Effects of low molecular weight agar and Lactobacillus plantarum on growth performance, immunity, and disease resistance of basa fish (Pangasius bocourti, Sauvage 1880)

• Pangasius bocourti fed with 2 g kg−1 LMWA enhanced growth performance.
• Fish fed diet 108 cfu g−1 of Lactobacillus plantarum improved growth performance.
• Diet of 2 g kg−1 LMWA and L. plantarum increased fish immunity and disease resistance.
• Combination of LMWA and L. plantarum stimulated immunity and disease resistance.

This study evaluated effects of low molecular weight agar (LMWA) and Lactobacillus plantarum singly or combined on growth performance, immunity and disease resistance of basa fish (Pangasius bocourti). Two hundred forty fish were divided into four treatments, i.e. 0 g kg−1 LMWA (Control), 2 g kg−1 LMWA, 108 cfu g−1L. plantarum, and 2 g kg−1 LMWA + 108 cfu g−1L. plantarum. Following 7, 14 and 28 days of the treatment, specific growth rate (SGR), feed conversion ratio (FCR), serum lysozyme, phagocytosis, respiratory burst and alternative complement activity (ACP) were measured. A Completely Randomized Design with four replications was applied. At the end of the feeding trial, five fish were randomly selected for a challenge test against Aeromonas hydrophila. The results showed that fish fed diet of 2 g kg−1 LMWA and 108 cfu g−1 of L. plantarum singly or combined significantly enhanced SGR, FCR, serum lysozyme, phagocytosis, respiratory burst, alternative complement activities and post-challenge survival rate of P. bocourti. The results inferred that dietary of LMWA and L. plantarum stimulated growth, immunity and disease resistance of the P. bocourti.