Changes in the photosynthetic activity of Microcystis colonies after gut passage through Nile tilapia (Oreochromis niloticus) and silver carp (Hypophthalmichthys molitrix)

The photosynthetic activity of cyanobacteria (predominantly Microcystis spp.) after passage through the digestive tract of Nile tilapia (Oreochromis niloticus) and silver carp (Hypophthalmichthys molitrix) was determined by CCD fluorescence imaging, using slow complementary area approach, during a 4‐day cultivation of fish faeces in algal ZBB medium. The cyanobacteria colonies exhibited a 92–95% reduction in of activity (P<0.001) after passage through Nile tilapia, whereas there was a significant (P<0.01) stimulation of photosynthetic activity after passage through the silver carp gut.     

Hemoglobin genotypes of turbot (Scophthalmus maximus): consequences for growth and variations in optimal temperature for growth

We studied the growth properties of three different hemoglobin genotypes of juvenile turbot (Scophthalmus maximus) reared at 10, 14, 18 and 22 °C. The genotype Hb-I(2/2) displayed the overall highest growth rate in the temperature range 14–22 °C, whereas no differences were found at sub-optimal temperature (10 °C). The differences in growth were largest at optimal temperatures where the Hb-I(2/2) genotype displayed 13% higher growth than the two other genotypes. Optimal temperature for growth (T _opt.G) varied between the genotypes with the genotype Hb-I(2/2) displaying the highest T _opt.G (23.0 °C) and Hb-I(1/1) the lowest (19.0 °C). The biological significance of this link between biochemical genetic variation and physiological properties might be influences on growth pattern, ultimate size and age at first maturity. This is the first reported quantitative trait locus (QTL) for this species.     

Dactylotrypes longicollis (Wollaston 1864) (Coleoptera, Scolytidae) introduced to the Slovak Republic

A total of 28 seeds of Phoenix canariensis, collected on the littoral of Croatia (former Yugoslavia) in August 1998, were brought to the Slovak Republic in order to grow palm trees In artificial conditions. Surprisingly, the seeds yielded 284 specimens of bark beetles which were identified as Dactylotrypes Iongicollis. This is the first evidence for the introduction of D. longicollis to the Slovak Republic.     

Insemination of Susceptible Heifers with Semen from a Non-Viraemic Bull with Persistent Bovine Virus Diarrhoea Virus Infection Localized in the Testes

Bulls shedding bovine viral diarrhoea virus (BVDV) in semen and simultaneously having a high concentration of circulating antibodies may cause reproductive problems and spread the viral infection within cattle populations. To investigate this in detail, three heifers were inseminated with BVDV‐infected semen from a non‐viraemic, seropositive Holstein–Friesian bull, named `Cumulus'. One control heifer was inseminated with semen from a healthy bull that was free of BVDV. All four heifers remained clinically healthy throughout the experiment. The conception succeeded in the control animal and in two of the three heifers inseminated with semen containing BVDV. The heifer with the failed conception was the only one that became systemically infected with BVDV. This animal was deemed non‐pregnant by ultrasonic examination on day 34 after insemination and showed no signs of subsequent oestrus during the entire experimental period. At slaughter, 42 days after insemination, there were no histopathological changes in the ovaries and virus was not detected in ovarian tissue. The fact that seronegative dams served with semen from persistently infected bulls have occasionally produced persistently infected calves together with the present findings and the fact that non‐viraemic, seropositive bulls can constantly shed BVDV, suggest that the use of semen from such bulls in BVDV‐free herds could have far‐reaching consequences, especially if it led to the birth of persistently infected (P1) calves.     

Comparison of the effects of tercleucine and tryptophan superanalogs of LH-RH on gonadotropin secretion in heifers

In six heifers without sexual organs the effects were compared of the superanalogues LH-RH [(D-Tle6) and (D-Trp6)] on the secretion of luteinizing hormone (LH) and follicles of stimulating hormone (FSH). The superanalogues were given i. m. at dosages of 10, 50 and 100 micrograms pro toto. Dosages of 50 and 100 micrograms of both superanalogues had a greater effect on the secretion of LH than the dosage of 100 micrograms. The highest average concentration of LH during the time of application (D-Tle6) was recorded in the dosage of 10 micrograms (7.84 ng.ml-1). The average concentrations of LH after application (D-Trp6) were within the range of 5.46 to 9.29 ng.ml-1. Because of the great variability of the concentrations of LH no significant differences were ascertained due to the influence of dosage. From a comparison of the concentrations of LH with the same dosage it emerged that (D-Trp6) after an application of 50 micrograms significantly increased the concentration of LH from the 60th to the 240th minute and thus had a more protracted effect. With dosages of 10 and 100 micrograms of the superanalogues no statistically significant differences were recorded after two hours from application. With (D-Trp6) the higher stimulative effect on the secretion of LH was statistically confirmed. The highest concentrations of follicles of stimulation hormone (FSH) (204.6 and 228.6 ng.ml-1) were found from the 40th to the 100th minute after the application of dosages of 50 and 100 micrograms (D-Tle6). The protracted effect was greatest with a dosage of 100 micrograms (270 mins). (D-Trp6) at a dosage of 100 micrograms caused the greatest effect on the secretion of FSH (226.8 ng.ml-1 for a period of 180 mins). The lower dosages of analogues scarcely differed in response. The dosage of superanalogues has an influence on the concentration of FSH in peripheral blood and on the duration of the protracted effect.     

Effect of monensin on fermentation of hay and wheat bran investigated by the Rumen Simulation Technique (Rusitec). 1. Basal parameters of fermentation.

An experiment was performed with Rumen Simulation Technique (Rusitec) in which the fermentation of mixed ration of hay (12.8 g/d) and wheat bran (3.2 g/d) was compared with the fermentation of the same diet in the presence of 2, 5 and 10 mg of monensin/d. The duration of the experiment was 12 days. During the first six days the fermentation conditions in Rusitec were stabilized. Monensin significantly depressed the digestibility of dry matter and fibre digestion--neutral detergent fibre (NDF), acid detergent fibre (ADF) and cellulose but only after using 2 mg monensin/d. Addition of monensin depressed the production of VFAs--acetate, butyrate and isovalerate and acetate:propionate ratio. Production of propionate was increased and production of methane and CO2 was decreased in the presence of monensin. It can be explained by changes in the production of VFAs and redistribution of metabolic hydrogen. The recovery of nitrogen was satisfactory (about 100%) and its distribution in the effluent was increased by monensin. The recovery of protein (measured as alpha--NH2 groups) and distribution of protein in the effluent and residues was increased with the increasing dose of monensin.     

Superovulation and uterine lavage in relation to subsequent conception in donor cows

On the Slusovice co-operative farm, embryo transfer has been practised since 1984 as a method of controlled reproduction of the heifer and cow herd. The effect of superovulation, embryo recovery and administration of 500 micrograms Oestrophan Spofa upon the donors' conception rate and upon their resuming a new reproduction cycle was studied on this farm. The effect of superovulation, induced by FSH-P (Folicotropin, Spofa), was evaluated in 162 cows, out of which 121 (74.69%) got in calf after three inseminations. Fifty-nine (48.76%) of the pregnant cows got in calf after the first insemination, 38 (31.40%) after the second insemination, and 24 (19.83%) after the third insemination. Having been subjected to embryo collection and luteolysis, the donors conceived within 67.6 days, on an average, and the animals superovulated within 60 days post partum conceived within 59.11 days. The average SP of the superovulated animals was about 148 days but in the donors from which the embryos had been recovered within 60 postpartal days the SP did not exceed 110 days. Hence the earlier postpartal superovulation of cycling cows speeds up the resumption of reproduction in the donors and increases the numbers of recovered embryos. Repeated superovulation had no influence on the fertility of the cows but adequately prolonged the service period.     

Biochemical changes in the peripheral blood in cows 45 days after parturition]

Blood samples were collected from v. jugularis in five-day intervals from parturition to postpartum day 45 in the rearing conditions of a dairy cow production herd, consisting of 10 groups with 10 pluriparous cows each (crossbreds of Bohemian Pied cattle with Holstein-Friesian cattle). In blood serum the following activities were determined photometrically: aspartate aminotransferase--AST (0.36-0.47 mukat.l-1), gamma-glutamyl transferase--GMT (0.50-0.83 mukat.l-1) and lactate dehydrogenase--LD (7.22-9.10 mukat.l-1); their average values were at an almost constant level. Only did AST and GMT values decrease slightly from day 25 after parturition. The glucose average content on the day of parturition (4.07 mmol.l-1) steeply decreased to postpartum day 5 (2.79 mmol.l-1), and later on, it increased irregularly. The average values of total protein (66.7-73.2 g per 1) slightly increased from postpartum day 20. The values of urea (2.33-2.37 mmol.l-1) and bilirubin (3.49-5.15 mmol.l-1) did not show any larger changes in dependence on the time elapsing from parturition. The average content of creatinine (124-162 mmol.l-1) increased irregularly from postpartum day 15 and then it decreased. Cholesterol concentrations were gradually increasing from 2.58 mmol.l-1 on the day of parturition to 4.99 mmol.l-1 on day 45 after parturition. The average contents of calcium (2.20-2.66 mmol.l-1) and phosphorus (1.75-2.27 mmol.l-1) were irregularly increasing until day 20 after parturition. Also the average content of magnesium (0.86-1.15 mmol.l-1) rose from day 25 after parturition.     

Use of the skin test in the evaluation of true levels of cellular immunity and levels after experimental administration of glucan and levamisole in feed-lot bulls]

Applicability of a skin test induced by dinitrofluorobenzene (DNFB) to quantification of the actual level of cellular immunity (CI) in vivo and its level after an experimental immunomodulation intervention were evaluated in two breeds (40 animals in each) of fattening bulls (10-11 months old). At the selected methodical procedure of intensity determination of the delayed type of hypersensitivity (DTH), its average value reached 4.5 +/- 1.5 mm in 80 animals, while in 77.5% of bulls its level ranged from 3.6 to 9.6 mm, in 18.7% from 2.0 to 3.5 mm and in 3.8% remained less than 2.0 mm. Evident expression of the reaction points to the possibility of application of the used methodical procedure of the skin test using DNFB to quantify the level of CI response in vivo in cattle. Percentual representation of animals according to the intensity of skin reaction (Tab. I) and concentration of total serum immunoglobulins (Cs-Ig) and serum IgG (Tab. II) indicates the different cellular and humoral state of animals in investigated breeds. This is also confirmed by the recorded average values of mentioned parameters which were significantly lower (P less than 0.01; or 0.05) in animals of the first breed (4.0 +/- 1.3 mm; 28.3 +/- 4.4 U ZST, 18.4 +/- 3.5 g.l-1) than in breed 2 (4.9 +/- 1.6 mm; 32.5 +/- 3.8 U ZST; 20.3 +/- 3.5 g.l-1). The animals of each breed were divided into four experimental groups with the approximately equal actual levels of DTH (Tab. III).(ABSTRACT TRUNCATED AT 250 WORDS)     

Chemical contamination of the cervical mucus in cows in relation to pregnancy and age factors]

Applying the method of absorption atom spectrometry (AAS), the contamination of cervical mucus by chemical elements (Cd, Pb, Hg, Cr, Cu, Zn) was demonstrated in the oestrus period of cows in different ecological agricultural regions of the North Moravian region. The results of observation revealed only a statistically significant difference (P less than 0.05) in Cd contents in the test groups; test group mean = 0.015 micrograms.g-1 Cd, control group mean = 0.006 micrograms.g-1. Cr findings in cervical mucus are of priority importance, the same applies to Cu findings. Zinc was found to be an element influencing negatively the conception of cows. The Zn values in cervical mucus of nonpregnant cows were demonstrated to be significantly higher (P less than 0.01) (conception--group = 0.841 micrograms.g-1, conception + group = 0.219 micrograms.g-1 Zn. So called sum of chemical elements: Cd + Pb + Hg + Cr + Cu + Zn was proposed and evaluated as a picture of the total contamination of cervical mucus. This characteristic was also influenced by the Zn findings in the group of pregnant and nonpregnant cows. Zn: Cd antagonism in cervical secretions of barren and pregnant cows was statistically highly significant (P less than 0.01). Chemical elements in cervical mucus were determined for the first time in a digested sample of cervical secretion. The correlation coefficients used for the cows (n = 99) from a contaminated region showed that the content of chemical elements in cervical secretion was not influenced by the age of cows. The content of chemical elements in cervical secretion was not increasing with the age.