Effects of dietary fatty acids on the reproduction of South American female catfish Rhamdia quelen (Quoy & Gaimard, 1824)

The effects of a diet supplemented with 5% marine fish oil, 5% refined palm oil, 5% soybean oil, and a combination of the three on reproductive parameters of females Rhamdia quelen was investigated. Spawning was artificially induced to evaluate rates of fertilization, hatching and larvae normality. Fatty acid profiles of the diets, ovaries and oocytes were determined. A higher spawning rate (%) was observed for diets containing fish oil (78.65 +/- 3.60) and palm oil (77.15 +/- 3.97), followed by oil mix (65.46 +/- 4.57). The diet containing soybean oil was associated with significantly lower fertilization (60.14 +/- 5.66; P < 0.05) than the palm and fish oil diets. Lower fertilization may be explained by a high level of n-6 fatty acids in the diet, which possibly accelerate the oocyte maturation. Satisfactory fecundity (P > 0.05) were observed for all tested diets, whit 289.77 +/- 23.90 (palm oil) until 323.31 +/- 38.45 oocytes g(-1) body weight (fish oil). The treatments were not shown to influence oocyte size, larval size or rate of larva deformity. Oocyte fatty acid composition was like that of gonads. Docosahexaenoic (DHA; C22:6 n-3) fatty acid was preferentially deposited in ovaries and oocytes. Ratios of n3/n6, DHA/EPA, EPA/ARA, did not affect the reproductive performance of females. Therefore, regarding female reproductive performance, the vegetable lipid sources tested are suitable for being used in R. quelen diet, and palm oil, in particular, is considered an excellent alternative to fish oil.