Qualité microbiologique du lait cru ovin collecte dans la steppe centrale de l’Algérie

L’objectif de l’étude consiste à évaluer la qualité microbiologique du lait cru ovin collecté localement, en milieu steppique Algérien dans la région de Djelfa situé à 300 km au sud d’Alger. Au total 51 échantillons de lait ont été prélevés pour des fins analytiques. La contamination moyenne est de 2,3.107 cfu/mL pour la flore totale contre 1,1.105 pour les coliformes totaux et 1,5.104 pour les coliformes fécaux. Pour la flore fongique, les laits sont plus contaminés en levures qu’en moisissures (2,4.105 vs 3,4.103 germes/mL respectivement). Les Streptocoques fécaux sont détectés chez 43,14% des échantillons par contre E.coli n’est décelée que chez 17,65% des laits. Par ailleurs, 28% des prélèvements sont positifs vis-à-vis de Clostridium contre 9,8% pour Staphylococcus aureus. En revanche, tous les laits sont exempts de Salmonella. Pour ce qui est de la recherche des anticorps brucelliques, 13,73% des laits analysés sont positifs au Ring-test. La mauvaise qualité du lait reflète bien les conditions déplorables de production et la non-observance des bonnes pratiques hygiéniques lors de la traiteMots-clés : brebis, lait cru, qualité hygiénique, microorganismes pathogènes, Algérie.Microbiological quality of raw ewe’s milk in Algerian middle steppeThe objective of this study was to assess the microbiological quality of raw milk sheep collected in Algerian steppe. A total of 51 samples of bulk milk were examined. The results obtained show the unsatisfactory quality of milk analyzed. The average contamination is 2,3.107 cfu/ml for the total flora against 1,1.105 for total coliforms and 1,5.104 for fecal coliforms. For the fungal flora, milk is more contamined with yeast than fungi (2,4.105 vs 3,4.103 germes/ml respectively). Fecal streptococci were detected in 43,14% of the samples were E.coli is detected in 17,65% of the milk. In addition, 28% of samples are positive for Clostridium against 9,8% for Staphylococcus aureus. All milk are free from Salmonella. In terms of Brucella antibody, 13,73% of milk are ring test positive. The poor quality of milk reflects the deplorable conditions of production and non-observance of good hygiene practices during milking.Keywords : Ewe, Raw milk, Hygienic quality, Pathogens, Algeria

Inference of breed structure in farm animals: Empirical comparison between snp and microsatellite performance

Knowledge of population structure is essential to improve the management and conservation of farm animal genetic resources. Microsatellites, which have long been popular for this type of analysis, are more and more neglected in favor of whole-genome single nucleotide polymorphism (SNP) chips that are now available for the main farmed animal species. In this study, we compared genetic patterns derived from microsatellites to that inferred by SNPs, considering three pairs of datasets of sheep and cattle. Population genetic differentiation analyses (Fixation index, FST ), as well as STRUCTURE analyses showed a very strong consistency between the two types of markers. Microsatellites gave pictures that were largely concordant with SNPs, although less accurate. The best concordance was found in the most complex dataset, which included 17 French sheep breeds (with a Pearson correlation coefficient of 0.95 considering the 136 values of pairwise FST, obtained with both types of markers). The use of microsatellites reduces the cost and the related analyses do not require specific computer equipment (i.e., information technology (IT) infrastructure able to provide adequate computing and storage capacity). Therefore, this tool may still be a very appropriate solution to evaluate, in a first stage, the general state of livestock at national scales. At a time when local breeds are disappearing at an alarming rate, it is urgent to improve our knowledge of them, in particular by promoting tools accessible to the greatest number

Composition and Nitrogen Distribution of Ouled-Djellal and Rumbi Algerian Ewe's Milk

Abstract: The chemical composition and nitrogen distribution of milk from two ewe's breed (Ouled-Djellal and Rumbi) (n = 20 each) reared in Algerian area steppe, were studied. The ewes were balanced for age and weight. All were in middle period of lactation. Individual milk samples were taken from each ewe third time from lactating period during spring season. Rumbi ewe's milk gave the highest values (p≤0.01) for lactose (4.89±0.61%), solid non-fat (11.19±0.87%) and density (1037.57±3.78) than Ouled-Djellal ewes (4.38±0.45%, 10.24±0.77% 1033.82±2.59, respectively) and lowest values (p≤0.01) for freezing point (-0.57±0.05°C vs -0.53±0.02°C). No significant difference was observed between the two breeds on fat, protein, total solids. The mean percentages were 6.26±1.38%, 5.54±0.76 and 16.51±1.44%, respectively for Ouled-Djellal ewes, while those of Rumbi's were 5.66±3.52%, 5.91±1.10% and 16.85±3.32%, respectively. No statistical differences related to the breed were found in the milk for all nitrogen fractions. Rumbi ewe's milk contains about 1.01% nitrogen however Ouled-Djellal's hold about 0.96%. Total nitrogen content is distributed between non-protein nitrogen (0.09% in all breeds) and protein nitrogen (0.93 vs 0.87% for Rumbi and Ouled -Djellal ewes respectively). The protein nitrogen includes casein nitrogen (0.76 vs 0.71) and whey protein nitrogen (0.20 vs 0.19%) from Rumbi and Ouled-Djellal ewes, respectively. Algerian sheep breeds were not actually selected for their milk production; selection program should be implemented to improve milk production and increase fat and protein contents. Thus further studies should carry out on milk ability and milk yield of these breeds

Phenotypic characterization of the major sheep breed in Algeria

International audienceNorth Africa represents a livestock biodiversity hotspot with breeds that have evolved in conditions as harsh as varied. In Algeria, among the eight major sheep breeds, the Ouled-Djellal receives the preference of most farmers thanks to its reputation of best meaty breed. In this study, the phenotypic variability of the Ouled-Djellal was investigated taking into account the multiplicity of management practices and environments, using multivariate discriminant analysis, as recommended by the Food and Agriculture Organization (FAO). A total of 1104 females and 84 males were sampled in a large area including the cradle of the breed, with 18 quantitative measures (20 for males) and 14 qualitative traits. This study provides the first fine phenotypic characterization of an Algerian breed. Moreover, two patterns of phenotypic structuration were highlighted (i) the four regions sampled were clearly discriminated; hence the use of main markets in each region induced gene flows mostly restricted within the boundaries of the region (ii) sheep reared in altitude showed lower conformation than sheep reared in plains; hence our results postulated that high plateaus are not optimum production environment for Ouled-Djellal. Some local breeds are highly adapted to specific harsh environments encountered in the Algeria; the spread of the Ouled-Djellal in the country, without regard of production environment characteristics, represents a danger for most of the other breeds progressively abandoned or genetically diluted with the Ouled-Djellal because of crossbreeding practices

Search for Selection Signatures Related to Trypanosomosis Tolerance in African Goats

Livestock is heavily affected by trypanosomosis in Africa. Through strong selective pressure, several African indigenous breeds of cattle and small ruminants have acquired varying degrees of tolerance against this disease. In this study, we combined LFMM and PCAdapt for analyzing two datasets of goats from West-Central Africa and East Africa, respectively, both comprising breeds with different assumed levels of trypanotolerance. The objectives were (i) to identify molecular signatures of selection related to trypanotolerance; and (ii) to guide an optimal sampling for subsequent studies. From 33 identified signatures, 18 had been detected previously in the literature as being mainly associated with climatic adaptations. The most plausible signatures of trypanotolerance indicate the genes DIS3L2, COPS7B, PD5A, UBE2K, and UBR1. The last gene is of particular interest since previous literature has already identified E3-ubiquitin ligases as playing a decisive role in the immune response. For following-up on these findings, the West-Central African area appears particularly relevant because of (i) a clear parasitic load gradient related to a humidity gradient, and (ii) still restricted admixture levels between goat breeds. This study illustrates the importance of protecting local breeds, which have retained unique allelic combinations conferring their remarkable adaptations

Search for Selection Signatures Related to Trypanosomosis Tolerance in African Goats

Livestock is heavily affected by trypanosomosis in Africa. Through strong selective pressure, several African indigenous breeds of cattle and small ruminants have acquired varying degrees of tolerance against this disease. In this study, we combined LFMM and PCAdapt for analyzing two datasets of goats from West-Central Africa and East Africa, respectively, both comprising breeds with different assumed levels of trypanotolerance. The objectives were (i) to identify molecular signatures of selection related to trypanotolerance; and (ii) to guide an optimal sampling for subsequent studies. From 33 identified signatures, 18 had been detected previously in the literature as being mainly associated with climatic adaptations. The most plausible signatures of trypanotolerance indicate the genes DIS3L2, COPS7B, PD5A, UBE2K, and UBR1. The last gene is of particular interest since previous literature has already identified E3-ubiquitin ligases as playing a decisive role in the immune response. For following-up on these findings, the West-Central African area appears particularly relevant because of (i) a clear parasitic load gradient related to a humidity gradient, and (ii) still restricted admixture levels between goat breeds. This study illustrates the importance of protecting local breeds, which have retained unique allelic combinations conferring their remarkable adaptations

The problems associated with sour gas in the oilfield industry and their solutions

Fossil fuels are still a necessary and important part of modern living, keeping cars running and houses heated for example. As demands have risen and reservoirs of oil and natural gas have depleted, it has become increasingly more important to tap into fields that were once classified as undesirable. Sour fields, fields high in acidic gases, such as hydrogen sulfide and carbon dioxide, are one such option. There are many difficulties and dangers associated with working sour fields, such as toxicity of the sour gases, hydrate formation, and corrosion of equipment, that have prevented these resources from being used in the past. Many varied methods of overcoming these problems have been developed, from removing the sour components to inhibiting their effects. This review highlights the major issues raised by sour fields as well as a wide range of solutions in use today