Effects of dietary essential amino acid deficiencies on the growth performance and humoral immune response in silvery‐black porgy (Sparidentex hasta) juveniles

A 6‐week feeding trial was conducted for determining the effects of dietary essential amino acids (EAA) deficiencies on growth performance and non‐specific immune responses in silvery‐black porgy juveniles (4.7 ± 0.1 g initial weight). Eleven isoproteic (ca. 47%) diets were formulated including a control diet containing the optimum quantity of EAA, and ten EAA‐deficient diets. All diets contained 36% fish meal and 18.5% crystalline EAA and non‐essential amino acids (NEAA) as the main source of dietary proteins. All the EAA and NEAA incorporated in the crystalline amino acids mixture of the control diet simulated the amino acids profile of the fish meal. The other 10 EAA‐deficient diets were formulated by the deletion of each of the 10 EAA (crystalline form) from the control diet and replaced by a mixture of NEAA for the adjustment of dietary nitrogen contents. At the end of the experiment, fish fed with threonine‐deficient diet showed the lowest survival rate (p < .05), whereas growth performance decreased in fish fed all EAA‐deficient diets, although the reduction in body growth varied depending on the EAA considered. Plasma total protein decreased in all experimental groups except for fish fed the phenylalanine‐deficient diet. Fish fed with arginine‐ and lysine‐deficient diets had the lowest plasma C3, C4, lysozyme, total immunoglobulin and total superoxide dismutase activity (p < .05). Present results indicated that lysine, methionine and threonine were the most limiting EAA in terms of growth performance; however, arginine, threonine and lysine were the most limiting EAA for innate immunity responses in silvery‐black porgy juveniles.     

Dietary Chitosan Nanoparticles: Potential Role in Modulation of Rainbow Trout (Oncorhynchus mykiss) Antibacterial Defense and Intestinal Immunity against Enteric Redmouth Disease

Bio-nanotechnology employing bio-sourced nanomaterial is an emerging avenue serving the field of fish medicine. Marine-sourced chitosan nanoparticles (CSNPs) is a well-known antimicrobial and immunomodulatory reagent with low or no harm side effects on fish or their human consumers. In this study, in vitro skin mucus and serum antibacterial activity assays along with intestinal histology, histochemical, and gene expression analyses were performed to evaluate the impact of dietary CSNPs (5 g kg⁻¹ dry feed) on rainbow trout resistance against ‘enteric redmouth’ disease. Two treatment conditions were included; short-term prophylactic-regimen for 21 days before the bacterial challenge, and long-term therapeutic-regimen for 21 days before the challenge and extended for 28 days after the challenge. Our results revealed higher antibacterial defense ability and positive intestinal histochemical and molecular traits of rainbow trout after dietary CSNPs. The prophylactic-regimen improved trout health while the therapeutic regimen improved their disease resistance and lowered their morbidity. Therefore, it is anticipated that CSNPs is an effective antibacterial and immunomodulatory fish feed supplement against the infectious threats. However, the CSNPs seem to be more effective in the therapeutic application rather than being used for short-term prophylactic applications.     

The potential of spiders of different taxa and a predacious mite to feed on the carmine spider mite — a laboratory study

Four spider species and the predacious mitePhytoseiulus persimilis (Athias-Henriot) were examined in the laboratory for their capacity to feed on the carmine spider mite,Tetranychus cinnabarinus (Boisduval). The adult females ofChiracanthium mildei L. Koch showed the highest capacity for feeding onT. cinnabarinus (27.5 mites/day) and differed significantly from all other spider species, including the immatureC. mildei which consumed an average of 18.9 mites/day — nearly equal to that of the Oxyopidae species (16.8 mites/day). The salticid (10.1 mites/day) and theridiid (9.5 mites/day) spider species had the lowest capacity, which was nearly equal to that of the predacious miteP. persimilis (11.3 mites/day). Results indicate that spiders play an important role as mite predators.     

Effects of margosan-o™, azatin™ and RD9-repelin® on spiders,and on predacious and phytophagous mites

The effects of Margosan-O^TM, Azatin^TM and RD9-Repelin on the phytophagous miteTetranychus cinnabarinus (Boisd.), the predacious miteTyphlodromus athiasae, and the predatory spiderChiracanthium mildei were studied and compared in laboratory experimentsr.-No toxic effect of any of these neem formulations was observed onC. mildei. Margosan-O and Azatin were not toxic to eitherT. cinnabarinus orT. athiasae, but RD9-Repelin was highly toxic to both the phytophagous and the predacious mite.     

Resistance to carmine spider mite in watermelon

Resistance of 37Citrullus lanatus L. lines to the carmine spider mite,Tetranychus cinnabarinus (Boisduval), was evaluated in three laboratory experiments, each including seven plants per line. Infestation with ten adult female mites per leaf, of each plant, was done at the three-leaf stage. In experiment A, average counts 10 days after infestation of three leaves ranged from 42 to 144 mites per leaf. In experiment B, average counts 8 days after infestation of two leaves ranged from 40 to 286 mites per leaf. In experiment C, average counts 8 days after infestation of two leaves ranged from 15 to 196 mites per leaf. The results suggest that a definite variation in resistance against mite infestation exists among watermelon lines. Contribution from the Agricultural Research Organization. No. 1082-E, 1993 series.     

Photolysis of pirimicarb in water under natural and simulated sunlight conditions

The photostability of pirimicarb, (2-dimethylamino-5,6-dimethylpyrimidin-4-yl dimethylcarbamate) in aqueous media, under natural and artificial sunlight irradiation conditions, is reported. The pH of the irradiated solutions remained constant during degradation time. The photodegradation mechanism seemed to be similar under both conditions, but the half-life was found to be about three times longer under natural than under artificial conditions. Four main photo-products ( 1 , 2 , 3 and 4 ) were isolated and identified by spectroscopic methods. It is proposed that a common photodegradation pathway exists for pirimicarb under both irradiation conditions. The results obtained from the photodegradation of pirimicarb and of its four main products isolated on solid phase permit the construction of a possible photodegradation pathway. Photoproduct 4 (2-methyl-formylamino-5,6-dimethyl-4-hydroxypyrimidine) is here described for the first time.     

Distribution and incidence of faba bean necrotic yellows virus in Jordan

Faba bean necrotic yellows virus (FBNYV) was isolated from naturally infected faba bean plants in Jordan. The identification was based on host range, mode of transmission, symptomatology and serological properties. FBNYV occurred naturally in several leguminous crops including cultivated legumes and wild forage legumes, such as species of Medicago , Trifolium and Lathyrus . and infected other plant species belonging to the Malvaceae, such as Malva parviflora and Hibiscus esculentus . Such hosts may act as important natural reservoirs for both the virus and its aphid vectors. This is the first report of infection of M. parviflora and H. esculentus with FBNYV. The virus was not recovered from samples taken from some cultivated crops, including squash, cucumber, tomato, eggplant and pepper, growing near to faba bean fields. Also, it was not detected in commercial faba bean seeds collected from local companies or in seeds collected from infected faba bean plants. It was transmitted efficiently by Aphis craccivora . Serological testing of 1392 samples from faba beans showing virus-like symptoms and collected randomly from 16 locations (fields) in the Jordan Valley and Jarash areas showed that FBNYV occurred in 54.5% of the samples. These results indicate that FBNYV was an important pathogen of beans during the growing season of 1996 in Jordan.     

Effect of pesticides on spiders occurring on apple and citrus in Israel

Field experiments in an apple orchard and in a citrus grove were carried out to evaluate the effect of four commercial pesticides in common use in Israel against apple and citrus pests, on the spider populations inhabiting the trees. The spider populations on apple were markedly suppressed by the pesticides, the order of toxicity being Talstar (biphenate) >Mavrik (fluvalinate) > Smash (fenpropathrin) > Dursban (chlorpyrifos). When grapefruit trees were treated with carbaryl + formothion, 232 spiders were sampled in the unsprayed plot, 55 days after treatment, as compared with only 11 spiders in the treated plot. Two and 7 days after treatment with chlorobenzilate, the sample from the treated plot numbered 68 and 55 spiders, respectively, as compared with 50 spiders collected 24 h before treatment. In addition, laboratory tests were carried out to determine the susceptibility of the spiderChiracanthium mildei L. Koch to 17 pesticides. When the spiders were exposed to grapefruit leaves which had been dipped 1 h previously for 5 sec in the aqueous emulsions of the pesticides, chlorpyrifos, fenpropathrin, fenvalerate, phosphamidon and biphenate caused 100%, and cypermethrin and fluvalinate 60% mortality, whereas all the other pesticides tested - acaricides, fungicides and herbicides - caused about 10-40% mortality.     

Photolysis and hydrolysis of rimsulfuron

The degradation in the liquid phase of rimsulfuron and its commercial 250 g kg⁻¹ WG formulation (Titus®) was investigated. Photolysis reactions were carried out at 25 °C by a high-pressure mercury arc (Hg-UV) and a solar simulator (Suntest), while the hydrolysis rate was determined by keeping aqueous buffered samples in the dark. The effects of solvent and water pH on reaction kinetics were studied, and the results compared to literature data. Photoreactions of the commercial product in organic solvents were faster than pure rimsulfuron. Under simulated sunlight in water, the half-life for the photolysis reaction ranged from one to nine days at pH 5 and 9, respectively. The hydrolysis rate was as high as the photolysis rate, but decreased on increasing water pH. The main metabolite identified in neutral and alkaline conditions as well as in acetonitrile was N-[(3-ethylsulfonyl)-2-pyridinyl]-4,6-dimethoxy-2-pyridinamine, while N-(4,6-dimethoxy-2-pyrimidinyl)-N-[(3-(ethylsulfonyl)-2-pyridinyl)]urea and minor metabolites prevailed in acidic conditions. © 1999 Society of Chemical Industry     

Dietary fatty acid profiling in plant protein‐rich diets affects the reproductive performance,egg fatty acid profile and haematological parameters in female rainbow trout (Oncorhynchus mykiss)

The influence of dietary fish oil (FO) substitution with blends of vegetal oils (VO: canola, linseed, olive, sunflower, corn and coconut oils) in plant protein‐rich diets on reproductive performance and fatty acid dynamics of embryos was evaluated in female rainbow trout (Oncorhynchus mykiss) brooders (1.8 ± 0.1 kg). Four diets were formulated in which 20% (FO₈₀/VO₂₀), 50% (FO₅₀/VO₅₀), 75% (FO₂₅/VO₇₅) and 100% (VO₁₀₀) of FO were replaced by mixture of VO. The above‐mentioned diets were administered for a short period prior to spawning (3 months). Fish fed the VO₁₀₀ had the lowest fertilization rate (81.3 ± 2.3), whereas brooders fed the FO₈₀/VO₂₀ diet had the lowest survival rates at eyed embryo stage (83.7 ± 1.6%) and hatching rate (79.9 ± 3.1%). The fatty acid dynamics of embryos were not only affected by embryonic developmental stages, but also they were influenced by the dietary fatty acid profile. Our study confirmed that using blends of different VO sources and FM residual fat in the FO₂₅/VO₇₅ for the short‐term period prior to spawning seemed to be a good strategy in terms of successful reproduction for sparing high levels of FM and FO in diet of O. mykiss brooders.