Effects of supplemental dietary l‐carnitine and ractopamine on the performance of juvenile rainbow trout,Oncorhynchus mykiss

This study was carried out to investigate a possible protein‐sparing action of l ‐carnitine and ractopamine in rainbow trout, Oncorhynchus mykiss. An 8‐week feeding trial was carried out to evaluate the effects of supplementation of three levels of l ‐carnitine (0, 1 and 2 g kg^?1) and two levels of ractopamine (0 and 10 mg kg^?1) on growth performance, fillet fatty acid compositions and blood biochemical parameters in a 3 × 2 factorial experimental design. Ractopamine and 1 g kg^?1 carnitine improved the specific growth rate (1.03% and 1.05% day^?1), feed conversion ratio (FCR, 1.3 and 1.29), protein efficiency ratio (PER, 1.88 and 1.85) of fish and crude protein (73.5 and 73.8) content of fish fillet. l ‐carnitine and ractopamine increased the levels of albumin, total protein and globulin in the serum of fish. Apart from eicosapentaenoic acid and docosahexaenoic acid, other fatty acids of fish fillet were increased by ractopamine, while total saturated fatty acids were almost intact. However, the total n‐3 poly unsaturated fatty acids were reduced by l ‐carnitine supplementation (P<0.05). The present study showed that 1 g kg^?1l ‐carnitine and 10 mg kg^?1 ractopamine each can improve the performance of rainbow trout and their combination in diet could enhance the protein level and change the fatty acids profile in fillet muscle.     

Maltoporin (LamB protein) contributes to the virulence and adhesion of Aeromonas veronii TH0426

Aeromonas veronii is one of the main pathogens causing freshwater fish sepsis and ulcer syndrome. More and more cases have shown that it has become an important zoonotic and aquatic agent. In this study, a A. veronii TH0426 mutant strain (ΔlamB) with an in‐frame deletion removed nucleotides 10–1,296 of the lamB gene was firstly constructed to investigate its functions. The results showed that the LD₅₀ value of the mutant ΔlamB to zebrafish and mice was 13.7‐fold and 5.6‐fold higher than those of the wild‐type strain, respectively. The toxicity of wild‐type strain to EPC cells was 2.1‐fold and threefold higher than those of ?lamB when infected for 1 and 2 hr. Furthermore, the ability of biofilm formation and the adhesion and invasion to EPC cells of ?lamB significantly decreased for 5.6‐fold and 1.8‐fold separately. In addition, motility detection result indicated that ?lamB lost the swimming ability. The results of flagellar staining and TEM demonstrated that the flagella of ?lamB were shed. In general, the deletion of lamB gene caused a significant decrease in the virulence and adhesion of A. veronii TH0426, and it can be known that the lamB gene of A. veronii plays a crucial role in the pathogenesis.     

Impact of Wall Material on the Physiochemical Properties and Oxidative Stability of Microencapsulated Spray Dried Silver Carp Oil

This study aimed to microencapsulate silver carp oil by spray drying with different combinations of wall materials (gum Arabic, modified starch Hi-cap, maltodextrin, and inulin) and evaluate the effects of these combinations on the physiochemical and oxidative stability of the microcapsules. Feed emulsions were also investigated prior to spray drying. Modified starch-based microcapsules had higher encapsulation efficiency (91.22-92.78%) and yield (87.41-92.15%), excellent solubility (91.85-93.67%), good particle size (301.20-407.73 d.nm), color, and powder morphology. The presence of inulin reduced agglomeration in powders. All the powders exhibited good protection against lipid oxidation during 2 months of storage, whereas the modified starch and inulin combination provided the best stability.     

Hepatotoxic responses of 4-nonylphenol on African catfish (<Emphasis Type="Italic">Clarias gariepinus</Emphasis>): antixoidant and histochemical biomarkers

4-Nonylphenol (NP) toxicity in fish attracts much attention due to its ability in targeting several organs; however, the researches regarding its potential hepatotoxicity are conflicting and still require further investigation. Therefore, the objective of this study is to focus on this issue from the histophysiological point of view using NP intoxicated African catfish (Clarias gariepinus) as a model of hepatotoxicity. Twelve adult fish (6 per group) were divided into two groups; the first was considered as a control and the second was exposed to NP dissolved in water at a dose of 0.1 mg/kg BW for 3 weeks. A significant reduction in the hepatic alanine aminotransferase, aspartate aminotransferase, and lactate dehydrogenase levels was observed in NP-exposed fish. Concerning the oxidant/antioxidant balance, a significant depletion in superoxide dismutase, catalase, and glutathione peroxidase was found along with a significant elevation in total peroxide and malondialdhyde. The histopathological examination of the hepatic tissues revealed that NP had marked hepatotoxic effects including hepatitis, centrilobular and focal hydropic and fatty degeneration, fatty change (steatosis), hepatic coagulative necrosis, and nuclear alterations in addition to apoptosis of hepatocytes and necrosis of endothelial cells. Depletion of the glycogen and increased in pigments (lipofuscin and hemosiderin) content in the hepatocytes were also recorded. Hemosiderosis and proliferation of the connective tissue around the blood vessels and branches of bile ducts and in the portal areas were also observed. In light of these findings, it was concluded that NP has a well-defined hepatotoxic impact paving the road towards other studies to investigate other detrimental cyto-physiological influences of this aquatic pollutant.     

Comparative Performance of Copper and Silver Coated Stretchable Fabrics

The present work described the development of multifunctional, electrically conductive and durable fabrics by coating of silver and copper particles using a dipping-drying method. The particles were directly grown on fabric structure to form electrically conductive fibers. Particles were found to fill the spaces between the microfibers, and were stacked together to form networks with high electrical conductivity. The electrically conductive fabrics showed low resistance with high stretch ability. The utility of conductive fabrics was analyzed for electromagnetic shielding ability over frequency range of 30 MHz to 1.5 GHz. The EMI shielding was found to increase with increase in concentration of copper and silver particles. Furthermore, the heating performance of the copper and silver coated fabric was studied through measuring the change in temperature at the surface of the fabric while applying a voltage difference across the fabric. The maximum temperature (119°C for silver and 112°C for copper) were obtained when the applied voltage was 10 V. Moreover, the role of deposited particles on antibacterial properties was examined against pathogenic bacteria such as Staphylococcus aureus and Escherichia coli. At the end, the durability of coated fabrics was examined against several washing cycles. The fabrics showed good retention of the particles, proved by small loss in the conductivity of the material after washing.     

三个农林复合树种幼苗对施加磷肥的响应:生长和生节能力(英文)

对苗床培养的楹树、雨豆树和水黄皮袋装幼苗(6月龄)施以80kg·hm-2的磷酸盐,通过比较不同收获间隔期幼苗生长和生节情况,研究了施加磷肥对三个农林复合树种幼苗生长和生节作用。研究表明,施加磷肥显著促进雨豆树和水黄皮幼苗生长,但并未促进楹树幼苗生长。此外,施加磷肥还会显著增加楹树、雨豆树幼苗生节数和节大小,但对水黄皮幼苗作用较小,而且高收割间隔期会降低水黄皮生节表现。     

Subereamolline A as a Potent Breast Cancer Migration, Invasion and Proliferation Inhibitor and Bioactive Dibrominated Alkaloids from the Red Sea Sponge Pseudoceratina arabica

A new collection of several Red Sea sponges was investigated for the discovery of potential breast cancer migration inhibitors. Extracts of the Verongid sponges Pseudoceratina arabica and Suberea mollis were selected. Bioassay-directed fractionation of both sponges, using the wound-healing assay, resulted into the isolation of several new and known brominated alkaloids. Active fractions of the sponge Pseudoceratina arabica afforded five new alkaloids, ceratinines A–E (2–6), together with the known alkaloids moloka’iamine (1), hydroxymoloka’iamine (7) and moloka’iakitamide (8). The active fraction of the sponge Suberea mollis afforded the three known alkaloids subereamolline A (9), aerothionin (10) and homoaerothionin (11). Ceratinine B (3) possesses an unprecedented 5,7-dibrominated dihydroindole moiety with an epoxy ring on the side chain of a fully substituted aromatic moiety. Ceratinines D (5) and E (6) possess a terminal formamide moiety at the ethylamine side chain. Subereamolline A (9) potently inhibited the migration and invasion of the highly metastatic human breast cancer cells MDA-MB-231 at the nanomolar doses. Subereamolline A and related brominated alkaloids are novel scaffolds appropriate for further future use for the control of metastatic breast cancer.     

Actions of quinolizidine alkaloids on Periplaneta americana nicotinic acetylcholine receptors

BACKGROUND: Botanical insecticides do not play a major role as crop protectants, but they are beneficial in some applications. The authors investigated the actions of naturally occurring alkaloids on insect nicotinic acetylcholine (ACh) receptors (nAChRs) by evaluating their abilities to inhibit specific binding of [³H]imidacloprid (IMI) to nerve‐cord membranes from Periplaneta americana L. Two alkaloids were also tested for their actions on nAChRs expressed by cockroach neurons using patch‐clamp electrophysiology. RESULTS: Four natural quinolizidine alkaloids (matrine, sophocarpine, cytisine and aloperine) exhibited more than 50% inhibition of [³H]IMI binding at 10 µM , although other compounds were found to have no or low inhibitory activity. The rank order of potency based on concentration–inhibition curves was cytisine > sophocarpine ≥ aloperine ≥ matrine. Patch‐clamp analysis indicated that sophocarpine and aloperine were not agonists of nAChRs expressed in P. americana neurons, yet, at 10 µM , aloperine, but not sophocarpine, suppressed ACh‐induced inward currents significantly. CONCLUSION: Three of the four natural alkaloids tested possess structural moieties that are necessary for interaction with P. americana nAChRs. Aloperine, which possesses a unique structure and showed a distinctive dose–response curve, was found to act as an antagonist. Appropriate modifications of these alkaloids might result in novel insecticidal nAChR ligands. Copyright © 2008 Society of Chemical Industry     

Valuation of gamma irradiation for proficient production of parasitoids (Hymenoptera: Chalcididae & Eucoilidae) in the management of the peach fruit-fly,Bactrocera zonata (Saunders)

Recognizing the potential significance of using nuclear techniques in biological control, investigations were conducted on the rearing of parasitoids of the peach fruit-fly, Bactrocera zonata (Saunders) (Diptera: Tephritidae) to lead to a greater flexibility in the use of irradiated hosts. For improving mass production of the biological control agents, the use of irradiated fruit-fly larvae at the dose of 15 Gy proved useful for enhancing the parasitism and adult emergence of the larval parasitoid, Trybliographa daci (Weld) (Hymenoptera: Eucoilidae) due to no negative repercussions on parasitoid development. Overall, parasitism by the parasitoid increased with age of the host larvae; however, significantly higher parasitism occurred on 4 d-old irradiated larvae of B. zonata compared to those aged 5 d. The female parasitoids preferred the irradiated larvae, and significantly higher numbers of larvae were parasitized compared with non-irradiated larvae. There was no significant difference in adult parasitoid emergence with respect to the sex of the host. A radiation level of 80 Gy was the best dose for rearing of the pupal parasitoid, Dirhinus giffardii (Silvestri) (Hymenoptera: Chalcididae) owing to broad tolerances in the use of irradiation for the rearing of fruit-fly's parasitoids. Percentage parasitism by D. giffardii varied with host pupal age, and the preference of the female parasitoid was lower on 48 h old host pharate pupae due to optimum size and mass of host. Present findings further revealed that the 24 h old host pupae of B. zonata were relatively more suitable for the maximum parasitism and progeny production of D. giffardii. Parasitisms by D. giffardii and T. daci were significantly higher on B. zonata host when parasitoids were released at a density of 3000 individuals per acre (7500 per hectares) than the other release rates of parasitoids for the management of fruit-flies in mango orchards. The implementation of these findings ought to help improve the mass production of parasitoids and the effectiveness of releases of biocontrol agents for control of B. zonata in mango plantations.