The effect of domestication on a brown trout (Salmo trutta m fario) broodstock in Hungary

Molecular markers (PCR–RFLP and microsatellite) were used to investigate the genetic background of the only brown trout (Salmo trutta m fario) broodstock in Hungary which due to the hydrogeography of the country should theoretically belong to the Danubian lineage. PCR–RFLP (mitochondrial DNA control region and lactate dehydrogenase and somatolactin genes) as well as microsatellite (BFRO002, OMM1064, Ssa408uos, SsoSL417, SsoSL438) markers were used to distinguish between Danubian and Atlantic lineages of brown trout in the Lillafüred broodstock. Altogether 435 fish were tagged during the experimental period. Due to mortalities, fin clips were collected from 401 individuals. According to the genetic analysis of the mitochondrial DNA, the Danubian haplotype is present in only one individual (0.2 %) of the broodstock. Analysis of the nuclear markers revealed that alleles characteristic of both the Atlantic and the Danubian lineages are found in the population. However, Atlantic alleles dominate throughout the broodstock which is in Hardy–Weinberg equilibrium according to the investigated markers. Results indicate that the original broodstock that was introduced to the farm following its construction in 1933 was of the Atlantic lineage. Although later fish from a local stream were collected and added to the broodstock, the number of these was limited and they were almost exclusively males. Fish from this farm that are stocked by anglers can have a significant genetic impact on trout populations of natural streams.     

Bioactivity-guided isolation of antiproliferative compounds from Centaurea jacea L

Bioassay-guided fractionation of the chloroform extract of Centaurea jacea L. afforded the isolation of cirsiliol, apigenin, hispidulin, eupatorin, isokaempferide, axillarin, centaureidin, 6-methoxykaempferol 3-methyl ether, trachelogenin, cnicin, 4'-acetylcnicin and three aliphatic glucose diesters, including the new natural product 1β-isobutanoyl-2-angeloyl-glucose. The structures of the compounds were established on the basis of spectroscopic analyses (UV, MS and NMR). All compounds were isolated for the first time from this species. The compounds were evaluated for their tumour cell growth inhibitory activities on HeLa, MCF-7 and A431 cells. Different types of secondary metabolites (flavonoids, sesquiterpenes) were found to be responsible for the antitumour effects of the extracts; the highest activity was exerted by centaureidin, in addition to moderately active compounds (cirsiliol, isokaempferide, apigenin, hispidulin, cnicin and 4'-acetylcnicin).     

How can horseflies be captured by solar panels? A new concept of tabanid traps using light polarization and electricity produced by photovoltaics

Horseflies (Diptera: Tabanidae) can cause severe problems for humans and livestock because of the continuous annoyance performed and the diseases vectored by the haematophagous females. Therefore, effective horsefly traps are in large demand, especially for stock-breeders. To catch horseflies, several kinds of traps have been developed, many of them attracting these insects visually with the aid of a black ball. The recently discovered positive polarotaxis (attraction to horizontally polarized light) in several horsefly species can be used to design traps that capture female and male horseflies. The aim of this work is to present the concept of such a trap based on two novel principles: (1) the visual target of the trap is a horizontal solar panel (photovoltaics) attracting polarotactic horseflies by means of the highly and horizontally polarized light reflected from the photovoltaic surface. (2) The horseflies trying to touch or land on the photovoltaic trap surface are perished by the mechanical hit of a wire rotated quickly with an electromotor supplied by the photovoltaics-produced electricity. Thus, the photovoltaics is bifunctional: its horizontally polarized reflected light signal attracts water-seeking, polarotactic horseflies, and it produces the electricity necessary to rotate the wire. We describe here the concept and design of this new horsefly trap, the effectiveness of which was demonstrated in field experiments. The advantages and disadvantages of the trap are discussed. Using imaging polarimetry, we measured the reflection-polarization characteristics of the photovoltaic trap surface demonstrating the optical reason for the polarotactic attractiveness to horseflies.     

Bromocriptine inhibits salsolinol‐induced prolactin release in male goats

The secretion of prolactin (PRL) is under the dominant and tonic inhibitory control of dopamine (DA); however, we have recently found that salsolinol (SAL), an endogenous DA‐derived compound, strongly stimulated the release of PRL in ruminants. The aim of the present study was to clarify the inhibitory effect of DA on the SAL‐induced release of PRL in ruminants. The experiments were performed from late June to early July. Male goats were given a single intravenous (i.v.) injection of SAL (5 mg/kg body weight (BW)), a DA receptor antagonist (sulpiride, 0.1 mg/kg BW), or thyrotropin‐releasing hormone (TRH, 1 µg/kg BW) before and after treatment with a DA receptor agonist (bromocriptine), and the effect of DA on SAL‐induced PRL release was compared to that on sulpiride‐ or TRH‐induced release. Bromocriptine completely inhibited the SAL‐induced release of PRL (P < 0.05), and the area under the response curve (AUC) for a 120‐min period after the treatment with bromocriptine was 1/28 of that for before the treatment (P < 0.05). Bromocriptine also completely inhibited the sulpiride‐induced release (P < 0.05). The AUC post‐treatment was 1/17 that of pre‐treatment with bromocriptine (P < 0.05). Bromocriptine also inhibited the TRH‐induced release (P < 0.05), though not completely. The AUC post‐treatment was 1/3.8 that of pre‐treatment (P < 0.05). These results indicate that DA inhibits the SAL‐induced release of PRL in male goats, and suggest that SAL and DA are involved in regulating the secretion of PRL. They also suggest that in terms of the regulatory process for the secretion of PRL, SAL resembles sulpiride but differs from TRH.     

Der Einfluß der Waldpflanzen auf die Vermehrung der Schlunpfwespender Waldpflanzen auf die Vermehrung der Schlunpfwespen

Ohne Zusammenfassung     

Influence of feeding intensity on the growth, body composition and sexual maturity of male New Zealand White rabbits

An experiment was carried out with young male New Zealand White (NZW) rabbits to establish live body weight changes, body measurements, body composition and sexual maturity as a function of feeding intensity. Animals in Group 1 ('AL', n = 10) were fed ad libitum, while those in Group 2 ('RS', n = 10) received restricted feeding corresponding to 70% of the ad libitum level. The starting liveweights were practically the same (0.907 +/- 0.146 and 0.911 +/- 0.147 kg in Group AL and Group RS, respectively). The feeding trial lasted from 6 to 22 weeks of age. The average body weight was significantly higher in Group AL from 7 to 22 weeks of age. At 22 weeks of age the body weight of RS rabbits was 85.64% of the weight of AL animals (3.22 +/- 0.52 kg and 3.76 +/- 0.33 kg, respectively). Average body weights of RS males at 8, 9, 11, 19 and 21 weeks of age were similar to those of ad libitum fed (AL) animals at 7, 8, 10, 15 and 16 weeks of age, respectively. The growth of bucks fed restricted tended to be allometric. The most significant difference was found at 16 and 18 weeks of age, while the lowest difference occurred at 6, 12, 15 and 19 weeks of age. It can be stated that low-intensity feeding up to slaughtering weight causes backwardness in rear cannon length and this backwardness remains also after the 15th week, which is well over the optimal slaughtering age. Based on the present data, the 70% restricted feeding cannot be recommended either for the future breeding bucks or for broiler males reared for slaughter. To determine the major chemical components of the body, rabbits were euthanised. Original dry matter and crude fat content of the body significantly (P < 0.05) decreased under restricted feeding (41.42%; 32.48% and 16.73%; 7.35%) while the percentage of protein within the dry matter increased (49.6%; 65.0%) and fat decreased (40.17%; 22.1%) significantly. Libido unambiguously decreases as a consequence of feed deprivation. The most conspicuous difference was found in the level of blood testosterone. Although a few RS bucks produced semen but only much later than the rabbits fed ad libitum. On the other hand, there was no difference in the motility of spermatozoa and ejaculate volume in comparison with AL animals. There was no relationship between the body fat content and the reproductive status of bucks in the present trial.     

Echocardiographic characterisation of cardiac dilatation induced by volume overload in a canine experimental model

The aim of this study was to characterise the development of cardiac dilatation induced by chronic volume overload in 12 dogs. Bilateral arteriovenous fistulas were created between the common femoral arteries and the femoral veins, and the animals were serially studied with transthoracic echocardiography for a period of 12 weeks after the operation. Compared to the measurements obtained before the operation (week 0), the data obtained at the end of the experimental period showed significantly increased left ventricular volume measured by 2D-echocardiography (from 25.1 cm3 to 43.8 cm3, p < 0.0001 in diastole and from 8.6 cm3 to 16.8 cm3, p < 0.001 in systole), and left ventricular diameter measured by M-mode echocardiography (from 26.2 mm to 32.6 mm, p < 0.0001 in diastole and from 17.1 mm to 20.6 mm, p < 0.001 in systole). The size of the left atrium also increased in transversal (from 29.2 mm to 33.6 mm, p < 0.01) but not in longitudinal diameter. In spite of a significant cardiac chamber dilatation over the 12-week period, left ventricular systolic functional variables (fractional shortening, FS % and ejection fraction, EF %), and also the left ventricular systolic and diastolic free wall thickness remained unchanged. In this study we demonstrated that chronic progressive volume overload resulted in gradual dilatation of the canine heart, and that the pathological process can be monitored successfully by serial echocardiography. We found that left atrial dilatation occurred without the development of mitral regurgitation and/or detectable left ventricular dysfunction.     

Ascorbate dynamics in embryos and larvae of sea bass and sea bream, originating from broodstocks fed supplements of ascorbic acid

The transfer of L-ascorbic acid (AA) from broodstock to the fertilised eggs and it's dynamics in embryos and fasting larvae, has been studied in sea bass (Dicentrarchus labrax L.) and sea bream (Sparus aurata L.). Two types of diets were fed to the broodstocks: one containing sufficient ascorbate for normal growth and the other with an extra addition of a very high dose (2,000 mg/kg feed) of ethyl-cellulose-coated L-ascorbic acid.The concentration of AA and total ascorbate (L-ascorbic acid plus dehydroascorbic acid) was detected through several embryo and larval development stages, including larvae just before feeding. In sea bass and sea bream, the mean (SD) concentration of total ascorbate in fertilised eggs originating from broodstock fed AA supplemented diet, was 218.5 (17.7) and 122.4 (5.1) g/g wet weight respectively. This was significantly higher (P < 0.01) than the unsupplemented groups, which contained only 155.9 (6.9) and 103.9 (3.5) g/g wet weight respectively. A diet with a vitamin C content adequate for normal growth, may not be sufficient for broodstock when the goal is transfer of TAA to embryos. © Rapid Science Ltd. 1998