Dietary astaxanthin modulated the performance,gastrointestinal histology,and antioxidant and immune responses and enhanced the resistance of Litopenaeus vannamei against Vibrio harveyi infection

Aquaculture International - Astaxanthin (AX) is one of the commonly used feed supplements to enhance the growth performance and provide antioxidant and immune functions of several aquatic animals....     

Growth and body composition of rohu (Labeo rohita) fed diets containing oilseed meals: partial or total replacement of fish meal with soybean meal

A 56‐day feeding trial was conducted to evaluate growth, feed utilization and body composition of fingerling rohu, Labeo rohita (4.5 ± 0.2 cm; 2.58 ± 0.04 g), fed five isonitrogenous (350 g kg^?1 crude protein) and isoenergetic (15.7 kJ g^?1 metabolizable energy) diets in which the main protein contributors were: diet I, fish meal (FM); diet II, soybean meal (SBM); diet III, groundnut meal (GNM); diet IV, equal amounts of SBM, GNM and canola meal (CM); diet V, equal amounts of FM, SBM, GNM and CM. Fish were stocked in triplicate groups of 25 fish held in 70 L flow‐through tanks (water volume 55 L) and fed twice daily (0900 and 1700 hrs) to apparent satiation. Fish fed diet I exhibited the highest (P < 0.05) values for live weight gain and specific growth rate (% per day). Feed conversion and protein efficiency ratio were better (P < 0.05) in fish‐fed diets I and II. Fish‐fed diet II exhibited lower (P < 0.05) fat and ash contents in carcass. Based on these findings, a 70‐day trial (Experiment II) was conducted with six diets fed under the same conditions where FM was incrementally replaced with SBM. Fingerling L. rohita (6.7 ± 0.4 cm; 4.07 ± 0.02 g) were used for the study. Crystalline l ‐methionine was added to diets containing more than 250 g kg^?1 SBM. This second study showed no significant (P > 0.05) variation in growth, feed utilization and carcass composition for fish fed the different diets. In conclusion, SBM was more effective than GNM or CM, as FM was replaced in feeds for fingerling L. rohita and could completely replace FM when supplemented with methionine and fortified with minerals under the conditions of this study.     

Could EST-based markers be used for the marker-assisted selection of drought tolerant barley (<Emphasis Type="Italic">Hordeum vulgare</Emphasis>) lines?

To improve our knowledge on the genetic control of drought tolerance, the Oregon Wolfe Barleys (OWB), considered as a reference population in genetic mapping, were subjected to various types of water deficit. Overall, when investigating numerous environments and replications, 40 QTLs were identified in three developmental stages. Based on these loci five QTL clusters were separated, which affect various drought-related traits in at least two developmental stages. Several candidate genes were identified for each QTL cluster using an expressed sequence tag (EST)-based map with high marker density. The putative role of the candidates in drought tolerance is discussed. The phenotypic effect of three of the five candidate genes was also tested on 39 barley landraces and cultivars and a significant relationship was found between the allelic composition of these genes and yield production under stress conditions. This study presents a relevant example of the use of reliable QTL data in the candidate gene approach, while also demonstrating how the results could be practically utilized in marker-assisted selection (MAS).     

Metabolic resistance mechanisms to phosalone in the common pistachio psyllid, Agonoscena pistaciae (Hem.: Psyllidae)

The common pistachio psyllid, Agonoscena pistaciae, is the most damaging pest of pistachio in Iran, and is generally controlled by insecticides belonging to various classes especially, phosalone. The toxicity of phosalone in nine populations of the pest was assayed using the residual contact vial and insect-dip methods. The bioassay results showed significant discrepancy in susceptibility to phosalone among the populations. Resistance ratio of the populations to the susceptible population ranged from 3.3 to 11.3. The synergistic effects of TPP, PBO and DEM were evaluated on the susceptible and the most resistant population to determine the involvement of esterases, mixed function oxidases and glutathione S-transferases in resistance mechanisms, respectively. The level of resistance to phosalone in the resistant population was suppressed by TPP, PBO and DEM, suggesting that the resistance to phosalone is mainly caused by esterase detoxification. Biochemical enzyme assays revealed that esterase, glutathione S-transferase and cytochrome P450 monooxygenase activities in the resistant population was higher than that in the susceptible. Glutathione-S-transferases play a minor role in the resistance of the pest to phosalone.     

Denitrification enzyme activity and potential of subsoils under grazed grasslands assayed by membrane inlet mass spectrometer

The importance of subsoil denitrification on the fate of agriculturally derived nitrate (NO₃) leached to groundwater is crucial for budgeting N in an ecosystem and for identifying areas where the risk of excess NO₃ is reduced. However, the high atmospheric background of di-nitrogen (N₂) causes difficulties in assessing denitrification enzyme activity (DEA) and denitrification potential (DP) in soils directly. Here, we apply Membrane Inlet Mass Spectrometry (MIMS) technique to investigate indirectly DEA and DP in soils by measuring N₂/Ar ratio changes in headspace water over soil. Soils were collected from 0-10, 15-25 and 60-70 cm depths of a grazed ryegrass and grass-clover. The samples were amended with helium-flushed deionized water containing ranges of NO₃ and carbon (glucose-C) and were incubated for six hours in the dark at 21 °C. The peaks for N₂/Ar ratio, declined with increasing soil depth, indicating a reduced substrate requirements to initiate DEA en-masse (15-30 mg NO₃-N alone or with 60-120 mg glucose-C, kg⁻¹ soil). The dissolved N₂O concentrations were very small (0.004-0.269 μg N kg⁻¹ soil) but responded well to the added N and C, showing a reduction in DEA with soil depth. In three separate studies, only subsoils were incubated for 3 days at 12 °C with 20-30 mg NO₃-N ± 40-60 mg glucose-C, kg⁻¹ soil. Denitrification capacity (DC, NO₃ only treatment) was not statistically different to the control (no amendment) within a land use (0.03-0.05 vs. 0.07-0.22 mg N kg⁻¹ soil d⁻¹), the highest being in ryegrass subsoils receiving groundwater. The DP was significantly (P < 0.0001) higher in subsoils under ryegrass than under grass-clover (0.50-0.71 vs. 1.15 mg N kg⁻¹ soil d⁻¹). The rates of DP (NO₃ + glucose-C) increased significantly (P < 0.0001) in unsaturated and saturated subsoils (0.92 and 2.19 mg N kg⁻¹ soil d⁻¹, respectively) of grass-clover, due to the higher reductive state resulting from the 10 day pre-incubation. Available C accelerated denitrification in soils and superseded the temporary elevation in oxidative state due to NO₃ addition. The substrates load differences between the land uses regulated the degree of denitrification rates. Results suggest that both dissolved N₂O measured by gas chromatography and N₂/Ar ratio measured by MIMS to indirectly determine DEA, and the latter to quantify total DC/DP in soils can be used. However, interference of oxygen in the MIMS system should be considered if available C is added or is naturally elevated in soil or groundwater.     

Field study of the interaction between Orobanche crenata Forsk. and some new lines of Vicia faba L. in Egypt

In Egypt, some newly derived lines of faba bean (Vicia faba L.) as well as Giza 402, all of which had shown a certain resistance against the parasitic weed Orobanche crenata Forsk., were tested in the field. For reasons of comparison, the susceptible cultivars Giza 3 and Reina Blanca were included in this test. Faba bean plants and Orobanche attachments were regularly harvested and examined. The susceptible cultivars completely collapsed before the end of the growing season, whereas others, particularly line 402/294, remained alive until pod formation was completed. It appeared that fewer Orobanche spikes emerged on the new lines and Giza 402. Evidence is given that this was not due to avoidance mechanisms, such as smaller root mass, a deeper root system or lack of germination stimulants. Numbers of Orobanche attachments per unit of lateral root length were found to be low. Hence, it could be concluded that these lines are partially resistant; this resistance must be due to some defence mechanism in their roots. The few Orobanche plants attached grew very fast so that final Orobanche dry weight was similar in resistant and susceptible host plants. Further experiments, including broomrape-free controls, are required to study whether some tolerance mechanism might be involved.     

Growth criteria of two common cyanobacteria isolated from Egyptian flooded soil,as influenced by some pesticides

Higher rates of the two organophosphorus Insecticides (dimethoate and dursban) induced severe drop in the dry weight gain of Nostoc muscorum and Anabaena oryzae. The fungicide karathane seemed to be inhibitory to the growth of Anabaena whereas all levels of the fungicide, except the two higher stimulated the growth of Nostoc. Trifluralin at all levels inhibited the growth of both organisms. However the magnitude of inhibition was always more pronounced in Anabaena. The lowest concentrations of dursban and dimethoate favored chlorophyll a synthesis in the cells of both cyanobacteria. Contrary to chlorophyll, total carotenoid accumulation was significantly suppressed. Moderate and higher doses of karathane and trifluralin increased chlorophyll a biosynthesis in Nostoc and to lesser extent in Anabaena, a phenomenon that was accompanied by significant increase in total carotenoid content. Glucose uptake by both organisms from media was accelerated following adminestration of all pesticides, an effect that was intensified with further increase in concentrations. Dimethoate and dursban favored the total carbohydrate accumulation in the cells of both organisms, whereas karathane and trifluralin accentuated the process, more prominently in Nostoc.     

The complete elimination of vicine and convicine from the faba beans by combinations of genetic selection and processing techniques

Out of sixty six faba bean (Vicia faba) cultivars and genotypes grown locally in Egypt and in Syria, the genotype 123 A/45/76 proved to be lowest in its vicine and convicine contents. Furthermore, soaking of this bean variety in 1% acetic acid at 40°C for 48 h resulted in reducing the total vicine and convicine contents of the beans by 90%. Home-made faba beans processing including soaking prior to cooking as in the case of bean cakes resulted in considerable reduction of the vicine and convicine contents by 56 and 34% respectively.     

Chemical composition and nutritional quality of sorghum flour and bread

Two Saudi Arabian sorghum cultivars, white and reddish white, were investigated for their chemical and nutritional quality. The two cultivars were similar in proximate composition (white 15.3% protein, reddish-white 15.9% protein), mineral profile, fatty acid composition, vitamin content (except vitamin-B₁₂ was higher in reddish-white), in vitro protein digestibility (IVPD) and calculated protein efficiency ratio (C-PER). White sorghum had lower tannins (0.09% catechin equivalent) compared to the reddish-white (0.27% catechin equivalent). Lysine was the first limiting amino acid in both with chemical scores of 45 and 47 for the proteins of white and reddish-white cultivars, respectively. Baking had no effect on proximate, fatty acid and amino acid composition. However, it increased the Na and Ca contents but decreased the K, P, and pantothenic acid contents. Tannins were not detected in the breads. Breads fermented for 18 h had higher vitamin-B₁₂ and pantothenic acid levels but lower P content than unfermented breads. A slight increase in tyrosine, lysine, methionine contents as well as C-PER was also observed in fermented bread.     

Plant Density and Nitrogen Effects on Maize Phenology and Grain Yield

ABSTRACT

Nitrogen (N) and plant density are considered some of the most important factors affecting crop phenology (days to tasseling, silking, and maturity), morphology (leaves plant^?1, seeds ear^?1, ears 100 plants^?1) and grain yield. The effects of plant density and N on phenology, morphology, and yield of maize (Zea mays L.) at Peshawar in northwestern Pakistan were evaluated during 2002 to 2004. The 2 × 3 × 6 factorial experiment was designed having two plant densities (60,000 and 100,000 plants ha^?1) and three N levels (60, 120, and 180 kg N ha^?1) applied to main plots, while six split application of N in different proportions were applied to subplots in two equal, three equal, three unequal, four equal, five equal and five unequal splits at sowing and with 1st, 2nd, 3rd, and 4th irrigation at two week intervals. All the phenological characteristics were significantly affected by year, plant density, rate and timing of nitrogen application. Year and plant density had no significant effect while rates and split application of N had significant effects on the leaf number plant^?1 and seed number ear^?1. Year, plant density and N rate had significant effects while N splits had no significant effects on the number of ears 100 plants^?1 of maize. Significantly higher grain yield was observed under high plant densities, high N rate and split application of N, while its response to year effects was statistically non-significant. Tasseling, silking and physiological maturity were delayed and maximum grain yield was obtained from those plots maintained at higher plant density. Delaying in the phenological characteristics while increasing the number of leaves and seeds plant^?1, and number of ears 100 plant^?1 through high rate and split application of N results in maximum yield of maize at Peshawar. This study suggested that maize production can be maximized through high plant density and high N split application.