Karina Godoy; Cristian Sandoval; Carlos Manterola-Barroso; Paulo Salinas; Luis A. Salazar & Mariana Rojas

In salmon farming systems, X-ray images are used to evaluate the spine and fins, but these do not allow quantifying the minerals that make up the bone, for different techniques that are destructive are used. Variable Pressure Scanning Electron Microscopy (VP SEM) coupled to an Energy Dispersive X-ray spectroscopy detector (EDX), allows us to analyze the microstructure and at the same time determine chemical elements, percentages, and distribution present at specific points in a sample. Five control and five jaw deformity trout, from freshwater and in the smolt stage were used. The structure and mineralization of the bone were analyzed, an ave- rage six quantification points were chosen per region of interest (ROI) and then they were analyzed by Scanning Electron Microscopy (VP SEM-EDX). The data obtained have shown the average mass percentage of calcium in trout joint bone was 8.07 % and 14.48 % in jaw deformity and control trout, respectively; and the average mass percentage of phosphorus is 4.07 % and 7.60 %, in jaw deformity and control trout, respectively. Other elements present in the sample were also identified, such as magnesium, sodium, carbon, oxygen, nitrogen, sulphur, fluorine, zinc, aluminium, and iron, with special interest the increase of carbon in the analyzed samples with mandibular deformity and the presence of aluminum in all samples. The VP SEM-EDX Technique allows direct evaluation, without destruction of the sample and with minimal sample preparation. In bone, the most frequent application of SEM-EDX is the measurement of the content of calcium (Ca) and phosphorus (P) and the relationship that exists between these elements, calcium/phosphorus (Ca/P), in the sample. At the same time, the technique allows us to detect other microelements from water or food that can eventually cause alterations in fish, confirming the hypothesis that elemental microanalysis is useful for salmon farming.

GODOY, K.; SANDOVAL, C.; MANTEROLA, C.; SALI- NAS, P.; SALAZAR, L. A. & ROJAS, M. Evaluation of mineralization in jaw and teeth of rainbow trout (Oncorhynchus mykiss) using variable pressure scanning electron microscopy coupled to energy-dispersive X-ray spectroscopy detector. Int. J. Morphol., 40(2):530-539, 2022.