Although intestinal fungi play important roles in host health and disease,the composition and diversity of fungal communities remain poorly reported in fish.In this study,fungi in the fore-,mid-,and hindintestine of t...Although intestinal fungi play important roles in host health and disease,the composition and diversity of fungal communities remain poorly reported in fish.In this study,fungi in the fore-,mid-,and hindintestine of tilapia(Oreochromis mossambicus)and bighead carp(Aristichthys nobilis)from Hongchaojiang Reservoir in Guangxi,China were investigated by ITS sequencing.Based on this,we obtained 1763478 high-quality tags,which clustered into 1089 operational taxonomic units(OTUs).In total,404 OTUs were annotated,of which 310,68,and 26 belonged to Ascomycota,Basidiomycota,and other,respectively.Results show significant differences in the community composition of intestinal fungi between tilapia and bighead carp but not within their different intestinal segments.Furthermore,154 of the 404 annotated OTUs were considered reliable and were classified into three trophic modes and nine guilds.The three trophic modes consisted of 108 OTUs of saprotrophic fungi,41 OTUs of pathotrophic fungi,and five OTUs of symbiotrophic fungi.The top three most abundant OTUs overall(i.e.,Otu000002,Scopulariopsis acremonium;Otu000018,Alternaria palandui;Otu000034,Aureobasidium pullulans)showed lower abundance in the hind-intestinal segments of bighead carp,suggesting uneven distribution of these fungi in this species.In addition,saprotrophic and pathotrophic fungi were markedly decreased in the hindintestine.It is indicated that the fungal community was not only related to host species specificity but also to the respective physiological functions of different intestinal segments.These findings provide valuable information on the composition,structure,and potential function of the intestinal fungi community associated with different intestinal segments in tilapia and bighead carp under natural conditions,thus highlighting the importance of fungi as an integral part of the inte stinal microbiota in maintaining host health.展开更多
Study of the feeding capacity of silver carp and bighead carp by means of experimental ecologyshowed that the filtering frequency of silver carp was slightly greater than that of bighead carp,but thatthe latter’s suc...Study of the feeding capacity of silver carp and bighead carp by means of experimental ecologyshowed that the filtering frequency of silver carp was slightly greater than that of bighead carp,but thatthe latter’s suction volume was much greater than the former’s so the filtering rate(filtering frequency mul-tiplied by the suction volume)of silver carp was smaller than that of bighead carp.The filtering efficien-cy of silver carp for phytoplankton was greater than that of bighead carp for them.The removal ratesof silver carp for phytoplankton were greater than those of bighead carp,but for zooplankton the formerwere smaller than the latter.For food particles about 70 μm both removal rates were almost equal.The feeding habits of the two species in natural waters is also discussed in the paper.展开更多
Myosin subfragment-1 was prepared from the myofibrils of bighead carp (Aristichthys nobilis). The myosin subfrag- ment-1 was proved to have the activity of tripolyphosphatase (TPPase) responding to the hydrolysis of s...Myosin subfragment-1 was prepared from the myofibrils of bighead carp (Aristichthys nobilis). The myosin subfrag- ment-1 was proved to have the activity of tripolyphosphatase (TPPase) responding to the hydrolysis of sodium tripolyphosphate (STPP). The optimum temperature and pH for the TPPase of myosin subfragment-1 were 30℃ and pH 5.0, and at pH 8.0 the TPPase also showed a high activity. Mg2+ was necessary to TPPase. The TPPase activity of myosin subfragment-1 was activated by Mg2+ under low concentrations, but was inhibited when the concentration was over 17 mmolL-1. The TPPase activity was also affected by KCl. The optimum concentration of KCl for TPPase was 0.3 molL-1 under the condition of 17 mmolL-1 Mg2+. The TPPase activity was significantly inhibited by EDTA-Na2. Reagents such as KBr, KI and KIO3 could inhibit the TPPase effectively. K2Cr2O7 as well as KMnO7 and KNO3 exhibited weak inhibiting effects. The TPPase converted STPP to pyrophosphate (PP) and orthophosphate (Pi) stoichiometrically with a KM of 3.2 mmolL-1.展开更多
The effect of various concentrations of nitrobenzene on the mortality and abnormality rate of bighead and silver carp embryos were studied to provide reference for the evaluation of the effect of nitrobenzene to aquat...The effect of various concentrations of nitrobenzene on the mortality and abnormality rate of bighead and silver carp embryos were studied to provide reference for the evaluation of the effect of nitrobenzene to aquatic organisms and aquatic environment. The results showed that the development of bighead and silver carp embryos was delayed, the mortality and abnormality rates were raised when the embryos were treated with ≥0.010 mg·L^-1 nitrobenzene, and with ≥0.085 mg· L^-1 nitrobenzene, the mortality rates showed 100%展开更多
Silver carp, Hypophthalmichthys molitrix, and bighead carp, Aristichthys nobilis, habitually celebrated for their being cultured easily with fewer diseases and high-yield, have suffered from a new severe epidemic dise...Silver carp, Hypophthalmichthys molitrix, and bighead carp, Aristichthys nobilis, habitually celebrated for their being cultured easily with fewer diseases and high-yield, have suffered from a new severe epidemic disease recently. The spread of the epizootic has been far and wide, from several provinces in South China to the Beijing and Tianjin area. The affected fish suffered heavy mortafity in one week, and even died off.展开更多
基金the Guangxi Science and Technology Major Project(No.AA17204095-8)the Open Fund of Guangxi Key Laboratory of Aquatic Genetic Breeding and Healthy Aquaculture(No.GXKEYLA2019-05)the China-ASEAN Maritime Cooperation Fund(No.CAMC-2018F)。
文摘Although intestinal fungi play important roles in host health and disease,the composition and diversity of fungal communities remain poorly reported in fish.In this study,fungi in the fore-,mid-,and hindintestine of tilapia(Oreochromis mossambicus)and bighead carp(Aristichthys nobilis)from Hongchaojiang Reservoir in Guangxi,China were investigated by ITS sequencing.Based on this,we obtained 1763478 high-quality tags,which clustered into 1089 operational taxonomic units(OTUs).In total,404 OTUs were annotated,of which 310,68,and 26 belonged to Ascomycota,Basidiomycota,and other,respectively.Results show significant differences in the community composition of intestinal fungi between tilapia and bighead carp but not within their different intestinal segments.Furthermore,154 of the 404 annotated OTUs were considered reliable and were classified into three trophic modes and nine guilds.The three trophic modes consisted of 108 OTUs of saprotrophic fungi,41 OTUs of pathotrophic fungi,and five OTUs of symbiotrophic fungi.The top three most abundant OTUs overall(i.e.,Otu000002,Scopulariopsis acremonium;Otu000018,Alternaria palandui;Otu000034,Aureobasidium pullulans)showed lower abundance in the hind-intestinal segments of bighead carp,suggesting uneven distribution of these fungi in this species.In addition,saprotrophic and pathotrophic fungi were markedly decreased in the hindintestine.It is indicated that the fungal community was not only related to host species specificity but also to the respective physiological functions of different intestinal segments.These findings provide valuable information on the composition,structure,and potential function of the intestinal fungi community associated with different intestinal segments in tilapia and bighead carp under natural conditions,thus highlighting the importance of fungi as an integral part of the inte stinal microbiota in maintaining host health.
文摘Study of the feeding capacity of silver carp and bighead carp by means of experimental ecologyshowed that the filtering frequency of silver carp was slightly greater than that of bighead carp,but thatthe latter’s suction volume was much greater than the former’s so the filtering rate(filtering frequency mul-tiplied by the suction volume)of silver carp was smaller than that of bighead carp.The filtering efficien-cy of silver carp for phytoplankton was greater than that of bighead carp for them.The removal ratesof silver carp for phytoplankton were greater than those of bighead carp,but for zooplankton the formerwere smaller than the latter.For food particles about 70 μm both removal rates were almost equal.The feeding habits of the two species in natural waters is also discussed in the paper.
基金This work was supported by the National Natural Science Foundation of China （No. 30671632）supported by the National High-tech Research and Development Project of China （No. 2006AA09Z444）.
文摘Myosin subfragment-1 was prepared from the myofibrils of bighead carp (Aristichthys nobilis). The myosin subfrag- ment-1 was proved to have the activity of tripolyphosphatase (TPPase) responding to the hydrolysis of sodium tripolyphosphate (STPP). The optimum temperature and pH for the TPPase of myosin subfragment-1 were 30℃ and pH 5.0, and at pH 8.0 the TPPase also showed a high activity. Mg2+ was necessary to TPPase. The TPPase activity of myosin subfragment-1 was activated by Mg2+ under low concentrations, but was inhibited when the concentration was over 17 mmolL-1. The TPPase activity was also affected by KCl. The optimum concentration of KCl for TPPase was 0.3 molL-1 under the condition of 17 mmolL-1 Mg2+. The TPPase activity was significantly inhibited by EDTA-Na2. Reagents such as KBr, KI and KIO3 could inhibit the TPPase effectively. K2Cr2O7 as well as KMnO7 and KNO3 exhibited weak inhibiting effects. The TPPase converted STPP to pyrophosphate (PP) and orthophosphate (Pi) stoichiometrically with a KM of 3.2 mmolL-1.
文摘The effect of various concentrations of nitrobenzene on the mortality and abnormality rate of bighead and silver carp embryos were studied to provide reference for the evaluation of the effect of nitrobenzene to aquatic organisms and aquatic environment. The results showed that the development of bighead and silver carp embryos was delayed, the mortality and abnormality rates were raised when the embryos were treated with ≥0.010 mg·L^-1 nitrobenzene, and with ≥0.085 mg· L^-1 nitrobenzene, the mortality rates showed 100%
文摘Silver carp, Hypophthalmichthys molitrix, and bighead carp, Aristichthys nobilis, habitually celebrated for their being cultured easily with fewer diseases and high-yield, have suffered from a new severe epidemic disease recently. The spread of the epizootic has been far and wide, from several provinces in South China to the Beijing and Tianjin area. The affected fish suffered heavy mortafity in one week, and even died off.
