Multi-Species Probiotics Ameliorate Salinity-Induced Growth Retardation In Striped Catfish Pangasianodon hypophthalmus

Salinity is regarded as one of the most crucial environmental parameters and salinity mediated stress adversely affect the aquaculture production. Probiotics might alleviate the salinity stress in fish. Here, we investigated the role of probiotics on growth (weight gain, specific growth rate), survivability, feed utility (feed conversion ratio), hemoglobin, glucose, structure of erythrocytes (cellular and nuclear abnormalities), and gut morphology of striped catfish (Pangasianodon hypophthalmus) reared in different salinities. The fingerlings (8.10 ± 0.20 g) were evenly distributed four different salinities (0, 4, 8 and 12 ppt) in three replicates with and without probiotics supplementation for 56 days. Multi-species probiotics containing Bacillus subtilis (5 × 10⁹ cfu/ml), B. thuringiencis (4 × 10⁹ cfu/ml), Lactobacillus plantarum (5.8 × 10⁹ cfu/ml), and L. buchneri (6.5 × 10⁹ cfu/ml) were used as 1.0 mL/L at the alternate day. The results of this study indicated that survivability, growth and feed utility were negatively affected with the increased salinity, however multi-species probiotics significantly ameliorated the negative effects of salinity. Moreover, multi-species probiotics significantly improved hemoglobin (g/dL) and glucose (mg/dL) level at different salinity in comparison with the non-probiotics treated groups. Frequencies of cellular and nuclear abnormalities of erythrocytes were increased significantly with the increase of salinity in non-probiotics groups, while those significantly declined in multi-species probiotics treated groups. Increased salinity level suppressed the immune response indices, while probiotics supplementation significantly improved the gut immune response irrespective of salinity level. Taken altogether, the current study revealed that application of multi-species probiotics can be an effective tool to reduce salinity stressors and improve growth and health status by upgrading hemato-biochemical profile and intestinal morphology of P. hypophthalmus at higher salinity.