Effect of phosphate dissolving bacteria on P-uptake by barley plants grown in a salt affected calcareous soil

In a pot experiment the effect of inoculation of a salt affected calcareous soil with phosphate dissolving bacteria (PDB) on dehydrogenase activity and P-uptake by barley plants was investigated. Four levels of artificial salinity were used, i. e., 0.2, 0.4, 0.8 and 1.2 % total soluble salts. Inoculation increased PDB in all treatments, but it did not affect the microbial activity in the soil as represented by dehydrogenase activity. The higher the salt level the lower the counts of PDB and dehydrogenase activity in the soil. A positive significant difference was recorded in P-uptake as a result of inoculation and a negative one as a result of increasing salinity.     

Induction of a malathion-resistant strain in the common predacious mite Amblyseius cydnodactylon (Acari: Phytoseiidae)

This study demonstrates a laboratory induction of a malathion - resistant strain in Amblyseius cydnodactylon Shehata & Zaher and effect of selection on reproduction. Initially 500 sensitive females obtained from a laboratory mass culture were exposed to malathion at LC70. Subsequent selections were conducted every two generations at progressive LC70 values and number of eggs/female/day was recorded at each selection. Experiments were carried out under laboratory conditions of 24-28°C and 70-80 % R. H. The LC70 in the parent generation was 5.19 ppm and increased to 20 ppm in F4 selection generation. The dosage mortality relationships continued to increase up to a maximum of 282.3 ppm in F16. The rate of developing resistance increased from 1.75 folds in F2 to 1.97 folds in F4 and gradually reached a maximum of 54.39 folds in F16. There was an obvious decrease in reproduction corresponded to increasing resistance. For example, the number of eggs/female/day in F 16 was 8 eggs, contrasting 3 eggs in the parent generation.     

Pathogenicity of peste des petits ruminants virus isolated from Egyptian goats in Egypt

2 Egyptian goats and Boscat rabbits were experimentally inoculated with peste des petits ruminants (PPR) local Egyptian strain (PPR, Egypt 87). The inoculated animals contracted the disease with minor clinical manifestations, accompanied by rise of neutralizing antibodies to PPR virus. Virus was isolated from ocular and nasal secretions, buffy coat, spleen, and liver. No contact infection was observed between inoculated and healthy goats.     

Comparison of faecal collection method with high- and low-quality diets regarding digestibility and faeces characteristics measurements in Nile tilapia

The need for unbiased digestibility estimation has led to the development of a number of faeces collection methods. However, there is still a large variation in apparent digestibility coefficient (ADC) of diet/ingredients between these methods. This study investigated the impact of dietary quality on ADC and faeces recovery measurements obtained by two faecal collection methods (Choubert and settling tank). The fish were fed five diets: a control diet as high‐quality diet, two levels of dried duckweed (20% and 40%) and two levels of fresh duckweed (20% and 40%), which were added to the control diet, as low‐quality diets. Apparent digestibility coefficient estimates were highly correlated (r>0.95) between both faecal collection methods. For all diets the ADC estimates were higher when using settling tanks compared with Choubert collectors. For the control diet differences in ADC between two collectors were small, but by inclusion of duckweed these differences increased. The recovery percentage of faeces was not correlated between both faecal collection methods (r=0.22, P=0.41). The estimated recovery percentage of faeces by settling tanks was about three times higher than by Choubert. In conclusion, the differences in ADC and faeces recovery measured by two faecal collection methods depend on diet quality.     

Chlorophyll meter as a tool for forecasting wheat nitrogen requirements after application of herbicides

Because limited information is available about the validated use of a chlorophyll meter for predicting nitrogen requirements for optimum growth and yield of wheat after application of herbicides, field experiments were carried out in the winter seasons of 2011/2012 and 2012/2013 under different weed and N fertilization treatments. Five weeded treatments, application of herbicides 25 days after sowing (DAS), hand pulling once at 55 DAS and a weedy check were combined with four N application rates. Weeds were completely absent in the non-fertilized plots, either with metribuzin or hand pulling as well as in isoproturon-treated plots fertilized with 190 or 285 kg N ha^?1. The grain yield was similar in the treatments of isoproturon × 190 kg N ha^?1, isoproturon + diflufenican × conditional N treatment (113.9) or 190 kg N ha^?1, hand pulling × conditional N treatment (104.8) or 285 kg N ha^?1 and metribuzin × 190 kg N ha^?1. Under weeded practices, conditional N treatment recorded the maximum nitrogen use efficiency and almost equaled the grain protein content of the 190 kg N ha^?1 application rate. N application based on SPAD readings saved about 40.0% and 44.8% N with isoproturon + diflufenican or hand pulling, respectively, compared to the recommended rate (190 kg N ha^?1) without noticeable yield loss.     

Bee pollen and propolis as dietary supplements for rabbit: Effect on reproductive performance of does and on immunological response of does and their offspring

To evaluate the effect of bee pollen (BP) and/or propolis (Pro) supplementation on rabbit does, 64 nulliparous NZW rabbits does were distributed among eight groups (eight animals/group). One unsupplemented group was the control; the other seven groups were supplemented, respectively, with zinc bacitracin (ZnB) at 100 mg, BP at 150 and 300 mg, Pro at 150 and 300 mg, BP+Pro at 150 and 300 mg of each three times/week, day after day continuously along eight parities. The BP300, Pro300 and BP+Pro150 groups had higher body weight of litter at birth and number of kids born alive. The BP supplementation at 150 mg increased plasma total protein and albumin than the control group. The BP or Pro at 150 mg decreased plasma T₃ than the other groups except for BP+Pro150. The ZnB group had significantly greater T₃/T₄ ratio compared to BP, Pro and BP+Pro at 150 mg. The BP+Pro150 group had less ALT than the control; BP300 and Pro 300 mg resulted in lower plasma AST than the groups Pro150 with or without BP and the control group. The plasma alkaline phosphatase of BP at 150 or 300 mg and BP+Pro150 was significantly greater than that of the Pro150 group. The BP+Pro300 group had higher WBCs than the other groups. In contrast, the lymphocytes were greater in the Pro and BP+Pro300 groups than in BP, Pro and BP+Pro at 150 mg. The groups supplemented with BP and BP+Pro at 150 and 300 mg had significantly greater SRBCs of doe rabbits and their offspring compared to the control and the ZnB group. The BP at 300 mg increased the serum albumin and α₁‐globulin than the control group. The Pro300 group had greater serum α₂‐globulin and β‐globulin than the control group. The total globulin was significantly greater for the 300 mg propolis‐supplemented groups than the control.     

Prevalence of serotypes G6 and G10 group A rotaviruses in dairy calves in Quebec.

Fecal samples from diarrheic and nondiarrheic dairy calves (1 to 3 weeks old) from 12 regions of Quebec, collected between 1992 and 1994, were screened for group A bovine rotavirus (BRV) using a combination of 2 VP6-specific monoclonal antibodies (MAbs) in an enzyme-linked immunosorbent assay (ELISA). The overall prevalence of BRV infection was 26.4% (107/405). In diarrheic calves, BRV infection reached 74.3% (55/74), but only 15.7% (52/331) in nondiarrheic calves. BRV-positive samples were serotyped by enzyme-linked immunosorbent assay (ELISA) using G6 and G10 specific MAbs. The analysis of 107 field samples revealed that, in diarrheic calves, 34.5% (19/55) were G6, 27.2% (15/55) were G10, 9% (5/55) were G6 and G10 positive, and 29.9% (16/55) were G6 and G10 negative. In nondiarrheic calves, 19.2% (10/52) were G6, 19.2% (10/52) were G10, 7.6% (4/52) were G6 and G10 positive, and 53.6% (28/52) were G6 and G10 negative. Rotavirus dsRNA was extracted from BRV-positive samples and examined by polyacrilamide gel electrophoresis (PAGE). Of 107 samples tested, 74 (69.1%) were positive, and all the samples demonstrated a typical group A rotavirus migration pattern.     

Induction of a malathion-resistant strain in the common predacious mite Amblyseius cydnodactylon (Acari: Phytoseiidae)

This study demonstrates a laboratory induction of a malathion - resistant strain in Amblyseius cydnodactylon Shehata & Zaher and effect of selection on reproduction. Initially 500 sensitive females obtained from a laboratory mass culture were exposed to malathion at LC70. Subsequent selections were conducted every two generations at progressive LC70 values and number of eggs/female/day was recorded at each selection. Experiments were carried out under laboratory conditions of 24-28°C and 70-80 % R. H. The LC70 in the parent generation was 5.19 ppm and increased to 20 ppm in F4 selection generation. The dosage mortality relationships continued to increase up to a maximum of 282.3 ppm in F16. The rate of developing resistance increased from 1.75 folds in F2 to 1.97 folds in F4 and gradually reached a maximum of 54.39 folds in F16. There was an obvious decrease in reproduction corresponded to increasing resistance. For example, the number of eggs/female/day in F 16 was 8 eggs, contrasting 3 eggs in the parent generation.     

Potentiality of Soil Mulch and Sorghum Extract to Reduce the Biotic Stress of Weeds with Enhancing Yield and Nutrient Uptake of Maize Crop

Two field trials were conducted in 2018 and 2019 to develop practical and economically efficient weed control programs in corn. The experiment included six treatments (cowpea, rice straw, sorghum extract, hoeing, foramsulfuron herbicide and weedy check). The treatments were arranged in randomized complete block design with four replicates. Findings showed that reduction in total weed number was evident with application of hoeing, cowpea and rice straw in 2018 and 2019 seasons, in addition to foramsulfuron herbicide and sorghum extract in 2019. Cowpea, hoeing, foramsulfuron herbicide and rice straw recorded higher reduction in dry biomass of grassy weeds in both seasons. Reductions in N, P and K uptake by weeds because of rice straw and cowpea treatments were similar to hoeing treatment in both seasons. The increases in ear grain weight and grain yield ha^?1 due to cowpea and hoeing treatments were similar to rice straw one. In 2019 season, cowpea treatment was the superior practice for improving N, P and K uptake of maize, significantly leveling hoeing for K uptake. The values of gross returns and benefit/cost ratio of cowpea and sorghum extract, respectively, were higher than rice straw application. In conclusion, cowpea as a live mulch achieved acceptable weed control in maize by reducing weeds growth and lowering their ability to deplete the soil nutrients. Also, cowpea treatment improves growth and yield of maize with better utilization of nutrients. Thus, cowpea could be exploited as an eco-friendly method of weed management programs in maize cultivation.

     

Optimization of Collaborative Photo-Fenton Oxidation and Coagulation for the Treatment of Petroleum Refinery Wastewater with Scrap Iron

The photo-Fenton oxidation treatment combined with a coagulation/flocculation process was investigated for removal of chemical oxygen demand (COD) from a refractory petroleum refinery wastewater. Scrap iron shavings were used as the catalyst source. A response surface methodology (RSM) with a cubic IV optimal design was employed for optimizing the treatment process. Kinetic studies showed that the proposed process could be described by a two-stage, second-order reaction model. Experiments showed that precipitation of iron ions can be utilized as a post-oxidation coagulation stage to improve the overall treatment efficiency. More than 96.9% of the COD removal was achieved under optimal conditions, with a post-oxidation coagulation stage accounting for about 30% of the removal, thus confirming the collaborative role of oxidation and coagulation in the overall treatment. A low-velocity gradient of 8.0 s^?1 for a short mixing time of 10 min resulted in optimum post-oxidation coagulation. Comparison of photo-Fenton oxidation to a standard Fenton reaction in the same wastewater showed more rapid COD removal for photo-Fenton, with an initial second-order rate constant of 4.0 × 10^?4 L mg^?1 min^?1 compared to the Fenton reaction’s overall second-order rate constant of 7.0 × 10^?5 L mg^?1 min^?1.