Impact of the potato inoculation date on potato virus Y load and viral distribution in daughter tubers at harvest

Aged plants are more difficult to infect than young plantlets. This modification of susceptibility is described as mature plant resistance (MPR). For potato virus Y (PVY), MPR is known to lead to low infection rates of plants inoculated at the postflowering stage and a decrease in the number of infected daughter tubers. However, the impact of inoculation date on the capacity of PVY to accumulate in daughter tubers has not been studied so far. Field and greenhouse experiments were carried out to better understand PVY epidemiology and to help potato growers to evaluate consequences of early/late infections on the quality of their crops. In field trials, potato plants (cv. Bintje) were covered by insectproof nets from planting to harvest except for a 14-day period to expose plants to natural PVY infections. Under controlled conditions, potato plants were mechanically inoculated with PVY at different dates from preflowering stages (early inoculations) to postflowering stage (late inoculations). At harvest, daughter tubers were individually collected and analysed to define proportions and viral load of infected tubers according to the time between virus inoculation and harvest. Our results showed that although the age of plants at the time of inoculation can modify their susceptibility to PVY infection, in return, early and late PVY inoculations lead to similar rates of infected tubers at the plant scale and equivalent viral accumulation in infected tubers. All together, these data revealed that both early/late infections are high risks for the sanitary quality of potato tubers.     

The Antinociceptive and Anti-Inflammatory Activities of Caulerpin,a Bisindole Alkaloid Isolated from Seaweeds of the Genus Caulerpa

The antinociceptive and anti-inflammatory activity of caulerpin was investigated. This bisindole alkaloid was isolated from the lipoid extract of Caulerpa racemosa and its structure was identified by spectroscopic methods, including IR and NMR techniques. The pharmacological assays used were the writhing and the hot plate tests, the formalin-induced pain, the capsaicin-induced ear edema and the carrageenan-induced peritonitis. Caulerpin was given orally at a concentration of 100 μmol/kg. In the abdominal constriction test caulerpin showed reduction in the acetic acid-induced nociception at 0.0945 μmol (0.0103–1.0984) and for dypirone it was 0.0426 μmol (0.0092–0.1972). In the hot plate test in vivo the inhibition of nociception by caulerpin (100 μmol/kg, p.o.) was also favorable. This result suggests that this compound exhibits a central activity, without changing the motor activity (seen in the rotarod test). Caulerpin (100 μmol/kg, p.o.) reduced the formalin effects in both phases by 35.4% and 45.6%, respectively. The possible anti-inflammatory activity observed in the second phase in the formalin test of caulerpin (100 μmol/kg, p.o.) was confirmed on the capsaicin-induced ear edema model, where an inhibition of 55.8% was presented. Indeed, it was also observed in the carrageenan-induced peritonitis that caulerpin (100 μmol/kg, p.o.) exhibited anti-inflammatory activity, reducing significantly the number of recruit cells by 48.3%. Pharmacological studies are continuing in order to characterize the mechanism(s) responsible for the antinociceptive and anti-inflammatory actions and also to identify other active principles present in Caulerpa racemosa.     

Impact of reduced dietary crude protein levels and phytase enzyme supplementation on growth response,slurry characteristics,and gas emissions of growing pigs

This experiment was carried out to evaluate the effect of reduced dietary crude protein (CP) levels supplemented with or without exogenous phytase on growing pigs. Six dietary treatments arranged in a 3 × 2 factorial arrangements of 3 CP levels (containing 14%, 16%, and 18% CP) supplemented each with or without 5,000 FTU/g phytase enzyme. Thirty growing pigs (average weight of 17.80 ± 0.10 kg) were allotted to the six dietary treatments in a complete randomized design. The final weight, daily weight gain, and feed conversion ratio (FCR) increased significantly with increasing CP levels. While, phytase supplementation improved (p = .044) FCR in pigs. Total solid and volatile solid content of the slurry were higher (p = .001) in pigs fed 14% and 16% CP diets supplemented with phytase when compared with other treatment groups. Concentration of methane gas emitted was lowest (p = .001) in the slurry of pigs fed 14% CP diet with or without phytase and those fed 16% CP diet with phytase supplementation. In conclusion, reduction in dietary CP levels resulted in reduced weight gain and poor FCR. While, reduced CP with phytase supplementation reduced concentration of methane gas emitted.     

Evaluation of the durability of the <Emphasis Type="Italic">Barley yellow dwarf virus</Emphasis>-resistant <Emphasis Type="Italic">Zhong ZH</Emphasis> and <Emphasis Type="Italic">TC14</Emphasis> wheat lines

Serial passage experiments (SPE) of a Barley yellow dwarf virus-PAV (BYDV-PAV) isolate were performed on Zhong ZH and TC14 wheat lines to evaluate the durability of their resistance to BYDV. At different passage numbers (from the 2nd to the 114th), biological properties of the produced isolates were recorded either by monitoring infection percentages and virus titers of the first 3 weeks of viral infection or by measuring their impact on yield components. Statistical analyses using the area under pathogen progress curves and the area under concentration progress curves demonstrated that these two resistant lines induce, after only a few passages, a selection of variant(s) with significantly modified infection abilities. Isolates resulting from SPE performed on these lines induced important decreases of yield components. These results indicate that the use of Zhong ZH and TC14 lines in BYDV-resistant breeding programmes should be approached with caution.     

Assessment of antimicrobial drug administration and antimicrobial residues in food animals in Enugu State,Nigeria

Tropical Animal Health and Production - Imprudent administration of antimicrobial drugs in food-producing animals can facilitate the development and spread of antimicrobial-resistant organisms and...     

Stimulatory effect of dietary clove,Eugenia caryophyllata,bud extract on growth performance,nutrient utilization,antioxidant capacity,and tolerance of African catfish,Clarias gariepinus (B.), to Aeromonas hydrophila infection

The occurrence of pathogenic bacteria, Aeromonas hydrophila, in farm‐raised fish requires urgent attention. Continuous and indiscriminate use of antibiotics as growth promoters and disease control agents in aquaculture have been discouraged because of the risk of development of antibiotic‐resistant bacterial strains. There is steady interest in the use of botanicals, such as clove, Eugenia caryophyllata, buds extract (ECBE), as alternatives. Hence, the present study evaluated the effect of dietary ECBE supplementation on the growth performance, physiological, antioxidant, and immunity biomarkers of African catfish, Clarias gariepinus. Fish (11.7 ± 0.5 g) were fed diets containing 0.0 (control), 5.0, 10.0, or 15.0 g ECBE/kg diet up to apparent satiation twice daily for 12 weeks. After the feeding trial, fish from each treatment were challenged with A. hydrophila infection by intraperitoneal injection and kept under observation for 14 days to record any abnormal clinical signs and daily mortality. The results demonstrated that fish performance and feed intake were significantly enhanced with increasing ECBE levels, and its optimum level is 15 g/kg diet. Further, the dietary ECBE increased significantly the intestinal villi length/width and absorption area in a dose‐dependent manner. There are significant progressive increases in the values of red blood cells, hemoglobin, hematocrit, white blood cells, platelets, lymphocytes, and heterocytes, while monocytes, eosinophil, and basophils decreased significantly due to dietary ECBE in a dose‐dependent manner. Highest glucose, cholesterol, total protein, globulin, and albumin‐globulin ratios, aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), urea, and creatinine values were found in fish fed 15 g ECBE/kg diets, while lowest values were recorded in fish fed the control diet. Despite the high AST and ALT values, no visible lesions or damage were observed in the liver cells of fish fed ECBE‐enriched diets. In addition, the inclusion of ECBE in fish diets enhanced the antioxidant and immunity capacity. Fish mortality after the bacterial challenge was higher in fish fed the control diet (82.3%) than those fed ECBE‐enriched diets. The lowest fish mortality was observed in fish fed the 15 ECBE/kg diet (4.7%) [Correction added on 16 November 2018: this section has been revised for clarity.].     

Genetic differences for nitrogen uptake and nitrogen utilisation efficiencies in winter wheat

Due to economic and ecological factors, European agricultural practices are likely to go towards extensive systems with lower inputs of nitrogen (N) fertilisers. The objective of this study was to assess varietal differences for N use at two nitrogen levels. A set of 20 winter wheat (Triticum aestivum L.) genotypes was studied over 2 years in northern France on a deep loam soil without (N0) and with 170 kg ha⁻¹ N fertiliser (N+) as ammonium nitrate. Results were consistent on both years as the genotype×year or genotype×year×N level interactions were not significant. The genotype×N level interaction was highly significant except for total N utilisation efficiency (total above-ground dry weight/total above-ground N) and grain N concentration. The genotype×N level interaction for grain yield was mainly due to three contrasting genotypes: Cappelle, a cultivar from the 1940s, had the same yield at N0 and N+; Arche had a high yield at both N levels; and Récital had a high yield with added N and a very low one without N. The number of kernels/ear explained most of the variations of grain yield at N0 (48%) and N+ (80%), and of the interaction (67%). N uptake efficiency (total above-ground N/soil N supply) accounted for 64% of the variation in N use efficiency (grain yield/soil N supply), while at N0 and at N+ it accounted for only 30%. N utilisation efficiency (grain yield/total above-ground N) was then more important at N+ than at N0. Grain N explained most of total plant N variation at both N levels. The interaction for N use efficiency was best explained by the interaction of N uptake (63%). The applications of these results to a breeding programme to create varieties adapted to low-input management systems are discussed.     

A new process for the management of olive oil mill waste water and recovery of natural antioxidants

The high polyphenol content of the wastewater is the major environmental problem caused by the olive mills. A pilot scale system for the treatment of the olive oil mills wastewater was developed aiming at the recovery of high added value-contained polyphenols and the reduction of the environmental problems. The treatment system consists of three main successive sections: The first one includes successive filtration stages aiming at the gradual reduction of the wastewater suspended solids up to a limit of 25 microm. The second section includes passing of the filtered wastewater through a series of adsorbent resins (XAD16 and XAD7HP) in order to achieve the de-odoring and decolorization of the wastewater and the removal/ recovery of the polyphenol and lactone content. The third section of the procedure includes the thermal evaporation and recovery of the organic solvents mixture, which has been used in the resin regeneration process, and finally the separation of the polyphenols and other organic substance contents using fast centrifuge partition chromatography. The final outcome of the whole procedure is (i) an odorless yellowish wastewater with a 99.99% reduced content in polyphenols and 98% reduced COD, (ii) an extract rich in polyphenols and lactones with high antioxidant activity and high added value, (iii) an extract containing the coloring substances of the olive fruit, and (iv) pure hydroxytyrosol.