Spawning and egg quality of the tilapia Oreochromis niloticus fed solely on raw Spirulina throughout three generations

J. Lu, T. Takeuchi-2004
Aquaculture, 234(1-4): 625-640

Abstract:

In order to simplify the fish culture system in a Closed Ecological Recirculating Aquaculture System (CERAS), the feasibility of constructing a food chain of tilapia-Spirulina is being examined. This study investigated the reproductive performance of the tilapia Oreochromis niloticus fed solely on raw Spirulina platensis. The raw Spirulina (RS) was fed to the parent tilapia (SP) from 3.4 cm and to the progenies of the first generation (SF₁) and second generation (SF₂) from the onset of exogenous feeding, compared with the control parent fish (CP) and progenies (CF₁, CF₂) fed on commercial diets (CD). The parent fish (P) (n=6) in both groups of were cultured for 380 days, and the first generation progeny fish (F₁) (n=6) for 575 days and the second generation progeny (F₂) (n=6) for 380 days at 28±1 °C. The first spawning of brood stock of P, F₁ and F₂ in the groups of RS and CD occurred at almost the same age. There were no significant differences in the relative fecundities, spawning intervals, and egg sizes among SP, SF₁, SF₂, CP, CF₁ and CF₂. The fertilization rate and the hatching rate of the fertilized eggs, as well as the survival time of starved larvae from the parents fed the two types of diets were similar. The same results were also observed among the successive progenies (F₁, F₂). Significant differences in the fatty acid profile of eggs were observed between the RS and the CD groups, with RS group containing more linoleic acid, γ-linolenic acid, and Σn-6 highly unsaturated fatty acids (20:3n-6, 20:4n-6, 22:4n-6, 22:5n-6). It was concluded that tilapia fed solely on raw Spirulina could keep normal reproduction throughout three generations.

(Laboratory of Fish Culture, Faculty of Marine Science, Tokyo University of Marine Science and Technology (formerly, Tokyo University of Fisheries), Minato, Tokyo 108-8477, Japan, e-mail of T. Takeuchi: take@s.kaiyodai.ac.jp)

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