Immunonutritional Effects of Nucleotides and Olive Bioactive Extracts on Growth Performance and Survival of Pacific White Shrimp Upon Vibrio parahaemolyticus (AHPND) Challenge

ABSTRACT The sustainable advancement of aquaculture can be supported using functional feed ingredients with immunomodulatory activity. These studies evaluated the immunonutritional effects of dietary nucleotides (NU) and an olive bioactive extract (OE) in Pacific white shrimp (PWS), Penaeus vannamei . A 56‑day growth trial ( n = 1000 PWS; PL42‐43; 1.23 ± 0.23 g; 5.11 ± 0.27 cm) was conducted under a recirculating aquaculture system (RAS) using diets (5.47%–6.06% moisture; 43.03%–43.81% crude protein; 6.95%–7.69% crude lipid; 1.98%–2.28% crude fibre; 9.50%–9.65% ash) supplemented with 500 ppm NU (NU500), 500 ppm OE (OE500), a combination of 500 ppm NU and 500 ppm OE (NU500OE500) or a non‐supplemented control diet. In addition, a 10‑day acute hepatopancreatic necrosis disease (AHPND) challenge trial ( n = 600 PWS; PL35; 0.57 ± 0.11 g; 3.85 ± 0.36 cm) induced by Vibrio parahaemolyticus was performed using the same dietary treatments, together with a non‑challenged, non‑supplemented group (positive control). In the feeding trial, compared with the control, all supplemented groups exhibited significantly higher final body weight, weight gain, average daily gain and specific growth rate. Final biomass, feed intake and feed conversion ratio (FCR) were also significantly improved in the NU500 and NU500OE500 groups, with NU500OE500 achieving a significantly lower FCR than all other treatments. Total haemocyte count was significantly increased in the NU500OE500 group, while hyaline cell levels were elevated in all supplemented groups. Results from the challenge trial showed higher survival than the positive control (30.63 ± 4.70%) in the NU500 (33.95 ± 9.62%) and OE500 (40.99 ± 11.07%) groups, but a significant increase was observed only in the NU500OE500 group (55.80 ± 10.02%). In conclusion, the combined supplementation of NU and OE to PWS improved growth performance and immune response in the growth trial, and resistance to AHPND in the challenge trial, supporting its application in shrimp feed.