Introduction:
Vegetable protein sources are commonly used as replacement for fish meal (FM) in diets for Pacific white shrimp (PWS) Litopenaeus vannamei in some countries, including Vietnam and Indonesia. This has a negative impact on the health of PWS due to their high content in anti-nutritional factors. Nucleotides (N) modulate the immune response and could counteract this effect. The objective of this feeding trial was to evaluate the effects of dietary N supplementation on survival upon challenge with Vibrio parahaemolyticus in PWS receiving diets in which FM has been partially replaced by vegetable protein sources.
Methods:
A total of 600 PWS (0.72 ± 0.15 g) were used in this trial performed in Vietnam. After acclimatation for 2 days, PWS were classified into 6 groups (4 replicates/group; 25 PWS/90L-tank) and received different diets for 28 days: 1 group with no challenge (260FMNoCh – Negative Control; 26% FM); and 5 groups challenged with EMS/AHPND-causing V. parahemolyticus strain: 260FM (Positive Control group; 26% FM; 0% N), 260FMN (26% FM; 0.1% N), 234FMN (23.4% FM; 0.1% N), 221FMN (22.1% FM; 0.1% N) and 208FMN (20.8% FM; 0.1% N). FM was replaced by vegetable protein sources. PWS were followed-up for 10 days post-challenge. The N used in the study were Nucleoforce® (Bioiberica SAU, Spain).
Results:
All groups in which diets incorporated N showed higher survival rates than the Positive Control group during the post-challenge period, with a significant improvement (p<0.05) 15 hours post-challenge in groups 260FMN, 221FMN and 208FMN vs the Positive Control group (Figure 1).
Conclusions:
Nucleotides could be used as sustainable and effective functional ingredient in aquaculture given that, as observed in this study done in Vietnam, supplementation with 0.1% N in PWS receiving diets in which FM has been partially replaced by vegetable protein sources allows a higher survival rate upon challenge with EMS/AHPND-causing V. parahemolyticus strain.