory responses in weaner pigs experimentally infected with an enterotoxigenic strain of E. coli. METHODS: The experiment was conducted in a research facility with 192 individually-housed male weaner pigs (Landrace × Large White) weighing 6.6 ± 0.04 kg (mean ± SEM). The pigs were experimentally infected with an enterotoxigenic strain of E. coli and were allocated to a 2 × 3 factorial design with the respective factors being without and with 125 ppm ASA and three levels of Vit E supplementation (50, 100 or 200 IU/kg diet, dl-α-tocopheryl acetate). RESULTS: Acetylsalicylic acid supplementation improved average daily gain (P < 0.05) and tended to improve feed:gain ratio (P < 0.10) during the first 14 d after weaning. Acetylsalicylic acid supplementation also improved (P < 0.001) amino acid utilization efficiency (as assessed by plasma urea level) and tended to decrease (P < 0.10) PGE2 production in the liver without affecting small intestinal histology and tight junction protein mRNA expression in the jejunal epithelium. Vitamin E supplementation greater than 100 IU/kg diet sustained both the plasma Vit E concentration (P < 0.001) and plasma haptoglobin content (P < 0.001) after weaning. However, there was no additive effects of the combined supplementation of ASA and Vit E on performance, intestinal barrier function and inflammatory responses of weaned pigs. CONCLUSIONS: Although ASA and vitamin E improved amino acid utilization efficiency and reduced acute inflammatory responses, ASA and vitamin E did not additively reduce production of PGE2 and inflammatory responses in weaner pigs experimentally infected with an enterotoxigenic strain of E. coli.