Improvement of water quality with probiotics inclusion during simulated transport of Yellowfin Seabream Acanthopagrus latus larvae.

OBJECTIVE: The expansion of marine aquaculture requires the shipment of early life stages from hatcheries to breeding centers. Thus, maintaining water quality parameters during transportation is crucial. This experiment investigated the effects of a commercial probiotic mixture (PM) (consisting of Bacillus licheniformis, Bacillus subtilis, Pediococcus acidilactici, and Lactobacillus acidophilus with a total count of 107 CFU/g) on water quality, bacterial population, and the survival of larvae of Yellowfin Seabream Acanthopagrus latus during a 24-h simulated transportation experiment. METHODS: To simulate transportation, purified seawater was used as a control and purified seawater supplemented with 3 g of PM was used as the PM48 treatment. For the PM48 treatment, 3 g of PM was added to 1 L of purified seawater and mixed with 200 L of purified seawater 48 h prior to the main experiment. RESULT: The use of probiotics resulted in an increase in larval survival up to 93.3% compared with 89.85% in the control group. Initial sampling showed a statistically significant difference in NO 2 - levels between the control and PM48 treatments. After transportation, the pH of the control treatment showed a significant decrease. The total number of bacteria and the total number of Vibrio spp. in water and fish larvae showed that within 48 h, the probiotics became the dominant population in the PM48 treatment. After 24 h, water samples and larvae from the control treatment showed a significant increase in bacterial load. CONCLUSION: The results showed that probiotics can play a significant role in maintaining biotic and abiotic water quality parameters, leading to a better survival rate of larvae during transportation. These findings represent an important step in improving long-distance transport protocols.

Effects of dietary taurine amino acid on growth performance, mucosal and immune response, gene expression and antioxidant defence of asian seabass (Lates calcarifer).

BACKGROUND: The enhancement of fish immune system and growth performance throughout the administration of bio-friendly agents such as diet supplements (taurine) is considered a promising alternative in farmed aquatic species. MATERIALS AND METHODS: The present study was aimed to examine the effect of supplementation of dietary taurine (0, 5 g-TAU5 and 10 g-TAU10) in crystalline form (99% purity) in L. calcarifer juveniles, taking into account growth performance, general health indices and immune related-genes mRNA transcript abundance. RESULTS: The results confirmed that the supplementation of taurine enhances significantly all the growth parameters and a better flesh quality. While the blood biochemical and immunological factors didn't present any significant differences, the expression of growth-related genes showed that IGF-1 was almost 3 times higher in fishes fed diet Tau 5 and Tau 10 compared to the control group. CONCLUSIONS: Finally, it can be concluded that at the maximum dose tested (10 g) the treatment was effective for Asian seabass. In addition, Tau inclusion in an FM-based diet can increase the productivity parameters along with raising the antioxidant status.