Muscle quality traits and oxidative status of Iberian pigs supplemented with zinc and betaine under heat stress

The study analyzed the effect of supplemental zinc and betaine on meat quality and redox status of muscles (longissimus lumborum and gluteus medius) from heat- stressed pigs. Twenty-four pure Iberian pigs were assigned to one of three treatments (n = 8): control diet, Zn supplemented diet (120 mg/kg) and betaine supplemented diet (5 g/kg) that were all exposed to 30 °C during 28 days. No significant differences were observed in chemical composition and fatty acid profile of the muscles. The Zn diet improved the water retention capacity of longissimus, increased the antioxidant properties (ABTS and FRAP) and the glutathione peroxidase activity, and reduced the level of MDA. No significant effects associated to the betaine diet were observed in quality traits and antioxidant markers of muscles. These findings suggest that Zn supplementation may be used as a nutritional strategy to improve the antioxidant properties of meat of Iberian pigs subjected to heat stress conditions.

Impact of Heat Stress on Meat Quality and Antioxidant Markers in Iberian Pigs

Heat stress is associated with impaired meat quality and disruption of redox balance. This study investigated the effect of chronic exposure to high temperature on meat quality and antioxidant markers of muscles (longissimus lumborum and gluteus medius) of growing Iberian pigs. Twenty-four pure Iberian pigs were allocated during 28 days to one of three treatments (n = 8/treatment): thermoneutral conditions (20 °C) and ad libitum feeding (TN), heat stress conditions (30 °C) and ad libitum feeding (HS) and thermoneutral and pair-fed with HS (TN-pf). Muscles of the HS group had greater intramuscular fat content than the TN-pf group and higher Zn levels than TN and TN-pf, whereas differences on fatty acid composition were negligible. Heat exposure did not affect pH, color coordinates of redness (a*) and yellowness (b*) and MDA values but had a positive influence on lightness and drip losses. Moreover, chronic heat stress stimulated the activity of antioxidant defenses SOD, CAT and GPx. The statistical factor analysis adequately classified the muscles studied, but was unable to differentiate samples according with treatments. Findings of the present study support an adaptive response of the Iberian pig to high temperatures and show the high Iberian meat quality even under adverse climate situations.

Impact of genotype, body weight and sex on the prenatal muscle transcriptome of Iberian pigs

Growth is dependent on genotype and diet, even at early developmental stages. In this study, we investigated the effects of genotype, sex, and body weight on the fetal muscle transcriptome of purebred Iberian and crossbred Iberian x Large White pigs sharing the same uterine environment. RNA sequencing was performed on 16 purebred and crossbred fetuses with high body weight (340±14g and 415±14g, respectively) and 16 with low body weight (246±14g and 311±14g, respectively), on gestational day 77. Genotype had the greatest effect on gene expression, with 645 genes identified as differentially expressed (DE) between purebred and crossbred animals. Functional analysis showed differential regulation of pathways involved in energy and lipid metabolism, muscle development, and tissue disorders. In purebred animals, fetal body weight was associated with 35 DE genes involved in development, lipid metabolism and adipogenesis. In crossbred animals, fetal body weight was associated with 60 DE genes involved in muscle development, viability, and immunity. Interestingly, the results suggested an interaction genotype*weight for some DE genes. Fetal sex had only a modest effect on gene expression. This study allowed the identification of genes, metabolic pathways, biological functions and regulators related to fetal genotype, weight and sex, in animals sharing the same uterine environment. Our findings contribute to a better understanding of the molecular events that influence prenatal muscle development and highlight the complex interactions affecting transcriptional regulation during development.