Therapeutic Intervention with Dietary Chitosan Nanoparticles Alleviates Fish Pathological and Molecular Systemic Inflammatory Responses against Infections

Marine bio-sourced chitosan nanoparticles (CSNP) are antimicrobial and immunomodulatory agents beneficial for fish medicine. Herein, dietary CSNP was investigated for the amelioration of the systemic inflammatory responses of an induced fish model. One hundred and forty-four rainbow trout were assigned to one pathogen-free and non-supplemented group (negative control), and three challenged groups: non-supplemented (positive control), CSNP-preventive, and CSNP-therapeutic. After a feeding experiment extended for 21 days, the organosomatic indices (OSI) and molecular aspects were assessed. After a challenge experiment extended for further 28 days, CSNP-therapeutic intervention was assessed on fish survival and systemic inflammatory responses on pathology, histo-morphology, and molecular aspects. With CSNP administration, OSI nonsignificantly decreased and the relative expression of targeted inflammatory-mediator genes was significantly increased. The CSNP-therapeutic fish showed an RPS of 80% as compared to the positive control group, and CSNP-therapeutic administration retained the highest gene expression augmentation up to 28 days after the challenge. Notably, the splenic reticulin fibers framework of the CSNP-therapeutic group retained the highest integrity among the groups during the infection. After recovery, reticulin fibers density in the CSNP-therapeutic samples was significantly higher than in the negative control group, which indicates high innate immunity. Thus, CSNP showed promising biotherapeutic features enhancing fish resistance against infections.     

The Exploitation of Nematode-Responsive Plant Genes in Novel Nematode Control Methods

The molecular interactions between plants and sedentary nematodes are undergoing intense study, not only for reasons of fundamental research but also for the potential benefits to agriculture. The present technology allows the transformation of an increasing number of crop plants, providing new ways to introduce resistance against plant-parasitic nematodes. The ability of sedentary nematodes to induce specialized feeding sites in plant roots is one of the most fascinating aspects of this host–parasite interaction. Molecular approaches have been initiated to identify and characterize plant genes altered in expression after infection by sedentary nematodes. The results obtained indicate that many genes indeed become up-regulated upon nematode infection. Surprisingly, several so-called constitutive promoters that are normally used to achieve high expression in plant cells are completely ‘silenced’ in the feeding sites within days after nematode infection. Generally, there are two options available for the genetic engineering of nematode resistance: the synthesis of anti-nematode proteins or the localized production of a cytotoxic protein that interferes with the development of feeding cells. Nematode-induced promoters are very useful for the production by plants of sufficiently high levels of anti-nematode proteins at feeding sites. Alternatively, interfering with feeding-cell development is somewhat similar to the hypersensitive response evoked by nematodes in a naturally resistant plant. Here, destruction of specific plant cells can be achieved by the localized expression of a cytotoxin such as barnase, a potent ribonuclease. This approach, however, calls for a highly specific ‘non-leaky’ promoter, which is active only in the feeding cells. Another possibility is to use a two-component system, where the leakiness of the promoter in other tissues is counterbalanced by the constitutive expression of a neutralizing gene.     

Dietary simultaneous replacement of fish meal and fish oil with blends of plant proteins and vegetable oils in yellowfin seabream (Acanthopagrus latus) fry: Growth,digestive enzymes,antioxidant status and skin mucosal immunity

A 56‐day nutritional research was performed to examine the influence of alternative vegetal protein and lipid sources on performance of yellowfin seabream fry (Acanthopagrus latus) (0.5 ± 0.0 g). In this regard, five isoproteic (Ca. 500 g/kg) and isolipidic (Ca. 150 g/kg) diets were formulated in which fish meal (FM) and fish oil (FO) were simultaneously replaced with blends of plant proteins (PP, soybean meal and corn gluten) and vegetal oils (VO, canola and soybean oils) at 20% (SR20), 40% (SR40), 60% (SR40) and 80% (SR80) levels, respectively; meanwhile, a control diet (SR0) was formulated based on FM and FO. Growth and feed utilization were not influenced by experimental diets. The fatty acid profile of fillet drastically altered by dietary treatments. Fish fed with the SR60 and SR80 feeds had higher total protease, trypsin and α‐amylase activities than other treatments. The antioxidant enzyme activities and glutathione content in liver were enhanced in fish fed with the SR40, SR60 and SR80 diets. Skin mucosal immune parameters including total protein content, alkaline phosphatase and alternative complement pathway activities in the control group were relatively lower than the vegetal treatments. According to these results, it is recommended that 410 g/kg of FM and 45 g of FO/kg can be replaced with alternative vegetal sources in diet for A. latus fry.     

Distribution of lipid droplets is an indicator for egg quality in brown trout, Salmo trutta fario

In the eggs of the brown trout, Salmo trutta fario, lipid droplets are clearly visible beneath the oolemma on the surface of the protein yolk. When examining the distribution of lipid vesicles in egg batches of different quality, four categories of lipid vesicle distribution could be distinguished: In the first category, the lipid droplets were evenly distributed throughout the egg. These egg batches had a high quality (percentage of eggs developing to eyed stage embryos: 96.2 ± 5.2). Some lipid droplets had the tendency to coalesce in one pole of the egg in the second category. This coalescing of lipid droplets was accompanied with a reduction in egg quality to about 50% of the first category (% of eyed stage embryos: 40.6 ± 15.2). In the last two categories, the lipid droplets were mostly coalesced in one or two poles of the egg and the egg quality was very low (% of eyed stage embryos: 3.3 ± 2.9 and zero, respectively). In conclusion, examination of lipid droplets distribution, in brown trout, can distinguish between high and low quality eggs in an easy and reliable way.     

Docosahexaenoic Acid Is Naturally Concentrated at the sn-2 Position in Triacylglycerols of the Australian Thraustochytrid Aurantiochytrium sp. Strain TC 20

The Labyrinthulomycetes or Labyrinthulea are a class of protists that produce a network of filaments that enable the cells to glide along and absorb nutrients. One of the main two Labyrinthulea groups is the thraustochytrids, which are becoming an increasingly recognised and commercially used alternate source of long-chain (LC, ≥C₂₀) omega-3 containing oils. This study demonstrates, to our knowledge for the first time, the regiospecificity of the triacylglycerol (TAG) fraction derived from Australian thraustochytrid Aurantiochytrium sp. strain TC 20 obtained using ¹³C nuclear magnetic resonance spectroscopy (¹³C NMR) analysis. The DHA present in the TC 20 TAG fraction was determined to be concentrated in the sn-2 position, with TAG (16:0/22:6/16:0) identified as the main species present. The sn-2 preference is similar to that found in salmon and tuna oil, and differs to seal oil containing largely sn-1,3 LC-PUFA. A higher concentration of sn-2 DHA occurred in the thraustochytrid TC 20 oil compared to that of tuna oil.     

Integrated pest management of Tuta absoluta: practical implementations across different world regions

Journal of Pest Science - The South American tomato pinworm, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), has invaded most Afro-Eurasian countries and is threatening worldwide tomato...     

Pathological and Hormonal Changes in Freshwater Fishes Due to Exposure to Heavy Metals Pollutants

The concentrations of major heavy metals in organs of two cyprinid fish and in water collected from three sections of the Kor River, Iran, were determined using the induction coupled plasma method. The concentrations of heavy metals in tissue of fish from the middle sampling zone were significantly higher (p?<?0.05) than those from the other two sampling zones, whereas no significant differences (p?>?0.05) were detected between the two sexes and species. Estradiol in females and progesterone and testosterone in males from the middle study site were significantly (p?<?0.05) lower than values from the other two sites. Pathological changes in blood cells, liver, and kidneys of fishes were significantly higher in highly polluted areas (middle sampling zone). So heavy metals exposure can effectively decreases estrogenic and androgenic secretion in fish. These results show that industrial activities have polluted the river and that heavy metals exposure can induce pathological changes in fish organs.     

The effectiveness of various acaricides against resistant and susceptible carmine spider mites

Two colonies of the carmine spider mite,Tetranychus cinnabarinus (Boisd.), were raised on beans in the laboratory. One originated from roses in a greenhouse which had received acaricidal treatments, and the other fromViola odorata L. in a garden where no pesticides had been used. Laboratory evaluation indicated that the greenhouse strain was highly resistant to dicofol (Kelthane) and bromopro-pylate (Neoron), moderately resistant to propargite (Omite), and slightly resistant to cyhexatin (Plictran); in the garden strain, there was no resistance to any of these acaricides. On a strain of carmine spider mites which was identified and defined as resistant, several acaricides were evaluated in the laboratory for their contact toxicity to the mite by the slide dip method, and for their contact plus stomach toxicity by exposing the mites to sprayed leaves. Some of these acaricides were later tested in the field on two undetermined populations. Cyhexatin, triazophos (Hostathion), fentrifanil (PP-199) and R-28627 killed more than 90% of the mites by both methods and were effective in the field. NC-13292 was an ovicide only. Proclonol (R-8284) had a good effect in the slide dip method but was not so effective in the leaf exposure test. The compounds tested were phytotoxic to rose foliage only, but triazophos burned all the crops tested.     

Evaluation of Egyptian sheep production systems: I. Breed crosses and management systems

Our objective was to evaluate life-cycle performance of flocks of two Egyptian breeds, Rahmani (R) and Ossimi (O), and their crosses with Finnish Landrace (F) in two management systems. Management systems were one mating season per year (1M) and three mating seasons per 2 yr (3M). Breeds and crosses studied included purebred R and O, F1 crosses 1/2F-1/2R (FR) and 1/2F-1/2O (FO), and inter se matings of 1/4 F-3/4 R (RFR) and 1/4 F-3/4 O (OFO). A dynamic computer model was used to simulate animal performance and enterprise efficiency and profit. Two measures of lifecycle feed conversion (biological efficiency) were computed: kilograms of TDN input per kilograms of empty body weight output (TDN/EBW) and kilograms of TDN input per kilogram of carcass lean output (TDN/CLN). Profit was measured as gross margin (income minus variable costs per ewe per year, GM/EWE). Input parameters for the model were obtained from published results and analyses of data collected from experimental flocks of the same genetic stocks in Egypt. Profit for FR and RFR was 42 and 6% higher in 1M than in 3M. However, profit for all other genetic types was 4 to 8% greater in 3M than in 1M. Breed rankings changed depending on the measure of evaluation (i.e., biological efficiency or profit). Maximization of system output did not necessarily improve efficiency. Under accelerated lambing systems, greater overhead costs associated with labor and feed offset gains in ewe productivity. Genetic stocks should be matched to resources and management systems.