Effect of Parental Injection with Shark DNA on Morphometric and Meristic Characteristics of Nile tilapia (Oreochromis niloticus)

This study was conducted to evaluate the phenotypic effects (morphometric and meristic) of maternal injection of Nile tilapia with Shark DNA on F1 Nile tilapia progeny, and to assess their response to three different dietary protein levels. F1 progeny from injected (Genetically Modified, GM) and non-injected (Wild-Type, WT) Nile tilapia broodstock were reared for 90 days and fed on diets containing 22%, 26%, or 30% crude protein. Morphometric and meristic indices were analyzed using a 2-Way ANOVA.Results showed significant (P < 0.05) differences between the GM and WT phenotypes for several key morphometric indices, including Head Width (HW/HL), Body Depth (BD/SL), and Head Length (HL/SL), as well as meristic indices like Dorsal Fin Ray Count (DFRC). A significant (P < 0.05) interaction was detected for Caudal Peduncle Depth (CPD/SL) and Anal Fin Spine Count (AFSC), indicating that the GM fish responded differently to dietary protein levels than WT fish. For most indices, the 22% and 26% protein diets resulted in optimal or statistically similar values compared to the 30% protein diet, which demonstrated no significant advantage.In conclusion, this study provides evidence that maternal injection of Nile tilapia with Shark DNA can induce heritable morphometric and meristic changes in F1 Nile tilapia. Furthermore, these genetic modifications altered the progeny's physiological response to nutrient levels, suggesting that a 22-26% protein level is sufficient for optimal morphological development under these experimental conditions.