Research Article
Pathogenicity Assay of Probiotic-potential Bacteria (Bacillus Species) on Live Catfish (Clarias anguillaris) Juveniles
Issue:
Volume 11, Issue 1, March 2025
Pages:
1-9
Received:
18 July 2024
Accepted:
22 August 2024
Published:
14 January 2025
DOI:
10.11648/j.fem.20251101.11
Downloads:
Views:
Abstract: Pathogenicity test is one key criterion used in selecting probiotics for use in food producing animals. This experiment was aimed to ascertain the safety of 10 selected probiotic-potential Bacillus species (Bsp). Three hundred and sixty Clarias anguillaris juveniles were obtained from homestead fish ponds within Makurdi metropolis. The fingerlings were distributed in 10 experimental groups: Bsp1, Bsp2, Bsp3, Bsp4, Bsp5, Bsp6, Bsp7, Bsp8, Bsp9 and Bsp10 and 2 control groups viz: positive control (PC) and negative control (NC). Each group was assigned 10 fingerlings in replicate. The PC group received 0.2 x 108 CFUml-1 of pathogenic bacteria Vibrio alginolyticus, the NC received 0.2 mls of PBS and test groups received 0.2 x 108 CFUml-1 Bacillus strains. The groups were observed for 20 days for morbidity and/or mortality from respective test groups. Survival rate of 60% (PC), 70% (Bsp8), 80% (Bsp6), 90% (Bsp2) whereas 100% were recorded for the rest of the groups. The weight gain of the PC group was significantly lower (P ≤ 0.05) than all groups except for Bsp6. Also, Bsp7, recorded highest weight gain (20.82 ± 8.2 g) whereas Bsp1, Bsp2, Bsp4, Bsp5, Bsp8, Bsp9 and Bsp10 were significantly higher compared to both PC and NC. All physico-chemical parameters were within the reference interval (RI) for catfish. The 100% survival from Bsp1, Bsp3, Bsp4, Bsp5, Bsp7, Bsp9, and Bsp10 compared to PC were signs that these Bacillus strains were not pathogenic to the fish used, whereas Bsp2, Bsp6 and Bsp8 were mildly pathogenic to the experimental fish, though environmental factors could be incriminated. The high weight gain by Bsp7 (20.82 ± 8.30), Bsp1 (17.86 ± 4.24), Bsp2 (14.48 ± 1.65), Bsp4 and Bsp10 respectively (13.94 ± 4.80 and 13.36 ± 4.36) showcased the growth stimulation potentials in these isolates. The present study, showed that survival, growth performance, and regulation of physico-chemical parameters were significantly (P ≤ 0.05) high with Bsp7, Bsp1, and Bsp10, so can be regarded as safe and can improve growth performance in fish production. These 3 Bacillus strains were identified as B. subtilis (MN099359.1), B. subtilis MK085082.1 and B. velezensis (CP041145.1).
Abstract: Pathogenicity test is one key criterion used in selecting probiotics for use in food producing animals. This experiment was aimed to ascertain the safety of 10 selected probiotic-potential Bacillus species (Bsp). Three hundred and sixty Clarias anguillaris juveniles were obtained from homestead fish ponds within Makurdi metropolis. The fingerlings ...
Show More
Research Article
Chromium and Lead Tolerance of Fungi Isolated from Mining Sites in Santo Domingo, Chontales Nicaragua
Issue:
Volume 11, Issue 1, March 2025
Pages:
10-18
Received:
8 January 2025
Accepted:
22 January 2025
Published:
11 February 2025
DOI:
10.11648/j.fem.20251101.12
Downloads:
Views:
Abstract: Few studies have reported the isolation of microorganisms from mining sites in Nicaragua. The objective of this study is to isolate autochthonous fungi from mining sediments of Santo Domingo, Chontales in the central region of Nicaragua and assess them for the tolerance to chromium (Cr) and lead (Pb). For the isolation of fungi, serial dilution and plate seeding on solid cultivation of Potato Dextrose Agar (PDA) was used. The microorganisms were identified by macroscopic observation and microscopy based on the colony colour, shape, hyphae, conidia and spore arrangement. Molecular identification was performed by polymerase chain reaction (PCR) analysis, extracting DNA for amplification of internal transcribed spacer (ITS) regions for ITS1-STS4 for fungi. The PCR product was sequenced and compared with other sequences int the GenBank (NCBI). The fungal genomes Fusarium oxysporum, Pichia kudriavzevii, Trichoderma harzianum and Aspergillus awamori were identified. The tolerance index (TI) was determined from different concentrations of Cr and Pb, demonstrating that Fusarium oxysporum, Trichoderma harzianum and Aspergillus awamori are tolerant in the range of 1 to 5 mg L-1 for Cr and 52 to 207 mg. L-1 for Pb, according to the analysis of variance with the Duncan test. Since the tested species are autochthonous to the contaminated environment in Santo Domingo, they are interesting as a point of departure for soil remediation endeavours in the area.
Abstract: Few studies have reported the isolation of microorganisms from mining sites in Nicaragua. The objective of this study is to isolate autochthonous fungi from mining sediments of Santo Domingo, Chontales in the central region of Nicaragua and assess them for the tolerance to chromium (Cr) and lead (Pb). For the isolation of fungi, serial dilution and...
Show More
,
Abonyi Festus Otaka
