Physical characteristics extruded and pressed pellets for feed salmon (Oncorhyncus mykiss) and common carp (Ciprinus carpio)

The aim of this study was to evaluate the physical structure of the pellets produced in the aquaculture industry. For this reason, pellets for growthing with a diameter of 4 mm, extruded and pressed preparation for taking trout and carp, of Behdaneh factory in sari was tested. tested Grft.paramtr uniform pellet diameter, weight, humidity, immersion, spreading rate, solubility water and water-holding capacity. The results showed that the grain diameter feed made with extruded pellets compressed with a diameter of no significant difference. The results of the test weight, moisture and compressed pellets was less than the rate of expansion of the extruded pellets and showed significant differences (P <0.05), but the trout and carp pellets was not significantly different (P> 0.05). During the test floating pellets extruded and pressed pellet was completely submerged. Extruded pellet stability in water than compressed pellets and extruded pellets and pressed carp solubility in less than two types of trout pellets, but in neither case was no significant difference (P> 0.05). Water holding capacity (WHC) in the investigation of extruded and pressed statistically significant difference was observed (P <0.05) and extruded pellets in the water holding capacity was higher but not statistically significant difference in the diet of trout and carp (P> 0.05 ). Finally, it can be concluded that most of the pellets compressed extruded pellet durability, and this type of platform is more advantageous for use in fish feed.