Stress inhibits insulin release induced by feeding and arginine injection in barfin flounder Verasper moseri

We evaluated the effect of stress and adrenaline injection on insulin release in barfin flounder Verasper moseri. Flounders were fed to satiation and then exposed to 30 min of stress (chasing using a blunt stick), beginning 15 min after feeding. Plasma insulin concentrations were measured using a time-resolved fluoroimmunoassay for barfin flounder insulin. Peak insulin concentrations in the stressed flounders (3.4 ± 1.0 ng/ml, mean ± SEM) were lower than in the control group (8.3 ± 1.7 ng/ml). Similarly, in flounders injected with l-arginine (Arg; 3.5 mmol/kg body weight), the most potent insulinotropic factor for flounders, insulin levels were lower for up to 5 h in individuals exposed to chasing stress. Furthermore, plasma insulin levels did not increase after injection with Arg followed by exposure to 10 min of stress. This was also true for flounders co-injected with Arg (20 nmol/kg body weight) and adrenalin instead of the chasing stress. We conclude that stress induces a powerful and extended inhibition of insulin release in flounders, even when the stress is acute. We hypothesize that this effect is mediated partly by adrenaline release. Our results provide insight into the deleterious effects of stress on growth.     

Vitamin A affects haematology,growth and immune response of Nile tilapia (Oreochromis niloticus,L.), but has no protective effect against bacterial challenge or cold‐induced stress

Vitamin A (vitA) is an essential nutrient that acts as an endocrine regulator of several metabolic pathways, modulating normal growth and health status of animals. Although the importance of vitA for normal haematology and immune response is well documented for higher vertebrates, there is limited information on the physiological effects of vitA on fish. Therefore, we designed a 130‐day feeding trial to evaluate the effect of vitA supplementation on growth, haematology, immune function and resistance to experimental infection with Aeromonas hydrophila and cold‐induced stress. A group of 320 Nile tilapia fingerlings 7.49 ± 0.19 g weight (mean ± SD) were randomly stocked into 40 250 L‐aquaria and fed practical diets containing graded levels of vitA (0, 0.06, 0.12, 0.24, 0.48, 0.96, 1.92, 3.84 mg retinol (ROH) kg^?1 diet. Growth, haematology, plasma protein profile and immune response were significantly affected by vitA supplementation; however, no clear protective effect of vitA supplementation on disease and cold stress resistance were observed in this study. Clinical signs of vitA deficiency were: resting and abnormal swimming behaviour, exophthalmia, haemorrhages at the base of fins and on skin, serous fluids in abdominal cavity, neutropenia, reduction in red blood cell count, haematocrit and haemoglobin evolving to high mortality rates in a short period of time. A dietary level of vitA around 1.2 mg ROH kg^?1 may be required to prevent gross deficiency signs and promote proper growth and health status of Nile tilapia. VitA does not seem to have a pronounced effect on leucocyte differentiation, but clearly plays an important role on maintaining normal erythropoiesis.     

Toxicity and protectant potential of Piper guineense (Piperaceae) and Senna siamea (Fabaceae) mixed with diatomaceous earth for the management of three major stored product beetle pests

There is a dearth of knowledge on the available sources of botanical products for smallholder farmers in Africa and their bioactivity against stored-product pests. Many locally available plants across Africa exhibit both promising insecticidal, medicinal activity and are nutrient rich yet remain underutilized. Laboratory studies on toxicity of powders of Senna siamea and Piper guineense alone or combined with diatomaceous earth (DE) to adult Sitophilus granarius, Tribolium castaneum and Acanthoscelides obtectus were conducted in stored grains. Adult mortality was observed up to 7 d while progeny production was recorded 6–10 weeks. Adult A. obtectus were most susceptible (LD₅₀ 0.0084% and 0.0696% wt/wt for S. siamea and P. guineense, respectively), followed by S. granarius. T. castaneum was most tolerant (LD₅₀ 0.6589% and 0.6829% wt/wt for S. siamea and P. guineense, respectively). Combination of plant powders and DE controlled the beetles faster compared to the plant powders alone. LT₅₀ ranged from 20 h to 101 h for T. castaneum exposed to 1.0% S. siamea and 1.0% DE, and 0.5% P. guineense and 1.0% DE, respectively. Botanicals caused significant reduction of F₁ adults compared to the control. The potential of using botanicals combined with DE to control stored-product insects is discussed.     

Occurrence of Resistance-breaking Populations of Root-knot Nematodes on Tomato in Greece

Nine populations of Meloidogyne spp. from Greece have been identified as M. javanica or M. incognita using either isozyme phenotypes or the sequence characterized amplified region-polymerase chain reaction (SCAR-PCR) technique. Virulence against the Mi resistance gene was assayed by pot experiments in controlled conditions and revealed the ability of five populations of M. javanica and one population of M. incognita to reproduce on tomato cultivars containing that gene. A resistance-breaking population of M. incognita is reported for the first time in the country; the M. javanica populations constitute new records for the Greek mainland.     

Immunization by intrabronchial administration to 1-week-old foals of an unmarked double gene disruption strain of Rhodococcus equi strain 103+

Rhodococcus equi causes fatal granulomatous pneumonia in foals and immunocompromised animals and humans. However, there is no effective vaccine against this infection. In this study, the chromosomal genes isocitrate lyase (icl) and cholesterol oxidase (choE) were chosen as targets for mutation and assessment of the double mutant as an intrabronchial vaccine in 1-week-old foals. Using a modification of a suicide plasmid previously developed in this laboratory, we developed a choE-icl unmarked deletion mutant of R. equi strain 103+. Five 1-week-old foals were infected intrabronchially with the mutant and challenged intrabronchially with the parent, virulent, strain 2 weeks later. Three of the foals were protected against pneumonia caused by the virulent strain, but the other two foals developed pneumonia caused by the mutant strain during the post-challenge period. Since infection of 3-week-old foals by an icl mutant in an earlier study had shown complete attenuation of the strain, we conclude that a proportion of foals in the 1st week or so of life are predisposed to developing R. equi pneumonia because of an inability to mount an effective immune response. This has been suspected previously but this is the first time that this has been demonstrated experimentally.     

Characterization of different types of broiler bedding including dehydrated grass and their influence on production

The objective is to evaluate different bedding materials, including dehydrated grass, on performance and carcass yield and verify the physicochemical and microbiological characteristics of materials. The completely randomized experiment comprised 1,080 chicks in a 3 × 2 factorial design with three levels of dehydrated grass (0%, 25%, and 50%) and two bedding materials (rice husks and shavings). Total microorganism count and physicochemical characteristics, surface temperature of birds, and performance of birds were analyzed up to 42 days of age, when birds were slaughtered, and carcass yield was evaluated. The inclusion of grass showed a higher microbiological count after 1 day, stabilizing with materials after 28 days. The inclusion of 50% of dehydrated grass resulted in a higher surface bed temperature at 42 days. Inclusions above 25% of grass have a lower density and a greater water retention capacity, pH, moisture, and total nitrogen, in addition to a lower FDA in its structure. The highest ammonia emissions occurred with the inclusion of 25% of grass. The inclusion of dehydrated grass did not affect performance and carcass yield, favoring feed conversion at the initial stages. The inclusion of grass can replace up to 25% of shavings without harming physicochemical parameters of materials and birds' performance.     

Concentrate: forage ratio in the diet of dairy cows does not alter milk physical attributes

This study aimed to evaluate the effect of concentrate-to-forage ratio (C:F) on the performance, blood profile, and milk physicochemical characteristics of mid-lactation cows fed a corn silage-based diet. Twenty four Holstein cows, with BW 575?±?70 kg, body condition score (BCS) 3.1?±?0.2, milk yield 18.4?±?3.0 kg, and days in milk (DIM) 121?±?21 were randomly allocated into three treatments with C:F ratios of 35:65, 45:55, and 55:45 on a dry matter (DM) basis. Data was submitted to analyses of variance and regression. Increasing C:F from 35 to 55 % linearly enhanced milk production (22 to 23.6 kg day^?1) and serum urea nitrogen (16.8 to 19.6 mg/dL), while it linearly reduced lactose and fat in milk (4.8 to 4.6 %; 3.9 to 3.6 %, respectively). Body weight, BCS, milk acidity, ethanol stability, coagulation time, and milk and blood mineral contents did not differ among treatments. During the last period of measurements, increased C:F reduced urinary pH and milk urea nitrogen. Changes of concentrate-to-forage proportion from 35 to 55 % increased milk yield, altered chemical composition without changing BW, BCS, acidity, stability, and mineral content of milk and blood attributes.     

In vivo antioxidant activities of essential oils and their constituents from leaves of the Taiwanese Cinnamomum osmophloeum

Cinnamomum osmophloeum Kaneh is an indigenous tree species in Taiwan. In this study, phytochemical characteristics and antioxidant activities of the essential oils and key constituents from the leaves of two C. osmophloeum clones were investigated. The two trees possess two chemotypes, which were classified as the cinnamaldehyde type and camphor type. We demonstrated that the essential oils from C. osmophloeum leaves exerted in vivo antioxidant activities in Caenorhabditis elegans. In addition, trans-cinnamaldehyde and D-(+)-camphor, which respectively represent the major compounds in the cinnamaldehyde-type and camphor-type trees, exerted significant in vivo antioxidant activities against juglone-induced oxidative stress in C. elegans. Moreover, expressions of antioxidative-related genes, including superoxide dismutase (SOD) and glutathione S-transferase (GST), were significantly induced by trans-cinnamaldehyde and D-(+)-camphor from C. osmophloeum leaves. Our results showed that the essential oils from C. osmophloeum leaves and their major compounds might have good potential for further development as nutraceuticals or antioxidant remedies.     

Evaluating the degree of weathering in landslide-prone soils in the humid tropics: The case of Limbe,SW Cameroon

This study analyses the behaviour and mobility of major and some trace elements during the physical and chemical development of landslide-prone soil profiles in Limbe, SW Cameroon. The soils result from in situ weathering of Tertiary basaltic and picrobasaltic rocks. Textural and chemical characterisations, together with two mass balance models are applied to understand the mobility and redistribution of elements during the weathering of pyroclastic cones and lava flows. Weathering indices are used to estimate the extent of weathering. The chemical composition of the samples is evaluated by Inductively Coupled Plasma–Optical Emission Spectroscopy (ICP–OES) and their mineralogical composition by X-Ray Diffraction (XRD) analyses. It is observed that intensive weathering results in thick meta-stable soils in which significant loss of Ca, K, Mg, Na and Sr has taken place. There is a noticeable relative enrichment in all analysed trace elements (Ba, Zr, Y, Sc, V, Ni, and Co). Ti, Fe, Al, Mn, P and Ce tend to be leached in some horizons and concentrated in others. Zr, Ti, and Ce concentrations are greater in the soils than in the bedrock but show slight fluctuations in the soil and saprolites hence cannot be used as immobile elements for mass balance evaluations. Y increases progressively with advanced weathering. Major secondary mineral phases developed through weathering are a mixture of expanding (smectites) and non-expanding clays (kaolinite, halloysite and mica). The profiles show the presence of textural heterogeneities that can be exploited as slip surfaces. Data plotted in Si–Al–Fe diagram point out that the most advanced stage of weathering noted in these profiles is the kaolinisation stage.     

Disruption of duplicated yellow genes in Bactrocera tryoni modifies pigmentation colouration and impacts behaviour

Journal of Pest Science - Irradiated Queensland fruit flies (Bactrocera tryoni) used in Sterile Insect Technique (SIT) programmes are marked with fluorescent dyes to distinguish them from wild...