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Titre : Effect of Stocking Density on the Growth Performance of Nile Tilapia (Oreochromis niloticus) Fingerlings Reared in Fiberglass Tanks

Auteur Wael Mohammed Elfatih Mohammed Makki

Université de soutenance : Al Neelian University

Grade : M.Sc. in Fish Sciences (Fish culture). 2021

Résumé
This study conducted during the period from October 2019 to January 2020 to determine the effect of stocking density on the growth performance of fingerlings of the Nile tilapia (Oreochromis niloticus) reared in fiberglass tanks. The experiment designed for four treatments of different stocking densities (20, 40, 60, and 80 fish/250L) corresponding to density classes (A, B, C, and D) respectively. During the study all the fish were fed by a complete diet (35% protein) at a rate of 6% of their body weight/day for 12 weeks then changed to 4% for the last week. Statistical analysis revealed there were no significant differences (p ˃0.05) between four treatments in (Weight gain, Weight gain%, Daily growth rate, Specific growth rate%, and Feed conversion ratio). The result showed that the percent of weight gain, daily growth rate, and specific growth rate were positively proportional with stocking density. The highest mean weight was recorded (27.6g) for treatment (C), followed by (27.1g) treatment (D) and (22.5g) treatment (B), while the lowest weight was (20.1g) treatment (A). The food conversion rate was affected inversely with stocking density. The survival rate (SR%) of the treatment (A) recorded the highest one(80%), followed by treatment (C) (70%), treatment (B) (65.8%) ,and treatment (D) recorded the lowest survival rate (46.25%). Water quality characteristics showed significant differences (p >0.05) between all treatments. Ammonia (NH3), nitrite (NO2-), and nitrate (NO3-) Concentrations increased with increasing stocking density, while dissolved oxygen (DO) and pH decreased with increase stocking density. The study concluded that the best stocking density is treatment (C) (60 fish/250L) which is equivalent (240 fish/m3), and therefore it can be considered the optimum density for growing tilapia fish in fiberglass tanks

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