Nutritional Value of Microalgae and Cyanobacteria Produced with Batch and Continuous Cultivation: Potential Use as Feed Material in Poultry Nutrition

Recently, the demand for new alternative feedstuffs that do not contain chemical residue and are not genetically modified has been increased for sustainability in poultry production. In this respect, the usage of algae as animal feed is very promising as an alternative feed ingredient that reduces pollutant gases from animal production facilities. The aim of the current study is to investigate the usage possibility of algae, through determining nutritional value and production cost, as a feed ingredient in poultry nutrition. Three microalgae species, including <i>Scenedesmus</i> sp., <i>Ankistrodesmus</i> sp., and <i>Synechococcaceae</i>, were produced with batch and continuous cultivation to determine the difference in the lipid, protein, carbohydrate, fatty acid, and amino acid profiles, as well as the color characteristics and production cost. The highest lipid content of 72.5% was observed in algae biomass produced from <i>Synechococcaceae</i> with batch cultivation, whereas the highest protein level was found in algae biomass produced by <i>Synechococcaceae</i> under continuous cultivation practice (25.6%). The highest content of PUFA was observed in <i>Scenedesmus</i> sp. harvested from both batch and continuous cultivation (35.6 and 36.2%), whereas the lowest content of PUFA was found in <i>Synechococcaceae</i> harvested with continuous cultivation (0.4%). Continuously cultivated of <i>Scenedesmus sp</i>. had higher carbohydrate content than batch-cultivated <i>Scenedesmus</i> sp. (57.2% vs. 50.1%). The algae biomass produced from <i>Synechococcaceae</i> was found to have a higher content of essential amino acids, except lysine and histidine, compared to <i>Scenedesmus</i> sp. and <i>Ankistrodesmus</i> sp. Cultivation practices also affected the amino acid level in each algae species. The continuous cultivation practice resulted in a higher level of essential amino acids, except glycine. <i>Synechococcaceae</i> had richer essential amino acid content except for proline and ornithine, whereas continuous cultivation caused an incremental increase in non-essential amino acids. The lightness value was found to be the lowest (13.9) in <i>Scenedesmus</i> sp. that was continuously cultivated. The current study indicated that <i>Scenedesmus</i> sp. could be offered for its high PUFA and lysine content, whereas <i>Synechococcaceae</i> could have potential due to its high content of methionine and threonine, among the investigated microalgae and Cyanobacteria.