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1.
In a completely randomized block design experiment, 16 ruminally cannulated sheep (40 ± 2.1 kg)fed a 50% concentrate 50% forage diet (DM basis) were given intraruminal doses of powdered Yucca schidigera extract (YSE). Doses of 0 (control), 100, 200, or 300 mg kg-1 diet were given at 8 p.m. and 4 a.m. On 15, 16, and 17 d of the experimental period, ruminal contents were sampled 0, 2, 4, 6, and 8 h after dosing, and blood samples were collected at the end of the experiment (18th and 19th d). Acidity was not affected (P>0.05) by the addition of YSE. Compared with the control, ruminal propionate concentration was increased by 29.4 and 29.8% (P>0.05) and the acetic acid concentration was decreased by 15.1 and 19.8% (P>0.05) at 4 and 6 h after YSE (300 mg kg-1) dosing, respectively. Ruminal ammonia concentration in the first 2 h after feeding was higher (P<0.05) in the sheep that did not receive YSE (increased by 17.57 mg 100 mL-1) than in those that received 200 mg kg-1 (increased by 6.77 mg 100 mL-1) or 300 mg kg-1 (increased by 6.50 mg 100 mL-1) YSE. Protozoan populations in the rumen were lower (P < 0.05) in the animals that received 300 mg kg-1 of YSE compared with the control. All serum parameters of the four groups were in the normal range and were similar among the treatment groups (P>0.05), after being fed for 19 d with different doses of YSE. The effect of YSE on ruminal ammonia concentration likely resulted from a decreased concentration of protozoan populations and, presumably, from ammonia binding by YSE.  相似文献   

2.
This study was designed to control plant fertility by cell lethal gene Barnase expressing at specific developmental stage and in specific tissue of male organ under the control of Cre/lox system, for heterosis breeding of chili pepper (Capsicum annuum L.). Chili pepper inbred lines (A, D, E, and I) were transformed with Cre gene and Barnase gene situated between loxp, separately, by means of Agrobacterium co-culture. In this study, we had established a high transformation system by extensive study of affecting factors including genotype, selection of marker, and lethal dose. Cotyledon with petiole from 9-11-day-old seeding was pre-cultured on media MR[MB(MS mineral+vitamine B5)+BA(6-Benzyladenine) 5.0 mg·L^-1 +IAA(indoleacetic acid) 1.0 mg·L^-1+GA3(gibberellic acid) 1.0mg·L^-1+sucrose 3%+agar 6.5g·L^-1] for 2d. The explants were infected by Agrobacterium tumefaciens when their OD600(optical density at 600 nm)reached 0.6-0.9. After co-cultured for 4-5 d on media MC [MB+BA5.0 mg·L^-1+IAA 1.0 mg·L^-1 +GA3 1.0 mg·L^-1+sucrose 3% +agar 6.5 g·L^-1+AS (acetosyringone) 200μmol·L^-1, these cotyledons with petiole were cultured on selective differentiation medium in the media MT[MB medium supplemented with BA [5.0 mg·L^-1+ IAA 1.0 mg·L^-1+ GA3 1.0 mg·L^-1+ AgNO3 5.0 mg·L^-1+ CW (coconut water) 5% + Km (kanamycin) 65 mg·L^-1+ Cb (carbenicillin) 500 mg·L^-1+ 3% sucrose + agar 6.5 g·L^-1].The Kmr (kanamycin resistant) bud rosettes were elongated on selective elongation medium and rooted on rooting medium. PCR and Southern blotting analysis of Kmr plantlet indicated that the foreign genes had been integrated into the genome of pepper. The transgenic plants with Cre gene developed well, blossomed out, and set fruit normally. The transgenic plants with Barnase gene grew well with normal appearance of flower, but they showed different fertility from complete sterility, partial sterility to complete fertility, and similar results were obtained from in vitro pollen germination experiments.  相似文献   

3.
Three goats fitted with cannula were used to provide rumen liquor to investigate the effects of limiting amino acids on rumen fermentation and microbial community in vitro. The removal method was used in the current experiments. Treatments are total essential amino acid (TEAA), His-removal, Lys-removal, Met-removal, and branch chain amino acid (BCAA)- removal. Results indicated that, pH-value ranged between 5.9 and 6.8, with the highest mean value for the group with BCAA-removal (6.54) in the culture. Concentration of NH3-N ranged between 10.99 to 30.51 mg 100 mL^-1, with the group of TEAA recording the highest average NH3-N concentration (17.85 mg 100 mL^-1). Yields of microbial protein and limiting degree on microbial growth varied with treatments (P 〈 0.01), and the lowest accrued in treatment with BCAA-removal (0.1389, 0.1772, and 0.3161 mg mL^-1 for bacteria, protozoa, and mixed microbes, respectively), compared to the group with TEAA, microbial production of mixed microbes decreased by 44.52%. As for micro-flora, protozoa to bacteria ratio was the lowest for the group with Lys-removal (89.12%), while the highest for the group with BCAA-removal (127.60%) (P 〈 0.01). Furthermore, PCR-SSCP analysis revealed that, microbial profile subjected to substrates within bacteria and protozoa groups. It was therefore concluded that, dietary amino acid influenced both rumen fermentation and microbial characteristics.  相似文献   

4.
The effects of treatment of chlorine dioxide (ClO2) gas on postharvest physiology and preservation quality of green bell peppers were studied. Green bell peppers were collected in bags and treated with 0, 5, 10, 20, and 50 mg L-1 ClO2 gas at 10 ± 0.5℃ for over 40 d, and the changes in postharvest physiology and preservation quality of the peppers were evaluated during the storage. The inhibition of rot of the peppers was observed for all the tested ClO2 gas treatments. The rot rates of the treated samples were 50% lesser than those of the control after day 40 of storage. The highest inhibitory effect was obtained after 50 mg L-1 ClO2 gas treatment, where the peppers did not decay until day 30 and showed only one-fourth of the rot rate of the control at day 40 of storage. The respiratory activity of the peppers was significantly (P < 0.05) inhibited by 20 and 50 mg L-1 ClO2 treatments, whereas no significant effects on respiratory activity were observed with 5 and 10 mg L-1ClO2 treatments (P> 0.05). Except for 50 mg L-1 ClO2, malondialdenyde (MDA) contents in the peppers treated with 5,10, or 20 mg L-1 ClO2 were not significantly (P>0.05) different from those in the control. Degradation of chlorophyll in the peppers was delayed by 5 mg L-1 ClO2, but promoted by 10, 20, or 50 mg L-1 ClO2. The vitamin C content, titratable acidity,and total soluble solids of the peppers treated by all the tested ClO2 gas did not significantly change during the storage.The results suggested that ClO2 gas treatment effectively delayed the postharvest physiological transformation of green peppers, inhibited decay and respiration, maintained some nutritional and sensory quality, and retarded MDA accumulation.  相似文献   

5.
To study the growth effects of differing concentrations of bensulfuron-methyl on Chlorella pyrenoidosa and to evaluate the ecological risk, the effects of bensulfuron-methyl on the growth and the content change of chlorophyll and protein in Chlorella pyrenoidosa were studied through 96 h acute toxicity tests. Bensulfuron-methyl accelerated the growth of algae at lower concentrations (〈 1 mg L^-1) with content increase of chlorophyll or protein, and it inhibited the growth of algae at higher concentrations (〉 5 mg L^-1). The content of chlorophyll or protein in algae cells reduced with the increasing concentration of bensulfuron-methyl, exhibiting the good concentration-effect relationship. The 96 h-EC50 of bensulfuronmethyl upon the algae was 15.7 mg L^-1 Bensulfuron-methyl has inhibiting effect on the growth of Chlorella pyrenoidosa and is low in toxicity.  相似文献   

6.
This article discusses the effects of estrogen on the expression of estrogen receptor (ER), nerve growth factor (NGF), and choline acetyltransferase (CHAT) in the cerebellum of rats. The model of aging female rat was established to study the expression and distribution of ER, NGF, and ChAT in the cerebellum following 17β-estradiol treatment using the technique of immunohistochemical ultrasensitive SP in sprague-dawley rat. The immunoreactive productions were distributed in stratum Purkinje cell, nucleus dentatus, nucleus interpositus, and nucleus fastigii of cerebellum, and the ER positive production was mainly located in the plasma, cytoplasmic membrane, and neurite, and also existed in nucleus. The general tendency of the expression of ER, NGF, and ChAT positive production in the cerebellum cortex and nuclei of aging rat significantly decreases, while the intensity and quantity of the immunoreactive production ascends predominantly after 17β-estradiol treatment. Simultaneously, the positive neurite of Purkinje cell shows a similar tendency. The above- mentioned results suggest that the estrogen upregulates the expression of NGF and CHAT, and plays a vital role in sustaining and protecting the structure and function of cerebellum neurons. Furthermore, the similarity of their changing tendency implies that they were correlated and cooperated during the course in effect of estrogen on cerebellum. It also showed that the action of estrogen in cerebellum could be via genomic and nongenomic mechanism.  相似文献   

7.
In order to assess the effects of chemical properties of soil salinity on electrical conductivity of 1:5 soil/water extract (EC1:5), the study focused on revealing the main chemical factors contributing to EC of soil extracts and their relative importance. The relationship between EC1:5 and the chemical properties of soil salinity in the delta oasis of Weigan and Kuqa rivers, China, were studied using path coefficient analysis, a path analysis method. We studied each key element affecting EC1:5 either directly or indirectly. The results obtained show that the salt content, total dissolved solids (TDS), and the sum of the sodium ion concentration and the kalium ion concentration are the most influential factors on 1:5 soil/ water extract (EC1:5) in the 0-10 cm and the 30-50 cm soil layer. The results show that the sequence of direct path coefficients in the 0-10 cm and the 30-50 cm soil layers on soil conductivity is TDS→Na^+ + K^+→Salt content→Ca^2+→Cl-→the sodium dianion ratio (SDR)→pH→ SO4^2-→HCO3^-→Mg^2+→the soluble sodium percentage (SSP) sodium absorption ratio (SAR) and TDS→Salt content→Na^+ + K^+→Ca^2+→SDR→Mg^2+→HCO3^-→SSP→pH→SO4^2-→SAR→Cl^-. The salt content, chlorine ion, and SAR are the main factors affecting 1:5 soil/water extract (EC1:5) in the 10-30 centimeter soil layer. The order of direct path coefficients result is as follows: Salt content→Cl^-→SAR→SSP→TDS→Ca^2+→Mg^2+= SO4^2-→HCO3^-→pH→SDR→Na^- + K^+. Moreover, the effects of HCO3^-, pH were very weak. Though the direct path coefficients between EC1:5 and SAR, SO4^2- and Ca^2+ were not high, influence of other chemical factors caused the coefficients to increase, making the summation of their direct and indirect path coefficients relatively high. The models of the different soil layers were structured separately. Evidences showed that multiple regression relations between EC1:5 and most of the primary factors had sound reliability and very good accuracy. The research results can serve as a reference to the scientific management amelioration and utilization of saline in the Delta Oasis of Weigan and Kuqa rivers.  相似文献   

8.
One-day-old healthy ducklings (n = 100) were randomly allocated into two groups (n = 50, respectively) to investigate the effect of cytokines on ducklings with selenium poisoning. The ducklings in control group (Group Ⅰ) were fed with full rations containing 0.3 mg kg^-1 selenium, and the ducklings in selenium poisoning group (Group Ⅱ ) were fed with seleniumexcessive rations containing 8.0 mg kg^-1 selenium. One mL blood was collected by cardiac puncture at d 15, 30, 60, and 90 (n = 10, respectively), serum was separated by centrifugation. Contents of cytokines were determined by the radioimmunity method (RIA). The results showed that the contents of IL-113, IL-213 in Group Ⅱ were higher than that in control group at d 15 (P〉0.05), but were significantly lower at d 30, 60, and 90 (P〈0.01); the contents of IL-8β in Group II were significantly lower than that in control group (P〈0.01); the contents of erythropoietin (EPO) and IGF-2 in Group II were significantly lower in different degree than that in control group at d 60 and 90 (P〈0.01); the contents of granulocyte- macrophage colony stimulating factor (GM-CSF) in the two groups were lower in different degree and significantly lower at d 60 and 90 (P〈0.01). It can be concluded that the excessive selenium could result in a decrease in immunity and a series of clinical pathology changes, such as anemia, tissue hemorrhage, and necrosis.  相似文献   

9.
In this research work, 24 multiparous holstein cows were used to evaluate the effect of hypoglycemia on periparturient metabolism and lactation performance. The cows were arranged into two groups of hypoglycemia (L) and normal plasma glucose (N) based on plasma glucose level. The same diets were fed ad libitum from 28 days before expected calving date to 28 days after calving. The parameters relative to energy balance, such as dry matter intake (DMI), body weight (BW), milk yield (MY), and concentrations of plasma glucose, nonesterified fatty acids (NEFA), β-hydroxybutyric acid (BHBA), insulin (INS), glucagons (GLN), leptin (LP), neuropeptide Y (NPY) in plasma were measured at regular intervals. Incidence of hypoglycemia was higher prepartum than that of postpartum (88% vs. 50%), and the recurrence of hypoglycemia was reversed (31% vs. 100%). Hypoglycemia did not affect feed intake before and after calving. With the increase of postpartum feed intake, incidence of hypoglycemia decreased rapidly, even disappeared at 28 days of postpartum. Hypoglycemia had no impact on prepartum BW, but BW in L group was lower than that of cows in N group at 1 day and 14 days of postpartum (P〈0.05). Milk yield was not affected by hypoglycemia. Cows in L group had higher plasma NEFA concentration than cows in N group. It reached a peak (1442 μmol L^-1 vs. 1052 μmol L^-1) at day 1 of postpartum (P〈0.05). Plasma BHBA concentration of cows in L group was higher than that in N group, which reached a peak (2.01 mmol L^-1 vs. 1.34 mmol L^-1) at 14 days of postpartum (P〈0.05). Plasma concentration of INS and GLN was unaffected by treatment, but postpartum plasma GLN concentration obviously increased, especially in L group. Plasma concentration of LP and NPY before calving was unaffected by treatment, but postpartum LP level in L group was slightly lower than that in N group, and NPY level in L group was significantly higher than that in N group (P〈0.05). Overall, periparturient dairy cows are easy to develop hypoglycemia, which stimulates lipid metabolism. Adaptive changes of some metabolites and hormones, such as NEFA, BHBA, INS, GLN, LP, NPY are of benefit to increase feed intake and recovery of NEB in periparturient period, but there still are some issues on interaction of those endocrine factors in the energy balance of periparturient cows to be understood further.  相似文献   

10.
Shatian pummelo (Citrus grandis L. Osbeck cv. Shatian) is an elite variety in China, and the regeneration of the embryogenic callus is difficult. Diploid Shatian pummelo was used as the female and crossed with the allotetraploid somatic hybrid NS (Nova Tangelo + Succari Sweet orange), [ ( C reticulata Blanco x C. paradisi Macf.) cv. Nova + C sinensis L. Osbeck cv. Succari]. About 90 days after pollination, the embryos obtained from crosses were cultured on the solid media of MT + ME (malt extraction, 500 mg L^-1) and MT + GA3 (1 mg L^-1). The embryogenic callus was initiated from the embryoids and plantlets' hypocotyls and could be subcultured. Flow cytometry and SSR analysis verified that the callus was from the triploid hybrids. The callus had embryogenesis capacity and produced a large number of embryoids on MT +Lactose (50 g L^-1) medium after being subcultured for two years. It is comparatively easier to obtain the callus from the hybrid embryo than from Shatian pummelo itself. The callus is valuable for the conservation and utilization of Shatian pummelo.  相似文献   

11.
In this study, the oxidative damage of α-terthienyl (α-T) to the Spodoptera litura (SL) cell and its mechanism were investigated. MTT was used to compare the toxicity of α-T and rotenone to the SL cell. The output of malondialdehyde and relative content of glutathione were determined with 2-thiobarbituric acid (TBA) and 5, 5'-dithio-bis (2-nitrobenzoic acid) (DTNB), respectively. Transmission electron microscope (TEM) was employed to observe the influence of α-T on the membrane and organelle of the SL cell. The result showed that the IC50 value of α-T to the SL cell was 0.21 μg mL^-1, whereas the corresponding dose of rotenone was 12.25 μg mL^-1. The output of MDA had the same changing tendency with the concentration of α-T, whereas the content of GSH had the negative correlation with it. According to TEM, the cell membrane and karyotheca swelled and couldn't retain integrity, the intracellular substances leaked out, unidentified granules appeared in the SL cell. The mitochondria expanded, and the membrane and subcellular organelle were damaged severely. In this study, it was found that after oxidative damage induced by α-T, the output of MDA increased notably, whereas the relative content of GSH decreased. This indicated that the antioxidant ability of cell weakened. The result of TEM implied that the SL cell suffered from oxidative damage under the appointed dose.  相似文献   

12.
Root function in uptake of nutrients and the effect of soil water on the transfer and distribution of NO3^--N in arable soil were studied using summer maize (Zea mays L. var. Shandan 9) as a testing crop. Results showed that root growth and water supply had a significant effect on NO3^--N transfer and made NO3^--N distributed evenly from bulk soil to rhizosphere soil. Under a natural condition with irrigation, the difference of NO3^--N concentration at different distance points from a maize plant was smaller, while obvious difference of NO3^--N concentration was observed under conditions of limited root growth space without irrigation. Whether root growth space was restricted or not, the content of soil NO3^--N decreased gradually from 10 to 0 cm from the plant, being opposite to the root absorbing area in soils. When root-grown space was limited, changes of NO3^--N concentration at different distances from a plant were similar to that of water content in tendency. Results showed that NO3^--N could be transferred as solute to plant root systems with water uptake by plants. However, the transfer and distribution of NH4^--N were not influenced by root growth and soil water supply, being different to NO3^--N.  相似文献   

13.
刘华珍  彭克美 《中国农业科学》2004,37(10):1560-1563
 选用来自同一父母代的1日龄健康樱桃谷鸭60羽,饲喂1周后,随机分为2组:高能组和低能组,分别饲喂高能和低能日粮。饲喂4周后,处理动物:灌流固定,取全脑后固定4 h,入8%蔗糖溶液中4℃保存。制作石蜡切片,采用免疫组化链霉亲和素-生物素-过氧化物酶复合物法( Streptavidin -biotin-peroxidase complex method,SABC)进行染色,并用图像分析系统作半定量分析。结果显示:高能组室旁核(17.73±1.41个/19.46×103μm2)及腹内侧核(15.80±1.71个/ 19.46×103μm2)有大量的阳性胞体;低能组外侧区(11.25±1.53个/19.46×103μm2)也有大量的阳性胞体,而室旁核没有。上述研究结果表明,下丘脑5-羟色胺样神经元参与摄食和能量代谢的调节。  相似文献   

14.
Active oxygen quantum yield, insecticidal activities and stability of diphenylthiophene were studied for the first time. The results showed that maximum diphenylthiophene absorbency variety was 0.438 after irradiation for 280 min and that of α-terthienyl (α-T) was 0.480 after irradiation for 200 min with UV. LC50 values ofdiphenylthiophene and α-T against 3rd instar larvae of Aedes albopictus were 9.18 × 10-3 and 9.69 × 10-4 μg mL-1 when treated for 24 h, respectively. LC50 values of the two chemicals against the 3rd instar larvae of Plutella xylostella were 267.87 and 222.22 μg mL-1 when treated for 24 h, respectively. The half lives of diphenylthiophene and α-T in methanol were 113.62 and 10.65 h. Difference between quantum yield of diphenylthiophene and α-T was not significant and they all possessed high toxicity to Aedes albopictus and Plutella xylostella, but diphenylthiophene was more stable than α-T. It could be concluded that diphenylthiophene has overcome the deficiency of photoactivated insecticides which degraded quickly in the environment and could not be applied on the field. Diphenylthiophene could kill the insects and accelerate the degradation rate of triazophos. The benefits of diphenylthiophene can be further exploited and applied on the field.  相似文献   

15.
Relationship Between Root Chemical Signals and Grain Quality of Rice   总被引:2,自引:0,他引:2  
This study was designed to elucidate the relationship between root chemical signals and the quality of rice. Various rice genotypes were used. Zeatin (Z) + zeatin riboside (ZR), abscisic acid (ABA), 1-aminocylopropane -1-carboxylic acid (ACC), and organic acids in roots during grain filling and the appearance quality, cooking/eating quality were investigated. The correlations among them were analyzed. The results showed that Z + ZR concentrations in the roots at mid- and lategrain-filling stages were significantly and positively correlated with the gel consistency and alkali spreading value (r = 0.72^* - 0.90^**), whereas negatively correlated with the amylose content (r = -0.68^* - -0.78^**). ABA concentrations in roots at mid- grain-filling stage were significantly and negatively correlated with the gel consistency and alkali spreading value (r = -0.90^**-0.91^**), and positively correlated with the amylose content (r = 0.87^**). ACC concentrations in root exudates at mid-grain-filling stage were very significantly correlated with the percentage of chalky grains and chalkiness (r = 0.97^** - 0.98^**), and those at late-grain-filling stage Were significantly correlated with chalkiness and chalky size (r = 0.69^* - 0.96^**). The more the malic acid and succinic acid exuded from roots for a cultivar, the greater the breakdown values and the smaller the setback values in the starch profile, and the results were reversed for a cultivar with more tartaric acid and citric acid exuded from roots during the grain-filling period. The cultivar with more lactic acid in exudates had smaller gel consistency and alkali spreading values, but had greater amylose content. When roots were treated with exogenous ZR, ABA, and ACC during grain filling, effects of the chemicals on the rice quality were consistent with the relationships of the endogenous hormones (Z + ZR, ABA, and ACC) with the quality indexes. Using rape cake as organic fertilizer can increase the concentrations of malic acid and succinic acids exuded from roots as well as the breakdown value in starch profile and reduce the setback value. The results suggest that root chemical signals play important roles in the formation of rice quality, and dee quality could be improved through regulating the signals.  相似文献   

16.
An improved protocol has been developed for somatic embryogenesis and plant regeneration of recalcitrant cotton cultivars. High callus frequencies and embryogenic tissue were developed in MSB medium supplemented with gradient concentrations of KT and 2,4-D, their concentration decreasing from 0.1 to 0.01 mg L−1. Somatic embryos were successfully incubated in 1/2 macronutrient MSB suspension supplemented with 0.5 g L−1 glutamine and 0.5 g L−1 asparagine. Decrease in macronutrient concentration of MSB significantly alleviated browning and was beneficial to suspension cells. Transformation of somatic embryos into plants was induced in MSB medium supplemented with 3% sucrose, 0.5 g L−1 glutamine, 0.5 g L−1 asparagine, and 6.0 g L−1 agar. The effect of sucrose as carbohydrate was better than that of glucose for plant germination. Using this protocol, regenerated plantlets from the CCRI521 and Zhongzhi86-6 reached to as much as 19.6 and 18.5% somatic embryos, respectively.  相似文献   

17.
Cadmium (Cd) is a toxic environmental pollutant with a long biological half-life and can produce both hepatic and renal injuries in mammals and fish. Squid viscera meal (SVM), an effective attractant for aquatic animals, is widely used as an ingredient in aquafeeds. However, SVM is rich in Cd and its complexes. A study was conducted to evaluate the effects of dietary SVM on the growth and Cd deposition in the tissues of large yellow croaker, Pseudosciaena crocea R. Three practical diets were formulated to contain a 0, 50 and 100 g · kg−1 SVM diet, correspondingly containing a 0.21, 7.26 and 12.08 mg Cd · kg−1 diet. Each diet was randomly assigned to triplicate groups of 100 juveniles of large yellow croaker (mean initial weight, 9.75 ± 0.35 g) in floating sea cages (1.0 m × 1.0 m × 1.5 m). Fish were fed twice daily (05:00 and 17:00) to satiation for 8 weeks. The results showed that there were no significant differences in fish survival among the three dietary treatments, but significant higher specific growth rates (SGR) were observed in the fish fed diets with 50 or 100 g · kg−1 SVM diet compared to the control group (P < 0.05). The cadmium concentrations in fish tissues (muscle, liver, kidney and gill) were significantly influenced by the dietary SVM. The cadmium concentrations in all tissues significantly increased with increasing dietary Cd levels (P < 0.05). In all the dietary treatments, the highest Cd level was always observed in the kidney, followed by the liver and the gill. Fish fed diets with 50 and 100 g · kg−1 SVM had significantly higher Cd accumulations in the kidney (2.65, 4.44 mg · kg−1), liver (0.58, 0.93 mg · kg−1) and gill (0.35, 0.53 mg · kg−1) compared with the control group (0.42, 0.26 and 0.12 mg · kg−1, respectively). The Cd level in fish muscle, however, was undetectable in all treatments. Therefore, based on these results, accumulation of Cd in edible tissue (muscle) of farmed large yellow croaker is not a food safety issue. However, long-term feeding of diets with SVM may result in accumulation of Cd in the kidney, liver and gills of fish.  相似文献   

18.
In the present study, immunohistochemical method (SABC method) was used to examine the distribution of serotonin-like neurons in hypothalamus of Cherry Valley ducks bred with high energy diet and low energy diet respectively. All films were analysed by using a computer-assisted image analysis system. In high energy group, labelled neurons are widely distributed in paraventricular nucleus(PVN, 17.73± 1.41 neurons/19.46× 103 μm2) and ventromedial hypothalamus (VMH,15.8±1.71 neurons/19.46×103 μm2); in low energy group, labelled ceils are widely distributed in lateral hypothalamus (LH,11.25±1.53 neurons/19.46×103 μm2), yet there is no positive neuron in PVN. These results indicate that serotonin-like neurons in hypothalamus are involved in the regulation of food intake and energy metabolism.  相似文献   

19.
In order to understand the status of fixed ammonium, fixed ammonium content, maximum capacity of ammonium fixation, and their influencing factors in major types of tillage soils of Hunan Province, China, were studied with sampling on fields, and laboratory incubation and determination. The main results are summarized as follows: (1) Content of fixed ammonium in the tested soils varies greatly with soil use pattern and the nature of parent material. For the paddy soils, it ranges from 135.4 ± 57.4 to 412.8 ± 32.4 mg kg−1, with 304.7 ± 96.7 mg kg−1 in average; while it ranges from 59.4 to 435.7 mg kg−1, with 230.1 ± 89.2 mg kg−1 in average for the upland soils. The soils developed from limnic material and slate had higher fixed ammonium content than the soils developed from granite. The percentage of fixed ammonium to total N in the upland soils is always higher than that in the paddy soils. It ranges from 6.1 ± 3.6% to 16.6 ± 4.6%, with 14.0% ± 5.1% in average for the paddy soils and it amounted to 5.8 ± 2.0% to 40.1 ± 17.8%, with 23.5 ± 14.2% in average for upland soils. (2) The maximum capacity of ammonium fixation has the same trend with the fixed ammonium content in the tested soils. For all the tested soils, the percentage of recently fixed ammonium to maximum capacity of ammonium fixation is always bellow 20% and it may be due to the fact that the soils have high fertility and high saturation of ammonium-fixing site. (3) The clay content and clay composition in the tested soils are the two important factors influencing their fixed ammonium content and maximum capacity of ammonium fixation. The results showed that hydrous mica is the main 2:1 type clay mineral in <0.02 mm clay of the paddy soils, and its content in 0.02–0.002 mm clay is much higher than that in <0.002 mm clay of the soils. The statistical analysis showed that both the fixed ammonium content and the maximum capacity of ammonium fixation of the paddy soils were positively correlated with the total 2:1 type clay mineral content and hydrous mica content in <0.02 mm clay and 0.02–0.002 mm clay at the significant level of P0.01 or P0.05, respectively, but not correlated with the total 2:1 type clay mineral content and hydrous mica content in <0.002 mm clay significantly. It demonstrated that the ammonium-fixing matrix of the tested soils mainly exists in the 0.02-0.002 mm clay. The above-mentioned results showed that fixed ammonium is a major form of N in the tillage soils in Hunan Province, China. It would play an important role in N nutrition of crops, especially for upland crops, and deserve to be further researched.  相似文献   

20.
The propagation of laser light in kiwifruit (Actinidia deliciosa) tissue was measured by backscattering imaging and modelled with the Monte Carlo (MC) method. The parameters of the vision system (8 bit/channel camera, 27.42 μm/pixel resolution) and the laser module (785 nm, 45 mW, Ø1 mm) were utilized in simulation. The required number of the photons was optimized with time-resolved MC model. The injected photon pulse travelled further than the beam radius and the calculated intensity fell below the noise level of the camera within 1 ns time. This short pulse contains 2.49 × 108 photons and its application reduced computation load compared to the amount emitted within the integration time of 0.5–8.3 ms. The statistical effects of the optical properties of the tissue, scattering coefficient (μs) absorption coefficient (μa) and anisotropy factor (g), on photon flux was evaluated within ±20% range relative to expected mean values of μa = 0.9 cm−1 and μs = 40 cm−1. The anisotropy factor was taken into account using the Heyney–Greenstein phase function and was adjusted to g = 0.8 ± 20%. Because individual significance of each optical property was also analysed, scattering (μs) and transport corrected reduced scattering coefficients (μs=[1−g]μs) must be distinguished. The multi-factor ANOVA test pointed out the highest importance (p < 0.001) of the anisotropy factor amongst scattering and absorption coefficients.In the kiwi backscattering images, rotation of the intensity profiles was observed as a result of changing anisotropy. The measured and calculated profiles were compared to estimate the anisotropy factor of kiwifruits. Significant difference (p < 0.01) was found between anisotropy of premium quality and overripe pieces with respect to the fruit texture properties.  相似文献   

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