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排序方式: 共有195条查询结果,搜索用时 15 毫秒
101.
Taylor WG Elder JL Chang PR Richards KW 《Journal of agricultural and food chemistry》2000,48(11):5206-5210
Sulfuric acid hydrolysis of steroidal glycosides of Amber fenugreek was studied by capillary gas chromatographic analysis of diosgenin [(25R)-spirost-5-en-3-ol] and isomeric spirostadiene artifacts from 100 mg samples of seed material. Following extraction with 80% ethanol, highest recoveries of diosgenin occurred when hydrolyses were conducted in sulfuric acid, prepared at 1 molar (M) concentration in water containing 60-80% 2-propanol. Compared to a previous method with aqueous hydrochloric acid, the selected conditions of hydrolysis at 100 degrees C for 2 h with sulfuric acid in 70% 2-propanol reduced diene formation but did not completely eliminate these artifacts. Extraction of steroidal saponins with various alcohol/water mixtures prior to sulfuric acid hydrolysis gave similar recoveries of diosgenin. Application of the quantitative method to experimental samples of Amber, Quatro, and ZT-5 fenugreek, using 10 mg subsamples of crushed seed that had been defatted with petroleum ether and dried at 60 degrees C, gave diosgenin levels of 0.55, 0.42, and 0.75%, respectively. Levels of smilagenin and sarsasapogenin were very low in hydrolyzed seed extracts from ZT-5, a Canadian breeder line of fenugreek. 相似文献
102.
S Villaverde‐Morcillo MC Esteso C Castaño A Toledano Díaz A López‐Sebastián JL Campo J Santiago‐Moreno 《Reproduction in domestic animals》2015,50(5):750-755
Computer‐assisted systems for the assessment of sperm morphometry (ASMA systems) have been used successfully with several mammalian species. Unfortunately, they have so far been of little use for assessing bird semen, a consequence of the filiform shape of avian spermatozoa. This study compares two staining techniques (Hemacolor® and aniline blue staining) for the morphometric analysis of rooster and red‐legged partridge spermatozoa as part of a computer‐assisted light microscopy method. For both species, Hemacolor® staining provided a significantly higher percentage of measurable cells (93.7 ± 11.7% in roosters and 71.9 ± 15.3% in red‐legged partridges). Hemacolor® also showed greater repeatability (lower coefficients of variation) for length and area in roosters' sperm and for width in the case of red‐legged partridge's sperm. In the roosters, the Hemacolor® technique returned significantly (p < 0.05) larger sperm head width and area values than did the aniline blue technique, while the latter resulted in greater sperm head length values (p < 0.05). In the red‐legged partridge, no differences were seen in the results for sperm head width and area provided by the two techniques, but aniline blue staining was associated with longer length measurements. In conclusion, the morphometric values recorded differed depending on the staining method and species. However, the Hemacolor® technique might be deemed the more appropriate for computerized sperm assessment systems as it provides larger percentages of measureable cells and shows greater repeatability. 相似文献
103.
Effect of the Interaction Between Cryoprotectant Concentration and Cryopreservation Method on Frozen/Thawed Chicken Sperm Variables 下载免费PDF全文
FMK Abouelezz C Castaño A Toledano‐Díaz MC Esteso A López‐Sebastián JL Campo J Santiago‐Moreno 《Reproduction in domestic animals》2015,50(1):135-141
This work examines the effect of the interaction between different concentrations of two cryoprotectants – glycerol (GLY) and dimethylacetamide (DMA) – and two methods of cryopreservation – pellets produced by plunging into liquid nitrogen and gradual in‐straw freezing – on frozen/thawed chicken sperm variables. Sperm was cryopreserved using: (i) 6% DMA, following the in‐straw and the pellet methods (ii) 11% GLY, following the in‐straw and the pellet methods; and (iii) 8% GLY in the in‐straw method and 3% DMA in the pellet method (i.e. reduced cryoprotectant concentrations). When 6% DMA was used as the cryoprotectant, no differences were seen between the in‐straw and pellet methods in terms of frozen/thawed sperm variables or fertility (10.8% and 12.8%, respectively). The viability and motility variables of the frozen/thawed sperm produced using the in‐straw method with 11% GLY were higher (p < 0.05) than those recorded for the sperm preserved using the same cryoprotectant and concentration in the pellet method. However, fertility was extremely low in both groups (2.1% and 4.2% for the in‐straw and pellet methods, respectively). Finally, the use of 8% GLY in the in‐straw method returned higher sperm viability, intact acrosome and motility values than the use of 3% DMA in the pellet method (p < 0.01). No differences were seen, however, in the fertility results obtained (28.8% and 25.0%, respectively). These results suggest that cryoprotectant concentrations can be reduced and still provide acceptable fertility rates. 相似文献
104.
A Pilot Study to Compare Oxidative Status between Organically and Conventionally Managed Dairy Cattle During the Transition Period 下载免费PDF全文
The aim of this study was to assess the redox balance of organically managed dairy cattle (OMC; n = 40) during the transition period and to compare this with conventionally managed cattle (CMC; n = 22). Serum samples of dairy cows from two organic and one conventional farm were taken. Markers of oxidants production [reactive oxygen species] and total serum antioxidant capacity were measured in four different production stages: (i) far‐off dry (2 to 1 months before calving; 44 samples in CMC and 48 in OMC); (ii) close‐up dry (1 month until 3 days before calving; 44 CMC; 54 OMC); (iii) fresh (3 days to +1 month after calving; 44 CMC; 49 OMC); and (iv) peak of lactation (+1 to +3 months; 71 CMC; 78 OMC). Values were compared between production stages and against a metabolic baseline status (4th–5th month of pregnancy; 40 CMC; 30 OMC). Our results indicated that throughout the periparturient period, OMC had lower concentrations of reactive oxygen species, but also a lower antioxidant capacity than CMC. Indeed, when the two components of the redox balance were assessed together through the Oxidative Stress index, the values of this parameter were higher for OMC than for CMC, thereby implying a higher risk of oxidative stress. Therefore, further larger studies are needed to confirm the current observations, as organically reared animals might be exposed to a lack of antioxidants supply. 相似文献
105.
106.
Effect of different mini‐volume colloid centrifugation configurations on flow cytometrically sorted sperm recovery efficiency and quality using a computer‐assisted semen analyzer 下载免费PDF全文
LB Ferré JL Chitwood C Fresno HH Ortega ME Kjelland PJ Ross 《Reproduction in domestic animals》2018,53(1):26-33
Straws of sex‐sorted sperm are usually packaged at a low concentration (e.g., ~2.1 × 106 sperm/ml) and cost significantly more than unsorted conventional semen from the same sire. In order to maximize the efficiency of using sex‐sorted sperm under in vitro fertilization conditions, the selection of an appropriate sperm separation technique is essential. In this study, the effect of using different silane‐coated silica colloid dilutions and layering configurations during centrifugation of sex‐sorted sperm was examined over an extended period of incubation time. Sperm recovery and viability after centrifugation using the colloid separation technique were measured along with several sperm motility parameters using CASA. For this purpose, frozen and thawed sex‐sorted sperm samples were centrifuged using mini‐volume single‐layer (40%, 60% and 80%) and mini‐volume two‐layer (45%/90%, 40%/80% and 30%/60%) separation configurations using PureSperm®. A single layer of 40% PureSperm® recovered significantly more sex‐sorted sperm (78.07% ± 2.28%) followed by a single layer of 80% PureSperm® (68.43% ± 2.33%). The lowest sperm recovery was obtained using a two‐layer PureSperm® dilution of 45%/90% (47.57% ± 2.33%). Single‐layer centrifugation recovered more sorted sperm (68.67% ± 1.74%) than two layer (53.74% ± 1.74%) (p < .0001). A single layer of 80% PureSperm® exhibited the highest sorted sperm viability (72.01% ± 2.90%) after centrifugation (p < .05). The mini‐volume single layer of 80% PureSperm® was determined to be an effective alternative to a two‐layer centrifugation configuration for sex‐sorted sperm selection. In addition, single‐layer colloid dilution of 80% performed either as well as or significantly outperformed the other treatments, as well as the control, with regard to motility (MOT) for all time periods of analysis. 相似文献
107.
H M Ohlendorf J B Elder R C Stendell G L Hensler R W Johnson 《Pesticides monitoring journal》1979,13(3):115-119
Chicks of great blue herons (Ardea herodias) from four heronaries located near South St. Paul, Royalton, and Wabasha, Minnesota, and La Crosse, Wisconsin, were analyzed for organochlorines, Highest mean wet-weight concentrations, 6.43 ppm PCBs. 1.31 ppm DDE, and 1.90 ppm sigma DDT, were found in the South St. Paul chicks. Among chicks from the other three heronries, most levels were similar, but were significantly lower than levels in South St. Paul chicks. Lowest mean organochlorine levels, 0.37 ppm DDE, 0.38 ppm sigma DDT, and 0.22 ppm PCBs, were found in chicks from Royalton. All birds from South St. Paul and La Crosse contained residues of DDT and TDE whereas only one of the 10 birds from Royalton contained DDT and one contained TDE residues. Five of the 12 birds from Wabasha contained DDT; eight contained TDE. Except for PCB residues in La Crosse heron chicks, the rate of organochlorine residue accumulation in the birds was generally less than the rate of dilution caused by growth. 相似文献
108.
Spranklin D Elder S Boyle C McLaughlin R 《Journal of the American Animal Hospital Association》2006,42(2):121-126
The mechanical characteristics of toggle rods and Bone Biter anchors inserted through the medial acetabular wall for toggle pin repair of coxofemoral luxations were compared in 16 canine cadaver pelves. No differences were detected in maximum load to failure, displacement at failure, or energy to failure between the two constructs. Toggle rod constructs failed primarily by breakage of the suture at the rod eyelet. All of the Bone Biter anchor constructs failed when the anchors pulled through the medial acetabular wall. 相似文献
109.
Sweating has a variety of functions in mammals including pheromone action, excretion of waste products and maintenance of the skin surface ecosystem. In a small number of mammalian species, which includes humans and the Equidae, it also has an important role in thermoregulation. This review is focused specifically on the thermoregulatory role of sweat in Equidae and the causes of sweating failure (anhidrosis). The first part describes the glandular appearance, sweat composition, and output rates; and considers the latest theories on the glandular control and secretory mechanisms. It is concluded that the glands are not directly innervated but are controlled by the interplay of neural, humoral and paracrine factors. The secretory mechanism is not as simple as previously thought and is mediated by the dynamic interaction of activating pathways, including autocrine control not only of the secretory process but probably also of secretory cell reproduction, growth, and death. 相似文献
110.
Elder SJ Haytowitz DB Howe J Peterson JW Booth SL 《Journal of agricultural and food chemistry》2006,54(2):463-467
The purpose of this study was to determine the contents of three forms of vitamin K [phylloquinone, dihydrophylloquinone, and menaquinone-4 (MK-4)] in representative samples (including different samples within the same food category) of meat (n = 128), dairy and eggs (n = 24), and fast foods (n = 169) common to the U.S. diet. The findings of our analysis indicate that no single food item in these categories is a rich dietary source of any one form of vitamin K. However, these foods are often consumed in large quantities; hence, they may be of importance in overall contribution to total vitamin K intake. The presence of MK-4 in meat, eggs, and dairy foods could be important as physiologic functions unique to MK-4 are identified. 相似文献