Horst Kaiser

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Probiotics for aquaculture are generally only selected by their ability to produce antimicrobial metabolites; however, attachment to intestinal mucus is important in order to remain within the gut of its host. Five candidate probiotics (AP1-AP5), isolated from the clownfish, Amphiprion percula (Lacepéde), were examined for their ability to attach to fish(More)
Owing to the problem of antibiotic resistance and subsequent reluctance of using antibiotics, the use of probiotics in larviculture is becoming increasingly popular. During the early stages of development, manipulation of the larval digestive system seems possible through the addition of probiotics either through the culture water or via the livefood.(More)
The selection of probiotics for aquaculture is usually based on their antagonism towards pathogens. However, other criteria such as growth, attachment to intestinal mucus and production of beneficial compounds should also be considered. We suggest a protocol for the isolation and selection of potential probiotic bacteria based on their in vitro growth(More)
Biodiversity continues to decline at a range of spatial scales and there is an urgent requirement to understand how multiple drivers interact in causing such declines. Further, we require methodologies that can facilitate predictions of the effects of such drivers in the future. Habitat degradation and biological invasions are two of the most important(More)
Enscapsulated third-stage nematode larvae collected from the abdominal cavity of the Trinidadian hylid frog Hyla minuta are referred to the rare anisakid genus Brevimulticaecum. These are the first specimens of Brevimulticaecum from a tropical frog, and their presence may reflect the importance of amphibians as intermediate or paratenic hosts of reptilian(More)
Trichospirura amphibiophila n. sp. (Nematoda) is described from the abdominal cavity (encapsulated near the liver) of the frog Eleutherodactylus martinicensis (Anura: Leptodactylidae) from the island of La Désirade in the French Antilles. It is characterized by the length of its spicules (459 microns and 90 microns) and their length ratio (1:5), by the(More)
A high rate of sibling cannibalism is one of the principal obstacles in the rearing of larvae and juveniles of the African catfish Clarias gariepinus. This paper examines the underlying behavioural components of agonistic behaviour under culture conditions. Ten day old catfish larvae were stocked at 30 larvae l−1 in three tank designs with different surface(More)
The taxonomic status of two southern African coastal pipefish species, Syngnathus temminckii and Syngnathus watermeyeri, was investigated using a combination of morphological and genetic data. Morphological data showed that S. temminckii is distinct from the broadly distributed European pipefish Syngnathus acus, and a molecular phylogeny reconstructed using(More)
Competition for mating opportunities may involve exclusion of intrasexual competitors (direct) or defending resources necessary to attract mates (indirect). Male swordtails (Xiphophorus helleri) engage in direct competition. Moreover in natural populations they defend a home range. This study aimed to test whether this home range defence is a form of food(More)