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1.
In order to determine the potential of the earthworm Eudrilus eugeniae as waste processor and protein producer, the life history of this species was studied. The development, growth and reproduction of E. eugeniae were studied. Cattle dung was used as substrate with a moisture content of 70–80% and a temperature of 25°C. Data were gathered over a period of 300 days. It was found that cocoon production started within 24 h after copulation and can be sustained for at least 300 days. Cocoons are produced at an average rate of 1,65 cocoons per worm per day. The mean incubation period of cocoons is 16,6 days with a hatching success of 84% and 2,7 hatchlings per cocoon that hatched. Sexual maturity is attained by the offspring within 40 to 50 days after hatching. E. eugeniae is compared to other vermicomposting species.  相似文献   

2.
The pharmacokinetics and tissue residues of moroxydine hydrochloride were studied in gibel carp at water temperature of 15 and 25 °C. Samples (blood, skin, muscle, liver, and kidney) were collected over 10 days after the treatment and analyzed by high‐performance liquid chromatography with an ultraviolet detector. The results indicated that the influence of water temperature on the metabolism of the drug was significant. The plasma concentration–time data of moroxydine hydrochloride conformed to single‐compartment open model at the two water temperatures. There were higher absorption rate (t1/2ka) and longer elimination half‐lives (t1/2ke) at 15 °C (4.29 and 15.87 h, respectively) compared with those at 25 °C (3.02 and 4.22 h, respectively). The maximum plasma concentration (Cmax) and the time‐point of maximum plasma concentration (Tp) were 2.98 μg/mL and 10.35 h at 15 °C and 3.12 μg/mL and 4.03 h at 25 °C, respectively. The distribution volume (Vd/F) of moroxydine hydrochloride was estimated to be 4.55 L/kg at 15 °C and 2.89 L/kg at 25 °C. The total body clearance (CLb) of moroxydine hydrochloride was determined to be 0.25 and 0.49 L/(h·kg) at 15 °C and 25 °C, respectively; the areas under the concentration–time curve were 75.89 μg·h/mL at 15 °C and 42.33 μg·h/mL at 25 °C. The depletion of moroxydine hydrochloride in gibel carp was slower with a longer half‐life period, especially at lower water temperature that was tested.  相似文献   

3.
Abstract

One hundred seven Aeromonas spp., 26 Edwardsiella ictaluri, 6 E. tarda, 12 Plesiomonas shigelloides, and 6 Pseudomonas spp. (131 piscine isolates and 26 reference isolates) were studied with 36 biochemical tests from the Minitek system, 20 tests from the API 20E system, and corresponding standard tube tests. Isolates were incubated at 25°C. Arginine dihydrolase, ornithine decarboxylase, mannose, and citrate showed less than 95% agreement between the Minitek system and the tube tests. Arginine dihydrolase, lysine decarboxylase, nitrite reductase, Voges-Proskauer, and citrate showed less than 95% agreement between the API 20E system and the tube tests. The 26 reference isolates were examined with the three systems and were incubated at both 25 and 37°C. There were no major differences between tests run at 25 and 37°C except with nine Aeromonas spp. that did not grow well at 37°C. Both the Minitek and API 20E systems will reproduce standard biochemical tube test results with at least 95% accuracy when used to test warmwater fish pathogens incubated at 25°C. However, the numerical identification databases for both the Minitek and API 20E systems were not usable for identifying fish pathogens.  相似文献   

4.
The growth kinetics of virulence plasmid‐bearing Yersinia pseudotuberculosis (YPST) in sterile ground beef were studied at temperatures ranging from 0 to 30°C. In irradiated sterile ground beef, YPST replicated from 0 to 30°C, with corresponding growth rates (GR) ranging from 0.023 to 0.622 log CFU/h at 0–25°C, and the GR was 0.236 log CFU/h at 30°C. The maximum population densities (MPD) ranged from 8.7 to 11.0 log CFU/g. The growth and MPD of YPST were reduced significantly at 30°C. Models for GR and MPD of YPST in raw ground beef (RGB) as a function of storage temperatures were produced and displayed acceptable bias and accuracy. The models were validated with rifampicin‐resistant YPST (rif‐YPST) in sterile ground beef stored at 4, 10 and 25°C. The observed GR and MPD were within 95% of the predicted values. When compared to non‐sterile retail ground beef, the growth of rif‐YPST was not inhibited and displayed similar GR at 0, 10 and 25°C and MPDs as sterile ground beef at 10 and 25°C. Moreover, there was no loss of virulence plasmid in YPST during its growth in ground beef indicating that RGB contaminated with virulence plasmid‐bearing YPST could cause disease due to refrigeration failure, temperature (10–25°C) abuse, and if the meat was not properly cooked.  相似文献   

5.
对云南省桑蚕普种场2005年春季不同生产小组饲育的云蚕7、云蚕8蚕品种各项成绩进行了综合调查,通过对其调查的有关项目数据进行分析总结,发现蚕茧成绩中的“kg茧粒数”对蚕茧成绩中和蚕种成绩中的部分项目产生了影响,即:“kg茧粒数”与“g蚁收茧量、g蚁制种量、孵化率”呈负相关性,“kg茧粒数”与“g卵粒数”则呈正相关性。而对其它一些项目则无影响。  相似文献   

6.
In this study the effect of long‐term storage of liquid boar semen at different temperatures on motility, acrosome integrity and pH was investigated. Additionally, individual variation in sperm tolerance to storage at 10°C were examined. Beltsville Thawing Solution‐diluted AI doses from 16 randomly chosen Norwegian Landrace AI boars with proven fertility were split into subsamples and stored at 25, 20, 15 and 10°C, respectively. After 0, 24, 48, 72 and 96 h of storage, sperm motility, acrosome integrity and pH were determined. After 96 h, the initial percentage of motile sperm (77.8%) was significantly reduced to 52.2, 58.8, 50.9 and 42.8% by storage at 25, 20, 15 and 10°C, respectively. After an identical period of time, the percentage of acrosome intact sperm (95.8%) at time 0 became significantly reduced to 91.3, 91.3, 81.5 and 68.3% by storage at 25, 20, 15 and 10°C, respectively. The initial pH (7.21) decreased significantly to 6.96 and 7.06 after 96 h storage at 25 and 20°C, and increased not significantly to 7.25 for storage at 15°C and significantly to 7.29 at 10°C. In conclusion, the results from this study show that, according to the variables studied, 20°C is the least harmful of the four temperatures tested for the long‐term liquid storage of boar semen. Furthermore, remarkable differences in the individual resistance of boar semen to long‐term storage at 10°C were observed.  相似文献   

7.
Laboratory experiments were conducted to determine the influence of length of soaking period and water temperature treatments on the germination of Atriplex nummularia. Germination percentages increased significantly (P≤0,01) with increasing soaking period in water with a temperature of 20°C, while there was a tendency for a decrease in germination at the higher water temperature (30°C) treatment. The fruits were almost fully imbibed after 8 days of soaking at both water temperature treatments. Fruits germinated better in pots than in petri dishes, but for naked seeds the opposite was the case. Some of the unexplained findings should be further investigated.  相似文献   

8.
Abstract

The digenean Bolbophorus damnificus infects commercial channel catfish Ictalurus punctatus, causing mortality, lower feed consumption, and reduced growth in surviving fish. The purpose of this study was to determine the length of time for which B. damnificus prodiplostomulum metacercariae (juvenile trematode stage that infects fish) would remain viable (parasite appearing to be intact or exhibiting movement) in channel catfish. Fish (n = 210) were infected with molecularly confirmed B. damnificus cercariae harvested from naturally infected marsh rams-horn snails Planorbella trivolvis. During the first sampling (at 20 d postinfection), 8.3 ± 3.6 metacercariae/fish (mean ± SD) were found in the host muscle and visceral organs. The channel catfish were then acclimated to a water temperature of either 18°C or 28°C. After 11 months, 6.8 ± 3.5 and 5.9 ± 3.0 metacercariae/fish were found in groups held at 18°C and 28°C, respectively. The mean number of parasites per fish did not significantly differ between fish held at the two temperatures and did not significantly decline over time at either temperature. Fish examined from 13 to 30 months postinfection all contained viable metacercariae that were morphologically and molecularly identified as B. damnificus. At 18 months, 12 metacercariae (of which 11 were intact and 10 displayed movement) were found in the one fish sampled; at 30 months, the last fish sampled contained three intact metacercariae (one displayed slight movement). Our results indicate that B. damnificus metacercariae can remain viable in channel catfish for at least an 18–30-month production cycle during which they have the potential to affect fish growth; in addition, infected fish may serve as intermediate hosts for these metacercariae for at least 2.5 years postinfection.

Received July 14, 2010; accepted March 6, 2011  相似文献   

9.
The aim of this study was to determine the effects of various abiotic factors, such as light, physical stress (pipetting) and thermal shock, on the quality of fresh and cooled equine sperm. In experiment I, four sperm aliquots were subjected to different light exposures: (i) protected control samples (CTRL), (ii) exposed to UV light at 10 cm (UV10), (iii) exposed to UV light at 20 cm (UV20) and (iv) exposed to laboratory lighting (LAB). In experiment II, four semen aliquots were subjected to repeated pipetting for 0, 10, 20 and 30 times (CTRL, P10, P20 and P30, respectively). In experiment III, four semen aliquots at 15°C were subjected to thermal oscillations: (i) cooled control sperm at 15°C (CTRL), (ii) oscillations of 1.9°C/min to a temperature of 30°C (T30), (iii) oscillations of 1.4°C/min, with the temperature rapidly falling until reaching 1.3°C (T0R) and (iv) oscillations of 1.1°C/min, with the temperature slowly falling until reaching 4.2°C (T0S). The results revealed that after 30 min, UV10 and UV20 sperm samples showed significantly (p < .05) lower total and progressive motility values, sperm kinematic parameters and mitochondrial potential. After 45 min of exposure, differences were highly significant (p < .001). No significant differences (p > .05) were found for pipetting or thermal oscillations. The results suggest that, even if equine sperm samples are not handled in the laboratory under optimal conditions, fresh and cooled equine spermatozoa are able to resist the impact of various abiotic stimuli without any reduction in their quality. This study analyses the effect on normospermic samples, but future research could look at the tolerance that asthenozoospermic equine samples have to these abiotic influences.  相似文献   

10.
Abstract

Outer membrane proteins (OMP) of 10 isolates of Edwardsiella tarda were compared by sodium dodecyl sulfate-polyacrylamide gradient gel electrophoresis. The OMP profile of the type strain E. tarda ATCC 15947 cultured at 25°C had five major protein bands of 40, 36.5, 34, 28.5, and 25 kDa and a large number of minor proteins ranging in size from approximately 10 to 120 kDa. Differences between the OMP profiles of the isolates of E. tarda included the inconsistent presence of the 34- or 36.5-kDa proteins in five isolates of E. tarda and two major bands of 47 and 44 kDa that were present in only two isolates of E. tarda. There were no differences in the outer membrane protein profiles of 9 out of 10 isolates of E. tarda incubated at a temperature of 25°C compared with those at 35°C. To evaluate the effect of salinity, 10 isolates of E. tarda were cultured in brain heart infusion broth containing 0.5, 1.5, and 3.0% sodium chloride. Reactions of isolates of E. tarda to the different salinity levels were placed into three groups. The first group expressed more or fewer protein bands at 1.5% sodium chloride. The second group lost major bands at 3% salinity, whereas the third group had no change in the OMP profile with salinity. The OMP profile differences and the different reactions to salinity levels suggest that the isolates are heterogeneous.  相似文献   

11.
石德顺 《中国畜牧杂志》1991,27(2):12-14,31
本研究旨在了解投入液氮前的平衡温度及时间对兔胚冻后存活的影响。经0.5M蔗糖与1.5,2.0或2.5M乙二醇组成的冷冻液处理后的兔胚,在-30℃或-37℃平衡10或20分钟后即投入液氮保存或直接投入液氮保存。胚胎解冻在37℃的水浴进行。当平衡温度由-30℃下降到-37℃时,胚胎的冻后形态正常率及存活率均极显著下降(P<0.01)。在-30℃平衡20分钟与10分钟的冻后存活率无明显差异(P>0.05),但直接投入液氮时,冻后存活率则很低(8.3%)。由此表明:兔胚冻前在-30℃平衡10—20分钟是必要的。  相似文献   

12.
The influence of the application rates of cellulase preparation and glucose on silage fermentation at different temperatures was studied with the straw of naked barley (Hordeum vulgare L. emand Lam) and guineagrass (Panicum maximum Jacq.). Addition rate of cellulase and glucose, temperature and their interaction had significant effects on pH value, lactic acid content, butyric acid content and propionic acid content of naked barley straw silage and significant effects on all the parameters of guineagrass silage (P < 0.01). Temperature and interaction had significant effect on acetic acid content (P < 0.05) and no significant effect on NH3‐N content of naked barley straw silage (P > 0.05). Under all the temperatures, the pH values of barley straw and guineagrass silages were reduced by cellulase and glucose addition even at the lowest rate (P < 0.05), compared with their corresponding control. Lactic acid contents of silages were the highest within the same temperature and same additive when glucose and cellulase were added at the highest rates, whereas the effect of cellulase and glucose addition on butyric acid production varied with their application rates and silage storage temperature. The addition rate of restricting butyric acid fermentation was lower at 20°C than that at 30°C, and it was the lowest at 40°C where cellulase and glucose addition restricted butyric acid fermentation even at 0.1 g/kg and 10 g/kg, respectively, when compared to the control. While the addition rate was lower than the above level, cellulase and glucose addition also promoted butyric acid fermentation.  相似文献   

13.
抗寒桑品种龙桑一号育成   总被引:1,自引:0,他引:1  
桑树新品种龙桑一号具有抗寒性强,抗桑细菌病、褐斑病能力强的特性。在黑龙江省产叶量比对照种秋雨桑高10—31%,养蚕试验中春季万蚕收茧量增10%,秋季增25%。国家品种鉴定中,单位面积产叶量、产茧量、茧层量分别高于对照种15%、30%、31%。养蚕试验成绩:万蚕茧层量、五龄100公斤桑产茧量,万蚕产丝量,五龄100公斤桑产丝量,分别增12%、13%、11%、14%。  相似文献   

14.
Studies have been carried out to ascertain the effects of ammonia on the performance of White Leghorn hens housed in various environments of defined temperature and humidity. At 18° C. and 67 per cent relative humidity, the use of atmospheres containing 105 p.p.m. of ammonia by volume, significantly reduced egg production after 10 weeks’ exposure. No effects were observed on egg quality. However voluntary food intake was reduced in ammoniated atmospheres and live‐weight gain was lower. No recovery in production occurred when the treated groups were maintained for a further 12 weeks in an atmosphere free of ammonia.

When White Leghorn hens were housed at an environmental temperature of 28° C., body weight declined. The decrease in live‐weight was greatest at the high ammonia concentration of 102 p.p.m., and was significant after only 1 week's exposure to ammonia. Food intake of the controls was approximately 25 per cent lower at 28° C. than at 18° C., whilst 100 p.p.m. of ammonia further reduced food intake by more than 10 per cent. In one experiment at 28° C., egg production was significantly reduced after 7 weeks' exposure to ammonia.

In a subsequent trial, a high protein, vitamin and mineral diet prevented the onset of any deleterious effects of ammonia on egg production, even though food consumption fell to 75 g./bird/day at 29° C., 43 per cent relative humidity and 104 p.p.m. of ammonia. When a diet low in energy level was fed to hens subjected to high concentrations of ammonia, their voluntary food intake did not increase, and their production deteriorated rapidly.  相似文献   


15.
The thermoneutral zone (TNZ) reflects the adaptation of mammals to their natural habitat. However, it remains unclear how TNZ shifts in response to variations in ambient temperature. To test the hypothesis that ambient temperature plays a key role in determining TNZ variations between seasons, we measured metabolic rate, body temperature, and cytochrome c oxidase (COX) activity of several visceral organs in striped hamsters (Cricetulus barabensis) either acclimated to semi-natural conditions over a year, or subjected to a gradual decrease in mean temperature from 30 ± 1°C to −15 ± 1°C. The TNZ range in striped hamsters differed seasonally, with a wider TNZ and a lower lower-critical temperature in winter compared to summer. The hamsters showed a considerable leftward shift of lower-critical temperature from 30°C to 20°C after the ambient temperature of acclimation from 30°C down to −15°C, whereas the upper-critical temperature of TNZ remained fixed at 32.5°C. The resting metabolic rate in thermoneutral zone (RMRt), nonshivering thermogenesis (NST), and COX activity of brown adipose tissue, liver, skeletal muscle, brain, and kidneys, increased significantly in hamsters acclimated at lower ambient temperatures. Following acute exposure to 5°C and −15°C, hamsters acclimated to 32.5°C had significantly lower maximal NST and lower serum thyroid tri-iodothyronine (T3) levels compared to those kept at 23°C. These findings suggest that acclimation to the upper-critical temperature of TNZ impairs the hamsters’ thermogenic capacity to cope with extreme cold temperature. Reduced ambient temperature was mainly responsible for the leftward shift of TNZ in striped hamsters, which reflects the adaptation to cold environments.  相似文献   

16.
采用杂交选育和定向选择的育种方法,育成了优质、高效、好养的春秋兼用家蚕新品种川蚕23号。经四川省家蚕品种实验室鉴定和农村生产试养表明,新品种具有体质强健、耐高温多湿、龄期经过短、饲料效率高、茧丝品质优良、产量稳定的特点,已通过四川省家蚕品种审定委员会审定。新品种春季在农村试养鉴定的100 kg桑收茧量9.11 kg,比对照品种871×872提高8.58%;在实验室鉴定的成绩与对照品种菁松×皓月相当,虫蛹率96.20%,解舒率79.86%,鲜茧出丝率17.72%,洁净97.91分。新品种秋季在农村试养鉴定的100 kg桑收茧量7.54 kg,比对照品种洞.庭×碧.波提高3.98%;在实验室鉴定的虫蛹率93.05%,万蚕产茧量18.77 kg,分别比对照品种洞.庭×碧.波提高1.74个百分点、2.46%,一粒茧丝长1 150 m,解舒丝长932 m,解舒率81.04%,洁净94.82分,鲜茧出丝率16.90%,分别比对照品种洞.庭×碧.波提高41 m、83 m、4.50个百分点、3.06分、0.38个百分点。新品种在饲养条件和气候环境较差的蚕区饲养,能显示出良好的生产性能。  相似文献   

17.
Body weight, feed and water intake, heat production and serum prolactin responses of growing ram lambs were measured during and subsequent to temperature treatments of 10, 20 and 30°C, with daylengths of 8 or 16 h (8L:16D or 16L:8D). No differences were noted during the treatment period for responses obtained at 10 or 20°C; however, 30°C decreased feed intake and body weight, and increased water intake and serum prolactin level compared to responses of lambs at 10 or 20°C. The only noted response to daylength during the treatment period was a decrease in prolactin for lambs exposed to 8L:16D. Persistent carryover effects of the 30°C and 8L:16D treatments on feed intake and body weight were observed during post-treatment exposure to a 20°C, 16L:8D base condition. The 8L:16D treatment also resulted in reduced prolactin levels until the fifth week post-treatment. The results suggest that environmental manipulation in intensive housing can facilitate lamb performance.  相似文献   

18.
19.
Abstract

The effect of temperature and salinity on the elimination of enrofloxacin (EF) in Manila clams Ruditapes philippinarum was investigated. The clams, cultured under different temperatures and salinities (16°C and 30‰, 22°C and 30‰, or 22°C and 20‰), were exposed to EF at 5 μg/mL of water in a medicated bath. After a 24-h exposure, the concentration of EF in various tissues was measured by high-performance liquid chromatography and the elimination rate of EF in those tissues was investigated by regression analysis. After the treatment, the initial concentrations of EF among tissues were (in decreasing order) plasma > gill > visceral mass > foot > adductor muscle. In all tissues the elimination half-life (t 1/2) of EF in the clams cultured at 22°C and 20‰ and 16°C and 30‰ were markedly longer than in those cultured at 22°C and 30‰, and the t 1/2 at 16°C and 30‰ was slightly longer than that at 22°C and 20‰. Slight differences were also observed in t 1/2 values among various tissues. These data indicate that both temperature and salinity had significant effects on the elimination of EF in the Manila clams and that lower temperature or salinity could result in slower elimination.

Received January 21, 2011; accepted December 2, 2011.  相似文献   

20.
The coat of seven ‘Landseer’ Newfoundland dogs was irradiated using an infra-red source for 25 min. In each dog, at a site of each colour (black and white), skin and coat temperatures were monitored, and coat air humidity measured with a specially designed instrument. Almost no differences were noted at sites with differing coat colour. Skin temperature rose from 35 °C to a plateau at 39 °C, whilst coat temperature rose from 30 °C to 41 °C. Relative humidity of coat air initially rose, then fell significantly (P < 0.001). The absolute humidity initially almost doubled (P < 0.001), but then fell, although remaining significantly higher than that of ambient air. It was concluded that an initial burst of sweating was followed by lower but continuing secretion. This was not, however, of great importance in cooling. In a separate study the skin temperature of black coated dogs exposed to bright sunshine was explored. The mean temperature was almost identical to that of the plateau skin temperature noted in Newfoundland dogs.  相似文献   

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