Hamdi S.,Montpellier SupAgro |
Chevallier T.,Montpellier SupAgro |
Ben Aissa N.,Institute National Agronomique Of Tunis Inat |
Ben Hammouda M.,Ecole Superieure dAgriculture du Kef ESAK |
And 3 more authors.
Soil Biology and Biochemistry | Year: 2011
Quantification of microbial activities involved in soil organic carbon (SOC) decomposition is critical for the prediction of the long-term impact of climate change on soil respiration (SR) and SOC stock. Although the temperature sensitivity of SR is especially critical in semi-arid regions, such as North West Tunisia, where the SOC stock is low, little research has been carried out in these environments. More needs to be known about factors, such as SOC availability that influence temperature sensitivity. In this study, soil samples were incubated with and without glucose addition for 28 days after a 28-day pre-incubation period. Pre-incubation and incubation was carried out at 20°C, 30°C, 40°C and 50°C. Respiration measurements were taken with temperature, glucose addition and incubation time as independent variables. The highest pre-incubation temperature reduced the temperature sensitivity of SR during the subsequent incubation period, both with and without glucose addition. Soil samples pre-incubated at 50°C had the lowest SR at all subsequent incubation temperatures and the lowest temperature sensitivity of SR, even after glucose addition. However, after glucose addition, the effect of a high pre-incubation temperature on soil respiration lasted only two days. Measuring the water-soluble carbon (WSC) in soil samples suggested that the high pre-incubation temperature may have killed part of the microbial biomass, modified microbial communities or solubilized SOC. For quantifying the possible effect of global warming, in particular heat waves, on soil respiration in the soil studied, the results indicate a moderate response of soil respiration to temperature at high temperatures, as shown by Q10 close to 1.7, even in the range 40-50°C. © 2010 Elsevier Ltd.
Chabbouh M.,University of Carthage |
Chabbouh M.,Institute National Agronomique Of Tunis Inat |
Sahli A.,University of Carthage |
Bellagha S.,University of Carthage |
Bellagha S.,Institute National Agronomique Of Tunis Inat
Journal of the Science of Food and Agriculture | Year: 2013
BACKGROUND: The effects of spicing on the physicochemical and microbial characteristics and drying behaviour of kaddid, a Tunisian dry-cured meat, were studied. In addition, the quality characteristics of traditional sun-dried kaddid and processed convective-dried kaddid were compared. RESULTS: Spicing had no significant effect on the pH and water activity of brined beef meat at 21% (w/w), but it reduced the product water and salt contents. Effects of spicing on brined meat microbial flora were the appearance of sulfito-reducer bacteria, an increase in total mesophilic aerobic flora (+15%) and staphylococci (+26%) and a decrease in faecal coliforms (-23%). The salted beef meat sorption behaviour was affected by spicing. Besides, spicing increased the kaddid drying rate, allowing a significant decrease in the drying process time (-33%). Traditional and processed kaddid presented comparable microbial characteristics. Both drying methods led to a reduction in the number of total mesophilic aerobic flora in unspiced and spiced kaddid and of faecal coliforms in spiced kaddid. CONCLUSION: The study showed that spicing, as a step in kaddid meat processing to enhance the final product flavour, caused changes in the salted meat physicochemical and microbial characteristics and accelerated the drying rate. Convective drying at 30 °C is recommended to produce kaddid having the same characteristics as the traditional product. © 2013 Society of Chemical Industry.
Chebbi N.,Institute National Agronomique Of Tunis Inat |
Chebbi N.,Institute Superieur Of La Peche Et Aquaculture Of Bizerte Ispa |
Mastrototaro F.,University of Bari |
Missaoui H.,Institute National Agronomique Of Tunis Inat |
Missaoui H.,Institute Superieur Of La Peche Et Aquaculture Of Bizerte Ispa
Cahiers de Biologie Marine | Year: 2010
A total of 12 species of ascidians was collected in the Bizerte lagoon and 16 species in El Bibane lagoon. Two of them, Aplidium caeruleum and Pseudodistoma ärnbäcki, were recorded for the first time in Tunisia and the non indigenous species Microcosmus squamiger was found for the first time in El Bibane lagoon. Distribution and abundance of ascidian species were significantly different in the two lagoons. In Bizerte lagoon, the most abundant species are the nonindigenous Ascidiella aspersa, Ciona intestinalis, Styela plicata and Styela canopus species able to tolerate environmental stress and low rate of water renewal. In El Bibane lagoon, the most abundant species is Ecteinascidia turbinata, which tolerates extremes of salinity and temperature. Certain species of ascidians could be classified as indicators of environment degradation. The abundance recorded of some of them in Bizerte lagoon, can be confirmed a high degree of environmental stress for this lagoon and the lack of effect in the El Bibane lagoon.
Neifar M.,Tunis el Manar University |
Jaouani A.,Tunis el Manar University |
Ayari A.,Tunis el Manar University |
Abid O.,University of Sfax |
And 4 more authors.
Chemosphere | Year: 2013
Olive Cake (OC) generated by the olive oil industries, well implanted in Tunisia, represents a major disposal and potentially severe pollution problem. This work presents the study of bioconversion of OC in solid state fermentation with the medicinal mushroom, Fomes fomentarius so as to upgrade its nutritional values and digestibility for its use as ruminants feed. The fungus was cultured on OC for 7-30. d, and subsequently the chemical composition, lignocellulolytic enzyme activities and in vitro digestibility of the resultant substrate were determined. The results obtained showed an increase in the crude protein ranging from 6% to 22% for the control and for treated OC, respectively. Significant (P<0.05) decreases in the values of neutral detergent fiber (hemicelluloses, cellulose and lignin), acid detergent fiber (lignin and cellulose) and acid detergent lignin were detected (23%, 13% and 10%, respectively). The estimated in vitro digestibility improved from 9% (control) to 25% (treated OC). The present findings revealed F. fomentarius to be an efficient organism for lignocellulolytic enzymes production and simultaneous enhancement in crude protein and in vitro digestibility of OC. © 2013 Elsevier Ltd.
Boufaroua M.,International Center for Agricultural Research in the Dry Areas |
Slimani M.,Institute National Agronomique Of Tunis Inat |
Oweis T.,International Center for Agricultural Research in the Dry Areas |
Albergel J.,CIRAD - Agricultural Research for Development
Global Nest Journal | Year: 2013
In Tunisian semi-arid regions, where water is a rare commodity and the large dams cannot be justified considering the very limited water contributions and the very high evapotranspiration, innovative techniques of harvesting water have been adopted. Tunisia has initiated a policy of small dam construction aiming to combine land and water management with socioeconomic development. They also target erosion control and protection of downstream infrastructure. Integrated rural development is achieved through the provision of a scarce but vital renewable resource. Using the results of multi-disciplinary research carried out in a network of 25 hill lakes implemented in a semi-arid area, the present article shows the role of small dams in the mobilization and management of water and soil resources. The issues involved in integrated development around hill reservoirs are closely linked to the sustainability of water. The agricultural development must be adapted to the life expectancy of the dam and the availability of water in dry periods. The recharge of the groundwater in the aquifers improves the potential for development. However, the impact of the stored water on health must be studied. The environmental impact of the lake structures is linked to the quality of the water and the maintenance of its supply. © 2013 Global NEST Printed in Greece. All rights reserved.