In vitro inhibition of aeromonas hydrophila growth by ethanolic extracts obtained from leaves of various ficus species (Moraceae)

рыбы, болезни рыб, инфекционные болезни рыб, аэромоноз, аэромонады, ингибирование роста, питательные среды, этанольные экстракты, фикус, листь

Water as a source of macronutrients and micronutrients for fish with special emphasis on the nutritional requirements of two fish species: the common carp (Cyprinus carpio) and the rainbow trout (Oncorhynchus mykiss)

In contrast to terrestrial animals, fish can ingest minerals from food or directly from water. Although micro- and macro-elements are needed in small quantities, they play a key role in many metabolic processes. Trace mineral and macromineral deficiencies may go unnoticed due to an absence of clear clinical symptoms in fish. Absorption processes are determined by various factors, mostly mineral concentrations in water but also other water parameters. The required dietary supplementation of macronutrients and micronutrients is very difficult to determine, and the amount of nutrients absorbed by fish from water is equally difficult to measure. Interactions between elements should also be taken into consideration. Many authors emphasize that phosphates may reduce the absorption of most micronutrients. Also, the current parameters of the water can affect the bioavailability. Some elements such as calcium, chlorine and sodium can be absorbed from ambient water in a quantity sufficient to meet the demand for this element. Other elements, however, require supplementation in a diet. For example, studies indicate the need for supplementation of phosphorus, zinc, copper and manganese. Most research concentrates on feedstuff as a source of micro- and macronutrients. Meanwhile, information concerning bioavailability of minerals directly from water is scarce. The aim of this study was to analyse literature from a different perspective, and concentrate on water as a source of minerals in fish nutrition. Measurements of water parameters such as temperature, pH, nitrate and nitrite levels and the amount of dissolved oxygen are a regular component of environmental control in fish farming. Determination of micro- and macro-element levels, however, remains uncommon in aquaculture. Measurements of these parameters could suggest which elements need to be supplemented and which are found in water in amounts that satisfy the needs of the fish

Application of DNA vaccines in fish

Vaccination is a most cost-effective way of controlling infectious diseases in fish. However, some vaccination techniques when applied to hatchery conditions are not as effective as we expect them to be. Modern molecular biology techniques offer a number of opportunities for improving existing bacterial or viral vaccines or creating new ones. One of the most promising trends in vaccinology is development of DNA vaccination. DNA vaccines are based on the gene encoding specific antigen, which is expressed in vaccinated organism and induces the host immune system. DNA vaccines, compared to conventional vaccines, have many advantages including ability to trigger wider immune response, bigger stability and possibility of large-scale production. To date, there are several reports indicating effectiveness of DNA vaccines used against fish pathogens

Aktywność antybakteryjna etanolowych ekstraktów uzyskanych z liści różnych gatunków fikusów w stosunku do patogenu ryb, Citrobacter freundii

The diversity of culturable bacteria inhabiting the Baltic sea surface waters was more divergent at a polluted location than at clean areas. The most important members of the family Enterobacteriaceae that are pathogenic to fish are the enteric redmouth disease agent, Yersinia ruckeri and two species of Edwardsiella, E. tarda and E. ictaluri, Serratia, Proteus and Citrobacter have all been implicated as potential fish pathogens. The use of pharmaceutical substances is rather limited in fish compared to mammalian therapeutics. Medicinal herbs play an alternative role to antibiotic therapy in aquaculture. Ficus species (Moraceae) leaves possess great medicinal potential for the therapy of bacterial and fungal infections and may be used as a natural antiseptic and antimicrobial agent in veterinary. Accordingly, these products can be used in aquaculture as therapeutic and prophylactic agents against fish pathogens, with antimicrobial properties. Present study aimed to investigate the in vitro antimicrobial activity of the ethanolic leaf extracts of various Ficus species against fish pathogen, Citrobacter freundii. The antimicrobial susceptibility testing was done on Muller-Hinton agar by disc diffusion method (Kirby-Bauer disk diffusion susceptibility test protocol). Our results demonstrate that various species of Ficus had mild antibacterial in vitro activity against C. freundii isolated locally from infected eel (Anguilla anguilla L.). The results proved that the extracts from F. drupacea, F. septica, F. deltoidea as well as F. hispida, F. mucuso, F. pumila, F. craterostoma exhibit a favorable antibacterial activity against C. freundii. These validate scientifically their inhibitory capacity attributed by their common use in folk medicine and contribute towards the development of new treatment options in aquaculture based on natural products. The chemical analysis of the aforementioned plant extracts should be performed to determinate their chemical composition and identify the exact phytocompounds responsible for antimicrobial activity against C. freundii. In addition, they should be subjected to pharmacological evaluations with the aim of assessing their in vivo efficacy, toxicity, potential adverse effects, interactions and contraindications. Given the increasing rate of resistance development in bacterial pathogens in aquaculture environments, medicinal plants with antibacterial properties are very important as natural resources for new active compounds.Zioła lecznicze odgrywają rolę alternatywnej terapii antybiotykowej w akwakulturze. Substancje biologicznie aktywne pozyskiwane z roślin mają równie dobre, a nawet bardziej skuteczne działanie w porównaniu z tradycyjnymi lekami syntetycznymi, w dodatku nie wywołują oporności drobnoustrojów, która często pojawia się podczas antybiotykoterapii. W różnych regionach świata tradycyjnie w celach medycznych stosowane są różne gatunki roślin tropikalnych, m.in. fikusy (Moraceae). Głównym celem badań była ocena wrażliwości patogenu ryb Citrobacter freundii na etanolowe ekstrakty z liści wybranych gatunków fikusów. Przeciwbakteryjne działanie ekstraktów oceniano in vitro, stosując metodę dyfuzyjnokrążkową. Nasze wyniki wskazują, że różne gatunki Ficus wykazują in vitro łagodne działanie przeciwbakteryjne przeciwko C. freundii izolowanego lokalnie z zainfekowanego węgorza (Anguilla anguilla L.). Przeprowadzone badania wykazały, że największą aktywność przeciwbakteryjną wobec szczepu C. freundii wykazały etanolowe wyciągi uzyskane z liści gatunków fikusów: F. drupacea, F. septica, F. deltoidea, F. hispida, F. mucuso, F. pumila, F. craterostoma. Wstępne badania screeningowe wskazują zatem, że wyciągi z liści niektórych gatunków fikusów o właściwościach antybakteryjnych mogą stanowić alternatywne środki terapeutyczne przeciwko infekcjom bakteryjnym w akwakulturze. Produkty te mogą być stosowane jako środki terapeutyczne i profilaktyczne, niemniej jednak powinni jeszcze zostać przeprowadzone bardzo intensywne badania dotyczące ich właściwości przeciwbakteryjnych

Selected Parameters of Nutritional and Pro-Health Value in the Common Carp (Cyprinus carpio L.) Muscle Tissue

This study analysed the effect of the type of production on the nutritional and health value of common carp muscle tissue, especially lipid-related indexes. The muscle tissue of common carps originating from three types of fish farms with different technological levels (i.e., intensive, low-intensive, and semiextensive) was studied. The type of production technology, especially the intensive breeding technique, has been shown to have a significant effect on dry weight, total protein, and total fat content in the common carp muscle tissue under study. The muscles of fish originating from these farms were characterised by the highest values of the mentioned indicators, which amounted to 24.6%, 18.74%, and 1.58%, respectively, for dry matter, protein content, and total fat content. The type of feed used in intensive, low-intensive, and semiextensive common carp breeding has been proven to have a highly significant effect on the fatty acid profile. As regards unsaturated fatty acids, monounsaturated fatty acids were dominant in all cases. The muscle tissue of fish cultured in farms with a semiextensive technological level was characterised by the highest content of unsaturated fatty acids. Moreover, the ratio of polyunsaturated fatty acids to saturated fatty acids was, in this case, the most favourable. Dietary indices of atherogenicity (AI) and thrombogenicity (TI) were studied as well. In all analysed cases, the values of these indices were very favourable and several times lower than for other animal fats