Animal Science Graduate Program, State University of Mato Grosso do Sul-UEMS, Aquidauana, Mato Grosso do Sul, Brazil.
Aquaculture Department, Federal University of Santa Catarina, Florianopolis-UFSC, Florianopolis, Santa Catarina, Brazil.
PLoS One. 2020 May 22;15(5):e0233636. doi: 10.1371/journal.pone.0233636. eCollection 2020.
This study assesses the respiratory dynamics related to stress parameters and resting time before slaughter, in the quality of surubim (Pseudopatystoma spp.) fillets. A completely randomized design was conducted using five treatments: resting time before slaughter of 0, 2, 4, 8 and 24 hours, with 15 fish sampled per treatment. Time 0 corresponded to the treatment without resting time, where the fish were slaughtered immediately after arriving at the processing plant. The resting time did not affect the electrolyte balance, hemoglobin, plasma, hepatic glycogen, myofibrillar fragmentation index (MFI) and water holding capacity (WHC) of surubins. However, with increased resting time, there was a significant decrease in muscle glycogen and an increase in blood pH and blood bicarbonate levels. Additionally, respiratory parameters showed an increase in pO2 and, consequently, in O2 saturation and a decrease in pCO2.The hematocrit and MCV values of the surubins after 24 hours of resting decreased significantly. In the first hours of resting, the highest values of erythrocytes and CHCM were observed. The lowest level of stress was observed for fish having 24 hours of resting. Fish having longer resting periods (8 and 24 hours) presented fillets with a higher pH (P <0.05) and the rigor mortis establishment time was shorter for the first 2 hours and 24 hours of resting time. There was a linear decrease in fillet lightness and an increase in the intensity of red (CIE a*) color up to 24 hours when resting was increased. In CIE b*, a linear decrease (P <0.05) of the yellow intensity of the fillets was observed as the surubim resting time increased. A resting time of 4 to 8 hours before slaughter is effective in reestablishing homeostasis after transporting surubim, providing fillets with higher quality and a greater length of the pre-rigor mortis period.
本研究评估了与应激参数和宰前休息时间相关的呼吸动力学，以评估苏里南鱼（Pseudopatystoma spp.）鱼片的质量。采用完全随机设计，使用 5 种处理方法：宰前休息时间为 0、2、4、8 和 24 小时，每个处理组取样 15 条鱼。时间 0 对应于没有休息时间的处理，即鱼到达加工厂后立即屠宰。休息时间并不影响电介质平衡、血红蛋白、血浆、肝糖原、肌原纤维碎片化指数（MFI）和水保持能力（WHC）。然而，随着休息时间的增加，肌肉糖原显著减少，血液 pH 值和血液碳酸氢盐水平增加。此外，呼吸参数显示 pO2 增加，因此 O2 饱和度增加，pCO2 降低。经过 24 小时休息后，苏里南鱼的血细胞比容和 MCV 值显著下降。在休息的最初几个小时内，观察到红细胞和 CHCM 的最高值。休息 24 小时的鱼应激水平最低。休息时间较长（8 小时和 24 小时）的鱼鱼片 pH 值较高（P<0.05），僵直时间在休息前 2 小时和 24 小时时较短。鱼片的亮度呈线性下降，CIE a颜色强度增加，直到休息时间增加到 24 小时。随着苏里南鱼休息时间的增加，CIE b的黄色强度呈线性下降（P<0.05）。宰前 4 至 8 小时的休息时间可以有效地恢复苏里南鱼运输后的体内平衡，提供更高质量的鱼片，并延长僵直前阶段的时间。
