Document Type : Research Paper
M.Sc Student of aquaculture, Khorramshahr University of Marine Scince and Technology, Khorramshahr, Khuzistan, Iran
Department of Fisheries, Faculty of Marine Natural Resources. Khorramshahr University of Marine Sciences and Technology, Khorramshahr, Khuzistan, Iran
Department of Marine Biology, Faculty of Marine Science, Khorramshahr University of Marine Sciences and Technology, Khorramshahr, Khuzistan, Iran
This study evaluates the effects of different levels of acidifier: Sodium diformate and citric acid on body composition, serum enzymes and the alimentary canal tissue in rainbow trout (Oncorhynchus mykiss). For this purpose, 630 fingerling fish(mean weight: 16.55 ± 0.72 g), were randomly distributed in twenty one 200-L fiberglass tanks (30 fish per tank). This study was performed 60 days with seven experimental treatments: control (only fed with commercial diet: FFT2), three levels of sodium diformate added to diet: 0.2% (treatment A), 0.4% (treatment B), 0.6% (treatment C) and also three levels of sodium diformate in combination with citric acid with an equal rates: 0.1% (treatment D), 0.2% (treatment E) and 0.3% (treatment F). The fish were fed 2 % based of body weight three times daily at 8:00, 12:00 and 16:00 for two months. The results indicated that different levels of sodium diformate and citric acid supplements used had no significant effect on the activity of serum enzymes of rainbow trout in comparison with the control treatment (p>0.05); while it had significant effects on the protein, ash and moisture of the body composition among the experimental treatments (p<0.05). The maximum height and width of microvilli, the number of goblet cells, the thickness of serous membrane, parin and submucosal layer of intestine along with the thickness of muscle layer were observed in treatment D, which exhibited significant differences with other treatments (p<0.05) and the minimum rate of the mentioned factors was recorded in the control treatment. Adding 1% sodium diformate and 1% citric acid to diet of rainbow trout can be useful because of the improving body composition indices, including an increase in protein and ash, as well as improving intestine histological indices.