Interaction of dietary garlic (Allium sativum), onion (Allium cepa), and probiotic on the growth performance and health status of juvenile rainbow trout (Oncorhynchus mykiss)

Abstract

Eight-week feeding trial was conducted to estimate the effects of dietary probiotic (P), garlic (G), and onion (O) powders on growth, hematology, and serum parameters in the juvenile rainbow trout (Oncorhynchus mykiss). Seven practical diets were formulated to be isonitrogenous (49% protein) and isolipidic (20% lipid) and the diets included the P, O, and G at the concentrations of 0.1, 1, and 1%, respectively, at the replace of wheat flour. Rainbow trout fed the G supplemented diet displayed a higher specific growth rate (SGR) when compared with fish fed the P and the mix of probiotics and onion (PO) (P < 0.05). The feed conversion ratio (FCR) of the fish fed the G diet was lower than the P diet (P < 0.05). Net protein utilization (NPU) of the juveniles fed the O and PO diets was higher than the other experimental groups, except the G (P < 0.05). The group fed the G diet exhibited significant differences in the packed cell volume (PCV) and hemoglobin (Hb) levels of groups fed the P and PO (P < 0.05). There were no significant differences in terms of white blood cell (WBC) and red blood cell (RBC) counts (P > 0.05). Significant differences were recorded among the serum alkaline phosphatase (ALP), while juveniles fed the G and PG diets were higher than the P and O groups (P < 0.05). The results of this study demonstrated that supplementing diets with garlic can improve some growth parameters such as SGR and PER for rainbow trout.