Influence of Multistrain Probiotics on Growth, Hematology, Gut and Liver Morphometry, and GH and IGFs Genes Expression in Rohu (Labeo Rohita) Fry

Probiotic is regarded as an effective feed additive to increase the growth, feeding efficiency, survivability, and overall productivity of fishes in aquaculture. The following study was intended to examine the effects of multistrain probiotics on growth, blood indices, histomorphometry of gastrointestinal tract and liver, and growth hormone (GH) and insulin-like growth factors (IGFs) genes expression in rohu Labeo rohita. Probiotic containing Bacillus subtilis, B. thuringiencis, Lactobacillus plantarum, and L. buchneri was inoculated in water and three different doses, that is, 0 mL/L (control), 0.5 mL/L (lower dose, T1), and 1.0 mL/L (higher dose, T2) were used in this study. Each treatment had three replicates and fishes were reared in aquarium for 60 days. Results revealed that substantially higher weight gain (WG) and specific growth rate (SGR) along with least apparent feed conversion ratio (AFC) were documented in probiotic treated fish which was significantly different than that of control, however, higher dose (1.0 mL/L) showed best performance. Blood–biochemical indices such as red blood cell (RBC), white blood cell (WBC), hemoglobin (Hb), and glucose (Glu) level were observed statistically higher in probiotic additive culture water. Moreover, the inoculation of multispecies probiotic positively altered the intestinal histometry. Besides, immune response features of intestine were observed significantly higher in probiotic treated fish. The nucleus shape and distances between liver tissues (DLTs) were also improved with the upward doses of probiotic application. The mRNAs levels of GH in the pituitary and IGF-1 and IGF-2 in the liver were significantly higher in probiotic treated fish. In a nutshell, this study suggested that the inclusion of multistrain probiotics showed promising improvement in growth performance and feed conversion efficiency; additionally, uplifted the intestinal structure integrity, liver morphology, and GH and IGFs genes expression in rohu.