Abstract. The purpose of the study was to obtain preliminary data on the effect of dietary protein on the growth of the thick-lipped grey mullet (Chelon labrosus) juveniles reared in net sea-cages. The juveniles (6.2 ± 0.61 g) were obtained from the wild and were stocked into net sea-cages at a stocking rate of 100 juveniles per cubic meter and fed with experimental diets including 25, 30, or 35% crude protein for 87 days. The highest mean weight and specific growth rate (SGR) were 39.5 g and 2.13% day -1 , respectively, at protein levels of 30%. The diet also resulted in the most efficient feed conversion ratio of 1.61.
Ethyl acetate extracts from 70 strains of marine-derived fungi, isolated from sponges, were screened against four fish pathogenic bacteria. Sixteen of the fungal isolates exhibited antibacterial activity against at least one pathogen. All the strains showed antibacterial activity against Vagococcus salmoninarum. Three isolates showed strong inhibition against all test pathogens and they may therefore be remarkable as a broadspectrum antimicrobial. Nine isolates showed antibacterial activity against Lactococcus garvieae, six were against Vibrio anguillarum, and four isolates inhibited the growth of Yersinia ruckeri. Co-culture of the fungus with the mix of the pathogen bacteria led to the induction of bioactivity in two isolates. Aspergillus iizukae produced strong and broadspectrum antibacterial activity against pathogens with minimum inhibitory concentrations of 0.8-406 mg mL À1 . The screening results confirmed the sponge associated fungi as a source of environmentally friendly antimicrobials that may contribute the sustainable development of aquaculture. In addition, co-culture technique is a promising strategy to increase antimicrobial activity that can stimulate the production of novel compounds, and increases the antimicrobial activities of marine derived fungi.
Fast, cheap and simple HPLC methods have been gaining importance in the field of antibiotic residue analysis especially in the context of environmentally friendly and sustainable aquaculture. An effective column-switching technique for HPLC using online extraction column was developed to eliminate the time consuming pretreatment procedures and to facilitate the high throughput analysis of sulfadiazine in fish plasma and muscle as well as in water samples. The standard curves for the determination of sulfadiazine residues from biological matrices and water have good linearity (r 2 > 0.996). The average recovery ranged from 92.2 to 118% with the relative standard deviations of 0.3-9.3%. Limits of detection were determined as 5.7 mg L À1 for water, 8.1 mg L À1 for plasma and 9.6 mg kg À1 for muscle, while limits of quantification were 18.9 mg L À1 for water, 26.9 mg L À1 for plasma and 31.9 mg kg À1 for muscle, respectively. Intra-and inter-day precisions were 0.3-9.3 and 0.4-6.7%, respectively. With the retention time of 12 min and total analysis time less than half an hour, this method provides an effective online extraction process and good sensitivity in liquid chromatography, and can be applied for the determination of residual sulfadiazine in water, fish plasma and muscle at lower than maximum residue level of 100 mg kg À1 fish.
The objective of the study was to investigate the effect of high temperature on sex ratios of early stage rainbow trout (Onchorhynchus mykiss) in commercially farmed populations from distinct hatcheries. Almost 32500 larvae from five different farms were used in experiments as thermal groups and their corresponding controls. Temperature treatments were conducted at 17.5°C for 40 days starting at day 10 after hatching. In only one population, the sex ratio was skewed significantly in favor of females in thermally treated group (67.5%), when compared to control group (52.1%) and there was deviation from the expected 1:1 ratio. In the treatment group the females grew 8.3% more than males. However there was no repeatiblity and any skewness in sex ratio of progenies from photoperiod induced spawning. Survival rates were not affected by the thermal treatments. The results showed that the increasing of femaleness of farmed stocks is possible by thermal treatment in rainbow trout and which depends on percentage of thermosensitive individuals rather than genetic background of population.
As from January 2010 The Israeli Journal of Aquaculture-Bamidgeh (IJA) will be published exclusively as an on-line Open Access (OA) quarterly accessible by all AquacultureHub (http://www.aquaculturehub.org) members and registered individuals and institutions. Please visit our website (http://siamb.org.il) for free registration form, further information and instructions. This transformation from a subscription printed version to an on-line OA journal, aims at supporting the concept that scientific peer-reviewed publications should be made available to all, including those with limited resources. The OA IJA does not enforce author or subscription fees and will endeavor to obtain alternative sources of income to support this policy for as long as possible.
Natural products and their derivate compounds have been underlined of new drugs along centuries. The compounds which are named secondary metabolites are produced by organisms against to predators in nature. Initially various terrestrial plants were investigated for achieve valuable drugs leads. Recent years, pharmaceutical research into natural products has declined on the grounds of isolation of similar metabolites and high-throughput screening of synthetic products. On the other hand, resistant strains of pathogens are increasingly prevalent in hospitals and in the community. New diseases is pressing need to develop new drugs, but progress in developing them has been slow. Therefore, particularly the emergence of health issues suggests that the discovery of new scaffolds such as cytarabine (Ara-c), vidarabine (Vira-A1) and salinosporamide A should be a priority. New technologies provide smart screening methods to discover new natural drugs from untapped biological resources. Especially advances in rapid genetic sequencing, coupled with manipulation of biosynthetic pathways, may provide a vast resource potential for the discovery of new pharmaceuticals. These technological advances encourage renewed interest in natural products and the natural drug discovery. In this review, we focused on marine metabolites also bring the marine chemical diversity up to its therapeutic potential, while it is offering an extremely rich resource for novel compounds. Özet: Yüzlerce yıl boyunca yeni ilaçların temelini doğal ürünler ve bunlardan elde edilmiş bileşikler oluşturmuştur. Sekonder metabolitler olarak adlandırılan bu bileşikler doğada organizmalar tarafından düşmanlarından korunma amacıyla üretilmektedir. Son yıllarda benzer metabolitlerin izole edilmesi ve ayrıca sentetik üretimin yüksek tarama olanakları sunmasının da etkisiyle doğal ürünlere yönelik ilaç araştırmaları oldukça azalmıştır. Bununla birlikte çeşitli patojenlerin hastanelerde ve toplumda dirençli suşlar geliştirmesi giderek daha yaygınlaşmaktadır. Yeni hastalıklar yeni ilaçların keşfini zorunlu hale getirirken, bütün bunlarla mücadele için gerekli olan yeni antimikrobiyallerin geliştirilmesinde ilerleme yavaş olmaktadır. Bu nedenle özellikle sağlık alanındaki bu ve benzeri problemler cytarabine (Ara-c), vidarabine (Vira-A1) ve salinosporamide A gibi yeni küçük molekül yapılı bileşiklerinin keşfinde öncelik olması gerektiğini göstermektedir. Yeni teknolojiler henüz araştırılmamış biyolojik kaynakların doğal ilaç keşiflerinde kullanılmasını sağlayan oldukça etkili akıllı tarama yöntemleri sunmaktadır. Özellikle hızlı genetik sekanslama ile birlikte biyosentetik yolakların manipulasyonundaki ilerlemeler yeni ilaçların keşfi için büyük bir kaynak sunabilecek potansiyele sahiptir. Teknolojideki bu ilerlemeler yeni ilaç keşfine ve doğal ürünlere olan ilginin tekrar artmasını da sağlamıştır. Bu derlemede, yeni bileşikler için son derece zengin bir kaynak sunarken aynı zamanda tedavi edici potansiyeli olabilecek denizel kimyasal çeşitliliği bir araya getiren denize...
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