The effects of dietary inclusion of a Saccharomyces cerevisiae fermentation product in a commercial catfish ration on growth,immune readiness,and columnaris disease susceptibility

ABSTRACT

We evaluated a Saccharomyces cerevisiae fermentation product (Diamond V Original XPC) in hybrid catfish (Ictalurus furcatus x I. punctatus) for its potential effects on growth, blood parameters, and disease resistance. The trial featured four levels of inclusion that were added to a commercial 32% protein floating catfish ration. Following six weeks of feeding, we observed marginally heightened resistance to columnaris disease and saw significant changes in the levels of immune effectors in the serum, including lysozyme, complement, and immunoglobulin.     

A respirometer system to measure critical and recovery oxygen tensions of fish under simulated diurnal fluctuations in dissolved oxygen

We describe a computer-operated recirculating respirometer system (ca. 140 L water) with six respirometer chambers and a reference chamber (L × W × H: 26 cm × 12 cm × 20 cm; volume 6.24 L) that simulates diurnal dissolved oxygen (DO) fluctuations normally occur in aquaculture ponds. A gas-mixing device, “Digamat” proportionately dissolves gaseous nitrogen and oxygen (and if desired, carbon dioxide) in water to achieve DO levels from 1.0 to 40.0 kPa (0.3–14.0 mg L^?1) at different temperatures. A series of computer-operated valves sequentially allow water from respirometer chambers to a single oxygen probe to measure DO concentration. Oxygen consumptions of fish as the differences in DO concentrations between respirometer and reference chamber are used to calculate different metabolic rates (standard, routine, and active), and critical (P _c) and recovery (P _r) oxygen tensions of individually reared unfed and fed fish. An experiment was conducted to evaluate the ability of the system to measure metabolic parameters for individually reared Nile tilapia (Oreochromis niloticus L.) at three temperatures (low: 22.5, optimum: 27.5 and high: 33.5 °C). The fed fish had significantly higher P _c and P _r values at optimum and high temperatures than unfed fish. At low and high temperatures, both fed and unfed fish had higher P _c and P _r than at optimum temperature. The standard metabolic rate was significantly higher at higher temperatures (44.9, 51.7, and 77.7 mg O₂ kg^?0.8 h^?1 at 22.5, 27.5, and 33.5 °C, respectively).     

A GIS based spatially explicit model of dispersal agent behavior

Spatial simulation models of seed dispersal have been constructed at the landscape level under the assumption of ubiquitous or uniform dispersibility. The anisotropic nature of vegetation distribution caused by different dispersal agents such as wind, gravity, water and animals were ignored. We propose a prototype of a GIS-based spatially explicit model of dispersal agent behavior (SEMODAR) to simulate the seed dispersal process by considering the unique behavioral characteristics of each seed dispersal agent. As a result, the influence of dispersal agent behavior on the species coexistence in competitive communities with and without habitat destruction could be explored. The model consists of four module components: dispersal rules, species competition, species colonization, and habitat destruction. An experimental simulation was conducted using three hypothetical species with differing competitive and migration abilities in both intact and disturbed conditions for 250 years. The findings of this study support the theoretical expectation that inferior competitors can coexist with superior competitors given that the inferior competitors have efficient colonization ability. The simulation also reveals the important role of agent behavior in the seed dispersal process and the biased impact of environment fragmentation on superior competitors that are not superior dispersers.     

Natural regeneration of Pinus brutia Ten. in a recreational public forest in Zawita-Kurdistan region,Iraq

Zawita natural forest has recently has been subject to mass recreational activities during spring that have denuded large areas of the forest.It was thus essential to assess regeneration before designing optimizing strategies.To this end,we studied the overstory canopy and microhabitat conditions for recruitment of Pinus brutia Ten in 10 plots(20×25 m)on the southern aspects where the Zawita natural forest is still present.In total,1540 regenerating P.brutia were recorded,854 seedlings,597 saplings,and 89 trees.Seedlings and saplings were more frequent beyond the canopy than under the canopy of the parent trees.Regeneration requirements differed between seedlings and saplings.The probability of the occurrence of seedlings was negatively correlated with increasing litter depth and increasing soil compaction.The density of saplings only showed a positive significant correlation with increasing slope.The nearest neighbor index showed a trend toward a positive spatial association between understory shrubs with their neighboring seedlings at a mean distance of 1.6 m.Overall,the study highlighted the requirements for seedling regeneration as a relatively open canopy cover,a light understory litter layer,and noncompacted soils.These results are a step towards designing effective management and restoration programs.     

Wood‐rotting basidiomycetes are a minor component of fungal communities associated with Acacia hybrid trees grown for sawlogs in South Vietnam

Acacia hybrid (Acacia mangium × Acacia auriculiformis) clones are widely planted in Vietnam with a total of approximately 400,000 ha to meet the demand for pulpwood, sawn timber and wood chip exports. Silvicultural techniques such as pruning and thinning have been applied to improve productivity and sawlog quality of Acacia hybrid plantations. However, those techniques may also create opportunities for wood decay fungi to enter the Acacia hybrid stems through wounds and cause stem defects that reduce sawlog quality and the value of the plantation. The presence of fungal decay agents in Acacia hybrid trees was examined in two Vietnamese plantations. In July 2011, just prior to a second thinning, discoloured wood samples were taken from a three‐year‐old Acacia hybrid plantation at Phan Truong Hai for the isolation of fungi. In July 2012, approximately 18 months after pruning and thinning treatments, discoloured wood samples were taken from a three‐year‐old Acacia hybrid plantation at Nghia Trung for the isolation of fungi. DNA sequencing of the rDNA ITS identified the isolates. In May 2015, approximately 4 years after thinning and fertilizer treatments, discoloured and decayed wood samples were taken from the above (7‐year‐old) Acacia hybrid plantation at Phan Truong Hai for fungal identification. DNA was extracted directly from discoloured and decayed wood samples and fungal rDNA ITS amplicons sequenced on a Roche 454 sequencer. The results showed that silvicultural treatments did not affect the fungal communities associated with discoloured and decayed wood of Acacia hybrid plantation at Phan Truong Hai. A total of 135 fungal species or OTUs (operational taxonomic units) were identified, including 82 members of Ascomycota and 52 Basidiomycota.     

Effect of Plant Density on Wild Oat Competition with Competitive and Non Competitive Wheat Cultivars

Wild oat (Avena ludoviciana) is one of the worst weeds in wheat fields.The effect of wheat density on wild oat competition with more or less competitive wheat cultivars (Triticum aestivum) was investigated at the Experimental Farm of Plant Pests and Diseases Research Institute,Karaj,Iran.The experiment was established as a factorial combination of wheat varieties Roshan as non-competitive and Niknejad as competitive; three wheat densities (recommended density,recommended+25％,and recommended+50％,corresponding respectively with 300,375,and 450 plants m-2 for Roshan and 400,500,and 600 plants m-2 for Niknejad) and four wild oat densities (0,25,50,and 75 plants m-2) were selected for this experiment.Hyperbolic equations were used to describe relationship between yield and weed density.Increase in wheat density reduced wild oat biomass.Maximum wild oat biomass was achieved at the highest density of the wild oat together with the lowest wheat density.The results showed that higher densities of wheat are able to suppress wild oat dry matter production.Inter-specific competition in Niknejad was 1.7 times more than that in Roshan.Maximum yields of Niknejad and Roshan in the presence of wild oat were obtained at recommended density+25％ and recommended density,respectively.Increase in wheat density leads to a decrease in wheat yield due to an increase in intra-specific competition.Increase in wild oat density results in the reduction of wheat yield through decrease in fertile tiller per plant and spike m-2.     

Effects of compost interactions on the alterations in mineral biochemistry,growth, tuber quality and production of <Emphasis Type="Italic">Solanum tuberosum</Emphasis>

Incorporation of compost in soil will not only protect the environment, but also take advantage of the nutrients and organic matter contained in the compost to enhance soil fertility and crop production. Field experiments were carried out during the 2006/2007 and 2007/2008 growing seasons at the College of Food and Agriculture Farm, United Arab Emirates University. The experiments were established in randomized complete block design (RCBD) with four replications. The plot dimension was 3.2m×2.8 m, with four rows per plot. The treatments were designed to study the effect of compost rates on the potato production and soil fertility properties. Five rates of compost were investigated (control, 40, 80, 120 ton compost per hectare; and inorganic fertilizers (250 kg N·ha⁻¹, 250 kg P₂O₅·ha⁻¹ and 300 kg K₂O·ha⁻¹)). Results of the first growing season 2006/2007 showed that marketable tuber yield, plant height and specific gravity were greater in compost amended soil than in non-amended soil even if inorganic fertilizers were added. Application of 120 ton compost per hectare gave the highest total tubers number, marketable tuber yield, height and specific gravity.     

Influence of chemical and biological treatments on volatile oil composition of Artemisia annua Linn.

The relative abundance of isoprenoids and other volatile components in the aerial parts of Artemisia annua Linn. (Asteraceae) after different nutritional treatments was analyzed by GC and GC/MS. Hydro-distillation of untreated (control) plants yielded 0.28 ± 0.04% essential oil on fresh weight basis. Monoterpenes were predominant in the essential oil of which cis-limonene-1,2-epoxide (22.1%), artemisia ketone (11.5%), iso-pinocamphone (11.4%), thujyl alcohol (9.9%) and camphor (8.4%) were the major components. The essential oil distilled from A. annua treated with Azospirillum (2 ml/plant) amounted to 0.30 ± 0.03% of fresh weight and consisted mainly of neral (31.1%), β-caryophyllene (25.1%), artemisia ketone (10.0%), thujyl alcohol (9.4%), trans-bergamotene (8.5%) and spathulenol (4.8%). The essential oil from plants treated with basal N, P, K and S application (in the form of urea P₂O₅, K₂O and gypsum at a rate of 120, 50, 100 and 50 kg/ha, respectively) amounted to 0.32 ± 0.03% of fresh weight and consisted mainly of thujyl alcohol (33.3%), β-caryophyllene (15.5%), cis-undec-5-ene (14.4%), artemisia ketone (6.0%), trans-nerolidol (5.8%) and undec-4-ene (4.6%). The hydrodistillation of A. annua treated with Glomus (Mycorrhizal soil 50 g/plant) yielded 0.50 ± 0.02% essential oil on fresh weight basis. The sesquiterpenes were predominant in this essential oil and consisted of β-caryophyllene (51.2%), trans-bergamotene (15.4%), α-gurjunene (14.3%), germacrene D (5.1%) and ledol (4.5%) as major components. The only monoterpenes in the essential oil were neral, nerol and pulegone (each less than 1%). These findings suggest that A. annua treated with Glomus lacks glandular trichomes—the primary sites of synthesis of monoterpenes.     

Pattern of genetic inheritance of morphological and agronomic traits of sorghum associated with resistance to sorghum shoot fly, <Emphasis Type="Italic">Atherigona soccata</Emphasis>

Sorghum shoot fly, Atherigona soccata is an important pest of sorghum during the seedling stage, which influences both fodder and grain yield. To understand the nature of inheritance of shoot fly resistance in sorghum, we performed generation mean analysis using two crosses IS 18551 × Swarna and M 35-1 × ICSV 700 during the 2013–2014 cropping seasons. The F₁, F₂, BC₁ and BC₂ progenies, along with the parental lines were evaluated for agronomic and morphological traits associated with resistance/susceptibility to sorghum shoot fly, A. soccata. The cross IS 18551 × Swarna exhibited significant differences between the parents for shoot fly deadhearts (%) in the postrainy season. The progenies of this cross exhibited lower shoot fly damage, suggesting that at least one of the parents should have genes for resistance to develop shoot fly-resistant hybrids. Leaf glossiness, leafsheath pigmentation and plant vigor score during the seedling stage exhibited non-allelic gene interactions with dominant gene action, whereas 100 seed weight showed both additive and dominant gene interactions. Presence of awns showed recessive nature of the awned gene. Generation mean analysis suggested that both additive and dominance gene effects were important for most of the traits evaluated in this study, but dominance had a more pronounced effect.