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Atti N.,Laboratoire Of Productions Animales Et Fourrageres | Mahouachi M.,Ecole Superieure dAgriculture du Kef
Tropical Animal Health and Production | Year: 2011

This review summarises the main factors that influence meat production and quality in fat-tailed Barbarine (FTB) lambs. As a general feature, FTB lamb's growth is moderate, and the average daily gain ranges between 100 and 350 g. The carcass being relatively fatty, carcass fat content varies from 10% to 32%; white fat and rose meat are often dominant in these carcasses. The meat fatty acid profile of this fat-tailed breed is similar to that of thin-tailed ones, with a prevalence of palmitic, stearic and oleic acids. The order of dissected adipose tissues accumulation, estimated by allometry coefficients, is in agreement with observations in thin-tailed sheep. However, tail fat allometry coefficient is closer to kidney fat values rather than to the subcutaneous one. Concerning effects of feed level, growth of FTB lambs fed silage is higher than those fed oat hay. With moderate concentrate supply, FTB lambs' growth is more pronounced on pasture diet than on the feedlot (FL) diet. Furthermore, at similar slaughter weights, carcasses of lambs fed pasture diet have less tail and carcass fat than those from lambs fed FL diet (5% and 18% vs. 9% and 24% for grazing and FL lambs, respectively). No difference in fat colour, fat firmness or cooked meat flavour is observed between carcasses obtained at different slaughtering weight (i.e. from 25 to 35 kg). The tail docking of FTB improved lambs' growth particularly before weaning. Its effect on carcass composition and fat proportion depends on stage of slaughtering and type of fattening diet. For suckled lambs (4 months), the docking resulted in the lower carcass fat weight (and proportion), while for fattened lambs, carcass composition was similar for all types of lambs. Overall, FTB lambs always grow slower than Noire de Thibar lambs. This is particularly pronounced during the fattening phase. Then, for FTB breed, the possibilities to obtain heavy carcasses are at risks of fat accumulation, 22.8% vs. 14.4% for FTB and Noire de Thibar thin-tailed lambs, respectively. However, the main advantage of FTB breed is that adults are well adapted to food scarcity and may produce lambs even under harsh conditions. © 2011 Springer Science+Business Media B.V. Source

Mathlouthi N.,Ecole Superieure dAgriculture du Kef | Auclair E.,Lesaffre Feed Additives | Larbier M.,French National Institute for Agricultural Research
Livestock Research for Rural Development | Year: 2012

The present study aims to evaluate the effectiveness in broiler chicken of the yeast cell walls obtained after cytoplasm extraction, acidification and drying. A total of seven hundred and fifty 1-day-old male broilers were assigned to 6 treatments: the basal diet (T), the basal diet supplemented with either Avilamycine (AB) or yeast cell walls dried by atomisation and used at two rates: 500 or 1000 mg/kg of diet (PAB and PAH, respectively) or dried by hot cylinder and incorporated at two levels: 500 or 1000 mg/kg of diet (PCB and PCH, respectively).Throughout the trial period (1 - 42 days), the body weight (p < 0.01) of chickens fed T diet which was 2.130 kg was increased by 116 g (+5.4%) when the chicken fed PCB diet. The Avilamycine addition improved body weight of chicken by 6.2 % compared to T diet. The feed: gain ratio recorded in chickens fed T diet was 1.974. AB and PCB diets improved feed: gain ratio by 7.1 % and 9.3 to 10 %, respectively compared to control treatment. Growth performances of broiler chickens obtained with yeast cell wall dried by atomisation were smaller than those dried by hot cylinder. The effects of yeast cell wall doses (500 or 1000 mg/kg of diet) on body weight or weight gain was not significant. Moreover, yeast cell wall (PCB group) and Avilamycine addition in the diet reduced mortality rate (0.8 %) compared to T (6.4 %). In conclusion, the yeast cell walls can substitute growth promoter antibiotics because they allow the same performances in broiler chickens. Furthermore, it is important to specify the mechanisms of action of yeast cell walls. Source

Jemai I.,University of Tunis | Ben Aissa N.,Institute National Agronomique Of Tunisie | Ben Guirat S.,University of Tunis | Ben-Hammouda M.,Ecole Superieure dAgriculture du Kef | Gallali T.,University of Tunis
Soil and Tillage Research | Year: 2012

Conservation agriculture based on no-tillage (CA/NT) becomes a current tendency to enhance crop productivity by improving: (i) soil quality, (ii) water management and (iii) organic supply. In Tunisia, the applicability of CA was poorly documented. This study was carried out to evaluate changes in soil organic matter (SOM) and water properties generated by seven (NT7) and three (NT3) years of applying NT as compared to conventional tillage (CT). On three adjacent large plots, a field experiment was established since the growing season 2000/01 under rain-fed conditions on a clay loam soil in a dry subhumid zone of North Tunisia. In NT3 plot, a cultivation of wheat/fava bean sequence was investigated and residues biomass of 500kgha -1 and 450kgha -1 were left on the soil surface for wheat and fava bean, respectively. In NT7 plot, a cultivation of wheat/sulla sequence was investigated and residues biomass of 500kgha -1 and 700kgha -1 were left on the soil surface for wheat and sulla, respectively. However for the CT plot, a moldboard plowing at approximately 20cm depth was managed for continuous wheat production. The selected key parameters evaluated for a 0-30cm soil profile were SOM, bulk density (BD), total porosity (TP), macro-porosity (MP), micro-porosity (mP), soil water retention at field capacity (FC) and at permanent wilting point (PWP), available water content (AWC) and soil moisture content (SMC).NT7 have increased significantly (p< 0.05) levels of SOM at the top 30. cm soil layer, which in turn enhanced BD and TP of soil as compared to CT. However, improvement of these parameters was restricted to 0-10. cm layer with NT3. Both NT3 and NT7 have increased considerably (p< 0.05) mP at 0-30. cm thereby increasing soil water content at FC and PWP, whereas MP was remarkably reduced by NT treatments as compared to CT but reduction was less important in NT7 plot. AWC was significantly (p< 0.05) higher in NT7 across the 30. cm profile while NT3 and CT have similar effect to each other. SMC was improved at different soil depths by NT system during the whole agricultural season and the highest content was found with NT3. Soil moisture values increased with increasing soil depth in both NT3 and NT7 indicating a good water infiltration induced by these treatments. Hence, water storage properties in rooting zone could be enhanced by NT7 and NT3 but water availability for plants was more important with NT7. © 2012 Elsevier B.V. Source

Jemai I.,University of Tunis | Ben Aissa N.,Institute National Agronomique Of Tunisie | Ben Guirat S.,University of Tunis | Ben-Hammouda M.,Ecole Superieure dAgriculture du Kef | Gallali T.,University of Tunis
Journal of Environmental Management | Year: 2012

In semiarid areas, low and erratic rainfall, together with the intensive agricultural use of soils, has depleted soil organic carbon and degraded the soil's chemical, biological and physical fertility. To develop efficient soil-management practices for the rapid restoration of severely degraded soils, no-till, mulch-based cropping systems have been adopted. Thus, a study was conducted on a farm to evaluate the effect of a no-tillage system (NT) versus conventional tillage (CT) on the vertical (0-50 cm) distribution of soil organic carbon (SOC), bulk density (BD), total porosity (TP), structural instability (SI), stable aggregates and infiltration coefficient (Ks) in a clay loam soil under rain-fed conditions in a semiarid region of north-western Tunisia. CT consisting of moldboard plowing to a depth of 20 cm was used for continuous wheat production. NT by direct drilling under residue was used for 3 (NT3) and 7 (NT7) years in wheat/fava bean and wheat/sulla crop rotations, respectively. SOC was more significantly increased (p < 0.05) by NT3 and NT7 than by CT at respective depths of 0-10 and 0-20 cm, but a greater increase in the uppermost 10 cm of soil was observed in the NT7 field. NT3 management decreased BD and consequently increased TP at a depth of 0-10 cm. The same trend was observed for the NT7 treatment at a depth of 0-30 cm. Ks was not affected by the NT3 treatment but was improved at a depth of 0-30 cm by the NT7 treatment. Changes in BD, TP and Ks in the NT7 plot were significant only in the first 10 cm of the soil. Both NT3 and NT7 considerably reduced SI (p < 0.1) and enhanced stable aggregates (p < 0.05) across the soil profile. These differences were most pronounced under NT7 at a depth of 0-10 cm. The stratification ratio (SR) of the selected soil properties, except that of SI, showed significant differences between the CT and NT trials, indicating an improvement in soil quality. NT management in the farming systems of north-western Tunisia was demonstrated in this study to improve soil quality, especially in the surface layers, by increasing storage of organic carbon and enhancing the physical properties of the soil. These effects were most pronounced in the long term. © 2012 Elsevier Ltd. Source

Mahouachi M.,Ecole Superieure dAgriculture du Kef | Atti N.,Laboratoire des Productions Animales et Fourragres | Hajji H.,Laboratoire des Productions Animales et Fourragres | Hajji H.,Institute National Agronomique Of Tunis
The Scientific World Journal | Year: 2012

The objective of this study was to determine the effect of spineless cactus incorporation in food of dairy goats and growing kids on milk production and composition and on kid's growth and meat characteristics. Two experiments were conducted on Tunisian local goats. In the first, 30 females were divided into two groups; goats of Control group were reared on grazing pasture receiving indoor 0.5kg of hay and 0.4kg of concentrate. Goats for the second group (Cac-FL) were kept in feedlot and fed cactus ad libitum more 0.5kg of hay and 0.4kg of concentrate. In the second experiment, 14 kids were divided into 2 groups receiving 600g of hay. The Control group received ad libitum a concentrate containing 130g crude protein (CP) per kg of dry matter. The second group received cactus ad-libitum plus the half concentrate quantity of control one with 260gCP/kg DM (Cactus). The daily milk production averaged 485ml for Control group and 407ml for Cac-FL one. The milk fat content was significantly higher for Control than Cac-FL group. In the second experiment, animals in Control and Cactus groups had similar growth rate. Carcass fat was significantly lower in Cactus than in the Control group. Cactus in the diet was associated with more C18:2 and conjugated linoleic acid as well as a higher proportion of PUFA than Control ones. © 2012 M. Mahouachi et al. Source

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