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Kdidi S.,Arid Lands Institute | Kdidi S.,Tunis el Manar University | Calvo J.H.,CITA | Gonzalez-Calvo L.,CITA | And 3 more authors.
Small Ruminant Research | Year: 2015

The aim of this study was to assess the genetic diversity and differentiation patterns of four Tunisian sheep breeds. A total of 186 animals belonging to Barbarin (n= 59), Western Thin Tail (n =46), Black Thibar (n =40), and Sicilo Sarde (n =41) breeds were genotyped for a panel of 30 microsatellite markers. In addition, a sample of 29 Spanish Merino sheep breed was used as an outgroup for tree topology. All markers were highly informative with PIC values ranging from 0.588 to 0.885 and a mean number of private alleles of 0.016. In all breeds, inbreeding was indicated by heterozygosity deficiency with estimated F IS values varying from 0.134 (Barbarin) to 0.165 (Western Thin Tail), and a highly significant departure (p <0.01) from Hardy-Weinberg proportions was observed. Wright's F ST index indicated low genetic differentiation between Tunisian breeds (0.017). The lack of clear genetic differentiation was also evidenced by cluster analysis using STRUCTURE as well as by the significant gene flow observed between breeds, especially Barbarin and Western Thin Tail, on the basis of the estimated Reynolds' genetic distances (D R) and the number of migrants (N m). The highest D R values were observed between Sicilo Sarde and the three other breeds, reflecting different phylogenetic origins of this breed. The study represents a first step towards further genetic characterization of Tunisian sheep breeds and results presented here are useful for better management and conservation of sheep resources. © 2015 Elsevier B.V. Source

Ahmed M.O.,Institute National Agronomique Of Tunisie | Salem F.B.,Office de lElevage et des Paturages | Bedhiaf S.,Institute National Of Recherche Agronomique Of Tunisie | M'Naouer D.,Banque nationale des Genes
Biotechnology, Agronomy and Society and Environment | Year: 2010

The objective of this study was to investigate the genetic diversity and relationships among Tunisian camel populations in three different geographical locations (Kebili, Medenine and Tataouine) from Southern arid and semi-arid regions in Tunisia. Eight selected microsatellite markers were used for a sample of 90 dromedary genotypes. A total of 34 alleles were detected in the three populations. The number of alleles per locus varied from two to seven with an average of 4.25 alleles per locus. For each population the average of alleles per locus is 3.33, 3.71 and 3.87 for (Kebili, Medenine and Tataouine), respectively. The mean of the observed heterozygosity (Ho) were 0.43, 0.50, 0.57 and 0.52 for Kebili, Medenine, Tataouine and total populations, respectively. These values were lower than expected with heterozygosity (He) values 0.50, 0.57, 0.62 and 0.61, respectively. The average inbreeding coefficient was 15.3% in Kebili, 11.4% in Medenine and 8.3% in Tataouine. The mean estimates of F-statistics were FIT = 0.15, FIS = 0.071 and FST = 0.083. These values were significantly different from zero (p < 0.05) and suggest a moderate differentiation. An inbreeding rate of 15% was found. Estimated genetic distances revealed by the loci varied from 0 to 0.9 between dromedary individuals. The estimated genetic distances pair-wise showed 0.104 among Medenine-Tataouine, 0.280 between Kebili-Medenine and 0.290 between Kebili-Tataouine. The distance matrix was able to distinguish between two separate genetic entities: Nefzawa (Kebili) including Merzougui, G'oudi and M'hari ecotypes and the Aaradh group (Medenine and Tataouine) that includes Maghribi and Khaouar ecotypes. The results of this study did not confirm the present classification established by dromedary herders who divide the population into five different ecotypes, apparently based on the sociogeographical criteria. These preliminary results showed that microsatellites are promising tools for breed characterization. They indicated that the populations under investigation have a high genetic variability and would be suitable as genetic stocks for conservation and sustainable utilization programs. Source

Ould Ahmed M.,Institute National Agronomique Of Tunisie | Ben Salem F.,Office de lElevage et des Paturages | Bedhiaf S.,Banque nationale des Genes | Rekik B.,Institute National Agronomique Of Tunisie | Djemali M.,Institute National Agronomique Of Tunisie
Livestock Science | Year: 2010

Genetic diversity and relationships among three camel populations from three different geographic regions (Kebili, Medenine and Tataouine) in the South of Tunisia were estimated using a panel of six microsatellite markers. The total number of observed alleles across the three populations was 28. The mean number of alleles per locus was 3.33, 4, 4.17, and 4.67 for Kebili, Medenine, and Tataouine and across populations, respectively. The mean observed heterozygosity was 0.43, 0.43, 0.53 and 0.46 for Kebili, Medenine, and Tataouine and across populations, respectively. Observed heterozygosity values were lower than their respective expected heterozygosities (0.52, 0.57, 0.62 and 0.60). The mean estimates of F statistics were FIT=0.27, FIS=0.19 and FST=0.09. These values were significantly different from zero (p<0.05) and suggest a moderate differentiation of the camel population. The value of FST indicates that approximately 91% of the total genetic variation originates from differences among individuals within populations. Dromedaries in this study can be grouped into two distinct genetic entities: The Nefzawa (Kebili) and the Aaradh populations. © 2010. Source

Kdidi S.,Arid Lands Institute | Kdidi S.,Tunis el Manar University | Yahyaoui M.H.,Arid Lands Institute | Conte M.,Istituto Superiore di Sanita | And 6 more authors.
Livestock Science | Year: 2014

In this study, genetic variation of ovine prion protein in Tunisian sheep breeds was analysed. Sequencing of the entire coding sequence of prion protein gene (PRNP) was performed in a total of 201 samples belonging to four breeds (Barbarin, Western Thin Tail, Sicilo Sarde and Black Thibar). Five haplotypes (ARQ, ARR, ARH, AHQ and VRQ) and 10 genotypes were observed based on codons 136, 154 and 171, with different frequencies among the investigated breeds. The ARQ, ARR and ARH haplotypes were present in all breeds, the VRQ haplotype was observed at low frequencies in Barbarin and Western Thin Tail breeds. The ARQ and ARR haplotypes were the most common with frequencies ranging from 33.4% to 47.8% and from 26.5% to 46.5% respectively, in the different breeds. Moreover, 12 additional non-synonymous (Q101R, M112T, G127S/V, M137T, L141F, H143R, N146S, R151G, Y172D, N176K and H180Y) as well as 2 synonymous polymorphisms at codons 231 and 237 were found in the PRNP gene. Among them, the R151G polymorphism has never been described in sheep. Moreover an insertion of an octarepeat in the ARQ haplotype has been observed. These results represent the first survey on PRNP variability in Tunisian sheep and may serve as basis for the development of breeding programme to increase scrapie resistance in national sheep breeds. © 2014 Elsevier B.V. Source

Ben Salem M.,French National Institute for Agricultural Research | Kelifa H.,Office de lElevage et des Paturages
EAAP Scientific Series | Year: 2011

Beef production in Tunisia comes from native cows, exotic Holsteins and dual purpose breeds and their respective crossbreds. However, given the limited meat potential of these animals, domestic beef production does not meet the total demand of the population. Therefore efforts have been directed to identifying appropriate crossing breeds for increased production. First, exotic dual purpose breeds such as the Brown Swiss and the Tarantaise were introduced to determine their possible use in crossbreeding with dairy animals. However, although some improvement was made in meat production, crossbreeding with these breeds still did not help in achieving the desired production level. Meanwhile, the population increased and the improved revenue of households have served to emphasize the need for more beef production. Recently, alternative crossbreeding programs with beef breeds were implemented. The objective of this work is to evaluate, trough continuous field studies, the potential of using the White Blue Belgium (BBB) and the Charolais breeds in industrial cross breeding programs for increasing beef production. Data on breeding, birth weight (BW), calving ease, average daily gain (ADG) and carcass weight (CW) and value of crossbred animals were collected for the 2000-2006 period. A total of 467 producers and 24,000 cows were included in the study. Results showed that crossbreeding with beef breeds increased BW, ADG and CW 5 kg, 217 g and 77 kg, respectively. Carcass quality and market value were also improved. This suggests that crossbreeding with beef breeds is one of the successful methods which can be used in the country to reach self-sufficiency in domestic beef and improve farmers' revenue, while better meeting the consumer preferences in terms of meat quality. Source

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