The key performance traits of GenoMar tilapia’s premium genetic line, GenoMar 1000, and a market leading local strain were compared in both pond and cage production systems under commercial conditions in Brazil using common garden method. The size of the cages (Lake Palmas) and ponds (Tocantins) were 32 m3 and 500 m2, respectively. The stocking density in the cages and ponds were 55 juveniles per m3 and 2.48 juveniles per m2, respectively, with an expected harvest density of about 70 kg/m3 in cages and 3 kg per m2 in ponds. A commercial feeding program using locally available commercial feed was followed during the trial. Sampling weight to adjust the feeding was done every week. For the initial 6 weeks post-hatching, the tilapia was provided with commercial feed comprising 45% protein, followed by a switch to a feed containing 36% protein from week 7 to 9. As the tilapia continued to grow, this diet was further adjusted to one containing 32% protein starting from week 10. The mean (± sd) water temperature and dissolved oxygen in ponds and cages were 26 ± 1 and 29 ± 1 degree centigrade and 7 ± 1 and 6 ± 1 mg/l respectively.
The individual weight of all the fish in both ponds and cages during common garden experiment was measured 4 times (on an average every 30 days) from stocking to harvest. Growth at each phenotyping point was compared between the local strain and GenoMar 1000 using the linear statistical model to separate the effect of environment (ponds and cages) with the effect of strain (GenoMar 1000 and local strain). Kaplan-Meier estimators was used to compare the survival rates associated with different strains (GenoMar 1000 and local strain) and/or environments (ponds and cages). Further, Hazard ratio was used for the statistical analysis for survival at harvest. Uniformity was measured by calculating the coefficient of variation (CV) of body weight at harvest. Coefficients of variation were compared using the asymptotic test of Feltz and Miller implemented in the R package cvequality.
The results showed that GenoMar 1000 was superior for growth, survival, and uniformity, growing approximately 30% faster than the local strain (p <0.001). Notably, the 6% higher survival rates of GenoMar 1000 (p<0.001) suggesting stronger resistance to common fish pathogens affecting tilapia in reservoirs. At any particular time, the risk of death is significantly decreased (p<0.001) by 49% in GenoMar 1000, compared to the local strain of tilapia. Additionally, the strain’s enhanced 23% more uniformity (p<0.001) contributes to efficient processing yields and reduced processing costs. Economic analyses further underscore the strategic benefits, projecting substantial increases in harvest and approximately a 31-36% annual increase in profits. Overall, the results and absence of genotype by environment interaction demonstrate GenoMar 1000’s potential to enhance productivity, profitability, and sustainability in the Brazilian tilapia industry.