Effect of dietary supplementation of cinnamon (Cinnamomum verum Presl) extract to rainbow trout (Oncorhynchus mykiss W.) feed on the chemical and fatty acid profile of meat

G. Zhelyazkov* , Ts. Stoev

Department of Livestock-ruminants and technologies of animal products, Faculty of Agriculture, Trakia University, 6000 Stara Zagora, Bulgaria

(Manuscript received 4 March 2024; accepted for publication 10 June 2024)

Abstract. The aim of this study was to evaluate the effect of dietary supplementation with cinnamon (Cinnamomum verum Presl) on meat chemical composition and fatty acid profile in rainbow trouts (Oncorhynchus mykiss W. ), cultivated in a recirculation system. One hundred and twenty rainbow trouts were allotted into two variants – control (C) and experimental (C.v), each in two replication with thirty fish. The average intial body weight of fish was 41.55±7.76 g (control group) and 41.48±7.95 g (C.v group) and final live weights on the 60th day: 117.25±19.15 g (C) and 121.42±19.39 g (C.v). The trial was carried out in a recirculation system that maintained water chemical parameters optimal for rainbow trout farming. The 1% powdered cinnamon extract was given to fish from the C.v. group by lubrication of extruded feed granules with 5 ml/100 g feed sunflower oil, whereas the feed of controls was lubricated only with the same amount of sunflower oil. After the end of the feeding period, six groups from each group were euthanised, heads and viscera were removed, then they were filleted and deboned. The meat was minced, homogenised and chemical and fatty acid analyses were performed. The meat water, dry matter, lipid, protein and ash contents were not changed after feed supplementation with 1% cinnamon extract. However the tested phytoextract had a beneficial effect on the meat fatty acid profile. SFA content of meat was statistically significantly reduced along with considerable increase in the content of UFA, MUFA, PUFA and n-3 fatty acid groups. The levels of n-6 fatty acids were not influenced by the dietary supplementation with cinnamon extract. The beneficial effect of this additive on fatty acid content of meat was proved by the improved PUFA/SFA and n-6/n-3 ratios in the meat of group C.v. Both ratios were within the beneficial ranges from the point of view of human nutrition: above 0.4 and less than 5, respectively.