Nuevos indicadores de carnes DFD: estrés oxidativo, autofagia y apoptosis

Abstract

En el ganado vacuno, el estrés pre-sacrificio provoca la aparición de carnes conocidas como DFD (Dark, Firm, Dry), que se identifican por un descenso anómalo del pH muscular post-mortem y que muestran serios problemas de calidad, lo cual disminuye su valor comercial. El objetivo de este trabajo es conocer las diferencias en los procesos de estrés oxidativo, en los mecanismos de supervivencia/muerte celular (autofagia/apoptosis) y en biomarcadores proteómicos a las 24 h post-mortem, entre canales que mostraron un descenso normal de pH (pH = 5,4-5,8 a las 24 h post-mortem) utilizadas como CONTROL y canales con pH a las 24 h post-mortem (pH 24 ) > 6,0 clasificadas como DFD, con el fin de identificar los procesos del metabolismo muscular ligados a la aparición de carnes DFD.Se analizó el estrés oxidativo celular mediante el estudio de la actividad antioxidante total y los daños en macromoléculas (proteínas y lípidos). Las carnes DFD mostraron mayor actividad antioxidante (P < 0,05) a las 24 h post-mortem, así como mayor daño de proteínas (P < 0,05). También se analizaron biomarcadores de autofagia (Beclin-1 y LC3-II/LC3-I) y apoptosis (caspasa-3), así como los cambios producidos en el proteoma muscular. Los resultados demuestran la coexistencia de autofagia y apoptosis en el tejido muscular a las 24 h post-mortem, con diferencias de expresión significativas (P < 0,05) que permiten discriminar carnes DFD frente a carnes sin alteraciones de calidad (CONTROL).

Impact of Extraction Method on the Detection of Quality Biomarkers in Normal vs. DFD Meat

“…Proteomic studies have reported the differential expression of Hsp70 in meat with variable quality traits [ 22 , 38 ]. Several studies have correlated meat quality with Hsp70 under stress situations [ 39 , 40 , 41 ].…”

New Insights on the Impact of Cattle Handling on Post-Mortem Myofibrillar Muscle Proteome and Meat Tenderization

“…In the present study, band M24 was identified as FHL1 and, contrary to what was found for FHL2, only a significant decrease with post-mortem ageing and a significant interaction F × TL (E-NM > E-M = I-M > I-NM) was observed ( p < 0.001). Previous studies found increased intensity of FHL1 in DFD meat [ 16 , 22 , 57 ].…”

“…On the other hand, animal handling may affect animal’s emotional state, hence inducing pre-slaughter stress (PSS), whose influence on the post-mortem process of muscle-to-meat conversion has been shown in pigs [ 13 , 14 ] and in cattle [ 3 , 9 , 10 , 15 , 16 , 17 , 18 ]. Those biochemical changes were evidenced using several high-throughput OMICs methods, including proteomics that revealed, for instance, that the meat tenderizing process involves myriad pathways, such as the degradation of structural proteins, energy metabolism pathways, response to stress, apoptosis, autophagy, and signaling pathways [ 19 , 20 ] as confirmed recently by the integromics meta-analysis study of Gagaoua et al [ 21 ].…”

Caspase activity in post mortem muscle and its relation to cattle handling practices

“…Several studies have described the effect of handling practices on meat characteristics 24,32,33 and some of them have reported differences on caspase 3 expression patterns between normal and DFD samples, finding higher caspase 3 regulation levels in DFD samples at 24 h post mortem. 14,15 However, no studies have been previously reported concerning the relationship between caspase activity and stress-related factors. From our study we hypothesized that, depending on the external stimulus affecting animals before slaughter, different caspase activation responses could be triggered.…”

“…13 In this line, some authors found a higher expression of the caspase 3 large subunit in DFD beef samples at 24 h post mortem times. 14 In the present study, and for the first time, the study of apoptosis as a way to understand the influence of pre-slaughter handling practices on biochemical muscle characteristics of several bovine breeds is proposed. The research investigated the activity of executioner caspases 3/7 and initiator caspase 9 over time (2, 8, and 24 h post mortem) in loin samples of three Spanish beef cattle breeds managed under different feeding systems (intensive versus semi-extensive) and transport/lairage (mixed versus nonmixed with unfamiliar animals) conditions.…”