Transporting live silver catfish (Rhamdia quelen) with salt addition does not mitigate fish stress and negatively affects meat quality

Abstract This study evaluated the effects of NaCl added to water during silver catfish (Rhamdia quelen) transportation on stress and meat quality. Physiological indicators of stress (cortisol, glucose, circulating ions and liver glycogen) and meat quality parameters (rigor mortis, pH, instrumental color, psychotropic aerobic count and sensory analysis) were assessed. Adult silver catfish (n=380) were distributed in four experimental groups: T1: non-transported; T2: transported without NaCl water addition; T3: transported with 8.0-g NaCl L–1 water addition; T4: transported with 12.0-g NaCl L–1 water addition. The addition of NaCl was not effective at reducing blood cortisol in silver catfish (P>0.05). An osmotic imbalance was detected as an increase in sodium and calcium levels in the NaCl treatment groups. The 12.0-g NaCl L–1 treatment showed rigor mortis evolution in lesser time than the other treatments, and also presented redder meat color. The NaCl addition in transport water do not mitigate the stress in silver catfish, and in high concentrations (12.0-g L–1) was unfavorable for the homeostasis of fish and have negatively affected its meat quality.

摘要 本研究评估了银鲶（silver catfish, Rhamdia quelen）运输过程中向水体添加氯化钠对其应激反应与肉品质的影响。研究测定了应激相关生理指标（皮质醇（cortisol）、血糖、循环离子及肝糖原（liver glycogen））与肉品质参数（尸僵（rigor mortis）、pH、仪器测色、嗜温需氧菌计数（psychotropic aerobic count）及感官分析）。选取380尾成年银鲶，随机分为4个实验组：T1组（未进行运输）、T2组（运输时未向水体添加氯化钠）、T3组（运输时向水体添加8.0g·L⁻¹氯化钠）、T4组（运输时向水体添加12.0g·L⁻¹氯化钠）。向运输水体添加氯化钠无法有效降低银鲶的血液皮质醇水平，差异无统计学意义（P>0.05）。氯化钠处理组的钠、钙水平升高，提示机体出现渗透压失衡。12.0g·L⁻¹氯化钠处理组的尸僵进程快于其余各组，且鱼肉色泽更偏红润。综上，运输水体添加氯化钠无法缓解银鲶的应激反应，且高浓度（12.0g·L⁻¹）氯化钠会破坏鱼类体内稳态，对其肉品质产生负面影响。