Diferentes biomassas no acondicionamento de tilápias sp. após transporte sobre o retorno a homeostase

Abstract

Fish biomass is one of the success factors during fish transport and pond stocking. This study aimed to evaluate the effect of tilápia stocing density on the time to homeostasis recovery of tilapia after transport. For that, 490 tilapia juvenile around 51,42±8,28g were placed in adapted transport box and transported during five hours. At the end of this period, fish were placed in 500L 18 PVC boxes, filled whit water and maintained whit a volume of 100L, and a mean water flow of 0.05L/s. The tilapia juvenile were randomly distributed in boxes in an entirely random factorial outline of 2 x 3, with two biomasses 10.3 and 15.4 g/L and, three samplings in time, 24, 68 and 168 hours after transport, with three repetitions each. Water physical and chemical parameters were analyzed before and after transport, in the water used from the reservoir, and in the PVC boxes, during the study. Fish blood was collected by puncture from the caudal vasculature, for the determination of the following variables: glucose, hemoglobin, hematocrit, total number of erythrocytes, mean corpuscular volume, cortisol and ions, Na and K. The blood was centrifuged, and the serum stored -20°C until the analyses. The obtained data were submitted to an analysis of variance whit P>0.01 and the averages compared with the Tukey test at 5%. It was concluded that glucose was the best parameter the diagnosis of the occurrence of physiological stress in juvenile tilapia, contrary to expectations. The largest biomass of stand after transport reduced the glycemic content of tilapia, contrary to expectation. There was interaction between biomass and time of storage after transport to the variables blood glucose and hematocrit. This indicates the importance of the period and the condition of proper fish conditioning after transporting on the returning to homeostasis, a procedure that could be used for increased safety in handling subsequent transport in fish farms. You can suggest new research biomass testing at intervals greater than assessed.