The objective of this study is to analyze the prospective of the low water flows of the N'zo-Sassandra River located in the West of Ivory Coast. The hydroclimatic data used (rainfall, ETP, flow) extend on the one hand over the historical period (1961-2017) and on the other hand over the future period 2071-2100 (CORDEX data). The methodological approach adopted is based on the analysis of past low flows, the climate prospective analysis and the hydrological prospective analysis. The hydrological impact variable used is the annual minimum monthly mean flow (MAMF). Thus, a pessimistic climate forecast scenario was used (RCP 8.5.). This climate scenario was then fed into a rainfall-runoff hydrological model (GR2M model) calibrated to the 1961-1990 reference period and validated over the 1991-2017 period. In response to the climate forcing, future monthly low-flow rates (MAMF) were simulated. An increase in the number of flows in the class ]0-4] m3/s was observed, reflecting low flows in the 2071–2100-time frame. The best statistical law retained following the frequency analysis of the low-water flows is the lognormal law. By 2071-2100, a decrease in rainfall (-19.2%) and an increase in temperature (+3.9°C) are predicted in the N'zo-Sassandra watershed. Frequent low-water flows estimated from the lognormal law have shown a bias of -50.38%, which translates into a decrease of half of the frequent low-water flows by the end of the 21st century compared to the current period. This decrease in flows will have consequences on the availability of water resources for irrigation, fishing, breeding, drinking water supply, navigation, etc. This is why we propose as alternative resources for agricultural needs, groundwater which is less impacted by global changes.
This work consists in studying the productive and reproductive performance of Holstein dairy cows (n=77) reared in an intensive production system in a Mediterranean climate, as well as the factors of their variations. Meteorological data collected between 2017 and 2020 for the region of Beja, North-West of Tunisia, revealed that the average monthly values of ambient temperature (Ta), relative humidity (HR) and temperature-humidity index (THI), are respectively 19.97 ±1.24°C, 73.69±3.42%, and 66±1.74. During the 3 years of study, the cows were exposed to a hot summer season which began in Jun (THI= 76) and persisted until September (THI =77). On average, milk production at 305 days of lactation, milk fat (MG) and protein (MP) content, as well as somatic cell count (SCC) were respectively 5782 ± 358 Kg, 3.36 ± 1.65%, 3.12 ± 0.42% and 489 ± 305 x 103 cells/ml. Several factors significantly (P < 0.05) affect milk production. Indeed, the highest milk production is observed during the year 2020. When the THI increases, the drop of milk production is greater (-0.18kg/d, per THI point). Multiparous cows produce more milk than primiparous cows, with higher yields at peak lactation (30.0 kg/d) and a lower persistence coefficient (95.6%). Cows calved in winter produced more milk (+22%; P<0.05) than cows calved in summer. The interval between calving to the first insemination (IV-IA1), calving to fertilizing insemination (IV-IAF) and calving interval (IVV) were 87.4 ± 28.2 days, 134 ± 71 days and 425 ±75 days respectively. The success rate in 1st insemination (TRIA1) and three or more insemination, as well as number of inseminations per conception were respectively 29.1±18.5%, 9.7±5.5% and 2.11±1.6. In conclusion, control of breeding conduct, in particular the heat detection technique, is essential to improve the productivity of the Holstein cow raised in an intensive production system in a hot Tunisian climate.
Medicinal plants produced many secondary metabolites which constituted an important source of bioactive molecules. This study aims to determine organic extracts (EOs) antioxidant activity extracted from terminal branches of Pistacia lentiscus (P. lentiscus) collected at three different phenological stages (vegetative, flowering and fructification). For this, different extracts were prepared by maceration in various solvents with increasing polarity notably diethyl ether, ethyl acetate, dichloromethane, methanol and water. Antioxidant activity was reported by DPPH free radical scavenging, iron reducing capacity and total antioxidant capacity tests. Results showed that phenological stages and solvent polarities affected significantly P. lentiscus antioxidant activity. Furthermore, aqueous and methanolic extracts from vegetative stage present the highest total polyphenols, total flavonoids and condensed tannins contents. Methanolic extract from vegetative stage exhibited the greatest antioxidant activity and even exceeded that of synthetic antioxidants BHT and ascorbic acid. In this study, P. lentiscus represents an important source of antioxidant molecules. As a result, extracts of this plant could replace synthetic antioxidants in e food, pharmaceutical and cosmetic fields.
Currently, herbal medicine has proven its effectiveness and undeniable benefits in our daily lives, confirming that plants can prevent and treat. In this context, we are interested in carrying out an ethno-pharmacological survey on the traditional use of Melissa officinalis in the Tabarka region as well as phytochemical screening and the study of antioxidant and antibacterial activities. The survey conducted in the Tabarka region revealed that lemon balm was used in traditional medicine to treat a whole range of pathologies. Indeed, we have shown that Melissa officinalis is traditionally used for the treatment of various diseases and particularly those of the digestive system pathologies and nervous disorders. The survey also revealed three methods of preparation: decoction, infusion and maceration. The method of administration is highly dependent on the pathology to be treated. In the present work, the phytochemical screening showed that Melissa officinalis leaves aqueous extract (MOAE) presents an important scavenging action against the DPPH radical. Importantly, MOAE presented a broad spectrum of antibacterial activity and Gram +ve were more sensitive than Gram-ve bacteria. Thus, the bioactive components of lemon balm can be used as antioxidant and antibacterial substances.
The objective of this work is to carry out a comparative study between irrigated and rain-fed olive farms in arid area, Zarzis belonging to Southern Tunisia. In order to achieve this objective, a survey was carried out on nearly 30 farms: 13 are in the irrigated lands and 17 are in dry areas. As a first step, we proceeded through a socio-economic, technical and environmental assessment in order to determine the characteristics of each type of farms. As a second part, we tried to identify the strengths, weaknesses, opportunities and threats specific to the olive sector in this arid region, through SWOT method. The assessment shows that the irrigated farms were the object of modernization process, whose owners are really investors, aiming a rapid profitability by this farming activity. The farms are characterized by a high density of olive tree plantations and the stability of yields. Thus, they represent a source of employment in the region. On the other side, dry olive farms have a classic production system and low yields, generating not only a problem of profitability, but also of the viability of these farms, which explains the abandonment of these lands.
