Densidades de estocagem no descanso pré abate afetam o esforço respiratório e muscular e qualidade do filé de Tilápia do Nilo (Oreochromis niloticus)

Abstract

Nile Tilapia (Oreochromis nilticus) management procedures are directly linked to the final quality of the product. Given this context, the aim of this study was to evaluate the effect of pre-slaughter stocking density and different stunning methods (thermonarcosis and asphyxia) on the biochemical, respiratory and muscle injury parameters associated with the quality and sensory characteristics of tilapia fillets. Were evaluated Nile Tilapia with an average weight of 762±105 g. The experiment was conducted in a 2 x 2 factorial scheme, with two densities (50 and 300 kg of live weight/m³) and two stunning methods (thermonarcosis and asphyxia), with a control treatment (fish removed from the pond and immediately euthanized by medullary section), with a total of five treatments, with 15 repetitions per treatment (each fish was considered an experimental unit) in a total of 75 fish sampled. Blood gas analysis, evaluation of biochemical parameters, analysis of meat quality and sensory analysis were carried out. High depuration density (300 Kg/m3), combined with the asphyxia stunning method, promotes changes in respiratory dynamics and provides greater stress, less firm fillet texture and greater weight loss due to cooking, as well as changes in creatine kinase (CK) and its CK-MB isoenzyme, demonstrating greater muscle damage. While the density of 50 kg/m3 during pre-slaughter, combined with the stunning method of thermonarcosis, provide a longer period of permanence in pre rigor mortis, which will result in fillets with a better sensory profile.