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51.
The aim of this study was to assess monthly testicular development in the cultured breeding stock of sterlet, Acipenser ruthenus, using histological and serum sex steroid changes. Testicular development in the adult male was examined monthly and showed four distinct phases including resting, pre‐spawning, spawning and post‐spawning. Also, seasonal changes of the testes were described according to its variations in gonadosomatic index (GSI) during different phases of testicular development. Using histology, we identified continuous spermatogenesis and asynchronous gonad development pattern in the testes of male sterlet, which shows that regulation of annual gonadal cycle is influenced by season. Results also showed variation in the GSI value and number of spermatogenic cells according to each season during annual cycle of gonad, as the highest value of GSI was recorded during spawning phase (spring; March‐May). Hormonal profiles of 11‐ketotestosterone (11‐KT) showed peak, which indicated a seasonal pattern of gonadal development. The 11‐KT concentration increased considerably during the spermatogenesis (pre‐spawning phase) and remained quite high throughout the pre‐spermiation period. In the final phase of testicular development (spawning phase), the 11‐KT markedly dropped. This study undertook an examination of complete reproductive development in cultured sterlet sturgeon to provide a valuable guide for the future sterlet studies, and allows comparison of reproductive development between sturgeon species.  相似文献   
52.
The parasitic weed, Striga gesnerioides, is a major threat to cowpea productivity throughout the savannas of West and Central Africa. The identification of sources of S. gesnerioides resistance and their incorporation into breeding programs would be a beneficial strategy to combat the devastation caused by the parasite in cowpea fields. In this study we examined one hundred and ninety-four (194) accessions, four commercial varieties and two controls collected from a mini core collection of cowpea held at the International Institute of Tropical Agriculture genebank for resistance to S. gesnerioides race 3 (SG3), the most prevalent race in Nigeria, using phenotypic screening and molecular marker analysis. Our studies identified two cowpea accessions, Tvu-1272 and Tvu-16514, that are resistant to S. gesnerioides SG3. Resistance in these lines is associated with the molecular marker SSR1, known to segregate with the gene conferring resistance to SG3 in the cultivar B301. Phenotypically, resistance in Tvu-1272 and Tvu-16514 is expressed as a hypersensitive response at the site of infection on the roots. Allelism tests indicated that the gene that conferring SG3 resistance in Tvu-1272 is independent of that conferring resistance in B301. Tvu-1272 and Tvu-16514 will provide additional new sources of resistance to Striga and races prevalent in Nigeria.  相似文献   
53.
Objective To evaluate the effect of the number of days exposure to a prepartum transition diet on mineral, energy and protein metabolism in dairy cows. Design A prospective cohort study. Procedures The prepartum transition diet consisted of ryegrass pasture, cereal hay, grain, grain by-product, protein meals, BioChlor®, rumen modifiers, minerals and vitamins and contained 13.9% crude protein, 10.0 MJ metabolisable energy/kg and a dietary cation anion difference of −35 meq/kg dry matter. Forty cows were bled bi-weekly from their introduction to the prepartum transition diet until day 35 of lactation. Blood samples were submitted for estimation of a range of metabolites. Cubic smoothed splines were fitted to scatterplots of metabolite concentration as a function of day relative to calving and the area under the curve (AUC) was calculated. Linear regression modelling determined the effect of days exposed, age, body condition score (BSC) and calving day on AUC. Results The prepartum AUC of blood phosphorus and beta-hydroxybutyrate increased and the AUC of blood calcium and cholesterol decreased with increasing days exposed to the diet. The postpartum AUC of beta-hydroxybutyrate and non-esterified fatty acids decreased with increasing days exposed but increased with days exposed × age and days exposed × BCS, respectively. The AUC of other metabolites did not vary significantly with number of days exposed. Conclusions Increasing exposure to the prepartum diet significantly altered the AUC of blood metabolites associated with mineral, energy and protein metabolism in ways consistent with improvements in production and reproduction previously reported and the result suggests links between energy, protein and skeletal metabolism.  相似文献   
54.
A 5‐year‐old male Miniature Schnauzer was presented with unilateral cryptorchidism and signs of feminization. Abdominal ultrasonography revealed an enlarged right testis and a large, fluid‐filled cavity that appeared to arise from the prostate. Computed tomography revealed the cavity to be consistent with an enlarged uterine body, arising from the prostate, and showed two structures resembling uterine horns that terminated close to the adjacent testes. The dog had a normal male karyotype, 78 XY. Gonadohysterectomy was performed and both the surgical and the histological findings confirmed the presence of a uterus in this male animal, resulting in a diagnosis of persistent Mullerian duct syndrome (PMDS). The enlarged intra‐abdominal testis contained a Sertoli cell tumour. Computed tomography proved to be an excellent diagnostic tool for PMDS.  相似文献   
55.
Many studies have investigated the effects of pH, temperature, and salinity on the surface-active properties of various surfactants, although in most cases the variables have been studied separately, without considering the effects of any interactions between them. In the present study, a Box-Behnken factorial design was applied to study the effects of pH, temperature, and salinity on the surface-active properties of a biosurfactant produced by Lactobacillus pentosus. The data obtained enabled development of a second-order model describing the interrelationships between operational and experimental variables, by equations including linear, interaction, and quadratic terms. The variable that had the greatest effect on the surface-active properties of the biosurfactant was pH. Moreover, at pH 3-5.5, decreases in salinity and temperature acted synergistically, reducing the surface tension of the biosurfactant; at pH 8, the same effect was observed with increasing salinity and temperature.  相似文献   
56.
The main pedological, geomorphological and cryogenic features of Keller Peninsula, part of Admiralty Bay, King George Island, Maritime Antarctica, were mapped and quantified with emphasis on the relationship between the ice retreat process, melt-out, landform development and soil distribution. Moraines, protalus, scree slopes, inactive glacial cirques, uplift marine terraces, biogenic landforms, arêtes and Felsenmeer were mapped. Scree slope is the main landform, covering approximately 25% of the peninsula, indicating prominent paraglacial features. Inherited, glacial landforms, such as lateral moraines, highland plateau and exhumed U shaped-valleys, are now being exposed in north Keller by ice shrinkage of former ice protecting cover. Landforms influenced soil formation and stability. Cryosols and Leptosols (WRB) roughly corresponding to Gelisols and Entisols (SSS), respectively, are the most common soil classes, with an overall tendency of absent permafrost in the coastal areas, changing to sporadic permafrost at mid-slope, and discontinuous permafrost with greater altitude and substrate stability.  相似文献   
57.
Important genomic imprinting changes usually occur following the in vitro production (IVP) of bovine embryos, especially in the imprinting pattern of components of the IGF system. This study aimed to evaluate the effects of a transient episomal overexpression of the IGF2 gene in bovine IVP embryos following embryo cytoplasmic microinjection (CMI) at the 1-cell stage on embryo survival, early and late developmental kinetics and morphological quality up to Day 7 of development. Selected cumulus–oocyte complexes (COCs) were matured and fertilized in vitro and subsequently segregated into six experimental groups: non-CMI control group and five CMI groups at increasing doses (0, 10, 20, 40 and 80 ng/μl) of a GFP vector built for the episomal expression of bovine IGF2. Zygote CMI was effective in delivering the expression vector into the ooplasm, irrespective of the groups, with 58% of positive GFP fluorescence in Day 7 blastocysts. Considering developmental rates and late embryo kinetics, the 10-ng/μl CMI vector dose promoted a lower blastocyst rate (10.4%), but for blastocysts at more advanced stages of development (93.0% blastocysts and expanded blastocysts), and higher number of cells (116.0 ± 3.0) than non-CMI controls (23.3%, 75.0% and 75.0 ± 6.8 were obtained, respectively). In conclusion, CMI at the 1-cell stage did not compromise subsequent in vitro development of surviving embryos, with the 10-ng/μl group demonstrating a possible growth-promoting effect of the IGF2 gene on embryo development, from the 1-cell to the blastocyst stage.  相似文献   
58.
Chlamydia psittaci was detected by PCR in the lung and equine foetal membranes of two aborted equine foetuses and one weak foal from two different studs in Victoria, Australia. The abortions occurred in September 2019 in two mares sharing a paddock northeast of Melbourne. The weak foal was born in October 2019 in a similar geographical region and died soon after birth despite receiving veterinary care. The detection of C. psittaci DNA in the lung and equine foetal membranes of the aborted or weak foals and the absence of any other factors that are commonly associated with abortion or neonatal death suggest that this pathogen may be the cause of the reproductive loss. The detection of C. psittaci in these cases is consistent with the recent detection of C. psittaci in association with equine abortion in New South Wales. These cases in Victoria show that C. psittaci, and the zoonotic risk it poses, should be considered in association with equine reproductive loss in other areas of Australia.  相似文献   
59.
There are several skin grafting methods described in the human and animal literature. Currently, there are five types of free grafts used in horses: pinch and punch grafts, split and full-thickness sheet or mesh grafts and tunnel grafts. Published methods of tunnel grafting describe the use of alligator forceps. The alligator forceps create a poor tunnel and are excessively traumatic to the granulation bed. This technique utilised a 13G Jamshidi needle that was placed across the granulation bed and created a uniform tunnel. The Jamshidi needle was atraumatic to the granulation bed increasing the opportunity for graft survival. A twin bladed scalpel allowed for the quick creation of uniform width grafts. Removal of the overlying tunnel ‘roof’ took place 5–14 days later to allow graft expansion. This case series included five horses with distal limb wounds and one with a wither injury. Four horses required general anaesthesia for graft placement and three required general anaesthesia for the removal of the tunnel roof. The acceptance of the grafts varied from 70% to 100%. Graft expansion to cover the granulation tissue took 2–5 months. This case series demonstrates that this technique of graft production and placement is an easy method for achieving successful skin grafting. Compared to other graft types, tunnel grafts are more readily accepted. Cosmetic and functional results achieved are better than those with pinch and punch grafts. Tunnel grafting does not require expensive equipment or advanced training, and in some cases can be performed under standing sedation.  相似文献   
60.

Rotaviruses have a worldwide distribution and the infection is associated with diarrhea in young of ruminants as well as children. However, limited data exist on its prevalence and types in Yobe state, Nigeria. Detection of rotavirus A and types in ruminant population in Yobe state was the aim of the study. A total of 470 diarrheic fecal samples were collected and tested for rotavirus and types using serology and molecular techniques respectively. A prevalence rate of 2.98% (14/470) was found in the three species with specific rates of 2.9% (6/202), 3.8% (6/158), and 1.8% (2/110) in goat, sheep, and cattle respectively. The prevalence rates of 3.6% (12/331), 1.2% (1/84), and 1.8% (1/55) were for those aged < 1–3, 4–6, and 7–9 months old, respectively, while 4.9% (9/185) and 1.7% (5/285) were in males and females respectively. Rotavirus genes VP7 and VP4 were detected in 2 (14.3%) out of the 14 ELISA-positive samples while deduced amino acid sequences of the major variable regions revealed the genes to belong to types G3P[11] strain. Significant association was found between the infection and sex (P < 0.05) unlike in the species and age groups of the ruminants. The circulation of rotavirus virus in ruminants and type G3P[11] in cattle has been confirmed in the study. Hence, there is a need for continuous surveillance, awareness campaign, and assessment of the economic losses and public health implications of rotavirus infection in Nigeria.

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