Effects on fatty acids, biochemical composition and growth of rotifer (Brachionus plicatilis) fed with different concentrations of Nannochloropsis sp.

The density of microalgae and nutrient content have impact on the population growth rate, egg rate and nutritional values of rotifers. The aim of this study was to investigate the effects of different concentrations of the alga Nannochloropsis sp. (N10: 10x10⁶, N20: 20x10⁶, N30: 30x10⁶ cells mL^-1) on the growth, egg rate, biochemical composition and fatty acid profile of the rotifer Brachionus plicatilis. To maintain a consistent algae density, an equivalent quantity was supplemented to compensate for any reduction. The study was started with three replicates, each with an initial inoculation density of 200 Brachionus individuals mL^-1 . The investigation spanned 5 days, during which population parameters (total number of individuals, proportion of individuals with eggs and growth rate) were calculated. After the study period, rotifers were harvested for subsequent biochemical and fatty acid analyses. Notably, the N30 group showed the highest proportions of crude protein (54.41%) and crude lipid (34.5%). The N20 group displayed the most substantial content of total fatty acids, recording a value of 70.69%. Consequently, the N30 group, with a concentration of 30x10⁶ cells mL^-1, emerged as the most proficient group, demonstrating superior performance in both population growth and biochemical composition.