This study investigated the effects of fish meal replacement by Spirulina platensis meal on growth, survival, body biochemical composition, and reproductive performance of Trichopodus trichopterus until the first spawning for 16 weeks. The fish fed dietary algal meal at levels of 2.5, 5, 10, and 20 % against those received fish meal only as control. The results showed that indicators such as belly diameter, feed intake, feed conversion ratio (FCR), and viscerosomatic index were significantly different between treatments with 5 and 10 % algal replacements (P \ 0.05). The growth factors including final weight, weight gain, total length, fork length, and body height of fish did not show significant differences (P [ 0.05) between the treatments. Feed intake increased up to 10 % replacement level and then decreased, though the best FCR values (0.77-0.79) were obtained with 2.5 and 5 % substitutions. The body lipid content showed a statistically marked decrease (P \ 0.05) as a result of the algal replacements, but the amounts of protein and moisture were not significantly (P [ 0.05) different between treatments. All fish fed S. platensis meal had greater gonadosomatic indices (19.4-21.85 %) than that of the control in spite of insignificant differences (P [ 0.05) in their ovary weights (2.07-2.21 g). Absolute fecundity ranged between 7300 and 12,700 eggs/female with the highest amount in fish fed with replaced S. platensis levels of 2.5-10 %. The second-order polynomial regression analysis between absolute fecundity and substitution levels of algal meal was y = -0.5319x 2 ? 106.87x ? 7812.9 (R 2 = 0.9642), and the optimal substitution level was determined to be 8.13 % for maximum absolute fecundity. Hatching percentages in the control and 20 % replacement were much lower (P \ 0.05) than those in the other treatments (78-86 %). Given the relative enhancement of growth parameters and & Abolghasem Esmaeili Fereidouni a.esmaeili@sanru.ac.ir significant improvement in reproductive performance of broodstock three-spot gourami, 8.1-9.6 % S. platensis meal instead of fish meal is recommended in the diets.

Five isonitrogenous (420 g kg−1 crude protein) and isoenergetic (16.3 kJ g−1) practical diets were formulated to contain fish oil (FO), Kilka fish oil (KFO), linseed (LO), canola (CO) and soybean (SBO) oils fed to juveniles of three‐spot gourami (Trichopodus trichopterus) (initial weight 1 ± 0.03 g) three times per day to apparent satiation for 14 weeks. Results showed the mean final weight of brooders was not significantly affected by dietary oil sources. Specific growth rate for fish fed in SBO and CO diets was statistically higher than for fish fed diet LO. Fish fed diets CO and KFO showed in significantly higher GSI value compared with other diets. Absolute fecundity was greatest in fish fed diets KFO and CO, which significantly differ with other treatments. Except for KFO diet, high fertilization percentages (87.3–93.45%) were observed in other treatments. Fatty acid composition of muscle and egg was found to be positively correlated with their respective dietary lipid sources. High levels of EPA, DHA and n‐3 HUFA in brooders fed diet FO negatively affect egg quality parameters. Therefore, the results demonstrated that vegetable oil‐based diets (CO, SBO and LO, respectively) can positively affect on growth performance of juveniles compared with fish oil‐based diets. Furthermore, CO and LO diets, respectively, showed positive effects on reproductive performance in T. trichopterus compared with fish oil diets during experimental period under controlled conditions.