The global aquaculture is expanding rapidly, with tilapia being the second most produced fish worldwide. However, the availability of high-quality fry remains a challenge in the production chain. Stress from adverse conditions negatively impacts fish health, leading to losses and increased disease susceptibility. Nutritional management, particularly through additive supplementation, offers a solution to enhance fish performance. Proper nutrition of broodstock affects the quality of eggs, larvae, and fry, benefiting future generations. Supplementing diets with fatty acids like DHA and organic minerals can improve metabolic health and boost resistance in tilapia offspring.
Therefore, 60 male and 180 female Nile tilapia were placed in 20 cages (3×2×1m) placed in earthen ponds. The broodstock were fed four different diets, containing two levels of DHA (0% and 1%) and two sources of mineral premix (100% inorganic Zn, Mn, and Se; and 50% organic Zn, Mn, and Se). The broodstock underwent reproductive management with continuous mating and egg collection every five days. The collected eggs were incubated, and after hatching, 12,000 8-day-old tilapias were placed into aquariums (60L) operating as a recirculating system (28.0 ± 1.0ºC). The offspring obtained from each of the four dietary treatments were fed for 34 days with five different diets, containing two levels of DHA (0% and 1%) and two sources of mineral premix (100% inorganic Zn, Mn, and Se; and 50% organic Zn, Mn, and Se), as well as another diet containing 2% DHA and 100% organic Zn, Mn, and Se. At the end of the rearing period, growth and survival were assessed. Subsequently, 21 fry from each aquarium were subjected to a bacterial challenge by immersion with Streptococcus agalactiae (2.26×10⁵ CFU/mL) in a recirculating system. After 24 hours of exposure, the fish were counted, and the survival rate was assessed. The results were analyzed using two-way ANOVA and Tukey’s test (Statistica 7.1).
Although the effects of DHA are more evident in health parameters, the greater vigor of these larvae may be associated with the greater availability of nutrients during vitellogenesis, consequently constituting a better-quality calf. It is concluded that feeding tilapia broodstock with diets supplemented with 1% DHA and inorganic minerals improved the growth and vigor of the offspring.