This study investigated the use of salt as a mitigating agent for bacterial contamination and physiological responses of tilapia in a simulation of pre-slaughter transport. Bacteria concentration, haematological parameters and muscle dehydration were evaluated. Adult tilapia (568 ± 141 g) were fasted for 24 h and subjected to a simulation of transport for 4 h in four salinities: 0, 7, 14 and 21 g of salt L⁻¹. The concentration of 21 g of salt L⁻¹ resulted in the lowest concentration of aerobic mesophilic heterotrophic bacteria on the skin of tilapia and in the transport water. Salinity did not influence the haematological parameters of haematocrit, monocytes, eosinophils, basophils, haemoglobin and mean corpuscular haemoglobin concentration. The concentrations of 14 and 21 g of salt L⁻¹ had the lowest plasma protein values and led to lymphopaenia and neutrophilia. The concentration of 7 g of salt L⁻¹ had values similar to baseline level for lymphocyte, neutrophil, white blood cell counts and plasma protein. Hyperglycaemia and thrombocytopaenia occurred in all treatments. Increased dehydration of muscle tissue with increased salinity was observed. The concentration of 7 g of salt L⁻¹ promoted the fewest physiological changes. However, it is recommended the transport at high salinity of 21 g of salt L⁻¹ for bacterial control.

中文翻译：

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盐度梯度对屠宰前罗非鱼（Oreochromis niloticus）皮肤和水微生物群落及生理反应的影响

本研究调查了在模拟屠宰前运输中使用盐作为罗非鱼细菌污染和生理反应的缓解剂。评估细菌浓度、血液学参数和肌肉脱水。成年罗非鱼 (568 ± 141 g) 禁食 24 小时，并在四种盐度下模拟运输 4 小时：0、7、14 和 21 g 盐 L ^-1。21 g 盐 L ^-1的浓度导致罗非鱼皮肤和运输水中的需氧嗜温异养细菌浓度最低。盐度不影响血细胞比容、单核细胞、嗜酸性粒细胞、嗜碱性粒细胞、血红蛋白和平均红细胞血红蛋白浓度的血液学参数。14 克和 21 克盐 L 的浓度^-1的血浆蛋白值最低，导致淋巴细胞减少和中性粒细胞增多。7 g 盐 L ^-1的浓度值与淋巴细胞、中性粒细胞、白细胞计数和血浆蛋白的基线水平相似。所有治疗均发生高血糖和血小板减少症。观察到随着盐度增加，肌肉组织脱水增加。7g 盐L ^-1的浓度促进了最少的生理变化。但是，建议在高盐度下运输 21 g 盐 L ^-1以进行细菌控制。