Sea cucumbers, Apostichopus japonicus Selenka, were fed diets containing non-immunostimulant (basal diet), 0.2% β-glucan and 0.02% glycyrrhizin in a recirculatory water system for 45 days, and subsequently challenged...Sea cucumbers, Apostichopus japonicus Selenka, were fed diets containing non-immunostimulant (basal diet), 0.2% β-glucan and 0.02% glycyrrhizin in a recirculatory water system for 45 days, and subsequently challenged with Vibrio splendidus by injection at 1.0×108 cfu/sea cucumber for 15 days.Phagocytic capacity (PC), intracellular superoxide anion production (ISAP), ly-sozyme (LSZ) activity and superoxide dismutase (SOD) activity in the coelomic fluid were analyzed on the 0th, 5th, 10th and 15th days after injection.Results showed that after the 45-day feeding period, PC, ISAP, LSZ activity and SOD activity in sea cucumbers fed with dietary β-glucan or glycyrrhizin were significantly higher than in those fed with the basal diet.On the 5th day after infection, all the immune parameters examined in the sea cucumbers injected with V.splendidus decreased in value significantly.On the 15th day, PC, ISAP and LSZ activity returned to levels similar to those on the 0th day.For the sea cucumbers injected with saline, there were no significant differences in all the immune parameters examined and in the cumulative morbidity during the 15-day challenging trial.After injecting with V.splendidus, the cumulative morbidity of sea cucumbers fed with the basal diet was significantly higher than those fed with dietary β-glucan or glycyrrhizin when challenged with V.splendidus challenged sea cucumber fed with the basal diet was significantly higher than those fed with dietary β-glucan or glycyrrhizin.There was no significant difference in cumulative morbidity between the dietary β-glucan and glycyrrhizin treatments over time.展开更多
A study on the nonspecific immunity of Litopenaeus vannamei ever inhabiting freshwater and seawater was carried out at different molt stages by comparing their total hemocyte count(THC) and respiratory burst(RB) and a...A study on the nonspecific immunity of Litopenaeus vannamei ever inhabiting freshwater and seawater was carried out at different molt stages by comparing their total hemocyte count(THC) and respiratory burst(RB) and activity of phenol oxidase(PO), nitric oxide synthase(NOS) and lysozyme(LY). Two-way ANOVA showed that salinity and molt stage independently affected THC and RB and the activity of PO, NOS and LY of juvenile L. vannamei significantly(P < 0.05). The THC and RB and the activity of NOS gradually increased from the post-molt stages(A and B) to the pre-molt stages(D0–D3), which were common in shrimps inhabiting freshwater and seawater. The activity of PO peaked at the inter-molt stage(C), and touched the lowest at the post-molt stage in freshwater and pre-molt stage in seawater. The activity of LY was stable over the molt cycle. The RB and the activity of PO, NOS and LY of juvenile L. vannamei were significantly lower in freshwater than in seawater; whereas THC was significantly higher in freshwater than in seawater(P < 0.05). It was concluded that the post-molt stage(especially stage A) was critical to shrimp culture, which should be intensively attended when L. vannamei was cultured in freshwater.展开更多
The present study was conducted to evaluate the feasibility of replacing fish meal(FM) with bioactive peptides(BPs) in diet of white shrimp(Litopenaeus vannamei). The changes in growth performance, body composition, n...The present study was conducted to evaluate the feasibility of replacing fish meal(FM) with bioactive peptides(BPs) in diet of white shrimp(Litopenaeus vannamei). The changes in growth performance, body composition, non-specific immunity, and water quality were examined after the shrimp were fed four diets, in which 0%(control), 33.3%, 66.7% and 100% of FM was replaced by BPs, respectively. The groups were designated as Con, 1/3BPs, 2/3BPs, and 3/3BPs. A total of 720 shrimp with an initial body weight of 1.46 ± 0.78 g were fed the experimental diets for 56 days. The results revealed that: 1) the weight gain rate(WGR) in 1/3BPs, 2/3BPs, and 3/3BPs was significantly higher than that in Con(P < 0.05), while no significant difference was found on survival rate and feed conversion ratio(FCR); 2) the whole-body crude protein(CP) and crude lipids(CL) were significantly different among groups, while there was no significant difference between crude ash and phosphorus contents; 3) the levels of acid phosphatase(ACP), lysozyme(LZM), superoxide dismutase(SOD), phenol oxidase(PO) and bactericidal activity increased significantly with the inclusion of BPs; 4) in terms of water quality, no significant difference was found in p H and dissolved oxygen among diets during the whole experimental period. Moreover, even though nitrite and ammonium levels tended to increase with time, there was no significant difference among groups. The results indicated that BPs is an applicable alternative of protein source, which can substitute FM in the diets of L. vannamei; it is able to effectively promote growth performance and improve immunity. Moreover, BPs in the diets had no negative impact on water quality.展开更多
Aims The aim of this paper is to assess morphological and leaf stoichiometric responses of Dendrosenecio keniensis and Lobelia gregoriana to extreme environmental conditions along an elevation gradient in tropical mou...Aims The aim of this paper is to assess morphological and leaf stoichiometric responses of Dendrosenecio keniensis and Lobelia gregoriana to extreme environmental conditions along an elevation gradient in tropical mountains.Methods In this study,we assessed the variation of the morphological traits,including plant height,leaf area,leaf thickness,leaf dry weight,specific leaf area and the leaf stoichiometry traits nitrogen,carbon and phosphorous of the two endemic species D.keniensis and L.gregoriana.We further explored the relations of these morphological traits to soil organic carbon,soil total nitrogen,soil phosphorous,annual mean temperature,annual mean precipitation,annual total solar radiation,water vapor pressure and the topographic variables aspect,slope and hill shade along the elevation gradient.Ninety 10 m×10 m sampling plots were set up along the elevation gradient ranging from 3500 to 4300 m.We used 1 km×1 km grid cells to rasterize our study area in ArcGIS 10.5 for easy access to data pertaining to the climate of each elevation band.We performed linear regression of the morphological and leaf stoichiometric traits with elevation as explanatory variable.We conducted correlation analysis on the morphological and leaf stoichiometric traits with climatic,soil and topographic variables along the elevation gradient.Important Findings Dendrosenecio keniensis had wool-like pubescent leaves while L.gregoriana had mucilage packed succulent and waxy cuticle leaves to avoid freezing.Both species exhibited reduced metabolic rates as shown by the low leaf phosphorous content.Our results also showed that changes in morphology and leaf stoichiometry were determined by a combination of climate,soil and topographic variables that change along elevation on Mount Kenya.The observed variations in the morphological and leaf stoichiometric traits of D.keniensis and L.gregoriana,which grow side by side along the elevation gradient,were interpreted as adaptation to the harsh environmental conditions.展开更多
基金supported by grant No.2006AA100313 from the National High Technology Research and Development Project of P.R. China (863 Project)
文摘Sea cucumbers, Apostichopus japonicus Selenka, were fed diets containing non-immunostimulant (basal diet), 0.2% β-glucan and 0.02% glycyrrhizin in a recirculatory water system for 45 days, and subsequently challenged with Vibrio splendidus by injection at 1.0×108 cfu/sea cucumber for 15 days.Phagocytic capacity (PC), intracellular superoxide anion production (ISAP), ly-sozyme (LSZ) activity and superoxide dismutase (SOD) activity in the coelomic fluid were analyzed on the 0th, 5th, 10th and 15th days after injection.Results showed that after the 45-day feeding period, PC, ISAP, LSZ activity and SOD activity in sea cucumbers fed with dietary β-glucan or glycyrrhizin were significantly higher than in those fed with the basal diet.On the 5th day after infection, all the immune parameters examined in the sea cucumbers injected with V.splendidus decreased in value significantly.On the 15th day, PC, ISAP and LSZ activity returned to levels similar to those on the 0th day.For the sea cucumbers injected with saline, there were no significant differences in all the immune parameters examined and in the cumulative morbidity during the 15-day challenging trial.After injecting with V.splendidus, the cumulative morbidity of sea cucumbers fed with the basal diet was significantly higher than those fed with dietary β-glucan or glycyrrhizin when challenged with V.splendidus challenged sea cucumber fed with the basal diet was significantly higher than those fed with dietary β-glucan or glycyrrhizin.There was no significant difference in cumulative morbidity between the dietary β-glucan and glycyrrhizin treatments over time.
基金supported by a project of The Major State Basic Research of China (2009CB118706)
文摘A study on the nonspecific immunity of Litopenaeus vannamei ever inhabiting freshwater and seawater was carried out at different molt stages by comparing their total hemocyte count(THC) and respiratory burst(RB) and activity of phenol oxidase(PO), nitric oxide synthase(NOS) and lysozyme(LY). Two-way ANOVA showed that salinity and molt stage independently affected THC and RB and the activity of PO, NOS and LY of juvenile L. vannamei significantly(P < 0.05). The THC and RB and the activity of NOS gradually increased from the post-molt stages(A and B) to the pre-molt stages(D0–D3), which were common in shrimps inhabiting freshwater and seawater. The activity of PO peaked at the inter-molt stage(C), and touched the lowest at the post-molt stage in freshwater and pre-molt stage in seawater. The activity of LY was stable over the molt cycle. The RB and the activity of PO, NOS and LY of juvenile L. vannamei were significantly lower in freshwater than in seawater; whereas THC was significantly higher in freshwater than in seawater(P < 0.05). It was concluded that the post-molt stage(especially stage A) was critical to shrimp culture, which should be intensively attended when L. vannamei was cultured in freshwater.
基金supported by the Science-Technology Supporting Project of the National Twelfth Five-YearPlan of China (No. 2012BAD25B01)
文摘The present study was conducted to evaluate the feasibility of replacing fish meal(FM) with bioactive peptides(BPs) in diet of white shrimp(Litopenaeus vannamei). The changes in growth performance, body composition, non-specific immunity, and water quality were examined after the shrimp were fed four diets, in which 0%(control), 33.3%, 66.7% and 100% of FM was replaced by BPs, respectively. The groups were designated as Con, 1/3BPs, 2/3BPs, and 3/3BPs. A total of 720 shrimp with an initial body weight of 1.46 ± 0.78 g were fed the experimental diets for 56 days. The results revealed that: 1) the weight gain rate(WGR) in 1/3BPs, 2/3BPs, and 3/3BPs was significantly higher than that in Con(P < 0.05), while no significant difference was found on survival rate and feed conversion ratio(FCR); 2) the whole-body crude protein(CP) and crude lipids(CL) were significantly different among groups, while there was no significant difference between crude ash and phosphorus contents; 3) the levels of acid phosphatase(ACP), lysozyme(LZM), superoxide dismutase(SOD), phenol oxidase(PO) and bactericidal activity increased significantly with the inclusion of BPs; 4) in terms of water quality, no significant difference was found in p H and dissolved oxygen among diets during the whole experimental period. Moreover, even though nitrite and ammonium levels tended to increase with time, there was no significant difference among groups. The results indicated that BPs is an applicable alternative of protein source, which can substitute FM in the diets of L. vannamei; it is able to effectively promote growth performance and improve immunity. Moreover, BPs in the diets had no negative impact on water quality.
基金supported by National Science Foundation of China(31800176)Sino-Africa Joint Research Center,CAS,China(Y323771W07,SAJC201322).
文摘Aims The aim of this paper is to assess morphological and leaf stoichiometric responses of Dendrosenecio keniensis and Lobelia gregoriana to extreme environmental conditions along an elevation gradient in tropical mountains.Methods In this study,we assessed the variation of the morphological traits,including plant height,leaf area,leaf thickness,leaf dry weight,specific leaf area and the leaf stoichiometry traits nitrogen,carbon and phosphorous of the two endemic species D.keniensis and L.gregoriana.We further explored the relations of these morphological traits to soil organic carbon,soil total nitrogen,soil phosphorous,annual mean temperature,annual mean precipitation,annual total solar radiation,water vapor pressure and the topographic variables aspect,slope and hill shade along the elevation gradient.Ninety 10 m×10 m sampling plots were set up along the elevation gradient ranging from 3500 to 4300 m.We used 1 km×1 km grid cells to rasterize our study area in ArcGIS 10.5 for easy access to data pertaining to the climate of each elevation band.We performed linear regression of the morphological and leaf stoichiometric traits with elevation as explanatory variable.We conducted correlation analysis on the morphological and leaf stoichiometric traits with climatic,soil and topographic variables along the elevation gradient.Important Findings Dendrosenecio keniensis had wool-like pubescent leaves while L.gregoriana had mucilage packed succulent and waxy cuticle leaves to avoid freezing.Both species exhibited reduced metabolic rates as shown by the low leaf phosphorous content.Our results also showed that changes in morphology and leaf stoichiometry were determined by a combination of climate,soil and topographic variables that change along elevation on Mount Kenya.The observed variations in the morphological and leaf stoichiometric traits of D.keniensis and L.gregoriana,which grow side by side along the elevation gradient,were interpreted as adaptation to the harsh environmental conditions.
