Sticky layer of Clarias gariepinus eggs cause the clumping of eggs immediately after fertilizatio... more Sticky layer of Clarias gariepinus eggs cause the clumping of eggs immediately after fertilization, this create low oxygen, and increase pathogenic infection, thereby reducing fertilization and hatching rate hence reduces in mass production of C. gariepinus seed. Although various substances are use in the removal of the sticky layer, no information is available about the use of watermelon. Therefore, the present study, aim in exploring the potential of using watermelon in removing the sticky layer of C. gariepinus to enhance production. Fertilized eggs were treated with watermelon juice (T1) for comparison with 14 g L-1 milk solution (T2 as de-adhesion reference) and water as control (T0 as adhesion reference). The treatments were agitated with aeration for 30 minutes, rinsed with water, and poured on respective netted hatching trough, with water recirculation for incubation at 27 0C for 24 h period. Except for T0, no clumping of eggs was observed in the remaining groups. Slight var...
Aquaculture is prone to pH fluctuations depending on dominating microbial pathway in the manageme... more Aquaculture is prone to pH fluctuations depending on dominating microbial pathway in the management. The present study takes advantage of the influence of pH in changing the properties of charcoal to condition the pH and improve nutrient removal. Two Synthetic aquaculture wastewaters of 100 mg/L TAN were designed to test the pathway's nutrient removal and pH stability. Glucose at 15 C/N was added to one wastewater, favoring heterotrophic pathway. The other was free of organic carbon, favoring autotrophic pathway. Powdered charcoal was added to each pathway at 0.5, 1.0, 2.0, and 4.0% (charcoal weight/volume of media) compared to the 0 % group without charcoal. The result revealed that as charcoal percentages increase, the pH shifts towards stabilization and improves nutrient removal (p ≤ 0.05). At 4.0% charcoal, the pH was stabilized at 6.0 – 7.5 in heterotrophic and 7.5 – 7.9 in autotrophic pathways, which are within the optimum range for the survival of aquatic organisms, corre...
Determination of diversity and function of the bacteria in fish gut is essential to understanding... more Determination of diversity and function of the bacteria in fish gut is essential to understanding the interaction between intestinal bacteria and their host organism. This study compared intestinal bacterial community of black seabass (Centropristis striata) hatched by the same breeding farm but reared in different aquaculture systems, an indoor recirculating aquaculture system (RAS) and an inshore net pen (INP). The fish were fed with formulated feed manufactured by same feed company. Bacteria in fish gut, formulated feed and seawater were identified by 16S rRNA high throughout sequencing (HTS). Total 1484 OTUs, which belonged to 34 phyla and 79 genera, were identified from fish gut, formulated feed and seawater. In fish gut, 24 phyla and 43 genera were identified. Proteobacteria, Fusobacteria, and Firmicutes dominated at the phylum level in fish gut in INP, while Proteobacteria and Firmicutes dominated in fish gut in RAS. Photobacterium, Vibrio, and Cetobacterium dominated at the genus level in fish gut in both INP and RAS. One OTU of Photobacterium occurred in all the fish gut samples, suggesting this bacterium might be the main component of the core microbiota. No significant difference was found in bacterial diversity in fish gut between INP and RAS, suggesting genetic background should be a primary factor determining intestinal bacterial community of black seabass. Bacterial diversity in seawater was high relative to that in fish gut and formulated feed, regardless in INP or RAS. The common OTU between fish gut and seawater was more than that between fish gut and formulated feed in INP, while the common OTU between fish gut and seawater was slightly less than that between fish gut and formulated feed in RAS. These results reveal that the bacteria in formulated feed and seawater could influence the bacteria in fish gut, and their priority in shaping intestinal bacterial community depended on the bacterial composition in feed and seawater. This study reveals that intestinal bacterial community of black seabass was influenced by both genetic background and environmental factors.
Sticky layer of Clarias gariepinus eggs cause the clumping of eggs immediately after fertilizatio... more Sticky layer of Clarias gariepinus eggs cause the clumping of eggs immediately after fertilization, this create low oxygen, and increase pathogenic infection, thereby reducing fertilization and hatching rate hence reduces in mass production of C. gariepinus seed. Although various substances are use in the removal of the sticky layer, no information is available about the use of watermelon. Therefore, the present study, aim in exploring the potential of using watermelon in removing the sticky layer of C. gariepinus to enhance production. Fertilized eggs were treated with watermelon juice (T1) for comparison with 14 g L-1 milk solution (T2 as de-adhesion reference) and water as control (T0 as adhesion reference). The treatments were agitated with aeration for 30 minutes, rinsed with water, and poured on respective netted hatching trough, with water recirculation for incubation at 27 0C for 24 h period. Except for T0, no clumping of eggs was observed in the remaining groups. Slight var...
Aquaculture is prone to pH fluctuations depending on dominating microbial pathway in the manageme... more Aquaculture is prone to pH fluctuations depending on dominating microbial pathway in the management. The present study takes advantage of the influence of pH in changing the properties of charcoal to condition the pH and improve nutrient removal. Two Synthetic aquaculture wastewaters of 100 mg/L TAN were designed to test the pathway's nutrient removal and pH stability. Glucose at 15 C/N was added to one wastewater, favoring heterotrophic pathway. The other was free of organic carbon, favoring autotrophic pathway. Powdered charcoal was added to each pathway at 0.5, 1.0, 2.0, and 4.0% (charcoal weight/volume of media) compared to the 0 % group without charcoal. The result revealed that as charcoal percentages increase, the pH shifts towards stabilization and improves nutrient removal (p ≤ 0.05). At 4.0% charcoal, the pH was stabilized at 6.0 – 7.5 in heterotrophic and 7.5 – 7.9 in autotrophic pathways, which are within the optimum range for the survival of aquatic organisms, corre...
Determination of diversity and function of the bacteria in fish gut is essential to understanding... more Determination of diversity and function of the bacteria in fish gut is essential to understanding the interaction between intestinal bacteria and their host organism. This study compared intestinal bacterial community of black seabass (Centropristis striata) hatched by the same breeding farm but reared in different aquaculture systems, an indoor recirculating aquaculture system (RAS) and an inshore net pen (INP). The fish were fed with formulated feed manufactured by same feed company. Bacteria in fish gut, formulated feed and seawater were identified by 16S rRNA high throughout sequencing (HTS). Total 1484 OTUs, which belonged to 34 phyla and 79 genera, were identified from fish gut, formulated feed and seawater. In fish gut, 24 phyla and 43 genera were identified. Proteobacteria, Fusobacteria, and Firmicutes dominated at the phylum level in fish gut in INP, while Proteobacteria and Firmicutes dominated in fish gut in RAS. Photobacterium, Vibrio, and Cetobacterium dominated at the genus level in fish gut in both INP and RAS. One OTU of Photobacterium occurred in all the fish gut samples, suggesting this bacterium might be the main component of the core microbiota. No significant difference was found in bacterial diversity in fish gut between INP and RAS, suggesting genetic background should be a primary factor determining intestinal bacterial community of black seabass. Bacterial diversity in seawater was high relative to that in fish gut and formulated feed, regardless in INP or RAS. The common OTU between fish gut and seawater was more than that between fish gut and formulated feed in INP, while the common OTU between fish gut and seawater was slightly less than that between fish gut and formulated feed in RAS. These results reveal that the bacteria in formulated feed and seawater could influence the bacteria in fish gut, and their priority in shaping intestinal bacterial community depended on the bacterial composition in feed and seawater. This study reveals that intestinal bacterial community of black seabass was influenced by both genetic background and environmental factors.
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