Center for Sustainable Development, College of Arts and Sciences, Qatar University, Doha 2713, Qatar.
Center for Sustainable Development, College of Arts and Sciences, Qatar University, Doha 2713, Qatar.
Sci Total Environ. 2022 Aug 20;835:155538. doi: 10.1016/j.scitotenv.2022.155538. Epub 2022 Apr 27.
The demand for aquaculture feed will increase in the coming years in order to ensure food security for a growing global population. Microalgae represent a potential fish-feed ingredient; however, the feasibility of their sustainable production has great influence on its successful application. Geographical locations offering high light and temperature, such as Qatar, are ideal to cultivate microalgae with high productivities. For that, the environmental and biological interactions, including field and laboratory optimization, for solar production and application of two native microalgae, Picochlorum maculatum and Nannochloris atomus, were investigated as potential aquaculture feed ingredients. After validating pilot-scale outdoor cultivation, both strains were further investigated under simulated seasonal conditions using a thermal model to predict light and culture temperature cycles for the major climatic seasons in Qatar. Applied thermal and light variations ranged from 36 °C and 2049 μmol/m/s in extreme summer, to as low as 15 °C and 1107 μmol/m/s in winter, respectively. Biomass productivities of both strains varied significantly with maximum productivities of 32.9 ± 2.5 g/m/d and 17.1 ± 0.8 g/m/d found under moderate summer conditions for P. maculatum and N. atomus, respectively. These productivities were significantly reduced under both extreme summer, as well as winter conditions. To improve annual biomass productivities, the effect of implementation of a simple ground heat exchanger for thermal regulation of raceway ponds was also studied. Biomass productivities increased significantly, during extreme seasons due to respective cooling and heating of the culture. Both strains produced high amounts of proteins during winter, 54.5 ± 0.55% and 44 ± 2.25%, while lipid contents were high during summer reaching up to 29.6 ± 0.75 and 28.65 ± 0.65%, for P. maculatum and N. atomus respectively. Finally, using acute toxicity assay with zebra fish embryos, both strains showed no toxicity even at the highest concentrations tested, and is considered safe for use as feed ingredient and to the environment.
为了确保全球不断增长的人口的粮食安全，未来几年对水产养殖饲料的需求将会增加。微藻是一种有潜力的鱼类饲料成分；然而，其可持续生产的可行性对其成功应用有很大影响。卡塔尔等光照和温度较高的地理位置非常适合以高产量养殖微藻。为此，研究了包括现场和实验室优化在内的环境和生物相互作用，以评估两种本地微藻（Picochlorum maculatum 和 Nannochloris atomus）作为潜在水产养殖饲料成分的太阳能生产和应用。在验证了小规模户外养殖后，进一步在模拟季节性条件下使用热模型研究了这两种菌株，以预测卡塔尔主要气候季节的光照和培养温度循环。应用的热和光变化范围从极端夏季的 36°C 和 2049 μmol/m/s 到冬季的低至 15°C 和 1107 μmol/m/s。两种菌株的生物量生产力均随夏季适度条件下的最高生产力而有显著差异，P. maculatum 和 N. atomus 的最高生产力分别为 32.9±2.5 g/m/d 和 17.1±0.8 g/m/d。这两种菌株在极端夏季和冬季条件下的生产力均显著降低。为了提高年生物量生产力，还研究了实施简单地热水交换器以调节养殖池温度的效果。由于培养物的冷却和加热，在极端季节中生物量生产力显著提高。在冬季，两种菌株都产生了大量的蛋白质，分别为 54.5±0.55%和 44±2.25%，而在夏季，脂质含量很高，分别达到 29.6±0.75%和 28.65±0.65%，对于 P. maculatum 和 N. atomus 分别如此。最后，使用斑马鱼胚胎的急性毒性测定法，两种菌株即使在测试的最高浓度下也没有显示出毒性，被认为是安全的可用于饲料成分和环境。
