Title : Influence of dietary nucleotide supplementation on growth performance, biometric indices, and reproductive development at first maturity in Nile Tilapia (Oreochromis Niloticus): A field trial
Abstract:
A feeding trial was performed to evaluate the efficacy of dietary nucleotide (NT) supplementation (Nucleoforce, Bioiberica SAU, Spain) on growth performance, biometric indices, reproductive development, and survival of female Nile tilapia (Oreochromis niloticus) under farm conditions. Fish were fed diets supplemented with 0 mg kg?¹ (control), 250 mg kg?¹, 500 mg kg?¹, and 750 mg kg?¹ NT for 30 days. Growth parameters including mean weight gain (MWG), feed conversion ratio (FCR), and condition factor (K) showed no significant differences among treatments. Additionally, the NT-supplemented groups exhibited significantly higher survival rates (NT500 mg kg?¹: 73±0.21%; NT750 mg kg?¹: 57±0.15%) compared to the control (43±0.21%), highlighting the potential of nucleotide supplementation in improving survivability. Biometric indices such as gonadosomatic index (GSI), hepatosomatic index (HSI), and viscera somatic index (VSI) showed notable patterns. A significant increase in HSI and VSI was observed in the 500 mg kg?¹ group (1.28 ± 0.40) vs Control (1.05 ± 0.69), indicating a shift in nutrient allocation toward reproductive readiness. Macroscopic and histological gonad examinations confirmed advanced ovarian development in all nucleotide-supplemented groups, with most fish reaching the ripe stage (IV), while the control group remained at the perinucleolar stage (II). These findings suggest that nucleotide supplementation supports energy utilization during reproductive development. Correlation analysis indicated that mortality rates were influenced by fluctuations in temperature and dissolved oxygen during the wet season. In conclusion, while dietary nucleotide supplementation did not significantly improve growth performance, it enhanced reproductive maturation and survival, underscoring its potential to improve reproductive efficiency and stress resilience in O. niloticus under variable environmental conditions.
