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Bouallegue M.,High Agronomic Institute of Chott Mariem | Steri R.,Centro Of Ricerca Per La Produzione Delle Carni E Il Miglioramento Genetico | M'hamdi N.,National Institute of Agronomy of Tunis | Hamouda M.B.,Institution of Agricultural Research and Higher Education
Journal of Animal and Feed Sciences | Year: 2015

Different equations were employed to directly model individual lactation curves of Tunisian Holstein-Friesian cows using 260 241 test day records for milk yield, fat, and protein contents. Eleven mathematical models were compared. Parametric curves (Legendre polynomials, Ali and Schaeffer (AS), Wood, and Wilmink models) and regression splines were tested. Goodness of fit was assessed by considering the adjusted R-square ranked according to five classes, statistical criteria, and residuals analysis. Regression splines (quadratic and cubic spline models with three knots) showed better fitting performances and greater flexibility for all milk traits. The sixth-order Legendre orthogonal polynomial model and the Ali and Schaeffer model also gave the best fit for milk traits compared with the three-parameter models (Wood and Wilmink) and with the lower-order polynomial models, but the AS model was less correlated for fat content (R = 0.87), gave a moderate correlation (R = 0.90) for protein content, and had less similarity between the observed and estimated lactation curves. The performance of Legendre orthogonal polynomials and quadratic splines was strongly affected by the models' order and the number of knots. Source

El Hamrouni-Aschi K.,National Institute of Agronomy of Tunis | Larbi Khouja M.,National Water Research Institute | Boussaid M.,National Institute of Applied science and Technologies | Akrimi N.,National Institute of Agronomy of Tunis | Toumi L.,Superior Institute of Biotechnology of Beja
Chemistry and Biodiversity | Year: 2013

The essential oils isolated from leaves, wood, and cones of the Tunisian endemic cypress Cupressus sempervirens L. var. numidica Trab. collected from three natural populations were characterized by GC-FID and GC/MS analyses. In the wood, leaf, and cone oils, 38, 35, and 26 constituents, representing 94.4, 97.8, and 98.5% of the total oil composition, respectively, were identified. Monoterpenes constituted the major fraction of the oils from all organs and for all populations. The oils were found to be of an α-pinene (64.2%)/δ-car-3-ene (11.1%) chemotype with considerable contents of α-humulene (3.4%) in the leaf oil, cedrol (2.8%) in the wood oil, and sabinene (3.2%) in the cone oil, respectively. α-Pinene, δ-car-3-ene, limonene, carvacrol methyl ether, α-humulene, and α-amorphene were the main components that differentiated the oils of the three organs in the cypress of Makthar. Copyright © 2013 Verlag Helvetica Chimica Acta AG, Zürich. Source

Hamrouni K.E.,National Institute of Agronomy of Tunis | Neffati M.,Arid Lands Institute | Khouja M.L.,National Water Research Institute | Boussaid M.,National Institute of Applied science and Technologies | And 2 more authors.
Acta Horticulturae | Year: 2013

The chemical composition of essential oils obtained by hydro-distillation of leaves, wood and cones of Cupressus dupreziana (Cupressaceae) was analyzed by GC and GC/MS. Thirty-one constituents were identified. Monoterpenes constitute the main chemical groups in the oils from the three organs. The species is an a-pinene (67.2%)/sabinene (9.1%) chemotype. However, different chemotypes were observed in the oil extracted from leaves where a-pinene (55.7%) and a-amorphene (9.4%) were found to predominate. A significant variation between organs was observed. The main components, differentiating between the three organs, are camphene, β- pinene, sabinene and myrcene. Source

Badri M.,Center de Biotechnologie de la Technopole de Borj-Cedria | Bouhaouel I.,National Institute of Agronomy of Tunis | Arraouadi S.,Regional Center for Agriculture Research | Taamalli W.,Center de Biotechnologie de la Technopole de Borj-Cedria | And 2 more authors.
Plant Genetic Resources: Characterisation and Utilisation | Year: 2015

We analysed the natural variation of drought response in 11 Tunisian populations of Medicago truncatula sampled from environments that varied in soil composition, salinity and water availability. Plants were cultivated in a greenhouse under well-irrigated and water-deficit treatments (50% of field capacity), and a number of traits associated with drought response were measured. Variance analysis indicated that the variation of phenotypic traits was explained by the effects of population, line, treatment, and population × treatment and line × treatment interactions, with treatment being the one with the greatest effect. A large degree of phenotypic variation for most traits in the two water treatments was found within populations. Most of the measured characters showed higher broad-sense heritabilities (H 2) in well-irrigated treatment than in water-deficit treatment. Furthermore, the largest population differentiation (Q ST) for most of the measured traits was observed under drought stress. Most of the correlations between measured traits under both treatments were positive. Four groups of lines differing in drought tolerance were identified, with 45 susceptible, 14 moderately susceptible, 31 tolerant and 23 most tolerant lines. The tolerant group experienced lowest reductions in the length of plagiotropic axes, length of stems, number of internodes and number of leaves. The large phenotypic variation of M. truncatula in response to drought stress can be used to identify genes and alleles important for the complex trait of drought tolerance. Copyright © NIAB 2015 Source

Belhassen T.,National Institute of Agronomy of Tunis | Simon E.,Societe Industrielle Lesaffre | Potel A.,Societe Industrielle Lesaffre | Auclair E.,Societe Industrielle Lesaffre | Bergaoui R.,National Institute of Agronomy of Tunis
World Rabbit Science | Year: 2016

A study was conducted to determine the effect of live yeast supplementation in the diet of rabbit does on their mortality and reproductive performance and the performance of their progeny. A total of 52 cross-bred rabbit does (New Zealand×Californian) were divided into 2 groups differing in diet offered during 2 reproductive cycles and containing (group S; n=26) or not (group C; n=26) 1 g of yeast (Actisaf Sc 47, S.I. LESAFFRE, France)/kg of feed. Natural mating was performed 11 d after kindling and kits were weaned at 28 d of age. Body weight of litters was measured at birth, 21 d and at 28 d of age (weaning). Mortality of kits and rabbit does was monitored daily, and fertility of rabbit does and viability rate of kits at birth were also determined. Weight and litter size at birth and at weaning, litter weight gain during lactation and length of gestation were similar between the 2 groups during the 2 cycles. The mortality of does during the experiment was higher in group C than in group S (27 vs. 4%; P<0.05). Fertility rate of rabbits does and viability rate of kits at birth were higher (P<0.05) in rabbits fed with the supplemented diet than those with the control diet during the second lactation. In the first cycle, kit mortality was lower in S group (15.5%) than the C group (24.7%) during the first 21 d (P<0.05). However, no difference was observed during the second lactation. In conclusion, our results suggest that the inclusion of yeast in the diet of rabbit does could trigger positive effects on the fertility and mortality of rabbit does, as well as on the viability rate of kits at birth. © WRSA, UPV, 2003. Source

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