This study investigated the onion powder supplement in the diet of the Common carp (Cyprinus carpio) on growth, corpse composition and hematological parameters. Twenty fish, averaging 18±1.9 g., were randomly stocked into tanks. Onion powder was added to the basic diet of 39% crude protein and 18% crude lipid at the concentrations of 0, 0.5, 1 and 2%, as four experimental diets. Respectively by hand at a rate of 3-5% of body weight twice daily for 45 days. Blood samples were collected from caudal vein of apparently healthy fish at the end of trial using syringe and hematological indices (WBC, RBC, Hb, PCV, Neurophyl, Monocyte and Lymphocyte) were determined. The optimal growth performance and feed efficiency was observed in fish which were fed the 0.5% onion powder diet despite of no significant difference with the control group (P>0.05). There were no significant differences in survival rate among all groups (P>0.05). Also, no significant differences was observed in crude protein of corpse (P>0.05), while total lipids and ash decreased significantly at the concentrations of 0.5% onion powder (P<0.05). No significant difference in hematological parameters between treatments were found (P>0.05), although the fish fed the 0.5% onion powder diet showed an enhancement of blood variables compared to the other groups. In conclusion, it can be suggested that dietary inclusion of 0.5% onion powder was effective at improving growth, feed efficiency, body composition and hematological parameters of common carp.

The aim of the present study is to compare hematological and biochemical parameters of common carp (Cyprinus carpio) fed with separate and combined levels of multi-enzymes commercial feed. A total number of 96 common carp fingerlings weighing 13.06±2.56 g and total length 9.25±1.34 cm were distributed in six treatments including control (without multienzyme), 1000 and 1500 mg/kg Combo, 1000 and 1500 mg/kg Natuzyme and combined treatment of 1000 mg/kg Combo plus 1000 mg/kg Natuzyme into 12 tanks at a density of 8 fish per tank. At the end of a 8-week feeding trial, blood sampling was done to measure hematological parameters. Results showed that there were significant differences in final weight, body weight increase and feed conversion ratio among treatments (p<0.05). Some treatments had an increase (p<0.05) in RBC, contents of hematocrit and hemoglobin, WBS (except 1500 mg/kg Natuzyme) and lymphocyte number compared to the control. The highest number of lymphocyte was seen in 1000 mg/kg Natuzyme and 1500 mg/kg Combo which had significant difference with other treatments (p<0.05). The maximum content of triglyceride was recorded in 1000 mg/kg Natuzyme that had significant difference with the control and combined treatment (p<0.05). There were differences between levels of liver enzymes among treatments (p<0.05). The highest content of amylase, protease and lipase were observed in 1500 mg/kg Combo and 1000 mg/kg Combo, respectively which showed significant difference with others (p<0.05). According to the results, Natuzyme and Combo can be effective in the improvement of hematological and biochemical parameters of common carp fingerlings.
 

In order to survey on effects of  dietary Thyme (Thymus vulgaris) extract on common carp 180 Fish with average weight of 10.84±0.063 were divided into four groups  with three replicates (each replicate with 15 fihs), and fed with different levels of dietary Thyme extract including 0, 0.5, 1 and 2 % for 70 days. At the end of rearing period 30 fish from each group were exposed to 13 ppt sea salt for 12 hours and were studied for hematological parameters. In this regard, sampling were done in times of  before salinity stress and 6, 24, 72 hours post salinity stress from caudal peduncles.  In this study supplementary thyme extract in food has no effects on growth performance after rearing period (P>0.05). in hematological study, after salinity stress hematocrit levels in treatments 0.5 % was increased compared to control group (p<0.05). And so hematocrit value in fish of treatments 1% and 2% groups were calculated significantly higher compare with control,  72 h post salinity stress (p<0.05). Hemoglobin levels just in the treatment groups were significantly increased after salinity stress  (p<0.05).The white blood cells (WBC)  and red blood cell (RBC)counts and so hematological indices (MCV, MCH, MCHC value) had no significant difference among all studied fish (P>0.05). Totally in this study supplementary 0.5, 1 and 2 % dietary thyme extract has no effect on growth performances and hematological parameters in common carp in salinity stress situation.