Improvement of the Growth Performance, Innate Immunity and Disease Resistance of Nile Tilapia (Oreochromis niloticus) against Vibrio parahaemolyticus 1T1 following Dietary Application of the Probiotic Strain Lactobacillus plantarum 1KMT

The impact of Lactobacillus plantarum 1KMT on the survival rate, growth performance, innate immunity and disease resistance of Oreochromis niloticus challenged with pathogenic Vibrio parahaemolyticus 1T1 was investigated. This study was conducted in the Fisheries Department of National Agriculture Research Centre (NARC), and Department of Biosciences of Comsats University Islamabad, Pakistan between August 2018 and August 2019. Sixty healthy fish (10.99 ± 1.1 g body weight) were acclimatised to laboratory conditions in 1000 L tank for 14 days. After, they were randomly divided equally into two groups G1 and G2 with one replication: G1 fed with the basal diet (BD) without probiotic (control), and group G2 was fed with 1x108 CFU.g-1 Lactobacillus plantarum 1KMT supplemented diet. The trial was conducted for a period of 60 days. The intestinal microflora, survival rate (SR), weight gain (WG), specific growth rate (SGR) and food conversion ratio (FCR) were checked after every ten days. After 60 days, the innate immune parameter levels were evaluated. For challenge study against Vibrio parahaemolyticus 1T1, eighteen fish from G2 were randomly selected and divided in two subgroups: G2A, with 1KMT continuous treatment and G2B in which treatment was stopped. After 21 days, the mortalities were recorded. The results showed that the intestinal microflora was significantly improved in G2 compared to G1. The survival rate was 96.5% and 86.0% in G2 and G1, respectively. The WG was not significantly affected, while the SGR and innate immunity parameters were significantly improved (p < 0.05) in G2 compared to G1. The mortality rate was 77.7% and 66.6% in G1 and subgroup G2B, respectively, while no mortality was observed in G2A after the challenge test. The Lactobacillus plantarum 1KMT improves the growth performance, survival rate, innate immunity and disease resistance of Nile tilapia.