C29 | Assessment of oxidative stress and animal welfare in equids slaughtered in the province of Reggio Emilia

G. Muresu Ibba¹, C. Cipolat Gotet², L. Fasolato³, M. Soncin⁴, M. Pazzola⁵, F. Pasetto¹. | ¹Az. USL Reggio Emilia, Servizio Sanità Pubblica Veterinaria; ²Dipartimento Scienze Medico Veterinarie Università di Parma - strada del Taglio 10 - Parma; ³Dipartimento Biomedicina comparata e Alimentazione Università degli studi Padova – Agripolis - Legnaro (PD); ⁴DVM, Servizio di Medicina di Laboratorio, Istituto Zooprofilattico Sperimentale delle Venezie (IZSVe) _Legnaro (PD); ⁵Dipartimento Di Medicina Veterinaria Università di Sassari - Sassari, Italia.

Animal cells produce free radicals and reactive species as part of normal metabolic processes. To counteract these potentially harmful effects, cells have developed complex defence systems through enzymatic and non-enzymatic pathways. However, particular living conditions can lead to excessive production of reactive metabolites without these being balanced by the antioxidant system, resulting in oxidative stress. In recent years, there has been much discussion about oxidative stress in relation to animal welfare and livestock production. Several studies on cattle and pigs have shown that high levels of oxidative stress result from suboptimal breeding and management conditions; these levels have a negative impact on carcass quality parameters and reduce the shelf life of meat. The harmful effects of oxidative stress on meat quality are well known, with reference to the increase in malondialdehyde (MDA) content in the carcass, an indicator of excessive lipid peroxidation, and reduced post-mortem calpain activity, with lower myofibrillar proteolysis. In equines, data are still scarce. The aim of this study was to evaluate oxidative stress in a group of slaughtered equines, correlating it with welfare aspects such as behavioural changes and transport times, as well as characteristics such as breed, sex, age and origin. The study was conducted on 80 clinically healthy DPA horses slaughtered at a recognised establishment in the province of Reggio Emilia. During the ante-mortem examination, information was collected on breed and aptitude, sex, age, origin (Belgium, France, Poland, Slovenia, Italy), transport time, and the presence of stereotypies. During jugulation, a blood sample without anticoagulant was taken from the left jugular vein of each subject. The samples were refrigerated and delivered to the IZSVe laboratory within 8 hours of collection, where they were centrifuged to separate the serum. The serum samples were tested for d-ROMs (reactive oxygen metabolites, indicators of oxidative damage) and OXY (determination of the plasma barrier to oxidation, which provides information on the ability of blood plasma to neutralise free radicals and protect the body from oxidative damage). Statistical evaluation was performed using different multivariate analyses such as ANCOVA, NP regression and PCAmix to study the contribution of each factor in the study (origin; breed; stereotypies; transport; age and sex) on the two parameters studied. Data collection during the ante-mortem visit revealed the presence of stereotypy in 25 subjects from France and Slovenia. Statistical analysis showed some factors particularly associated with high levels of biochemical descriptors, especially between the presence of stereotypies and high d-ROMs values (p value 0.0001) and breed (TPR P value 0.011). The highest OXY values were observed in horses of French and Italian origin (p values 0.022-0.039) in relation to travel methods and times. This study therefore demonstrated that oxidative stress is an indirect indicator of welfare at slaughter, with particular attention to the transport phase to the approved establishment.