Exophiala angulospora infection in hatchery‐reared lumpfish (Cyclopterus lumpus) broodstock

Samples from moribund lumpfish were collected in a marine hatchery in Scotland in 2015. Black nodules were noted on the skin, and gills and fungal hyphae were extensively distributed in musculature and internal organs. Multifocal chronic inflammatory lesions displaced structures in all affected organs. Mortalities commenced on completion of spawning in May and were evenly distributed over the second year in the temperature range 11–15°C. The main systemic infection causing agent was initially identified based on morphological characteristics as an Exophiala species. Ribosomal DNA (rDNA) ITS regions of the isolates were subsequently sequenced confirming the isolates belonged to Exophiala genus. All isolates fell in a single phylogenetic cluster, which is represented by Exophiala angulospora. Fish were treated with either formalin or Bronopol or a combination of both, but there was no effect on the pattern or numbers of mortalities. Isolates were also tested against three different concentrations of Latrunculin A, Amphotericin B and Itraconazole with no success. It is of utmost importance to increase the knowledge on pathogen–host interactions to successfully develop sustainable control methods.     

Ungewöhnliche Schäden durch Holzwespen (Siricidae,Hym.)

Ohne Zusammenfassung     

Versuche zur Bekämpfung der Hausratten mit Streupulver

Zusammenfassung 1. Das Streupulver (Delicia-Ratron-Streupulver) hat sich bis jetzt als ein recht brauchbares Hausrattenmittel gezeigt. wenn es in Verbindung mit geeigneten Ködern den Hausratten einverleibt werden kann.Eine Pulver- oder Köderscheu besteht nicht, dagegen kann von einer anlockenden Wirkung gesprochen werden. Die wiederholte Annahme anderer Giftköder durch Hausratten ist bekannt, diese Köder finden noch bessere Annahme. Bei der Auslage von Brotscheiben kann die unangenehme Verschmutzung der Auslegestelle durch das Pulver durch ein loses Einwickeln der Scheiben in Zeitungspapier verhütet werden.2. Der Zeitpunkt für die Anlage von Schüttungen war günstig. Von Anfang Oktober bis Ende März des nächsten Jahres haben die Hausratten die Winterquartiere bezogen. Ein gewisser, aber nicht durchschlagender Erfolg kann diesen Schüttungen zugesprochen werden, doch steht der Erfolg in keinem Verhältnis zum Aufwand an Material und Arbeitszeit.3. Die Ursache des angeblich gesteigerten Lärmes in den Einschüben der Zimmerdecken bedarf noch der Klärung.4. Das Streupulver war für mich ein neues Rattenmittel, dessen Anwendung und Wirkungsbreite ich durch eigene Versuche kennen lernen wollte. Eine solche Versuchsreihe, die Anlage von Schüttungen, die Suche nach geeignetem Ködermaterial konnte recht gut, im Zuge der pausenlosen Schädlingsbekämpfung, die hier eingeführt ist, erfolgen.     

261 Bisamratten im Aalfang

Ohne Zusammenfassung     

Monitoring the gravitational reflex of the ectoparasitic mite Varroa destructor: A novel bioassay for assessing toxic effects of acaricides

We investigated the effect of several acaricides on Varroa destructor by monitoring the rhythmic expansion of the sternum, followed by a strong flexion of the legs, initiated when the mite was placed in a dorsal side-down position, as an indication of a mite’s vitality. The pulses generated by the force of the rhythmic expansions had an average duration of 3.11 s, force (amplitude) of 73 μN, and frequency of 0.228 Hz. These parameters remained constant for the first 10 h of recording, whilst significant changes occurred after 15 h. The rhythmic sternal expansion is an indication of a Varroa mite’s gravitational reflex, or attempt to return to an upright position; this reflex is observed in all invertebrates and vertebrates. The sternal expansion can be recorded for over 20 h, or for as long as the Varroa mite remains alive, and the expansion stops as soon as the mite is placed in a normal, upright position. Proper function of the chain of proprioceptors, interneurons, motorneurons, neuromuscular junctions, and muscles of Varroa is required for the initiation and maintenance of such a behavioural motor pattern. Any deleterious effect of synthetic chemicals or natural compounds (acaricides) may have a direct effect on one or more of these links, thereby disturbing or even inhibiting the reflex. Topical application of 1.81 × 10⁻³ mg/mite of amitraz completely inhibited the gravitational reflex within 60–70 min for all mites tested. The volatile acaricides formic acid (13.83 mg), thymol crystals (250 mg), and Apiguard® (1000 mg) eliminated the reflex within 10–35 min. This bioassay, based on the gravitational reflex, could be a useful tool for accurate assessment of the acaricidal action of numerous compounds under laboratory conditions, saving money and time necessary to conduct field trials.     

Stepwise function of natural growth for Scylla serrata in East Africa: a valuable tool for assessing growth of mud crabs in aquaculture

Predicting growth is critical in aquaculture, but models of growth are largely missing for mud crab species. Here, we present the first model of natural growth in juvenile and adult mud crabs Scylla serrata from East Africa using a stepwise growth function based on data on intermoult periods and growth at moult from field mark‐recapture, pond and laboratory studies. The results showed a sigmoid growth pattern in carapace width and suggest that S. serrata in East Africa will reach 300 g and sexual maturity ~9.9 months after settlement, and a commercial size of 500 g after 12.4 months. Analyses of the literature identified several issues with the common praxis to compare standard growth measures between aquaculture studies with different initial size or growing periods. Using the new growth function to estimate the proportional difference between modelled and obtained growth as an alternative method, we show that growth rates of S. serrata cultured in cage systems, which are dominant in East Africa, was <40% of the estimated natural growth and growth obtained in pond systems. The analysis also indicated that growth rates of S. serrata in Southeast Asia was over 50% higher compared with similar culture systems in East Africa, and that different species of mud crabs had large differences in growth rates. This study shows that growth in the present mud crab aquaculture systems in East Africa is below their expected potential. Further work is needed to identify the factors behind this observation.     

Age‐Related Pregnancy Results and Further Examination of Bitches after Aglepristone Treatment of Pyometra

The cystic endometrial hyperplasia and pyometra complex is one of the most common uterine diseases in bitches. The appearance of pharmacological preparations containing anti‐progestagens created new possibilities for pyometra treatment. The aim of this study was to evaluate the curative effect of the anti‐progestagen aglepristone treatment of pyometra in bitches of different ages. Twenty four bitches of different breeds, aged from 0.8 to 9.5 years (21–48 kg) exhibiting clinical pyometra symptoms (two groups – I ≤ 5 years, n = 14 and II >5 years, n = 10) were evaluated. Information about the general reproductive health was collected up to 54 months after anti‐progestagen treatment. Remission of clinical symptoms and return of blood chemistry results and total leucocyte count to referential values were achieved in all cases within 14 days of treatment. Bitches were naturally mated at the first, and when unsuccessful, the second oestrus after treatment. In group I, no recurrence of pyometra symptoms was observed during following cycle(s). Eight bitches (57.1%) had a full‐term pregnancy and the number of newborn pups ranged from 1 to 12. None of the bitches from the group II became pregnant. In conclusion, the basic indication for conservative pharmacological treatment of pyometra is preserving female fertility and obtaining offspring. The important conditions for successful aglepristone treatment are: the young age (up to 5 years) and the lack of detectible ovarian cysts. It seems necessary to mate bitches in the first or second oestrus after finishing treatment. The efficacy of treatment can be measured by the after‐treatment pregnancy rate.     

Variability in the composition of lupin (Lupinus angustifolius) meals influences their digestible nutrient and energy value when fed to rainbow trout (Oncorhynchus mykiss)

Over a series of seven separate experiments 76 different lupin (Lupinus angustifolius) meals were assessed for their digestible dry matter, protein, amino acid and energy characteristics when fed to rainbow trout. Two reference diets (a common basal diet and a reference lupin meal) were also included in each experiment. Minimal variance in the digestibility parameters of both reference diets was observed among the experiments ensuring that there was a high degree of robustness in the across-experiment evaluations. Using simple and multiple-regression techniques, principal diet and ingredient composition factors affecting diet and ingredient digestibilities and ingredient digestible values were explored within the dataset. Using simple linear regression, it was shown that nitrogen digestibility of the lupin meals was negatively influenced by ingredient lignin content, but positively affected ingredient protein (N × 6.25) content. The energy digestibility of the lupin meals was positively affected by a range of compositional features including protein, sum of amino acids and negatively affected by carbohydrate content. The digestible nutrient and energy content of the meals reflected the combined effects of both ingredient digestibilities and ingredient composition. The digestible nitrogen content of the lupin meals was positively affected by protein (N × 6.25), sum of amino acids and energy content, but was negatively affected by lignin and carbohydrate content. The digestible sum of amino acids was also positively affected by protein, sum of amino acids, but only negatively affected by carbohydrate content, not lignin content. The digestible energy content of the lupin meals was also positively affected by protein, sum of amino acids and their own energy density, but only negatively affected by carbohydrate content. Multiple linear regression modelling supported that together ingredient protein and lignin content were the strongest predictors of digestible protein value, explaining close to 60% of the variability in this parameter. Discrete reassessment of these relationships using non-linear analysis methods provided a stronger interpretation of the ingredient composition effects. In recognition of this, a functional model including terms for ingredient protein and lignin content on the digestible protein value was defined. This study demonstrates that within one raw material type that not only does significant variability in the digestible value of the raw materials exist, but that it is possible to identify compositional features of that raw material that are intrinsically influencing their own digestible value.