查看更多>>摘要：The effects of xylooligosaccharide (XOS) on growth performance,activities of digestive enzymes,and intestinal microflora of Chinese soft-shelled turtle Pelodiscus sinensis were investigated by adding different concentrations of XOS in the diet of juvenile P sinensis.The turtles with an average initial bodyweight of 12.264±0.32 g were randomly divided into five groups,which were fed with diets containing 0 mg/kg (control),50 mg/kg (Trial I),100 mg/kg (Trial Ⅱ),200 mg/kg (Trial Ⅲ),and 500 mg/kg (Trial ⅣV) XOS product (95％),respectively.The feeding trial lasted for 30 days.Indices described above were determined at the end of the experiment.The results showed that the diet supplemented with XOS could enhance the growth ofP.sinensis,and the growth rate of Trial Ⅲ was the highest.Feed conversion ratio (FCR) of the trials was lower than that of the control.All the trials had higher activities of intestinal digestive enzymes than the control.The amylase activity of Trial Ⅱ was the highest and was significantly different from that of the control,while the protease activity of the trials was not significantly but slightly higher than that of the control.The numbers of total aerobic bacteria and Enterobacteria of all the trials were significantly lower than those of the control.The number of Bifidobacteria of Trial Ⅱ ranked the largest,significantly higher than that of the control,whereas the number of Bifidobacteria of all the other trials was higher but not more significant than that of the control.The results demonstrated that XOS supplementation in the diet ofP.sinensis could enhance its growth and decrease FCR.Furthermore,it could enhance activities of intestinal protease and amylase and optimize its intestinal microflora.The recommended supplemental concentration of XOS in the diet of Juvenile P.sinensis should be 100-200 mg/kg.
查看更多>>摘要：Co-culture of roughskin sculpin and common carp,roughskin sculpin and medaka,and roughskin sculpin and freshwater shrimp were carried out in three earthen ponds from late May till late October of 2009 in a suburb of Qinhuangdao,Hebei Province,China.In the sculpin/medaka and sculpin/shrimp co-culture ponds,aquatic plants (cattail and reed) composing approximately 25％ of the pond area were settled.Commercial feed was administered in all the three ponds for the three forage animals:common carp,medaka and freshwater shrimp.In the sculpin/carp coculture pond,though common carp grew properly with a yield of 4550 kg per hm2,the sculpin gradually decreased in number,and eventually only a few were left.In the sculpin/medaka co-culture pond,the pelagic medaka and benthic roughskin sculpin made full use of the water column of the pond,with the former breeding continuously to provide fry and juveniles for the latter to prey on,yielding 61.4 kg roughskin sculpin per hm2 and 1550 kg medaka per hm2.In the sculpin/shrimp co-culture,adult freshwater shrimp were also bred to supply fry and juveniles for the growing roughskin sculpin to prey on,yielding 46.4 kg roughskin sculpin per hm2 and 304 kg shrimp per hm2,less than that in the sculpin/medaka co-culture,as both freshwater shrimp and roughskin sculpin lived in the same niches,i.e.the pond bottom and the plant stems and leaves,with the open water column left vacant.Further improvements were also proposed.
查看更多>>摘要：The study was conducted to investigate the ontogenic development of main digestive enzymes (pepsin,trypsin,amylase and lipase) activities in juvenile soft-shelled turtle (Pelodiscus sinensis) (initial mean bodyweight 3.63 ± 0.27 g),in order to provide data on the digestive physiology of the juveniles during the first 30 days after hatching (DAH).The soft-shelled turtles were reared in an indoor rearing system,and fed with a formulated diet four times daily from 2 to 30 DAH.The results showed that the specific growth rate (SGR) of soft-shelled turtle ranged from 1.31 to 4.00％/d during the first 30 DAH.The specific activities of pepsin in stomachic segments,trypsin,amylase and lipase in intestinal segments first decreased slightly then increased to the maximum value (P＜ 0.05).The specific activities of these enzymes were first detected on 1 DAH,and the lowest values were observed from 4 to 6 DAH,while the highest values were found from 22 to 30 DAH.Results of the present study indicated that the activities of digestive enzymes in softshelled turtle developed during the development and were well correlated with growth.
查看更多>>摘要：Sweet cherry (Prunus avium L.) is a kind of fruit with short postharvest life.Postharvest treatment of 1-methylcyclopropene (1-MCP:1.0,1.5 and 2.0 μL/L) was applied to cherry fruits,and its effects on postharvest fruit quality during 60-day-storage at cold temperature was investigated.Sweet cherry fruits were harvested at commercial fruit maturity and exposed to 1-MCP at 20± 1℃ for 24 h.Following 1-MCP treatments,the fruits were stored for 60 d at 90±5％ RH and,0± 1 ℃,in three concentrations of 1.0,1.5,and 2.0 μL/L 1-MCP,of which 1.5 μL/L 1-MCP had the most positive effect on fruit quality.Postharvest treatments of 1-MCP significantly reduced endogenous ethylene production,malondialdehyde (MDA) content,and polyphenol oxidase (PPO) activity in cherry fruits 60 d after cold storage when compared to untreated fruits.1-MCP treatment was associated with lower respiration rate and relative electric conductivity (REC) and maintained cell membrane integrity.The results indicated that the treatment 1-MCP was effective in inhibition of the declining of POD activity and CAT activity.In conclusion,1-MCP treatment could be a good candidate for maintaining postharvest quality of cherry,and 1-MCP could prolong the storage life of sweet cherry.
查看更多>>摘要：The objective was to study the technology for the separation and purification of oligomeric proanthocyanidins from Rhodiola rosea and establish the best operating conditions.First,the oligomeric proanthocyanidins was extracted by ethyl acetate from rough-extracted R.rosea liquid using an optimized technique.Its purification was achieved by macroporous resins.Five kinds of macroporous adsorbent resins were compared for the adsorption and desorption performance of procyanidins,the concentration and pH value of both the extracted sample and the eluant were investigated.According to the results,the optimized conditions were as follows:four times of extraction at 25 min each time was effective,the best volume ratio was 1.5:1 (ethyl acetate:extracted solution); AB-8 resin was the best choice; the concentration of the extracted sample was 4.0 g/L,and the pH was 4.5; the ratio of the diameter to height of the chromatography column was 1∶40 (cm); 50％ ethanol was used as the eluant at pH 5; and finally,the purity of procyanidins reached 88.3％.
查看更多>>摘要：The aim of this paper was to study the biochemical changes in fermented scallop flour paste (SFP) during different fermentation periods.SFP was prepared with scallop muscles,flour koji,salt,rice koji,and neutral protease at 40℃ for 12 days.Biochemical changes during fermentation were investigated.By reducing sugar content,formaldehyde nitrogen content,total acid content,and free amino acids (FAAs),the concentration of SFP was increased but water activity was decreased.Most FAAs were increased,and the amounts of glutamic acid,glyeine,alanine,and leucine were high.Some amino acid concentrations were higher than their taste threshold,such as the glutamate of umami,the glycine and alanine of sweet and umami,and the arginine and lysine of bitter and sweet.They contributed significantly to the characteristic taste of SFP.Therefore,SFP is a potential seasoning agent with nutritional properties and good taste.
查看更多>>摘要：In this study,oxidized starch was taken as raw material to prepare filming.Single factor and orthogonal experiments were conducted to investigate its properties.The results showed that the different concentrations of oxidized starch,glycerol,polyvinyl alcohol (PVA) and glutaraldehyde had significant effects on the properties of the oxidized starch/PVA films,among which the most important factor was glycerol,followed by the oxidized starch,PVA and glutaraldehyde.The optimum film-forming conditions were 6.0％ oxidized starch,6.0％ PVA,2.5％ glycerol and 0.6％ glutaraldehyde.
查看更多>>摘要：Effects of salt stress on the physiological and photosynthetic characteristics of Weigelaflorida were studied.The results showed that the leaf area of Weigelaflorida was enhanced at 0.1％ and 0.2％ salt concentration,but decreased obviously when salt concentration was higher than 0.3％.The symptom of the salt injury was not significant when the salt concentration was lower than 0.3％,but was significant when higher than 0.4％.The water content decreased gradually but the electrolyle leakage increased gradually with the increasing of salt concentration and time.The total content of chlorophyll was rising while salt concentration was lower than 0.3％,but decreased while salt concentration was higher than 0.4％.The proline contents increased gradually while salt concentration was lower than 0.5％,but decreased at 0.5％.The soluble sugar content increased gradually with the increasing of salt concentration and prolonging of treatment,but decreased at 0.4％ salt concentration 15 days after salt treatment.To the photosynthetic characteristics,the salt concentrations of 0.1％ and 0.2％ did not affect the photosynthetic characteristics of Weigela florida,when salt concentration was higher than 0.3％,the salinity significantly reduced Pn,Gs and Tr,but enhanced intercellular CO2 concentrations at the salt concentrations of 0.3％ and 0.4％.It was indicated that 0.1％ and 0.2％ salt concentrations had little influence on Weigela florida.The growth of Weigela florida was slightly decreased at the salt concentration of 0.3％ without effect on its normal growth.However,the salt concentration of 0.4％ affected the growth of Weigela florida obviously.Weigela florida died 7 days after treatment and it could not normally grow when salt concentration is higher than 0.5％.
查看更多>>摘要：The invasion behavior and infection process of Metarhizium anisopliae on different cuticle areas of Anoplophora glabripennis larvae were observed by scanning electron microscopy.The results indicated that M.anisopliae infected A.glabripennis larvae mainly through the intersegmental membrane where more attaching conidia,faster germination,and higher germination and penetration rates were observed.The secondary invasion area was around the valve.The two areas were vulnerable to infection from M.anisopliae.Twelve hours after vaccination,conidia germinated and bud-shaped protrusions formed on the cuticle of A.glabripennis larvae,then germ tubes and various attaching structures were produced.Conidia penetrated the integument into the hemocoele ofA.glabripennis larvae 36- 48 h later.
查看更多>>摘要：Apriona germari is a destructive stem-boring pest.To date,the control of the pest is still based largely on the chemical insecticides.To meet the needs of people's high pesticide efficacy and environment safety,the alternative management strategy must be proposed.Beauveria bassiana is one of the most widely studied and used entomopathogenic fungi.The potential of Beauveria bassiana used to control Apriona germari was here evaluated.The result showed that the infective rate of B.bassiana to adults was 20％,with no pathogenicity to eggs.But it showed a high pathogenicity to larvae.The laboratory bioassays showed that the mortality,when concentration was 1 × 10s conidia/mL,was 96.47％ ten days after inoculation.LTso of B.beauveria to Apriona germari larvae was 4.53 d at the concentration of 1 × 108 conidia/mL; LCso was 6.76 × 10s conidia/mL.The infecting experiments in field showed that,20 days after control,the mortality was 68.4％.The present results suggested that B.bassiana has an excellent potential for biological control of A.germari larvae.
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