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51.
52.
A series of five experiments were conducted to explore suitable conditions for storing of goldfish embryos in a chilled state. The factors studied were embryo stage, storage temperature, physiological saline solutions and goldfish artificial coelomic fluid (GFACF) medium, antibiotics (penicillin and streptomycin), antioxidants (vitamin E, vitamin C), buffer (Hepes, Tris) and BSA (bovine serum albumin). First, goldfish embryos at eight developmental stages were incubated in aerated and dechlorinated tap water at 0°C for 24 h. Result shows that early developmental stages were most sensitive to chilling. Heartbeat‐stage goldfish embryos were chilled at 0, 4 or 8°C for up to 72 h in water, and chilled storage was possible only for up to 18, 24 and 48 h at 0, 4 and 8°C, respectively, without a decrease in viability. Chilling of goldfish embryos at 8°C in GFACF medium and Dettlaff's solution instead of water and other physiological saline solutions prolonged their viability (p < 0.01). Nevertheless, viability of chilled embryos in GFACF medium was slightly, but non‐significantly, higher than in Dettlaff's solution. Supplementation of the GFACF medium with antibiotics, Hepes or BSA increased the viability of chilled embryos, but the tested vitamin E analogue Trolox, vitamin C or Tris concentration had no effect on embryo viability. The outcome of this series of experiments shows that heartbeat‐stage goldfish embryos could be chilled for 60 h in GFACF supplemented with 25 mm Hepes, 100 U/ml penicillin, 10 μg/l streptomycin and 1 g/l BSA in such a way that embryonic development does not proceed, and viability is not lost.  相似文献   
53.
The aim of this study was to determine the association between the oestrous response of pre‐pubertal gilts to gonadotrophin injection or boar exposure and their subsequent farrowing rate and litter size. At 154 days of age, randomly selected pre‐pubertal gilts received an intramuscular injection of 400 IU equine chorionic gonadotrophin plus 200 IU human chorionic gonadotrophin (PG600®; Merck Animal Health; n = 181). From the remaining pool of animals not treated with hormones, the first gilts showing signs of oestrus were selected to act as controls (n = 201). Boar exposure began at 155 days of age for both groups, and gilts were bred at a weight of approximately 130 kg. Comparisons were made between PG600®‐treated gilts exhibiting oestrus or not within 7 days post‐injection (early and late responders, respectively) and control gilts exhibiting oestrus or not within 30 days after beginning of boar exposure (select and non‐select control gilts, respectively). By 162 days, oestrus was detected in 67.5% of PG600®‐treated gilts compared with 5.7% of control gilts (p < 0.0001). The proportion of animals observed in oestrus at least three times before breeding was greater for select control gilts compared with early and late responder PG600®‐treated gilts (p  0.001). There were no significant differences in farrowing rate and litter size between the four treatment groups. These data indicate that PG600® is an effective tool to induce an earlier oestrus in gilts, that subsequent farrowing rate and born alive litter size compare favourably to that of select gilts and that gilts failing to respond promptly to hormonal stimulation do not exhibit compromised fertility.  相似文献   
54.
Ketamine has been implicated as causing increases in intraocular pressure. The purpose of this study is to document the effects of ketamine, diazepam, and their combination on intraocular pressure (IOP) in normal, unpremedicated dogs. Random-source dogs were assigned to one of five groups of 10 dogs each: ketamine 5 mg kg–1 (KET5), ketamine 10 mg kg–1 (KET10), diazepam 0.5 mg kg–1 (VAL), ketamine 10 mg kg–1 with diazepam 0.5 mg kg–1 (KETVAL), saline 0.1 mL kg–1 (SAL), all given intravenously. A baseline IOP was measured before injection, immediately after injection, and at 5, 10, 15, and 20 minutes following injection. IOP was increased over baseline immediately after injection in the KET5, KET10, and KETVAL groups; at 5, 10, and 15 minutes in the KET5 group; and at 20 minutes in the KETVAL group. The mean IOP change compared to SAL increased immediately after injection and at 5 minutes in the KET5, KET10, and KETVAL groups; at 10 and 15 minutes in the KET5 group, and at 20 minutes in the KETVAL group. The mean IOP increased up to 5.7, 3.2, and 3.1 mm Hg over mean baseline in the KET5, KET10, and KETVAL groups, respectively. All dogs in the KET5 group and the majority in the KETVAL and KET10 groups had an increase in their IOP over baseline. Ketamine caused a clinically and statistically significant elevation in IOP over baseline and compared to SAL. The concurrent addition of diazepam did not blunt this increase. Ketamine should be avoided in dogs with corneal trauma, glaucoma, or in those undergoing intraocular surgery.  相似文献   
55.
The embryonic collection techniques in dogs present a vast methodological variation and low recovery rates. The objectives were to compare and describe two techniques as to the recovery of canine embryos, on the 12th day after the first mating or artificial insemination. Embryos were recovered through uterine horn flushing in vivo, before performing the ovariohysterectomy (OHE) (Group 1; n = 9) or ex vivo, immediately after the OHE (Group 2; n = 9). In total, 43 and 47 embryonic structures were recovered in Groups 1 and 2, respectively. There was no significant difference (p > 0.05) between groups on recovery rates (72.8% and 81.0%, respectively). We inferred that both in vivo and ex vivo techniques allow a high rate of embryonic recovery; in the collection technique prior to the OHE, it is essential to carefully handle the reproductive system during the trans‐surgical period and that the 12th day (D12) after the first mating/artificial insemination is an efficient option for the high recovery rate of morulae and blastocysts.  相似文献   
56.
Methoprene, an insect growth regulator, was evaluated under field conditions against the main malaria vectors in the Islamic Republic of Iran. The effect of 5, 10 and 20 kg ha(-1) concentration ofmethoprene granule formulation and 100 and 200 mL ha(-1) concentration of EC formulation was measured to determine any changes in Anophelini larval abundance and IE ratio in both rice fields and artificial ponds. In artificial ponds, granular methoprene at a dose of 20 kg ha(-1) inhibited adult emergence by 77.1% after 1 day and 65.9% after 3 days. The emulsifiable concentrate formulation of methoprene at 200 mL ha(-1) inhibited adult emergence by 83.7% after 1 day and 32.2% after 3 days. In rice fields, inhibition of emergence was 44.3% at 20 kg ha(-1) granule and 35.8% for emulsifiable concentrate at 200 mL ha(-1) after 3 days. The results vary depending on the mosquito species, treatment methods, breeding places and type of formulation.  相似文献   
57.
Only a few studies have described hormonal treatments for induction of synchronicity and gamete collection in Nile tilapia (Oreochromis niloticus), both important for assortative matings in breeding programmes and essential for polyploidy technologies. In this study, we compared the effectiveness of carp pituitary extract (CPE), Nile tilapia pituitary extract (TPE), human chorionic gonadotropin (hCG) and gonadotropin‐releasing hormone (GnRH) protocols on the induction of spawning and egg production in Nile tilapia. Among the hormonal treatments analysed, only hCG was effective for producing viable gametes for in vitro fertilization. To verify the viability of this hormonal treatment, hCG was tested using different doses (1000, 2000, 3000, 4000 and 5000 IU/kg) in a large number of females (208 animals) from two Nile tilapia lines. The results indicated that hCG doses between 1000 and 5000 IU/kg could be used to induce final oocyte maturation in Nile tilapia with collection of stripped oocytes. This is the first study to report differential reproductive responses to hormonal treatment between tilapia lines: line 1 was more efficient at producing eggs and post‐hatching larvae after hCG induction than line 2. In conclusion, we demonstrated that the hCG protocol may be applied on a large scale to induce final oocyte maturation in Nile tilapia. The development of a protocol for in vitro fertilization in Nile tilapia may aid in breeding programmes and biotechnological assays for the development of genetically modified lines of Nile tilapia.  相似文献   
58.
The objectives of the present study were to determine ionic and organic composition of seminal plasma, sperm concentration and their relationships in the Persian sturgeon (Acipenser persicus). In this regard, ionic content (Na+, K+, Cl?, Ca2+ and Mg2+) and organic content (total protein, glucose, cholesterol and triglyceride) along with sperm concentration were measured in 17 specimens of the Persian sturgeon. The seminal plasma contained 59.53 ± 2.56 mm /l sodium, 9.1 ± 1.42 mm chloride, 4.72 ± 0.3 mm potassium, 1.45 ± 0.075 mm calcium and 0.7 ± 0.072 mm magnesium. The following organic contents were found: total protein 0.11 ± 0.02 g/dl, glucose 22.18 ± 4.16 mg/dl, cholesterol 6.67 ± 1.04 mg/dl and triglyceride 15.2 ± 0.65 mg/dl. The mean sperm concentration was estimated to be 1.6 ± 0.12 (×109 sperm/ml). A significant relationship was found between sperm concentration and K+ of seminal plasma (r = 0.533, p < 0.05). Significant correlations were observed between ionic contents: Na+ vs Cl? (r = ?0.854, p < 0.01) and Mg2+ vs K+ (?0.583, p < 0.05). Also, level of triglyceride was negatively correlated with Mg2+ (r = ?0.503, p < 0.05). Presented data could be considered as a complementary study for developing special extenders and protectant solutions for improving artificial fertilization in this valuable species.  相似文献   
59.
AIM: To examine the infective dose, incubation period and disease progression of an isolate of Salmonella enterica serotype Typhimurium definitive type 160 (DT160) originating from a naturally-infected house sparrow (Passer domesticus) during an outbreak of the disease in New Zealand.

METHODS: Thirty-six house sparrows captured from the wild and free of Salmonella spp were divided into six groups of six birds, housed individually, and inoculated orally with phosphate buffered saline (PBS) or 101, 102, 103, 105, 2 × 108 colony forming units (cfu) of the outbreak strain of S. Typhimurium DT160. The birds were observed for 10 days for clinical signs and/or mortality, and faecal samples were collected to determine excretion of S. Typhimurium. The birds were eutha- nised 11 days post-inoculation (p.i.) and a wide range of tissue samples were collected for histopathological examination, and culture and typing of Salmonella spp. Macro-restriction profiling by pulsed-field gel electrophoresis (PFGE) using XbaI was performed for the epidemiological typing of S. Typhimurium DT160 isolates.

RESULTS: Mortality in house sparrows inoculated with S. Typhimurium DT160 was dose-dependent, and 2/6 birds inoculated with 105 cfu and all six birds inoculated with 2 × 108 cfu died during the study. Infected sparrows displayed few clinical signs, apart from diarrhoea and/or polyuria, fluffed plumage, and sitting on the floor of the cage. Faecal excretion of DT160 occurred briefly in two birds inoculated with 102 cfu and four birds inoculated with 103 cfu, on most days in five birds inoculated with 105 cfu, and continuously in six birds inoculated with 2 × 108 cfu. DT160 was isolated from the livers of three birds which received 103 cfu, five birds dosed with 105 cfu, and all six birds given 2 × 108 cfu. Following necropsy, histopathological lesions similar to those seen in the natural disease were observed in the liver or spleen of three birds which received 103 cfu, and all birds dosed with ≥105 cfu.

CONCLUSION: The results indicate that an isolate of S. Typhimurium DT60 originating from house sparrows in New Zealand is pathogenic to these birds and that the response is dose- dependent. The persistence and excretion of the pathogen may last for at least 10 days. This confirms that sparrows infected with DT160 could be a source of infection to humans and other in-contact animals.  相似文献   
60.
AIM: To describe the pathology of crypt abscesses in the caeca of feral rabbits in the Manawatu region of New Zealand, and to examine the possible relationship between their prevalence and rabbit haemorrhagic disease (RHD) virus (RHDV) infection.

METHODS: During the course of a 3-year study of RHD, 173 wild rabbits (Oryctolagus cuniculus) were shot on three pastoral livestock farms in the Manawatu region of New Zealand. All rabbits were necropsied, and tissue samples of the caeca were examined histologically. The age of each animal was determined, and blood samples collected for the detection of RHDV antibodies. Logistic regression was used to model the odds of rabbits having crypt abscesses.

RESULTS: At necropsy, 63/173 (36.4%) rabbits were found to have small circular black nodules on the mucosal surface of their appendix caecum and/or sacculus rotundus. Microscopically, these were identified as small crypt abscesses composed of dilated sacs at the base of the mucosa that were often lined by a thin layer of attenuated epithelial cells. They usually contained large amounts of concentrically-laminated mucopolysaccharide material that was sometimes pigmented, inflammatory debris, and were often the site of a moderate multifocal appendicitis. Although RHDV was active in the study area, no association was found between RHDV antibodies in serum and the presence of lesions. The lesions were more common in older individuals and those born in summer or autumn.

CONCLUSIONS: This is the first report of crypt abscesses with inflammation and necrotic debris in the caeca of rabbits. No association between the occurrence of crypt abscesses and RHDV infection was identified. Wild rabbits born in a particular season were presumably exposed very early in life to conditions that caused the crypt abscesses to develop. Alternatively, association with season of birth may represent rabbits that were of similar age in a later stage of their lives, when they became exposed to the cause of the lesions, which remains unidentified.  相似文献   
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