Chlorella ellipsoidea is a freshwater green microalga that has great prospect for the sustainable development of aquaculture industry. Microalgae require optimal lighting conditions for efficient photosynthesis. The key to cost-effective algal biomass production is to optimize algae growth conditions. This study aimed to investigate the effects of various wavelengths viz. white (380–750 nm), green (510 nm), blue (475 nm), and red (650 nm) light-emitting diodes (LEDs) on the growth, pigment content (chlorophyll-a, chlorophyll-b, and β-carotene), and proximate composition of C. ellipsoidea with a photoperiod of 12 h:12 h light: dark cycle under indoor environmental conditions. C. ellipsoidea was cultured in Bold's Basal Medium for 18 days. The cell density (125.36×10⁵ cells ml⁻¹), cell dry weight (58.9 ± 4.57 mg L⁻¹), optical density (1.66 ± 0.08 g L⁻¹), chlorophyll-a (7.31 ± 0.04 μg ml⁻¹), chlorophyll-b (2.73 ± 0.13 μg ml⁻¹), and β-carotene (0.39 ± 0.04 μg ml⁻¹) content of C. ellipsoidea were significantly (P < 0.05) higher at 15^th-day when cultured under blue LED light exposure. Significantly lower growth and nutritional values were obtained under red LED light exposure compared to the control and other LEDs spectra. In Pearson correlation analysis, the cell density and cell dry weight values showed a strong positive correlation with the values of pigment contents of C. ellipsoidea in all the treatments. The LEDs light spectra showed significant effects on proximate composition of C. ellipsoidea. Protein and lipid contents of C. ellipsoidea were significantly higher in blue LED growth conditions compared to white, green, and red LEDs. C. ellipsoidea cells were 3˗7.04 μm in size and the maximum area of the cell was 38.94 μm² in blue LED treatment. Results of this study demonstrated that blue LED light spectra was the most suitable condition to induce nutritionally rich biomass production of C. ellipsoidea, which can be used as a potential source of fish feed towards sustainable aquaculture.

Organic fertilizer is one of the critical elements of organic and sustainable agricultural development. This study analyzes the economic impact of organic fertilizer on rice farms' yield and technical efficiency (TE) in Bangladesh. The Stochastic Production Frontier (SPF) approach has been employed by using a sample of 2652 rice plots covering seven broad agro-ecological zones of Bangladesh. It also addresses self-selection into the organic fertilizer choice using propensity score matching (PSM) that corrects observed selection bias that potentially influences both decisions to choose and technical efficiency. After PSM, organic fertilizer users produce 16.67% higher yield by using 12.1%, 9.40%, and 42.1% less labor, other inputs, and farm capital for rice production. The organic fertilizer users are significantly 3.79% more efficient than non-user, suggesting organic fertilizer substantially contributes to enhancing the technical efficiency of rice in Bangladesh. Moreover, the average treatment effect on the treated (ATETs) in different matching is positively significant and confirms the positive impact of organic fertilizer on rice farming. Government and non-government organizations should encourage farmers to extensively use organic fertilizer for better production through soil health development and reduce the pressure of chemical fertilizer import and use.

This study aimed to isolate and identify probiotic bacteria from the gut ofBarbonymus gonionotusand evaluate their effects on growth, hematological parameters, and breeding performances of the host. Five probiotic bacteria viz. Enterococcus xiangfangensis(GFB-1),Pseudomonas stutzeri(GFB-2),Bacillus subtilis(GFB-3),Citrobacter freundii(GFB-4), andP. aeruginosa(GFB-5) were isolated and identified using16S rRNAgene sequencing. Application of a consortium of probiotic strains (1–3 × 1.35 × 10⁹ CFU kg⁻¹) or individual strain such as GFB-1 (1.62 × 10⁹ CFU kg⁻¹), GFB-2 (1.43 × 10⁹ CFU kg⁻¹), GFB-3 (1.06 × 10⁹ CFU kg⁻¹), GFB-4 (1.5 × 10⁹ CFU kg⁻¹) or GFB-5 (1.43 × 10⁹ CFU kg⁻¹feed) through feed significantly improved growth, histological and hematological parameters and reproductive performances ofB. gonionotuscompared to untreated control. Moreover, the application of these probiotics significantly increased gut lactic acid bacteria and activities of digestive enzymes but did not show any antibiotic resistance nor any cytotoxicity in vitro. The highest beneficial effects on treated fishes were recorded by the application of GFB-1, GFB-2, GFB-3, and a consortium of these bacteria (T2). This is the first report of the improvement of growth and health ofB. gonionotusfishes by its gut bacteria.