GROWTH PERFORMANCE, BIOCHEMICAL BLOOD PARAMETERS AND MEAT QUALITY OF RAINBOW TROUT (ONCORHYNCHUS MYKISS W.) FED WITH CNICUS BENEDICTUS L. EXTRACT

Aquaculture development is influenced by various environmental factors and nutrition with herbal additives can affect the growth in aquaculture and to improve indicators such as digestibility, nutrition effectiveness and food taste. The purpose of this study was to trace growth performance, meat quality and biochemical blood parameters (glucose, urea, creatinine, total protein, albumin, ASAT, ALAT, Ca, P, Mg, triglycerides, cholesterol) of rainbow trout (Oncorhynchus mykiss W.) fed with additive blessed thistle (Cnicus benedictus L.) extract. To achieve the objective a control group (no added) and an experimental (with added 1363 mg.kg-1 of blessed thistle extract) option, each with a two repetition, were set in a recirculating system in the Aquaculture Base of the Faculty of Agriculture at the Trakia University. Forty specimens from the fish species rainbow trout with an average weight of fish 13.32+3.07 g (control) and 13.33+2.58 g (experimental) in good health condition were placed in each tank and cultivated for 60 days. At the end of the experiment were calculated average final weight, specific growth rates, feed conversion ratio, meat quality and blood parameters. Trout from the experimental group, fed with supplement had with 8.52% higher average final weight compared to the parameter value of fish from control (P<0.001). The blood biochemical parameters ASAT and ALAT in control variant were higher with 27.4% and 44% respectively, compare to values of this parameter of fish from the experimental (P>0.05). Experimental fish fed with additive blessed thistle have a higher electrolytes level of magnesium (Mg) with 5.26% compared to control group (P>0.05). The protein content in the fish of the control group and experimental were of close value, but not statistically proven. The blessed thistle supplementation in the diet led to lower the lipid content in the fillets of the rainbow trout with 19.7% compare to values of this parameter of fish from control group and was statistically proven (P<0.05). This result shows that fish fed with the supplement are more useful and dietetic in their quality as human food. Rainbow trout fed with blessed thistle supplement have better growth performance and blood parameters.