Microcystis aeruginosa (Kütz) incorporated diets increase immunity and survival of Indian major carp Labeo rohita (Ham.) against Aeromonas hydrophila infection

The aim of this study was to evaluate dietary dosages of Microcystis on the immune response and disease resistance against infections due to the opportunistic pathogen Aeromonas hydrophila in Labeo rohita fingerlings. Labeo rohita fingerlings were fed diet containing 0 (Control), 0.5, 1.0 and 5 g Microcystis powder kg^?1 dry diet for 90 days. Three replicate groups of fish averaging 20 ± 2 g were fed for 3 months daily. At 30 days interval, samples were assayed for different biochemical [serum total protein, albumin, globulin, albumin:globulin (A:G) ratio] and immunological (superoxide anion production, lysozyme and serum bactericidal activity) parameters. The results demonstrate that fish fed Microcystis showed increased levels of lysozyme, serum bactericidal activity, serum protein and albumin (P ≤ 0.05) as compared with the control group. After 90 days, fish were challenged with A. hydrophila and mortality (%) was recorded up to day 10 postchallenge. The group fed 1.0 g Microcystis kg^?1 dry diet showed the highest percentage survival (72%). These results indicate that Microcystis aeruginosa stimulates the immunity and makes L. rohita more resistant to infection by A. hydrophila when fed in dried form in feed.     

In planta detection of Macrophomina phaseolina from jute (Corchorus olitorius) by a sodium acetate-based direct PCR method

Macrophomina phaseolina (Tassi) Goid. is the most important pathogen of jute and primarily causes seedling blight, leaf spot and stem rot. The pathogen was detected from field samples by a simple method of direct PCR (dPCR) which obviates the steps of DNA extraction. The leaf bits were treated with a lysis buffer at 65°C for 25 min, whereas the stem pieces were initially incubated at 65°C for 5 min followed by incubation at 60°C for 25 min and the lysate was used as PCR template. Based on the type of tissue, the composition and concentration of lysis buffer systems were optimized. For leaf samples the optimized buffer system composed of 20 mmol l ^-1 tris (hydroxymethyl aminomethane (Tris)-Cl (pH 8.0), 1.5 mmol l ^-1 ethylene diamine tetra acetate (EDTA) (pH 8.0), 1.4 mol l ^-1 sodium acetate and 200 μg/ml proteinase K. Further, 3% PVP (w/v) and β-mercaptoethanol (1% w/v) were added into the buffer. In case of stem samples, PVP was not applied and higher concentrations were used for other components. M. phaseolina could be detected from both leaf and stem samples generating amplicon of 350 bp. This is the first report of detecting M. phaseolina by a direct PCR method without DNA extraction.     

Evaluation of a Biofloc System for Intensive Culture of Fathead Minnows,Pimephales promelas

This study was carried out to test the suitability of biofloc technology to improve the productivity of the fathead minnow, Pimephales promelas, a commercially important baitfish in North America. Biofloc growth was induced in treatment tanks by periodic additions of a carbon source (glucose) to maintain a C : N ratio of 12:1. Control tanks (no aeration and no carbon addition) accommodated densities equivalent to 1 million fish/ha, while treatment tanks (biofloc) had densities of 1, 2, 4, and 8 million fish/ha. Fish were fed 4% body weight using a 32% protein commercial diet. There were no significant differences in condition of fish harvested from control and treatment densities (P < 0.05). However, fish growth indicators such as final individual weight, feed conversion efficiency, and specific growth rate were significantly impaired at higher stocking densities. Survival rate was significantly lower in the 8 million/ha treatment (P < 0.05). Results were indicative of possible production efficiencies of twofold higher in biofloc systems stocked at or below 4 million/ha compared with traditional ponds. Although biofloc systems maintained the desired water‐quality parameters, biofloc microbial biomass did not seem to significantly enhance feed conversion and specific growth rates of fathead minnows.     

Bt cotton producing Cry1Ac and Cry2Ab does not harm the parasitoid Aenasius arizonensis (Girault): a host-mediated tritrophic assay

Phytoparasitica - Transgenic crops with genes from Bacillus thuringiensis (Bt) Berliner, a soil bacterium producing δ-endotoxin that is lethal to several phytophagous insects. Concerns related...     

Soil failure associated with crack propagation for an agricultural tillage tool

Tillage loosens soil to depths of 75–150 mm (3–6 in.). As the soil is tilled, the failure path precedes the motion of the tillage tool. Previous studies have examined soil forces acting on a tine by predicting different soil failure patterns. This paper quantifies the rate and the path of the cracks associated with soil failure front. The propagation of the soil failure path by observing the temporal profile of the leading edge of the failure crack with respect to the tool motion was examined. Crack propagations were analysed for sweep operating at 4 km h⁻¹ speed, and two operating depths of 75 and 100 mm using high-speed digital videography. Higher depth of operation showed distinct phases for crack development and propagation. Short and intermittent soil crack propagation with lower propagation growth rates was observed for shallow depth of operation. Crack growth rate has been observed to have a sinusoidal relation with time.     

Differential cadmium stress tolerance in wheat genotypes under mycorrhizal association

Arbuscular mycorrhizal (AM) fungi display efficient association with the land plants and is known to protect plants against various abiotic stresses including heavy metal stress. This work reports the synergistic effects of natural genotypic variation and AM association in cadmium (Cd) stress alleviation. Two genotypes of wheat viz. RAJ 4161 (resistant) and PBW 343 (sensitive) were subjected to different concentrations of Cd (0, 100, 200 and 300 mg Cd kg^?1 soil) for 30 days. Cd application resulted in increased lipid peroxidation and decreased plant growth. However, AM inoculated RAJ 4161 displayed significantly higher ascorbate peroxidase (APX), catalase (CAT), glutathione reductase (GR) and superoxide dismutase (SOD) activity and calcium (Ca), iron (Fe)and zinc (Zn) concentration in plants. The coordination of increased antioxidant activity and high nutrient content in RAJ 4161 indicated better protective mechanism as compared to PBW 343.     

Histopathological changes and tissue residue concentrations of monosex Nile tilapia (Oreochromis niloticus,L) fries exposed to oxytetracycline

Aquaculture International - The current study evaluated the biosafety of oxytetracycline (OTC) exposure for 30&nbsp;days in monosex Oreochromis niloticus fries. The fries were exposed to OTC...     

Hermaphrodite inbreds with better combining ability improve antioxidant properties in ridge gourd [Luffa acutangula (Roxb.) L.]

An experiment was conducted with the objectives to evaluate the breeding potential of hermaphrodite lines and to suggest suitable breeding approaches following half-diallel mating design for genetic improvement of antioxidant content and activity in ridge gourd [Luffa acutangula (Roxb.) L.] fruits. Twenty-eight genotypes, including seven parental lines and 21 crosses, were grown in randomized block design with three replications for fruit sample collection. The highly significant mean squares due to parents, hybrids and parents versus hybrids; and GCA and SCA for yield and antioxidants (ascorbic acid, total carotenoids, total phenolics, DPPH-RSA, ABTS-RSA and CUPRAC assay) indicate the existence of abundant genetic variation. The per se performance and combining ability of hermaphrodite parents (Satputia Long and Satputia Small) and hybrids of “monoecious × hermaphrodite” cross were found to be superior for antioxidants along with yield potential. The cross combinations with superior per se performance coupled with high SCA estimates and having at least one hermaphrodite parent would be useful for concentrating desirable alleles to improve the antioxidants and yield simultaneously. Thus, hermaphrodite lines in combination with monoecious counterpart have enormous potential to breed “genotypes for higher antioxidants” without compromising yield in ridge gourd.     

Development of expert system modeling based decision support system for swine manure management

Animal waste has always been considered as a resource for agricultural input as biofertilizer. However, the management is becoming more stringent due to environmental regulations. Livestock producers are faced with different manure management options that may be implemented into their operations. Given the expansion of the livestock industry, the implementation of environmental regulations, and the increasing importance of social and health issues, the selection of optimal manure management systems is becoming a strategically important task. Increasingly, integrated decision support systems (DSSs) are becoming necessary to assist decision makers in their evaluation of different manure management alternatives, like, liquid system, semi-solid system, solid system and bio-gas or bio-energy system based on combinations of different manure management sub-systems (collection, storage and application). To address this situation, a user-friendly computer program called Integrated Swine Manure Management (ISMM) is being developed for the Canadian Prairie provinces. Decision criteria including environmental, agronomic, social and health, greenhouse gas emission, and economic factors have been considered for the selection, design, and operation of the DSS. The expert system modeling is based on Visual Basic programming. Decision on adopting a particular combination of systems components is based on performance rating of the overall system. The program is interactive so that weighting factors for the different decision criteria can be varied to suit site-specific considerations. In this paper, the systems approach for development of an integrated liquid manure management system is discussed. Using a case study, sensitivity analysis of different combinations of management components is also reported for systems performance. The decision software compared satisfactorily with other available DSS packages.