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Volume 5, Issue 1 (6-2016)
Abstract
In this study the effect of three dietary treatments including; two concentrations (106 and 107 cells per ml) of the freshwater alga Chlorella vulgaris and one treatment of baker's yeast, Saccharomyces cerevisiae) on growth, protein and total and free amino acid composition of freshwater rotifer Brachionus calyciflorus were studied. Results showed that rotifers fed with high concentration of algae (107cell/ml) had significantly higher growth rate (0.56 ± 0.03) than other treatments. Maximum density of rotifers fed high concentration (1790 ± 10.7 ind/ml) significantly was higher than low concentration (525±41.1 ind./ml) and baker's yeast +oil treatments (115±2.1 ind/ml). The crud protein of rotifers fed yeast was significantly higher than rotifers fed with low density of algae (p<0.05). Total amino acids of rotifers fed yeast, low concentration and high concentration of algae were obtained 250.66±16, 112.15±10 and 198.82±14 mg/ g of sample, respectively that there were significant difference between them(p<0.05). The highest and lowest amounts of free amino acids were observed in rotifers fed yeast (8.77±1.1) and low concentration of algae (4.04±0.3), respectively (p<0.05). Based on this study it can be concluded that rotifers fed with algae showed a higher growth rate compared with those fed the yeast, although protein and free amino acids in rotifers fed yeast were higher in compared algae treatments. In addition, treatment with high concentrations of algae, amino acids showed a relative increase in the body.
Sirwe Ghaderpour, Nasrollah Ahmadifard, Naser Agh, Zakaria Vahabzadeh, Alicia Estevez,
Volume 10, Issue 3 (9-2021)
Abstract
Despite the positive role of rotifers in many hatcheries for feeding the early stages of aquatic larvae, the lower mineral content of zinc (Zn) is one of the disadvantages of rotifer compared to copepods. Therefore, it is necessary to increase its amounts through enrichment. For this purpose, in the present study, a combination of algae Isochrysis aff. galbana and Nannochloropsis oculata were enriched with zinc sulfate for 1 and 3 hours. Due to obtaining better results in 1 hour, its effects on the growth and enrichment of rotifer were surveyed. The 1: 1 alga composition was enriched with zinc sulfate at concentrations (45, 90, and 135 mg/l). The highest amount of zinc was observed in the mixed algal enriched with 90 mg/l for 1 h, which had the highest copper amount and there was no significant difference with the control group. Also, the manganese amount was higher than the other treatments except for the control group. After feeding the rotifers with enriched algae for 1 hour, the best treatment was 45 mg/l, which also contained the second level of zinc and the first level of manganese, copper, potassium, and sodium. On the other hand, this treatment had the highest number of eggs on the peak day of reproduction treatments (third day) and its population density in the last days was not significantly different from the control group (p <0.05). Zn-enriched rotifers can be used to feed marine fish to meet the nutritional needs of aquatic larvae.
