《渔业科学进展》虚拟专辑——浒苔研究及应用
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2024, 45(2):114-122.
DOI: 10.19663/j.issn2095-9869.20231027001
Abstract:
Microplastic pollution and excessive discharge of aquaculture tailwater have become important global issues. The use of filamentous algae to remove nitrogen, phosphorus, and microplastics in the same system has not been reported. In this study, we constructed an algal water purification and removal system and investigated its ability to remove microplastics, nitrogen, and phosphorus from the water column. Three kinds of filamentous algae were used, Spirogyra, Enteromorpha, and Cladophora, in microplastic removal experiments in the system; the three species of filamentous algae were the most effective in removing fibrous microplastics (88.50%, 79.50%, 75.50%) and the least effective in removing granular microplastics (67.50%, 53.00%, 55.00%), respectively. Spirogyra removed microplastics better than the other two algae; therefore, it was used for nitrogen and phosphorus removal experiments in the water column. The density of algae per unit area was set to 0 (control), 2, 4, and 6 g/dm2. Spirogyra showed a Total Nitrogen removal rate of 91.88% (4 g/dm2), a Total Phosphorus removal rate of 90.33% (6 g/dm2), and a PO43–-P removal rate of 90.38% (6 g/dm2) after 15 d. The density of 4 g/dm2 showed the highest removal rate, 90.38%. There were no significant differences between the experimental results of the 4 and 6 g/dm2 groups (P>0.05). The results showed that the system effectively removed fibrous microplastics and absorbed nitrogen and phosphorus from the water body and that an algal density per unit area of 4 g/dm2 was the most suitable for removing nitrogen and phosphorus in this system.
Microplastic pollution and excessive discharge of aquaculture tailwater have become important global issues. The use of filamentous algae to remove nitrogen, phosphorus, and microplastics in the same system has not been reported. In this study, we constructed an algal water purification and removal system and investigated its ability to remove microplastics, nitrogen, and phosphorus from the water column. Three kinds of filamentous algae were used, Spirogyra, Enteromorpha, and Cladophora, in microplastic removal experiments in the system; the three species of filamentous algae were the most effective in removing fibrous microplastics (88.50%, 79.50%, 75.50%) and the least effective in removing granular microplastics (67.50%, 53.00%, 55.00%), respectively. Spirogyra removed microplastics better than the other two algae; therefore, it was used for nitrogen and phosphorus removal experiments in the water column. The density of algae per unit area was set to 0 (control), 2, 4, and 6 g/dm2. Spirogyra showed a Total Nitrogen removal rate of 91.88% (4 g/dm2), a Total Phosphorus removal rate of 90.33% (6 g/dm2), and a PO43–-P removal rate of 90.38% (6 g/dm2) after 15 d. The density of 4 g/dm2 showed the highest removal rate, 90.38%. There were no significant differences between the experimental results of the 4 and 6 g/dm2 groups (P>0.05). The results showed that the system effectively removed fibrous microplastics and absorbed nitrogen and phosphorus from the water body and that an algal density per unit area of 4 g/dm2 was the most suitable for removing nitrogen and phosphorus in this system.
2 Estimation of carbon sequestration by Ulva prolifera and potential ways to increase the carbon sink
2022, 43(5):34-39.
DOI: 10.19663/j.issn2095-9869.20220331002
Abstract:
Ulva prolifera is the main species in green tides and also an important marine carbon sink organism. It is characterized by fast growth, diverse reproductive modes, and strong resistance to stress. It can form a large-scale biomass in a short time. We review the carbon fixation features in the growth and drift of U. prolifera. It possesses a unique high pH induced HCO3– assimilation mechanism, which can promote CO2 absorption from the air by floating U. prolifera. Moreover, it utilizes the Hatch-Slack Cycle (C4) to enhance carbon fixation rate under high light irradiation conditions. The diverse carbon assimilation and sequestration mechanisms enhance photosynthetic carbon sequestration ability and help the quick accumulation of floating algal biomass. These abilities make the carbon sequestrating efficiency of U. prolifera significantly higher than that of Saccharina japonica, Undaria pinnatifida, and Porphyra haitanensis. Since 2007, the largest green tide in the world occurred in the Yellow Sea and persisted over 15 years. The average annual distribution area of U. prolifera was greater than 30 000 square kilometers, with an average annual coverage area in excess of 500 square kilometers. The average annual outbreak of U. prolifera had a biomass greater than 1.5 million tons. The net carbon sequestration from 2008 to 2020 was estimated to be 25 000~275 000 tons, averaging over 78 000 tons. This figure is higher than that of Gracilaria, P. haitanensis, and U. pinnatifida, and only second to that of S. japonica. The great biomass and strong carbon sequestration ability of U. prolifera has made it a potential new and important marine carbon sink and carbon storage pathway. We suggest strengthening the salvage and resource utilization of U. prolifera. This approach is a win-win situation for carbon utilization and eutrophication removal. These measures will promote the green tide U. prolifera carbon sink in joining the carbon market as soon as possible, to become a new low-carbon economic resource.
Ulva prolifera is the main species in green tides and also an important marine carbon sink organism. It is characterized by fast growth, diverse reproductive modes, and strong resistance to stress. It can form a large-scale biomass in a short time. We review the carbon fixation features in the growth and drift of U. prolifera. It possesses a unique high pH induced HCO3– assimilation mechanism, which can promote CO2 absorption from the air by floating U. prolifera. Moreover, it utilizes the Hatch-Slack Cycle (C4) to enhance carbon fixation rate under high light irradiation conditions. The diverse carbon assimilation and sequestration mechanisms enhance photosynthetic carbon sequestration ability and help the quick accumulation of floating algal biomass. These abilities make the carbon sequestrating efficiency of U. prolifera significantly higher than that of Saccharina japonica, Undaria pinnatifida, and Porphyra haitanensis. Since 2007, the largest green tide in the world occurred in the Yellow Sea and persisted over 15 years. The average annual distribution area of U. prolifera was greater than 30 000 square kilometers, with an average annual coverage area in excess of 500 square kilometers. The average annual outbreak of U. prolifera had a biomass greater than 1.5 million tons. The net carbon sequestration from 2008 to 2020 was estimated to be 25 000~275 000 tons, averaging over 78 000 tons. This figure is higher than that of Gracilaria, P. haitanensis, and U. pinnatifida, and only second to that of S. japonica. The great biomass and strong carbon sequestration ability of U. prolifera has made it a potential new and important marine carbon sink and carbon storage pathway. We suggest strengthening the salvage and resource utilization of U. prolifera. This approach is a win-win situation for carbon utilization and eutrophication removal. These measures will promote the green tide U. prolifera carbon sink in joining the carbon market as soon as possible, to become a new low-carbon economic resource.
2022, 43(5):40-48.
DOI: 10.19663/j.issn2095-9869.20220331003
Abstract:
Carbon sequestration and carbon transfer through the food chain are important aspects of the carbon cycle in marine fisheries, and an essential part of the blue carbon sink of marine organisms. It includes not only the carbon used in shellfish and macroalgae farming at lower trophic levels in the food web, but also by certain organisms through feeding and growth activities. In marine ecosystems, macroalgae are one of the most important primary productive forces and one of the most efficient carbon-fixing organisms. They directly absorb carbon dioxide from seawater through photosynthesis, increasing the ocean carbon sink. Moreover, they promote and accelerate the diffusion of atmospheric carbon dioxide into seawater, helping to reduce it in the atmosphere. Macroalgae support many marine biota, including amphipods. Amphipods not only use the macroalgae habitat as shelter and nursery, but also as a source of nutrition. Moreover, amphipods provide a critical food source for other marine animals, such as fish, crustaceans, cephalopods, and even gray whales. Therefore, amphipods play an essential role in the material circulation and energy transfer in the food chain of the marine ecosystem. As primary consumers, the amphipods may also play an important role in the carbon sink process of marine fisheries by transferring the macroalgae fixed carbon to senior consumers. Additionally, amphipods prioritize ‘delicious’ macroalgae rather than treat them equally like many other invertebrates. They also reduce the biomass accumulation of this macroalgae and even affect its community structure. Consequently, studying the amphipods feeding selectivity to macroalgae is essential to understanding the relationship between macroalgae and algae-dwelling animals. Based on the above research background, this study investigated the feeding selectivity characteristics of Eogammarus possjeticus, an amphipod from the Shandong Peninsula, in relation to five different macroalgae, including Ulva prolifera, U. intestinalis, U. compressa, Chaetomorpha linum, and Cloniophora sp. The potential amphipods’ carbon sink characteristic was preliminarily discussed. The results showed that the feeding rates of E. possjeticus on U. intestinalis and U. prolifera were the highest, with daily feeding rates of 0.81 g of fresh weight/(g·d) and 0.80 g of fresh weight/(g·d), respectively, while the feeding rate of E. possjeticus on C. linum was the lowest of 0.19 g of fresh weight/(g·d). The proportion of E. possjeticus individuals living in macroalgae was the highest in Cloniophora sp., followed by U. intestinalis and U. prolifera. We analyzed the correlation between total organic carbon (TOC), total nitrogen (TN), carbon/nitrogen ratio (C/N), and dry weight/fresh weight ratio (DW/FW) of the macroalgae, as well as with the E. possjeticus feeding rate. A significant positive correlation was observed between the feeding rate and the macroalgae TOC concentration and C/N ratio (P<0.05). Nonetheless, the feeding rate negatively correlated with the TN concentrations and DW/FW ratio (P<0.05). These results suggested that the feeding selectivity of E. possjeticus to macroalgae was significantly correlated with TOC, TN, C/N, and DW/FW. It seemed that amphipods prefer to inhabit filamentous algae with complex structures and dense branches. In fact, amphipods give priority to Enteromorpha genus species with rapid growth rate and high carbon sequestration, which can accelerate the carbon transfer process of macroalgae to a higher trophic level species. The carbon transfer process enables marine animals at the top of the food chain to store carbon in the form of biological pumps. With the harvest of fisheries, some marine animals are removed from the seawater to promote carbon removal, while other animals not captured by humans continue to conduct carbon uptake and food chain transmission. In conclusion, amphipods have feeding selectivity to macroalgae, which may play the important role of carbon transfer channel in accelerating carbon sinks in marine fisheries.
Carbon sequestration and carbon transfer through the food chain are important aspects of the carbon cycle in marine fisheries, and an essential part of the blue carbon sink of marine organisms. It includes not only the carbon used in shellfish and macroalgae farming at lower trophic levels in the food web, but also by certain organisms through feeding and growth activities. In marine ecosystems, macroalgae are one of the most important primary productive forces and one of the most efficient carbon-fixing organisms. They directly absorb carbon dioxide from seawater through photosynthesis, increasing the ocean carbon sink. Moreover, they promote and accelerate the diffusion of atmospheric carbon dioxide into seawater, helping to reduce it in the atmosphere. Macroalgae support many marine biota, including amphipods. Amphipods not only use the macroalgae habitat as shelter and nursery, but also as a source of nutrition. Moreover, amphipods provide a critical food source for other marine animals, such as fish, crustaceans, cephalopods, and even gray whales. Therefore, amphipods play an essential role in the material circulation and energy transfer in the food chain of the marine ecosystem. As primary consumers, the amphipods may also play an important role in the carbon sink process of marine fisheries by transferring the macroalgae fixed carbon to senior consumers. Additionally, amphipods prioritize ‘delicious’ macroalgae rather than treat them equally like many other invertebrates. They also reduce the biomass accumulation of this macroalgae and even affect its community structure. Consequently, studying the amphipods feeding selectivity to macroalgae is essential to understanding the relationship between macroalgae and algae-dwelling animals. Based on the above research background, this study investigated the feeding selectivity characteristics of Eogammarus possjeticus, an amphipod from the Shandong Peninsula, in relation to five different macroalgae, including Ulva prolifera, U. intestinalis, U. compressa, Chaetomorpha linum, and Cloniophora sp. The potential amphipods’ carbon sink characteristic was preliminarily discussed. The results showed that the feeding rates of E. possjeticus on U. intestinalis and U. prolifera were the highest, with daily feeding rates of 0.81 g of fresh weight/(g·d) and 0.80 g of fresh weight/(g·d), respectively, while the feeding rate of E. possjeticus on C. linum was the lowest of 0.19 g of fresh weight/(g·d). The proportion of E. possjeticus individuals living in macroalgae was the highest in Cloniophora sp., followed by U. intestinalis and U. prolifera. We analyzed the correlation between total organic carbon (TOC), total nitrogen (TN), carbon/nitrogen ratio (C/N), and dry weight/fresh weight ratio (DW/FW) of the macroalgae, as well as with the E. possjeticus feeding rate. A significant positive correlation was observed between the feeding rate and the macroalgae TOC concentration and C/N ratio (P<0.05). Nonetheless, the feeding rate negatively correlated with the TN concentrations and DW/FW ratio (P<0.05). These results suggested that the feeding selectivity of E. possjeticus to macroalgae was significantly correlated with TOC, TN, C/N, and DW/FW. It seemed that amphipods prefer to inhabit filamentous algae with complex structures and dense branches. In fact, amphipods give priority to Enteromorpha genus species with rapid growth rate and high carbon sequestration, which can accelerate the carbon transfer process of macroalgae to a higher trophic level species. The carbon transfer process enables marine animals at the top of the food chain to store carbon in the form of biological pumps. With the harvest of fisheries, some marine animals are removed from the seawater to promote carbon removal, while other animals not captured by humans continue to conduct carbon uptake and food chain transmission. In conclusion, amphipods have feeding selectivity to macroalgae, which may play the important role of carbon transfer channel in accelerating carbon sinks in marine fisheries.
2021, 42(4):208-214.
DOI: 10.19663/j.issn2095-9869.20200816001
Abstract:
Owing to its non-toxicity, excellent biodegradability, film-forming property, and biocompatibility, sodium alginate (SA) is used as a common and promising raw material for biopolymer films. However, pure SA films tend to have defects in performance and functionality; therefore, blend films, consisting of two or more types of components, are more widely used as precursors for biopolymer films. To investigate the synergy between SA and Enteromorpha polysaccharide (EP), a degradable composite film was fabricated by blending SA and EP with glycerol as a plasticizer. The effect of different polysaccharide mass ratios, total mixed solution concentrations, and glycerol contents on the tensile strength, elongation at break, water vapor permeation, and water solubility of the films was investigated. In addition, the microstructure of the films was characterized through Fourier transform infrared spectroscopy and scanning electron microscopy. Results showed a good compatibility and synergy between SA and EP. Moreover, no obvious phase separation was observed in all SA/EP composite films. The component mass ratio, total concentration, and glycerol content had a significant influence on the properties of composite films. Among these factors, mass ratio had the most significant influence on the films. The addition of an appropriate amount of EP improved the tensile strength and elongation at break of the SA film and reduced its water vapor transmission rate; however, it slightly increased the water solubility of the SA/EP composite film. When the component mass ratio was modified from 10:0 to 8:2, the tensile strength increased from 99.22 MPa to 108.41 MPa, the elongation at break increased from 5.14% to 6.20%, and the water vapor transmission rate decreased from 6.445×10–11 g/(m·s·Pa) to 6.027×10–11 g/(m·s·Pa), which were the comprehensive optimal mechanical and barrier properties of the films. The total concentration and glycerol content of the SA/EP composite films were further optimized. The best total concentration and glycerol content were 1.6% (m/v) and 0.9% (m/v), respectively. The results demonstrate that the addition of EP enhanced the mechanical and barrier properties of the SA films and that there is a relatively strong synergistic effect between SA and EP.
Owing to its non-toxicity, excellent biodegradability, film-forming property, and biocompatibility, sodium alginate (SA) is used as a common and promising raw material for biopolymer films. However, pure SA films tend to have defects in performance and functionality; therefore, blend films, consisting of two or more types of components, are more widely used as precursors for biopolymer films. To investigate the synergy between SA and Enteromorpha polysaccharide (EP), a degradable composite film was fabricated by blending SA and EP with glycerol as a plasticizer. The effect of different polysaccharide mass ratios, total mixed solution concentrations, and glycerol contents on the tensile strength, elongation at break, water vapor permeation, and water solubility of the films was investigated. In addition, the microstructure of the films was characterized through Fourier transform infrared spectroscopy and scanning electron microscopy. Results showed a good compatibility and synergy between SA and EP. Moreover, no obvious phase separation was observed in all SA/EP composite films. The component mass ratio, total concentration, and glycerol content had a significant influence on the properties of composite films. Among these factors, mass ratio had the most significant influence on the films. The addition of an appropriate amount of EP improved the tensile strength and elongation at break of the SA film and reduced its water vapor transmission rate; however, it slightly increased the water solubility of the SA/EP composite film. When the component mass ratio was modified from 10:0 to 8:2, the tensile strength increased from 99.22 MPa to 108.41 MPa, the elongation at break increased from 5.14% to 6.20%, and the water vapor transmission rate decreased from 6.445×10–11 g/(m·s·Pa) to 6.027×10–11 g/(m·s·Pa), which were the comprehensive optimal mechanical and barrier properties of the films. The total concentration and glycerol content of the SA/EP composite films were further optimized. The best total concentration and glycerol content were 1.6% (m/v) and 0.9% (m/v), respectively. The results demonstrate that the addition of EP enhanced the mechanical and barrier properties of the SA films and that there is a relatively strong synergistic effect between SA and EP.
2020, 41(2):27-34.
DOI: 10.19663/j.issn2095-9869.20190221002
Abstract:
Large green tides of Ulva prolifera had become an annual event from 2007 to 2019 in the southern Yellow Sea and millions of tons of U. prolifera which were not salvaged settled to the bottom every year, releasing a large amount of biogenic elements such as C and N through degradation by microorganisms. This study discusses the effect of different temperature regimes on the release and the composition of dissolved organic matter (DOM) during the decomposition of U. prolifera. The results indicated that temperature significantly influenced the release of dissolved organic carbon (DOC) during 0~7 days (P<0.05): the DOC concentration at 20℃was significantly higher than that at 15℃ and 25℃. There was no significant difference in DOC concentration at different temperatures from day 7 to day 30 (P>0.05). For dissolved organic nitrogen (DON), temperature did not significantly affect the release of DON during the first 7 days (P>0.05). There were significant differences in DON concentration at different temperatures after 7 days (P<0.05): the concentration of DON was significantly lower at higher temperature (i.e. 25℃). The reason for this was that some organic nitrogen was converted to inorganic forms of nitrogen by microorganism during day 7 to day 30 and a higher microorganism abundance at 25℃ led to the transformation of more DON. The composition and fluorescence characteristics of fluorescent dissolved organic matter (FDOM) were evaluated by an excitation-emission matrix combined with parallel factor analysis (EEMs-PARAFAC). Three distinct dissolved organic matter fluorescent components (i.e. C1, C2, and C3) were identified using parallel factor analysis. C1, C2, and C3 were considered as tryptophan-like substances (also called protein-like substances), tryptophan-like substances and humic-like substances, respectively. The results showed that temperature had no significant impact on the composition of FDOM through comparing the relative content of three fluorescent components at different temperatures (P>0.05). While the fluorescence intensities of C2 and C3 were larger with the higher temperature (i.e. 25℃). Temperature affecting the fluorescence intensity markedly (P<0.05) may be caused by quicker microorganism decomposition rate under the higher temperature.
Large green tides of Ulva prolifera had become an annual event from 2007 to 2019 in the southern Yellow Sea and millions of tons of U. prolifera which were not salvaged settled to the bottom every year, releasing a large amount of biogenic elements such as C and N through degradation by microorganisms. This study discusses the effect of different temperature regimes on the release and the composition of dissolved organic matter (DOM) during the decomposition of U. prolifera. The results indicated that temperature significantly influenced the release of dissolved organic carbon (DOC) during 0~7 days (P<0.05): the DOC concentration at 20℃was significantly higher than that at 15℃ and 25℃. There was no significant difference in DOC concentration at different temperatures from day 7 to day 30 (P>0.05). For dissolved organic nitrogen (DON), temperature did not significantly affect the release of DON during the first 7 days (P>0.05). There were significant differences in DON concentration at different temperatures after 7 days (P<0.05): the concentration of DON was significantly lower at higher temperature (i.e. 25℃). The reason for this was that some organic nitrogen was converted to inorganic forms of nitrogen by microorganism during day 7 to day 30 and a higher microorganism abundance at 25℃ led to the transformation of more DON. The composition and fluorescence characteristics of fluorescent dissolved organic matter (FDOM) were evaluated by an excitation-emission matrix combined with parallel factor analysis (EEMs-PARAFAC). Three distinct dissolved organic matter fluorescent components (i.e. C1, C2, and C3) were identified using parallel factor analysis. C1, C2, and C3 were considered as tryptophan-like substances (also called protein-like substances), tryptophan-like substances and humic-like substances, respectively. The results showed that temperature had no significant impact on the composition of FDOM through comparing the relative content of three fluorescent components at different temperatures (P>0.05). While the fluorescence intensities of C2 and C3 were larger with the higher temperature (i.e. 25℃). Temperature affecting the fluorescence intensity markedly (P<0.05) may be caused by quicker microorganism decomposition rate under the higher temperature.
2019, 40(6):138-144.
DOI: 10.19663/j.issn2095-9869.20180718003
Abstract:
Marine macroalgae is used as a biofilter for aquaculture wastewater treatment. Marine macroalgae is used as a biofilter for aquaculture wastewater treatment. Ulva prolifera was cultivated at four different water temperatures (22.5℃, 25.5℃, 28.5℃, and 31.5℃) with a different inorganic nitrogen source (NH4Cl, NaNO2, and NaNO3) for each temperature to evaluate the purification efficiency of marine macroalgae U. prolifera on wastewater; all measurements were carried out in triplicate. The results show that, in the temperature range 22.5℃~31.5℃, the TAN uptake rates were 14.65, 14.88, 14.48, and 13.53 μmol/(g·h) in 96 h; the nitrite and nitrate uptake rates were 11.28, 10.48, 9.11, and 8.38 μmol/(g·h) and 9.41, 8.62, 8.80, and 7.35 μmol/(g·h) in 144 h, respectively. Both the temperature (P<0.01) and the nitrogen source (P<0.05) had significant effects on the growth rate of U. prolifera. The growth rate decreased as the temperature increased; further, at the same temperature with an ammonium source, U. prolifera showed the largest growth rate, followed by that with nitrite and nitrate sources. For the ammonium and nitrite sources, the content of chlorophyll a (Chl-a) increased with an increase in temperature; however, for the nitrate source, the content of Chl-a decreased first and then increased. Both the temperature and the nitrogen source had a significant effect on the carotenoid content (P<0.01), which increased with an increase in temperature. In the temperature range of 28.5℃~31.5℃, the carotenoid content in the nitrate source were found to be significantly higher than that in the other sources (P<0.05). The temperature and nitrogen source, thus, has a significant influence on the growth rate, Chl-a, and carotenoid content of U. prolifera. Overall, the TAN uptake rate was the highest, followed by the nitrite and nitrate uptake rates. However, the inorganic nitrogen uptake rate decreased as the temperature increased.
Marine macroalgae is used as a biofilter for aquaculture wastewater treatment. Marine macroalgae is used as a biofilter for aquaculture wastewater treatment. Ulva prolifera was cultivated at four different water temperatures (22.5℃, 25.5℃, 28.5℃, and 31.5℃) with a different inorganic nitrogen source (NH4Cl, NaNO2, and NaNO3) for each temperature to evaluate the purification efficiency of marine macroalgae U. prolifera on wastewater; all measurements were carried out in triplicate. The results show that, in the temperature range 22.5℃~31.5℃, the TAN uptake rates were 14.65, 14.88, 14.48, and 13.53 μmol/(g·h) in 96 h; the nitrite and nitrate uptake rates were 11.28, 10.48, 9.11, and 8.38 μmol/(g·h) and 9.41, 8.62, 8.80, and 7.35 μmol/(g·h) in 144 h, respectively. Both the temperature (P<0.01) and the nitrogen source (P<0.05) had significant effects on the growth rate of U. prolifera. The growth rate decreased as the temperature increased; further, at the same temperature with an ammonium source, U. prolifera showed the largest growth rate, followed by that with nitrite and nitrate sources. For the ammonium and nitrite sources, the content of chlorophyll a (Chl-a) increased with an increase in temperature; however, for the nitrate source, the content of Chl-a decreased first and then increased. Both the temperature and the nitrogen source had a significant effect on the carotenoid content (P<0.01), which increased with an increase in temperature. In the temperature range of 28.5℃~31.5℃, the carotenoid content in the nitrate source were found to be significantly higher than that in the other sources (P<0.05). The temperature and nitrogen source, thus, has a significant influence on the growth rate, Chl-a, and carotenoid content of U. prolifera. Overall, the TAN uptake rate was the highest, followed by the nitrite and nitrate uptake rates. However, the inorganic nitrogen uptake rate decreased as the temperature increased.
2019, 40(3):141-150.
DOI: 10.19663/j.issn2095-9869.20180420004
Abstract:
This study investigated the effects of dietary fish meal replacement by seaweeds or residues on growth performance and related biochemical indices of juvenile tiger puffer (Takifugu rubripes), with 2 fishmeal diets containing 60% and 45% fishmeal as the control 1, and the control 2, and other four diets with 30% fishmeal replaced by 10% four kinds of seaweeds or residues (Gracilaria verrucosa, Enteromorpha prolifera, Algae residue, Fungi residue) and vegetables protein(wheat gluten, corn gluten meal, and soybean meal), and they were named as C1, C2, JL, HT, ZZ, and JZ. Each diet was fed to three replicates of 25 tiger puffers with initial body weight of (17.33±0.55) g for 56 d. The results showed as follows: The special growth ratio (SGR) of HT group were significantly higher than that of other groups (P<0.05). The SGR of ZZ group was significantly higher than C2 and JL groups (P<0.05). The feed efficiency ratio (FER) of C1 and HT groups were significantly higher than C2 and JZ groups (P<0.05). The protein productive value (PPV) and protein efficiency ratio (PER) of C1 were significantly higher than C2 and JZ groups (P<0.05). No significant differences were found in activities of serum glutamic pyruvic transaminase (GPT), serum glutamic oxalacetic transaminase (GOT), liver GPT and liver GOT (P>0.05). No significant differences were found in activity of serum superoxide dismutase (SOD) and content of malondialdehyde (MDA). Crude protein content of whole body in JZ group was significantly higher than ZZ group (P<0.05). And crude lipid contents in whole body in HT and ZZ groups were significantly higher than C2 group (P<0.05). Above results showed that replaced 30% fish meal with 10% G. verrucosa, E. prolifera, algae residue or fungi residue and vegetable proteins have no adverse effect on the growth performance of juvenile tiger puffer, and E. prolifera can significantly improve the growth performance.
This study investigated the effects of dietary fish meal replacement by seaweeds or residues on growth performance and related biochemical indices of juvenile tiger puffer (Takifugu rubripes), with 2 fishmeal diets containing 60% and 45% fishmeal as the control 1, and the control 2, and other four diets with 30% fishmeal replaced by 10% four kinds of seaweeds or residues (Gracilaria verrucosa, Enteromorpha prolifera, Algae residue, Fungi residue) and vegetables protein(wheat gluten, corn gluten meal, and soybean meal), and they were named as C1, C2, JL, HT, ZZ, and JZ. Each diet was fed to three replicates of 25 tiger puffers with initial body weight of (17.33±0.55) g for 56 d. The results showed as follows: The special growth ratio (SGR) of HT group were significantly higher than that of other groups (P<0.05). The SGR of ZZ group was significantly higher than C2 and JL groups (P<0.05). The feed efficiency ratio (FER) of C1 and HT groups were significantly higher than C2 and JZ groups (P<0.05). The protein productive value (PPV) and protein efficiency ratio (PER) of C1 were significantly higher than C2 and JZ groups (P<0.05). No significant differences were found in activities of serum glutamic pyruvic transaminase (GPT), serum glutamic oxalacetic transaminase (GOT), liver GPT and liver GOT (P>0.05). No significant differences were found in activity of serum superoxide dismutase (SOD) and content of malondialdehyde (MDA). Crude protein content of whole body in JZ group was significantly higher than ZZ group (P<0.05). And crude lipid contents in whole body in HT and ZZ groups were significantly higher than C2 group (P<0.05). Above results showed that replaced 30% fish meal with 10% G. verrucosa, E. prolifera, algae residue or fungi residue and vegetable proteins have no adverse effect on the growth performance of juvenile tiger puffer, and E. prolifera can significantly improve the growth performance.
2018, 39(6):141-146.
Abstract:
Large-scale green tides have broken out annually in the Yellow Sea since 2007, which, upon twinning with floating Sargassum horneri, became a new hazard and increased the difficulty of preventing and controlling the green tide in Shandong Peninsula. In this study, the similarity of ITS and coxI sequences were analyzed using S. horneri samples collected from ten free-floating populations and three benthic populations in 2016 and 2017 along the offshore of China. The results showed that the coxI sequences of 51 samples were consistent, while there were two variable nucleotide sites within the ITS sequence. Based on genotypic differences, S. horneri samples could be sorted into four categories, among which the genotype of free-floating samples from Dalian Longwangtang, Daqin Island, and Nanhuangcheng Island of Yantai were identical. Free-floating samples from the Golden Beach of Qingdao and benthic samples from Daqin Island of Yantai and Zhangzi Island of Dalian were identical; free-floating samples from Lidao of Weihai and Dongtou of Wenzhou were identical; and free-floating samples from the Sculpture Garden, Wanggezhuang, Dazhushan of Qingdao, Rushan of Weihai, and benthic samples from Gouqi Island were identical. However, there was no difference in genotype among individuals within the same population, even among those occurring in different years. A phylogenetic tree based on ITS sequences of S. horneri showed that samples from China were clustered together; however, there was some genetic distance from the Korean samples. It is possible that the genetic variation of ITS and coxI regions is low in different coastal strains of S. horneri, and that drifting population could be of different origins. These findings will provide a basis for further understanding of the molecular genetic background of S. horneri along the offshore of China.
Large-scale green tides have broken out annually in the Yellow Sea since 2007, which, upon twinning with floating Sargassum horneri, became a new hazard and increased the difficulty of preventing and controlling the green tide in Shandong Peninsula. In this study, the similarity of ITS and coxI sequences were analyzed using S. horneri samples collected from ten free-floating populations and three benthic populations in 2016 and 2017 along the offshore of China. The results showed that the coxI sequences of 51 samples were consistent, while there were two variable nucleotide sites within the ITS sequence. Based on genotypic differences, S. horneri samples could be sorted into four categories, among which the genotype of free-floating samples from Dalian Longwangtang, Daqin Island, and Nanhuangcheng Island of Yantai were identical. Free-floating samples from the Golden Beach of Qingdao and benthic samples from Daqin Island of Yantai and Zhangzi Island of Dalian were identical; free-floating samples from Lidao of Weihai and Dongtou of Wenzhou were identical; and free-floating samples from the Sculpture Garden, Wanggezhuang, Dazhushan of Qingdao, Rushan of Weihai, and benthic samples from Gouqi Island were identical. However, there was no difference in genotype among individuals within the same population, even among those occurring in different years. A phylogenetic tree based on ITS sequences of S. horneri showed that samples from China were clustered together; however, there was some genetic distance from the Korean samples. It is possible that the genetic variation of ITS and coxI regions is low in different coastal strains of S. horneri, and that drifting population could be of different origins. These findings will provide a basis for further understanding of the molecular genetic background of S. horneri along the offshore of China.
2017, 38(5):122-129.
DOI: 10.11758/yykxjz.20160510001
Abstract:
In this study, the diets for sea cucumbers (Apostichopus japonicus Selenka) were formulated with Enteromorpha prolifera, Ulva lactuca, soybean meal, glucose, scallop side, shell powder, vitamins premix and mineral premix, and processed in four ways using Brewer’s yeast and alkaline protease. The final products were 5 groups of experimental diets including the control group, the fermented group, the hydrolyzed group, the composite group and the fresh-group. Each diet was randomly given to 3 replicates of 30 sea cucumbers of which the average body weight was (1.92±0.02) g. The results were described as follows. E. prolifera-diets had significant different effects on the survival rate (SR), the weight gain rate (WGR), the specific growth rate (SGR) and the feed coefficient (FC) (P<0.05). The SR in the composite group and the fresh group was higher than that in the hydrolyzed group (P<0.05), but was not significantly different from other groups (P>0.05). The WGR in the fresh group was higher than that in other groups (P<0.05). The FC in the fresh group was lower than in all other groups except for the composite group. Over the feeding time, the intestinal amylase activity (AMS) showed an increasing-decreasing-stabilized pattern in the control group, the fermented group, the composite group and the fresh group; however, AMS had been constantly declining in the hydrolyzed group. The intestinal cellulase activity in the hydrolyzed group tended to decrease over time, and in other groups, it was higher than the initial values and had been fluctuating. Except for the hydrolyzed group, the trypsin activity in all other groups showed no significant change. E. prolifera-diets also affected the activities of acid phosphatase (ACP), alkaline phosphatase (AKP) and superoxide dismutase (SOD) in the coelomic fluid to different extents (P<0.05). ACP in the fresh group was the highest and was significantly higher than all other groups (P<0.05) except for the composite group (P>0.05). SOD in the composite group was the highest and was significantly higher than the hydrolyzed group and the fermented group. These results suggested that juvenile sea cucumbers could benefit from the diets of the composite group and the fresh group in terms of the growth performance, the intestinal digestion and immunity. Our study also provided information on solving the shortage in raw dietary materials for sea cucumbers and making good use of E.prolifera.
In this study, the diets for sea cucumbers (Apostichopus japonicus Selenka) were formulated with Enteromorpha prolifera, Ulva lactuca, soybean meal, glucose, scallop side, shell powder, vitamins premix and mineral premix, and processed in four ways using Brewer’s yeast and alkaline protease. The final products were 5 groups of experimental diets including the control group, the fermented group, the hydrolyzed group, the composite group and the fresh-group. Each diet was randomly given to 3 replicates of 30 sea cucumbers of which the average body weight was (1.92±0.02) g. The results were described as follows. E. prolifera-diets had significant different effects on the survival rate (SR), the weight gain rate (WGR), the specific growth rate (SGR) and the feed coefficient (FC) (P<0.05). The SR in the composite group and the fresh group was higher than that in the hydrolyzed group (P<0.05), but was not significantly different from other groups (P>0.05). The WGR in the fresh group was higher than that in other groups (P<0.05). The FC in the fresh group was lower than in all other groups except for the composite group. Over the feeding time, the intestinal amylase activity (AMS) showed an increasing-decreasing-stabilized pattern in the control group, the fermented group, the composite group and the fresh group; however, AMS had been constantly declining in the hydrolyzed group. The intestinal cellulase activity in the hydrolyzed group tended to decrease over time, and in other groups, it was higher than the initial values and had been fluctuating. Except for the hydrolyzed group, the trypsin activity in all other groups showed no significant change. E. prolifera-diets also affected the activities of acid phosphatase (ACP), alkaline phosphatase (AKP) and superoxide dismutase (SOD) in the coelomic fluid to different extents (P<0.05). ACP in the fresh group was the highest and was significantly higher than all other groups (P<0.05) except for the composite group (P>0.05). SOD in the composite group was the highest and was significantly higher than the hydrolyzed group and the fermented group. These results suggested that juvenile sea cucumbers could benefit from the diets of the composite group and the fresh group in terms of the growth performance, the intestinal digestion and immunity. Our study also provided information on solving the shortage in raw dietary materials for sea cucumbers and making good use of E.prolifera.
2015, 36(5):101-110.
DOI: 10.11758/yykxjz.20150514
Abstract:
High scatter ratio (ScR) of feed diets and the lack of effective disease prevention and control method have been hindering the cage culture of sea cucumbers (Apostichopus japonicus). In this study we used adhesive feed with bio-gel and 3 types of feed supplements (Enteromorpha, microecologics and Chinese herbal medicine) to evaluate their effects on the growth and survival of the cultured sea cucumbers. We designed two categories of feed (adhesive feed with 20% bio-gel and control feed without bio-gel), and divided them into eight groups including the blank adhesive feed (AF-b), the enteromorpha adhesive feed (AF-en), the microecologics adhesive feed (AF-mi), the Chinese herbal medicine adhesive feed (AF-h), the blank control feed (CF-b), the enteromorpha control feed (CF-en), the microecologics control feed (CF-mi), and the Chinese herbal medicine control feed (CF-h). The survival rates (SR), the weight gain rates (WGR), the specific growth rates, the activities of protease, amylase, cellulose, and the microstructure of foregut were measured as the indicators of the effects of feed supplements during the 42-day feeding experiment. The average ScR of the adhesive feed groups (AF-b, AF-en, AF-mi, and AF-h) was reduced by 33.42% compared to the control groups (CF-b, CF-en, CF-mi, and CF-h). There was no significant difference between the 3 groups with food supplements (P>0.05). The WGR and SGR of AF-h were (41.50±1.39)% and (0.82±0.02) %/d respectively, which were the highest among all groups and the values were significantly different from other 4 groups (CF-b, AF-b, AF-en, and AF-mi) (P<0.05). The SR of AF-h (94.03%±2.28%) was the highest among all groups. The SRs of AF-h and AF-mi were significantly higher than that of CF-b and AF-b (P<0.05). The activity of amylase of AF-en, AF-mi and AF-h reached the maximum on the 10th, 20th and 30th day during the experiment, and the peak values were (1.70±0.05) U∙mg prot-1, (1.60±0.04) U∙mg prot-1 and (1.77±0.04) U∙mg prot-1 respectively. Compared to the other 4 groups, the activity of protease of AF-b fluctuated tremendously and reached (1.78±0.09) U·mg prot-1 on the 10th day during the experiment. The activity of cellulose of CF-b, AF-en and AF-b first increased during the early stage and decreased later; the activity of cellulose of AF-h continued to increase during the entire experiment; the activity of cellulose of AF-mi decreased during the first 20 days and then increased in the later 20 days. The microstructures of the foregut of the 5 groups (CF-b, AF-b, AF-en, AF-mi, and AF-h) were normal. The microscopic observation revealed an intense secretion activity of the epithelial cells in AF-mi and AF-h. The relative thickness of the mucosa of AF-b and the muscular layer of AF-en increased significantly (P<0.05). These results indicated that the adhesive feed with bio-gel could effectively decrease ScR of feed diets, and that WGR, SR and digestion activities could be increased with the addition of microecologics and Chinese herbal medicine. Furthermore, Enteromorpha did not affect the growth of cage-cultured sea cucumbers, which indicated that it could be used as a substitute in the feed diets for sea cucumbers.
High scatter ratio (ScR) of feed diets and the lack of effective disease prevention and control method have been hindering the cage culture of sea cucumbers (Apostichopus japonicus). In this study we used adhesive feed with bio-gel and 3 types of feed supplements (Enteromorpha, microecologics and Chinese herbal medicine) to evaluate their effects on the growth and survival of the cultured sea cucumbers. We designed two categories of feed (adhesive feed with 20% bio-gel and control feed without bio-gel), and divided them into eight groups including the blank adhesive feed (AF-b), the enteromorpha adhesive feed (AF-en), the microecologics adhesive feed (AF-mi), the Chinese herbal medicine adhesive feed (AF-h), the blank control feed (CF-b), the enteromorpha control feed (CF-en), the microecologics control feed (CF-mi), and the Chinese herbal medicine control feed (CF-h). The survival rates (SR), the weight gain rates (WGR), the specific growth rates, the activities of protease, amylase, cellulose, and the microstructure of foregut were measured as the indicators of the effects of feed supplements during the 42-day feeding experiment. The average ScR of the adhesive feed groups (AF-b, AF-en, AF-mi, and AF-h) was reduced by 33.42% compared to the control groups (CF-b, CF-en, CF-mi, and CF-h). There was no significant difference between the 3 groups with food supplements (P>0.05). The WGR and SGR of AF-h were (41.50±1.39)% and (0.82±0.02) %/d respectively, which were the highest among all groups and the values were significantly different from other 4 groups (CF-b, AF-b, AF-en, and AF-mi) (P<0.05). The SR of AF-h (94.03%±2.28%) was the highest among all groups. The SRs of AF-h and AF-mi were significantly higher than that of CF-b and AF-b (P<0.05). The activity of amylase of AF-en, AF-mi and AF-h reached the maximum on the 10th, 20th and 30th day during the experiment, and the peak values were (1.70±0.05) U∙mg prot-1, (1.60±0.04) U∙mg prot-1 and (1.77±0.04) U∙mg prot-1 respectively. Compared to the other 4 groups, the activity of protease of AF-b fluctuated tremendously and reached (1.78±0.09) U·mg prot-1 on the 10th day during the experiment. The activity of cellulose of CF-b, AF-en and AF-b first increased during the early stage and decreased later; the activity of cellulose of AF-h continued to increase during the entire experiment; the activity of cellulose of AF-mi decreased during the first 20 days and then increased in the later 20 days. The microstructures of the foregut of the 5 groups (CF-b, AF-b, AF-en, AF-mi, and AF-h) were normal. The microscopic observation revealed an intense secretion activity of the epithelial cells in AF-mi and AF-h. The relative thickness of the mucosa of AF-b and the muscular layer of AF-en increased significantly (P<0.05). These results indicated that the adhesive feed with bio-gel could effectively decrease ScR of feed diets, and that WGR, SR and digestion activities could be increased with the addition of microecologics and Chinese herbal medicine. Furthermore, Enteromorpha did not affect the growth of cage-cultured sea cucumbers, which indicated that it could be used as a substitute in the feed diets for sea cucumbers.
2015, 36(4):146-149.
DOI: 10.11758/yykxjz.20150422
Abstract:
Entenmorpha sp. is widely distributed along the coast of China, particularly in the eastern regions, but it has not been utilized fully. To investigate the adsorption of glucose, cholesterol and nitrite to the dietary fiber extracted from Entenmorpha sp. by the method of complex enzymes (protease and cellulase), different ratios of protease to cellulase (5:1, 10:1, 15:1, 20:1, and 25:1) were used to extract dietary fiber from Entenmorpha sp. The results showed that the ratio of protease to cellulase in the complex enzymes had obvious effects on the adsorption capabilities of the dietary fiber. With the increased protease in the complex enzymes, the adsorption of glucose and cholesterol to the dietary fiber increased and then decreased. The dietary fiber using the 10:1 ratio of protease and cellulase had highest adsorption of glucose (20.03 mg/g). The dietary fiber using the 15:1 ratio of protease to cellulose had the highest adsorption of cholesterol (21.93 mg/g). With the increased protease, the adsorption of nitrite to the dietary fiber increased. The dietary fiber had highest adsorption of nitrite (29.25 µmol/g) at the 25:1 ratio of protease to cellulose. Furthermore, the adsorption capabilities of the diary fiber in the simulated gastric fluid at pH 2.0 and the intestinal fluid at pH 7.0 were investigated. The adsorption of cholesterol to the dietary fiber was higher in the simulated intestinal fluid than that in the simulated gastric fluid, while nitrite was the opposite. The adsorption of glucose to the dietary fiber had no significant difference in the simulated intestinal and the simulated gastric fluids. These results indicated that the adsorption of nitrite to dietary fiber happened in the stomach and cholesterol happened in the intestinal, and that the adsorption of glucose to the dietary fiber happened both in the stomach and in the intestinal.
Entenmorpha sp. is widely distributed along the coast of China, particularly in the eastern regions, but it has not been utilized fully. To investigate the adsorption of glucose, cholesterol and nitrite to the dietary fiber extracted from Entenmorpha sp. by the method of complex enzymes (protease and cellulase), different ratios of protease to cellulase (5:1, 10:1, 15:1, 20:1, and 25:1) were used to extract dietary fiber from Entenmorpha sp. The results showed that the ratio of protease to cellulase in the complex enzymes had obvious effects on the adsorption capabilities of the dietary fiber. With the increased protease in the complex enzymes, the adsorption of glucose and cholesterol to the dietary fiber increased and then decreased. The dietary fiber using the 10:1 ratio of protease and cellulase had highest adsorption of glucose (20.03 mg/g). The dietary fiber using the 15:1 ratio of protease to cellulose had the highest adsorption of cholesterol (21.93 mg/g). With the increased protease, the adsorption of nitrite to the dietary fiber increased. The dietary fiber had highest adsorption of nitrite (29.25 µmol/g) at the 25:1 ratio of protease to cellulose. Furthermore, the adsorption capabilities of the diary fiber in the simulated gastric fluid at pH 2.0 and the intestinal fluid at pH 7.0 were investigated. The adsorption of cholesterol to the dietary fiber was higher in the simulated intestinal fluid than that in the simulated gastric fluid, while nitrite was the opposite. The adsorption of glucose to the dietary fiber had no significant difference in the simulated intestinal and the simulated gastric fluids. These results indicated that the adsorption of nitrite to dietary fiber happened in the stomach and cholesterol happened in the intestinal, and that the adsorption of glucose to the dietary fiber happened both in the stomach and in the intestinal.
