Evaluation of Bacillus licheniformis and Bacillus subtilis as probiotic and Fe ion effects on haematological parameters of rainbow trout, Oncorhynchus mykiss frys

Abstract

In this study, the effects of a commercial probiotic containing Bacillus licheniformis and Bacillus subtilis along with feriron solution were investigated on the haematological parameters of rainbow trout frys. The experiment was carried out in eight treatments and one control group for a period of 60 days after beginning of active feeding. In the experimental treatments, the frys were fed with dry diets containing various ratios of probiotic and feriron solution. The haematological parameters including number of white blood cells (WBCs) and red blood cells (RBCs), haemoglobin concentration (Hb), haematocrit percent, transferrin, ferritin and IgM concentrations were measured every 10 days over the course of the experiment. According to results, the probiotic receiving treatments had higher WBCs concentration than control group (P<0.05). The higher values of RBCs, Hct and Hb were observed in fish fed with diet containing feriron solution than other treatments (P<0.05). The highest values of serum Fe, transferin and ferritin were observed in treatments containing 1.2×109 CFU/g probiotic+7 mg/kg dry diet (T 7 ) or 5 mg/kg dry diet (T 8 ) feriron solution, while lowest values of these parameters were found in treatments containing 1.6 × 109 CFU/g probiotic+7 mg/kg dry diet (T 5 ) or 5 mg/kg dry diet (T 6 ) feriron solution (P<0.05). The IgM values had the highest and lowest levels in treatments that had received only probiotic (T 1 and T 2 ) (P<0.05) and those that received only feriron solution (T 3 and T 4 ), respectively. In conclusion, the high levels of WBCs and IgM are likely an immunity response to probiotic. Low levels of RBCs, Hct and Hb likely return to low levels of serum in treatments fed by diet without feriron solution. It seems that the Fe ion causes the proliferation of probiotic bacteria and in return probiotics help to digestion and subsequently the bioavailability of elements including Fe ion to serum.

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“…The WBC and monocyte values were also significantly increased in fish treated with L. plantarum. Similar to our results, recent studies suggest that the use of probiotic in some species such as Indian Magur, Clarius batrachus (Dahiya et al, 2012), Clarias gariepinus (Ayoola et al, 2013), Rainbow trout, Oncorhynchus mykiss (Naseri et al, 2015) and Kutum, Rutilus frisii kutum (Azarin et al, 2015) increased the WBC count. However, our results are also inconsistent with Jafarzadeh et al (2015) that WBC count showed a decreasing trend during the period of the experiment in all synbiotic supplement diets.…”

Growth performance, immune response, antioxidant capacity and disease resistance against Yersinia ruckeri in rainbow trout ( Oncorhynchus mykiss ) as influenced through singular or combined consumption of resveratrol and two‐strain probiotics

“…Consistent with previous reports, plant derivatives can promote the production of phagocytic cells in rainbow trout by stimulating lymphoid tissues such as the thymus and spleen (Rashmeei et al, 2020; Yılmaz & Ergün, 2018; Yonar, 2019). On the contrary, Naseri et al (2015) and Mohammadian et al (2020) documented, respectively, that Bacillus licheniformis and B . subtilis and L .…”