Histomorphological changes between short and long days in ovary guanacos (Lama guanicoe)     

Lina Maria Correa E  Ricardo D. Moreno  José Luis Riveros 《Anatomia, histologia, embryologia》2023,52(2):336-340

This is the first morpho-histological comparison of guanaco ovaries between reproductive (long-days) and non-reproductive (short-days) seasons, and oestrogen receptor-alpha (ERα) and beta (ERβ) detection. Different stages of follicle development were found in the cortical area, but no corpus luteum was detected. The size and frequency of antral follicles and large atretic follicles were higher in long-day ovaries than short-days, consistent with ovarian activity in this season. Differential expression of ERα and ERβ was observed in follicles at different stages of development between short and long days. These data reveal histological and molecular differences between reproductive and non-reproductive seasons of guanaco ovaries.  相似文献   

Natural Stable Isotopes for Determination of Gastrointestinal Transit Time in Fish          下载免费PDF全文

Lidiane Cristina Gonçalves de Sandre  Hellen Buzollo  Thiago Matias Torres do Nascimento  Lígia Maria Neira  Eduardo Gianini Abimorad  Rosangela Kiyoko Jomori  Carlos Ducatti  Maria Célia Portella  Dalton José Carneiro 《Journal of the World Aquaculture Society》2016,47(1):113-122

This study evaluated the application of stable isotopes of carbon as an alternative and more accurate method to determine gastrointestinal transit time (GTT) in fish by comparing it to the inert marker method. The stable isotope method detects alterations of the normal carbon flow in a biological system by analyzing naturally occurring isotopes of carbon, contrary to studies based on conventional techniques that apply external markers to the diet to determine GTT through visual observation of the color change in feces. Therefore, 320 pacu, Piaractus mesopotamicus juveniles were reared in 32 tanks under two different temperatures (25 and 29 C). The pacu juveniles received two different diets, one based on ingredients derived from C₃ photosynthetic cycle plants and the other based on C₄ plant ingredients, both containing titanium oxide (TiO₂) as a marker. After 40 d, the isotopic signature of the diets was changed, and the marker was replaced by chromic oxide (Cr₂O₃). In the isotopic technique, the feces were analyzed to determine the exchange in the isotopic ratio of carbon δ¹³C. Both methods found that GTT was faster (nearly 6 h) in fish at 29 C when using the C₄/C₃ feeding strategy and slower in fish at 25 C using the C₃/C₄ strategy (15 h by inert marker and 18 h by the isotopic method). In conclusion, GTT determination in pacu juveniles using the stable isotope technique exhibits the same accuracy obtained with the inert marker method at temperatures suitable (nearly 29 C) for the metabolism of these animals.  相似文献   

Physiological and sanitary condition of the white clam Dosinia ponderosa collected from a coastal area impacted by shrimp farm effluent     

Marcel Martínez-Porchas  Susana Maria Scheuren-Acevedo  Luis Rafael Martínez-Córdova  Teresa Gollas-Galvan  Ramon H. Barraza-Guardado  Fernando Enríquez-Ocaña  Edilmar Cortés-Jacinto  Marco A. Porchas-Cornejo 《Aquaculture International》2016,24(1):243-256

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Identification of genetic regions associated with black point in barley     

Priya R. Tah  A. Lehmensiek  Glen P. Fox  Emma Mace  Maria Sulman  Gary Bloustein  Grant E. Daggard 《Field Crops Research》2010,115(1):61-66

Black point (BP) can cause severe losses to the barley industry through downgrading and discounting of malting barley. The genetic improvement in BP resistance of barley is complex, requiring reliable screening tools, an understanding of genotype by environment interactions and an understanding of the biochemical mechanisms of melanisation involved in BP development. Thus the application of molecular markers for resistance to BP may be a useful tool for plant breeders. We have investigated the genetic regions associated with BP resistance in the barley F₂ population, Valier/Binalong. Quantitative trait loci (QTLs) contributed by the resistant parent Valier, were detected on chromosomes 2HS, 2HC, 3HL, 4HL and a QTL contributed by the susceptible parent, Binalong was detected on 5HL. Three of the four QTLs were detected in two distinctly different environments. The differences observed in BP resistance between these two environments and the implications for accelerated screening are discussed. Identified SSR markers in these regions may be useful for selecting black point resistance in related breeding materials.  相似文献   

Determination of total amitraz residue in honey by electron capture capillary gas chroma tography–a simplified method     

Maria Barbina Taccheo  Mauro De Paoli  Claudio Spessotto 《Pest management science》1988,23(1):59-64

A gas chromatographic method using a capillary column is described for the determination of total amitraz residue in honey samples. The method consists of a preliminary extraction of the sample, an alkaline hydrolysis, an extraction of the 2, 4-dimethylaniline formed, without the aid of steam distillation/continuous extraction, its derivatisation with heptafluorobutyric anhydride and a gas chromatographic determination using an electron capture detector. The method is very rapid and can be carried out in a test tube. The detection limit is 0.020 mg kg^?1 and recoveries are of the order of 85%.  相似文献   

An enzyme-linked immunosorbent assay (ELISA) for detection of antibodies against Toxocara vitulorum in water buffaloes     

Starke-Buzetti WA  Machado RZ  Zocoller-Seno MC 《Veterinary parasitology》2001,97(1):55-64

Toxocara vitulorum, a parasite of the small intestine of cattle and water buffaloes, is mainly acquired by calves via the colostrum/milk from infected cows. To understand the development of immune responses in calves, antibody levels to a soluble extract antigen (Ex) from T. vitulorum infective larvae were measured by an indirect ELISA with sera of 15 buffalo calves, which were sampled every 15 days for the first 180 days after birth and 9 buffalo cows during the perinatal period. From all serum samples examined during the first 180 days, antibody level was lowest and highest in calves at 1 day of age before and after suckling colostrum, respectively, suggesting that the origin of antibodies was the colostrum. Immediately after birth, antibody levels in suckled calves remained at high levels until day 15, began to decrease to lower levels between 15 and 30 days and remained relatively stable until 120 days. By comparing the immune responses of these animals with their parasitological status it was considered possible to determine if passively acquired or actively produced antibodies provided protection against the infection. High numbers of T. vitulorum eggs in the feces between 30 and 60 days indicated that passively acquired antibodies did not provide protection against the infection, at least during these first days, and the maximum fecal egg counts during 30-45 days were coincident with decreased antibody levels. Between 60 and 120 days, when serum antibodies were detected at reduced, but stable levels, adult nematodes were expelled from the intestines and no more T. vitulorum eggs were found, suggesting development of acquired resistance. However, the potential and functional protective role of the antibodies against T. vitulorum infection and the process of self-cure requires further investigation.  相似文献   

Traders' preference for goat characteristics in selected markets of Pangasinan, Philippines     

Maria Excelsis M. ORDEN  Wilfred E. JAMANDRE  Ernesto O. BROWN  Edgar A. ORDEN  Emilio M. CRUZ  Ana Marie P. ALO  Edwin C. VILLAR 《Animal Science Journal》2005,76(2):179-185

Preference for goat characteristics was determined from 42 traders in six markets in Pangasinan, an important trading center for goats in Luzon, the Philippines, and analyzed using a hedonic price model to determine whether these characteristics are important price determinants of goats. This information is important to goat raisers to respond to the needs of the local market, and thus to achieve a better price and higher income in goat raising. Meatiness, size, breed, sex and age (in descending order) were the dominant goat characteristics preferred by traders. Meatiness had the largest positive influence on price, with a price premium of US$6.24 (US$1.00 = PhP 53), whereas the age of the animal had the smallest influence at US$3.72. However, size and meatiness are manifestations of good breeds. Therefore, continued efforts to improve breeds in order to produce good quality goats are imperative to cater to market needs. Different characteristics implied different price premiums. Traders offered a higher price premium for better goat characteristics; thus, the improvement of these characteristics could result in higher returns for goat raisers.  相似文献   

Vitamin D status of wild Ricord's iguanas (Cyclura ricordii) and captive and wild rhinoceros iguanas (Cyclura cornuta cornuta) in the Dominican Republic.     

Jan C Ramer  Roberto Maria  Tim Reichard  Peter J Tolson  Tai C Chen  Michael F Holick 《Journal of zoo and wildlife medicine》2005,36(2):188-191

Calcidiol (25-hydroxyvitamin D) values are reported for 22 wild Ricord's iguanas (Cyclura ricordii) and seven wild rhinoceros iguanas (Cyclura cornuta cornuta). Calcitriol (1,25-hydroxyvitamin D) values are reported for 12 wild Ricord's iguanas and seven wild rhinoceros iguanas. These animals were captured as part of a larger health assessment study being conducted on Ricord's iguanas in Isla Cabritos National Park, Dominican Republic. A total of 13 captive rhinoceros iguanas held outdoors at Parque Zoológico Nacional were also sampled for comparison. Mean concentrations of 25-hydroxyvitamin D were 554 nmol/L (222 ng/ml) with a range of 250-1,118 nmol/L (100-448 ng/ml) for wild Ricord's iguanas, 332 nmol/L (133 ng/ml) with a range of 260-369 nmol/L (104-148 ng/ml) for wild rhinoceros iguanas, and 317 nmol/L (127 ng/ml) with a range of 220-519 nmol/L (88-208 ng/ml) for captive rhinoceros iguanas. On the basis of these results, serum concentrations of at least 325 nmol/L (130 ng/ml) for 25-hydroxyvitamin D should be considered normal for healthy Ricord's and rhinoceros iguanas.  相似文献   

Influence of pesticides on the activity and kinetics of invertase,urease and acid phosphatase enzymes     

Liliana Gianfreda  Filomena Sannino  Maria T. Filazzola  Antonio Violante 《Pest management science》1993,39(3):237-244

The effects of four pesticides (three herbicides, atrazine, paraquat, glyphosate, and an insecticide, carbaryl) on the activity and kinetics of an invertase (from yeast), a urease (from jack bean) and an acid phosphatase (from potato) were investigated. Glyphosate and paraquat showed a marked activation effect on invertase activity. From the dependence of V_max and K_m parameters on pesticide concentrations, a mixed-type activation mechanism was suggested. The kinetic behaviour of urease and acid phosphatase appeared to be uninfluenced by both pesticides. Methanol, used as solvent for both carbaryl and atrazine, inhibited invertase, urease and acid phosphatase with, respectively, competitive, non-competitive and uncompetitive mechanisms. The extent of the inhibition was different, as estimated by the values of the inhibition constant K₁. An additional inhibition effect of urease and invertase activities was achieved in the presence of carbaryl, whereas no influence was detected on the activity and kinetics of acid phosphatase. Finally, atrazine was shown to alter the kinetics of the enzymes only at higher concentrations.  相似文献   

Interference by the intracellular parasite Theileria parva with T-cell signal transduction pathways induces transformation and protection against apoptosis     

Dobbelaere D  Fernandez P  Machado J  Botteron C  Heussler V 《Veterinary immunology and immunopathology》1999,72(1-2):95-100

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