An exploratory experiment was conducted to evaluate the culture performance and total microbial load of the rotifer Brachionus calyciflorus reared on the microalga Chlorella sp. cultured with 50% of the standard Bolds’ Basal medium (BBM) supplemented with poultry manure filtrate (POMF), sheep manure filtrate (SHMF), water hyacinth root compost filtrate (WHRCF), water hyacinth leaf compost filtrate (WHLCF), water hyacinth root and leaf compost filtrate (WHR + LCF) and a control treatment with 100% BBM. The results indicated that the POMF-substituted culture of Chlorella sp. gave the highest mean cell density (1.83 × 108 ± 4.03 × 106 cells mL−1), followed by the 100% BBM culture (1.74 × 108 ± 1.44 × 106 cells mL−1), supporting 272 ± 6.4 and 122.2 ± 5.53 individuals mL−1 of B. calyciflorus, respectively. The SHMF culture had the third highest Chlorella sp. density (5.94 × 107 cells mL−1) and supported 83.4 ± 13.78 individuals mL−1 B. calyciflorus population. The three treatments with the compost filtrate from the different parts of the water hyacinth compost filtrate had the lowest Chlorella sp. cell density and B. calyciflorus population. In terms of the total viable bacteria of B. calyciflorus cultured on the substitution of the different organic media, B. calyciflorus cultured on 100% BBM and 50% POMF-based culture showed the lowest mean total bacterial counts (6.9 × 106 ± 9.9 × 105 and 8.05 × 106 ± 4.94 × 105 CFU mL−1, respectively). In contrast, the mean total bacterial counts were greater for the SHMF, WHR + LCF, WHLCF, and WHRCF groups (1.62 × 107 ± 2.83 × 105, 1.09 × 107 ± 7.78 × 105, 1.25 × 107 ± 7.07 × 104, and 1.03 × 107 ± 7.07 × 104 CFU mL−1, respectively). Although firm conclusions could not be drawn from the results obtained in this experiment due to low biological replicates, it can be stated that a 50% substitution of standard BBM medium for Chlorella sp. culture with organic manures such as POMF can be a sustainable alternative for culturing the rotifer B. calyciflorus for larval fish culture. We recommend further investigation of the potential of POMF as a synthetic medium substitute for Chlorella sp. culture as live feed for B. calyciflorus culture.

Reproduction rate and microbial load of the rotifer Brachionus calyciflorus (Pallas, 1766) fed on Chlorella sp. cultured on organic media

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2025年3月27日

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Solomon Melaku,
Abebe Getahun,
Seyoum Mengestou,
Akewake Geremew,
Amha Belay

摘要

An exploratory experiment was conducted to evaluate the culture performance and total microbial load of the rotifer Brachionus calyciflorus reared on the microalga Chlorella sp. cultured with 50% of the standard Bolds’ Basal medium (BBM) supplemented with poultry manure filtrate (POMF), sheep manure filtrate (SHMF), water hyacinth root compost filtrate (WHRCF), water hyacinth leaf compost filtrate (WHLCF), water hyacinth root and leaf compost filtrate (WHR + LCF) and a control treatment with 100% BBM. The results indicated that the POMF-substituted culture of Chlorella sp. gave the highest mean cell density (1.83 × 10⁸ ± 4.03 × 10⁶ cells mL⁻¹), followed by the 100% BBM culture (1.74 × 10⁸ ± 1.44 × 10⁶ cells mL⁻¹), supporting 272 ± 6.4 and 122.2 ± 5.53 individuals mL⁻¹ of B. calyciflorus, respectively. The SHMF culture had the third highest Chlorella sp. density (5.94 × 10⁷ cells mL⁻¹) and supported 83.4 ± 13.78 individuals mL⁻¹ B. calyciflorus population. The three treatments with the compost filtrate from the different parts of the water hyacinth compost filtrate had the lowest Chlorella sp. cell density and B. calyciflorus population. In terms of the total viable bacteria of B. calyciflorus cultured on the substitution of the different organic media, B. calyciflorus cultured on 100% BBM and 50% POMF-based culture showed the lowest mean total bacterial counts (6.9 × 10⁶ ± 9.9 × 10⁵ and 8.05 × 10⁶ ± 4.94 × 10⁵ CFU mL⁻¹, respectively). In contrast, the mean total bacterial counts were greater for the SHMF, WHR + LCF, WHLCF, and WHRCF groups (1.62 × 10⁷ ± 2.83 × 10⁵, 1.09 × 10⁷ ± 7.78 × 10⁵, 1.25 × 10⁷ ± 7.07 × 10⁴, and 1.03 × 10⁷ ± 7.07 × 10⁴ CFU mL⁻¹, respectively). Although firm conclusions could not be drawn from the results obtained in this experiment due to low biological replicates, it can be stated that a 50% substitution of standard BBM medium for Chlorella sp. culture with organic manures such as POMF can be a sustainable alternative for culturing the rotifer B. calyciflorus for larval fish culture. We recommend further investigation of the potential of POMF as a synthetic medium substitute for Chlorella sp. culture as live feed for B. calyciflorus culture.