Effect of Mechanical Vibrations During Transport Operations of Nilo Tilapia (Oreochromis niloticus)

Oscillatory movements present in the transport of live fish may compromise the physiological stability and the future performance of the animals. Therefore, the objective of this research was to evaluate the effect of mechanical vibrations in the transport of Nile tilapia through vibration levels and shocks occurred in transport boxes previously installed in a truck. The research was carried out in a fish farming integrating company in the state of Ceará, Brazil, with the monitoring of 5 live fish loads. The transport truck used was of the open type, with capacity for five boxes of fiberglass with a useful volume of 2400 L, density of 236 kg m-3. The data were recorded through five dataloggers, to monitor the vibration level (m s-2) and the occurrence and amplitude of mechanical shocks on the roads. Hematological, metabolic and ionic responses of fish were evaluated as well as visual observations of physical injuries. The most intense shocks occurred with the truck between 60 and 80 km h-1, with vibrations 1.151 m s-2 in the transport box, as well as in the water 0.489 m s-2. Larger vibration levels occurred on the asphalt road, with an average value of 1.13 m s-2, while on the dirt road they registered an average of 0.57 m s-2. Vibratory and mechanical stimuli presented secondary responses to blood level stress with alterations in glycemia, hematocrit, hemoglobin and magnesium ions. Physical lesions with 34% severe and 21% moderate, showed an uncomfortable environmental condition to fish.