Progeny Production of the Copepods Pseudodiaptomus euryhalinus and Tisbe monozota in Monospecific and Mixed Cultures

The objective of this research was to culture the calanoid copepod Pseudodiaptomus euryhalinus, Johnson 1939, and the harpacticoid Tisbe monozota, Bowman, 1962, in monospecific and combined cultures (P. euryhalinus : T. monozota at 1:1, 2:1, and 1:2 starting ratios), and to compare the nauplii, copepodite, and adult production. Mean total production ranged from 740.3 ± 137.5 organisms/L (P. euryhalinus) to 884.3 ± 489.7 organisms/L (T. monozota) for monospecific cultures. The 1:1 ratio mixed cultures gave 780.4 ± 155.8 organisms/L, those with the 2:1 and 1:2 P. euryhalinus and T. monozota starting ratios produced 710.1 ± 195.2 and 799.7 ± 232.5 organisms/L, respectively, and there were no significant difference among treatments. All mixed cultures gave significantly lower copepodite productions than the monocultures of each species. In addition, the tendency to a decreased progeny production of the initial females of T. monozota indicates that the outcome of long‐term mixed cultures would production either a high dominance of P. euryhalinus, or monocultures of this species .     

Standing laparoscopic castration in an equine male pseudohermaphrodite

This report describes the surgical anatomy and successful removal of the internal gonads in a 6-year-old male pseudohermaphrodite Friesian horse by standing laparoscopy. Gonads could not be identified by physical or ultrasonographic examination and bilateral standing flank laparoscopy revealed the presence of intra-abdominal gonads suspended from the dorsal aspect of the abdominal cavity by 10–15 cm long vascular pedicles. No evidence of female internal genitalia such as a uterus was found and bilateral gonadectomy was performed laparoscopically. Histological analysis of the excised gonads confirmed the diagnosis of male pseudohermaphroditism. Minor cosmetic surgery of the external genitalia to correct urinary misdirection was successfully performed 3 months after laparoscopic castration. Standing flank laparoscopic examination was excellent for identification and surgical removal of internal genitalia. Standing flank laparoscopy should be considered for inspection and removal of internal genitalia in intersex horses.     

The effects of applied crop residues on losses of Fe, Mn, Cu and Zn in run-off from a soil prone to crusting

Tillage practices may reduce the organic matter content in near-surface soil horizons causing crust formation. Surface conditions may cause an increase in surface run-off, thus enhancing contaminant transfer of heavy metals or an acceleration in nutrient loss. This study examines the effect of applying crop residues to the surface of tilled soils on heavy metal losses by run-off. Losses in iron (Fe), manganese (Mn), zinc (Zn) and copper (Cu) were analysed. Run-off and sediment yield were measured on 1 m² plots using a rainfall simulator with a constant 65 mm/h intensity. Four successive rainfall applications were performed, the first three at 25 mm each and the last at 65 mm. Added corn straw varied between 0 and 4 t/ha in the five studied treatments. After 140 mm cumulative rainfall, total heavy metal losses were as follows: Fe from 137 to 950 mg/L, Mn from 2.3 to 12.83 mg/L, Cu from 0.09 to 0.72 mg/L and Zn from 0.31 to 2.46 mg/L. Dissolved fractions were as follows: Fe from 0.014 to 0.229 mg/L, Mn from 0.034 to 1.45 mg/L, Cu from 0.002 to 0.013 mg/L and Zn from 0.02 to 0.12 mg/L. Total concentrations of the studied elements decreased exponentially due to the effect of corn straw on soil loss. However, dissolved contents of Fe and Cu scarcely varied. Significant positive linear correlations were observed between total heavy metal content and soil and sediment loss by run-off. It is concluded that the addition of straw to a soil of low fertility prevents heavy metal loss.     

The pathogenicity of rabbit coccidium Eimeria coecicola Cheissin, 1947

The pathogenicity of Eimeria coecicola for rabbits has been demonstrated in our experiments. The animals suffered from prolonged affection of appendix lasting at least 20 days. Pathological changes appeared with the development of merogony since day 4 post infection (DPI) and were characterized by an inflammatory infiltration and abundant pyogenic component in lamina propria, swelling and coalescence of upper parts of appendix mucosa above atrophied domes, where spaces filled with stagnating inflammatory exudate, endogenic stages of coccidia, and desquamated epithelia are formed. The alteration of the epithelium and exposure of the appendix lamina propria occur in relation with the gametogony in the period of about 10 DPI. Since 8 DPI, the epithelium of the infected endogenic stages of coccidia becomes hyperplastic, proliferates into lamina propria and is subjected to necrosis. Groups of immature oocysts and their fragments remain in lamina propria and are resorbed, at least for 10 days, by granulomatous inflammatory structures with abundant multinucleate cells of the type of foreign body cells.     

Regeneration in mouse skeletal muscle injured by Trichinella larvae

During the infection caused by Trichinella pseudospiralis serious damage to muscles is partly compensated with regeneration process. Short, thin fibrillae with central position of the nuclei--regenerating myotubes originate 20--40th day post infection in endomysial tubes remaining after damaged muscle fibres, left by migrating larva. On the 10th day post infection in the vicinity of moving larva activation of nuclei and increased origin of satellite cells under basal membrane occur. With development of the infection endothelia in the vicinity of altered fibrillae are increasing in number but there is small inflammatory and fibroproductive reaction only. During the infection caused by Trichinella spiralis and T. nativa, alteration of muscle fibres is accompanied by early inflammatory and fibroproductive reaction towards immediate surroundings of larvae. In a changed segment of muscle fibre with the larva--in pseudocyst there is altered basal lamina as well, built in increased glycocalyx and in the course of 20 days encased by connective tissue. Revascularisation and regeneration in a short damaged segment does not occur even during long-lasting infection because of separation by capsule.     

Chemotherapy of experimental toxoplasmosis with special reference to robenidine

Robenidine as an anticoccidial agent alone (in doses of 50 and 100 mg/kg) or in association with two other antiprotozoal compounds--pyrimethamine and sulfadoxine (in doses of 2.5 and 250 mg/kg, respectively) were tested in the treatment of chronically infected mice with an avirulent cyst-forming HF strain of Toxoplasma gondii. The efficacy of the used drugs was evaluated by the cysts number in the brains of treated mice versus control group, antibody level and viability of survived cysts by the consecutive infection of mice. According to these criteria none of the tested drugs alone or combined exhibited to be able to produce an effective cure of cyst-stage of toxoplasmosis in experimental mice.     

The effect of age on the fertility of males of Culex molestus (Diptera, Culicidae)

Older males of C. molestus have a markedly lowered fertility (even by 50%) and the image productivity of their progeny is much lower than that of freshly hatched males (more than 6X). This fact may hinder the population explosion particularly in those species whose individual generations coincide in the course of a year or are much diffused.     

Penetration of ovicidal fungus Verticillium chlamydosporium through the Ascaris lumbricoides egg-shells

The course of penetration of the ovicidal fungus Verticillium chlamydosporium Goddard through the Ascaris lumbricoides egg-shells was studied in electron miorographs. The contact area between the egg and the fungus is smooth at the stage of the contact of the ovicidal fungus with the egg surface, as well as at the stage of adhesion. No special attaching organs are formed which indicates that no mechanical penetration of the fungal hypha through the egg-shells is involved. Traces of enzymatical activity of the fungus penetrating upright through the egg-shells can be observed during the penetration stage proper. At the consumption stage, the branching of the ovicidal fungus becomes more dense and some hyphae grow through the egg envelopes parallelly under the egg surface. The fungus grows through all parts of the infected egg, even through its contents.     

Serotyping of Haemophilus paragallinarum isolates from Mexico by the Kume hemagglutinin scheme

A total of 42 isolates of Haemophilus paragallinarum from Mexico were serotyped by the Kume hemagglutinin scheme. Serovars A-1, A-2, B-1, and C-2 were recognized among 11 (26.2%), 7 (16.6%), 4 (9.5%), and 14 (33.3%) isolates, respectively. A further six isolates (14.3%) showed hemagglutinating activity but could not be classified into any serovar. Commercial vaccines containing Kume serovars A-1, A-2, B-1, and C-2 may provide better protection than those bi- or trivalent infectious coryza vaccines currently used in Mexico.