Effect of salinity on growth performance of tra catfish fingerlings (Pangasianodon hypophthalmus)

Abstract

Tra catfish (Pangasianodon hypophthalmus) is an important aquaculture species in Vietnam. The aim of the current study was to assess the growth performance of P. hypophthalmus fingerlings under different salinity conditions. The experiments were designed with salinities of 6, 9, 12 and 15 ppt in 500L tank, and stocking density was 50 fingerlings/ tank. Fingerlings were acclimatized gradually to reach particular salinity concentration at a rate of 2 ppt per day and were maintained at the expected salinity concentration for a week prior to the grow-out trial. The growth performance were evaluated using various indices, including net weight gain (NWG), daily weight gain (DWG), specific growth rate (SGR) and percentage of weight gain. The study also investigated the other indices that contributed to the growth performance, including food conversion rate (FCR) and daily food intake (DFI). Results after a 42-day experiment showed that NWG, DWG, SGR and percentage of weight gain were highest at 9 ppt and lowest at 15 ppt. The same pattern also observed for FCR and DFI. However, no significant differences were detected for all indices among the treatments and the control. While survival rates were found significantly different between the 15 ppt treatment and the lower salinities. We discuss the implication of these findings with relevance to the expansion of commercial Tra catfish culture in brackish water area and also the needs of further study. Keywords: Pangasianodon hypophthalmus, salinity, growth performance, survival