Globally, tilapia (genus Oreochromis) is the most widely farmed and second most important group of food fishes behind carps. Nile Tilapia (NT) is the most cultured species among tilapia because of its commercially valuable traits. Efforts in advancing these traits have led to genetic improvement through selective breeding programs such as the Genetically Improved Farmed Tilapia (GIFT strain) and genetic sex regulation (YY males). KSU’s NT research and Extension work aims to secure, develop, and disseminate genetic, educational, and training resources to advance U.S Tilapia Aquaculture. Objectives pursued include: (1) acquiring various NT strains, (2) crossbreeding YY males with females of different strains, (3) evaluating crossbred progeny for growth rates, sex and color segregation, and (4) identifying genetically improved crosses demonstrating superior traits for local, small-scale production.
Experimental fish were reared in recirculating aquaculture systems (RAS) at the KSU Aquaculture Research Center, Frankfort, KY. Tilapia broodstock were acquired for research studies from Louisiana Specialty Aquaculture LLC (Robert, LA), Miami Aqua-culture Inc. (Boynton Beach, FL), and Fishgen Ltd. (Swansea, UK). Two strains of red YY males were bred with three strains of NT females in four crosses (Figure 1). Progeny from the crosses were grown for 167 days in three replicate tanks (Figure 2). Final mean weight, feed conversion ratio (FCR), fillet yield (%), sex proportion, and color segregation were analyzed. The red Til-Aqua YY males crossed with dark GIFT females resulted in significantly improved growth (57 to 75% larger and 1.6 to 1.8 times the daily growth rate) compared to the other crosses. This cross was reproduced in February and March 2022, and the fish were made available to farmers in six Kentucky counties, and one Florida county. Future work will address marketing, and human nutrition of NT produced in Kentucky.