Laboratoire Of Biochimie Et Of Technobiologie

Tunis, Tunisia

Laboratoire Of Biochimie Et Of Technobiologie

Tunis, Tunisia
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Mabrouk Y.,Laboratoire Of Biochimie Et Of Technobiologie | Mabrouk Y.,Unite Technologies | Mejri S.,Laboratoire Of Biochimie Et Of Technobiologie | Mejri S.,Unite Technologies | And 5 more authors.
African Journal of Microbiology Research | Year: 2010

Broomrapes are achlorophyl holoparasites of many important economic dicotyledonous crops. As weeds, they significantly decrease crop yields. Orobanche crenata is an important constraint to Mediterranean area pea (Pisum sativum L.) cultivation, as no resistant variety is available. Our previous researches showed that several Rhizobium leguminosarum strains decrease damages caused by O. crenata in pea. The aim of this work was to characterize the resistance induced by R. leguminosarum against broomrape. Higher concentrations of phenolic compounds and lignin were observed in pea roots inoculated with Rhizobia, in comparison to non inoculated. Polyphenol oxidase and peroxidase activities were significantly higher in inoculated plants as compared to non-inoculated ones. These results suggest that the mechanisms of induced resistance by Rhizobia against O. crenata involve an elevated induction of the phenylpropanoid pathway, conferring mechanical and chemical barriers confronting the invading parasite. ©2010 Academic Journals.

Mellef J.,Laboratoire Of Pharmacie Toxicologie | Dridi A.,Service dAviculture et de Pathologie Aviaire | El Bahri L.,Laboratoire Of Pharmacie Toxicologie | Belhaj O.,Laboratoire Of Biochimie Et Of Technobiologie
Revue de Medecine Veterinaire | Year: 2010

The use of microbial phytase in poultry nutrition has remarkably increased during the last decade in order to reduce the faecal excretion of phosphorus and the consequent problems of environmental pollution. Many studies have demonstrated the beneficial effects of dietary phytase supplementation on growth performances, particularly on the weight gain, in broiler chickens. The improvement of performances was mainly obtained in young birds (142 days old) or in chickens fed with diets containing low contents of non phytic phosphorus for phytase dosages above 250 U/kg of food. Nevertheless, the food efficiency appeared improved only for phytase dosages superior to 600 U/kg. The dietary phytase supplementation in hen layers allows the reduction of mineral P in the ration without negatively affecting the egg production or the egg qualities. By markedly accelerating the phytate hydrolysis, the added enzyme promotes the intestinal assimilation of phosphates and divalent cations, increases N retention and notably decreases the P emissions in litter. Consequently, with the possibility of reducing dietary mineral P content coupled to a better organic P (phytate) utilisation, the phytase addition into poultry diets leads to drastically decreased P effluents and undoubtedly contributes to the adaptation of poultry production in an environment much closer to ecological standards.

Mellef J.,Laboratoire Of Pharmacie Toxicologic | Dridi A.,Service dAviculture et de Pathologic Aviaire | Agrebi A.,Laboratoire Of Biochimie Et Of Technobiologie | Belhaj O.,Laboratoire Of Biochimie Et Of Technobiologie
Revue de Medecine Veterinaire | Year: 2011

The aim of this study was to investigate the eventual beneficial effects of the phytase incorporation into a phosphorus-deficient aliment on the laying performance in hens. A total of 240 Shaver 2000 hens, 30 week old at the beginning of the experimental period, were randomly assigned into 4 equal groups according to the enzyme quantities (0, 400, 800 and 1 200 U/kg) added to corn-soya meal diet for 8 weeks. After a 4 week-long diet adaptation period, eggs were collected and weighted during 4 other weeks in order to determine the weekly and mean laying parameters (laying rate, egg mass, mean egg weight and food efficiency). The mortality rate was daily recorded and body weights were measured at the beginning and at the end of the egg collect period. The dietary additions of 800 and 1 200 U/kg phytase have induced a significant increase in the weekly and mean laying rates, in egg masses on weeks 37 and 38, as well as a significant improvement of the food conversion ratios for the whole collect period whereas the weight variations were markedly reduced in parallel and that the food intake has tended to decrease. The mortality rates and the frequency of abnormal eggs (limp or cracked) have remained low whatever the group. However, the mean egg weight has tended to be diminished when 1 200 U/kg phytase was used. All these results show that the moderate phytase incorporation into a corn-soya diet has improved the laying performances and sustained the body weight without altering the egg physical quality, probably because of increasing in the available P content in the diet.

Mejri S.,Center National des science technologiques et Nucleaires | Mejri S.,Laboratoire Of Biochimie Et Of Technobiologie | Mabrouk Y.,Center National des science technologiques et Nucleaires | Mabrouk Y.,Laboratoire Of Biochimie Et Of Technobiologie | And 2 more authors.
BioTechnology: An Indian Journal | Year: 2013

Successful production of faba bean crops under severe conditions and in the presence of a wide range of disease-causing fungi, parasitic weeds, nematodes, insects, mites and other pests depends on the integration of genetic resistance, hygienic management, monitoring of the target organisms and timely application of appropriate chemical and biological treatments. This paper reviews the strategies developed to enhance growth of faba bean, the limits and possible solutions. Control methods are being developed that comprise agronomical management techniques, chemical and biological control methods, genetic and induced resistance. However, the main concern is that to date, no single method of control provides complete protection against these pathogens and parasites. For that reason, an integrated approach is needed in which a variety of such techniques are combined, in order to maintain faba bean production under severe conditions. For inducing genetic diversity the use of ionizing radiation especially gamma rays, is well established. Induced mutations have been used to improve major crops which are seed propagated. Since the establishment of the Joint FAO/IAEA Division of the Nuclear Techniques in Agriculture, more than 1800 cultivars obtained either as direct mutants or derived fromtheir crosses have been released worldwide in 50 countries. In the presence of regression of faba bean culture in the world caused by selection pressure on the pathogens and pests, creating new varieties, continued breeding for novel resistance genes, development of new selective chemicals, screening for new biocontrol agents and the design of new management strategies will all be necessary. © 2013 Trade Science Inc. - INDIA.

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