1,720,978 research outputs found
Métabolisme du sélénium chez le dromadaire
No full textLe dromadaire, un pseudo ruminant adapté aux climats arides, dispose de particularités physiologique, biologique et métabolique qui lui confèrent ne légendaire réputation à survivre dans les conditions extrêmes des milieux désertiques considérées restrictives pour les autres ruminants. Les besoins en minéraux chez le dromadaire, particulièrement en éléments traces tels que le sélénium, ne sont pas élucidés. La complémentation en sélénium chez cette espèce aux Émirats Arabes Unis est une pratique quotidienne soit par injection de formes pharmaceutique, mélange minéral commercial et ce pour faire face aux problèmes de cardiomyopathie souvent attribués à un déficit ea sélénium. Cependant, cette complémentation est souvent anarchique et s'appuie sur les besoins estimés chez les bovins. L'importance croissante des implications du sélénium (Se) en nutrition animale nécessite pourtant d'approfondir son métabolisme (ingestion, dynamique de stockage-déstockage, excrétion) chez l'espèce cameline. D'après des études comparatives précédentes concernant les valeurs sériques du sélénium, il apparaît que le dromadaire exprime un comportement métabolique différent de celui de la vache, d'où la naissance du concept de notre présente étude qui consiste a explorer le métabolisme du sélénium (différents niveaux d'ingestion, distribution dams les organes, y compris les poils, excrétions urinaire, fécale et lactée) chez des dromadaires supplémentés avec du sélénium sous sa forme inorganique (sélénite de sodium). La concentration sérique du sélénium et l'activité enzymatique de la glutathion peroxydase (GSH-Px) comme indicateurs direct et indirect du statut en sélénium chez l'animal, ont été déterminés dans une série d'expérimentations tenant compte de différents états physiologiques de la chamelle (mon gestante, gravide, mise bas et lactation), chez le chamelon nouveau-né et non-sevré, et chez des jeunes animaux supplémentés à des doses potentiellement toxiques (jusqu'à 16 mg de Se/jour). Parallèlement d'autres paramètres biochimique, hématologique, minéraux, ainsi que la vitamine E ont été aussi analysés pour étudier l'effet de la supplémentation en sélénium sur ces paramètres. Au total 5 expérimentations ont été menées permettant d'analyser: (i) les facteurs de variation (sexe, âge, race et état physiologique) de la tuner en sélénium chez des animaux nom complémentés, (ii) l'effet du complémentation modérée (0, 2 et 4 mg/j) en sélénium sur le statut séténique de chamelles non gestantes, non lactantes, (iii) l'effet d'une complémentatlen modérée en sélénium (0 et 2 mg/j) sur des chamelles en fin de gestation et en début de lactation ainsi que sur tes produits (chamelon jusqu'à 3 mois), (iv) l'effet de la supplémentation élevée en sélénium (2, 4 et 8 mg/j) sur le statut séténique de chamelons de 2 ans, (v), la tolérante au sélénium de chamelons sevrés de 2 ans (8, 12 et 16 mg/j). Nous avons ainsi étudié la possibilité d'éviter la forme congénitale de myopathie en apportant du Se à la mère au dernier tiers de gestation, notamment pour une progéniture destinée à la course où le muscle cardiaque est facteur limitant. L'intoxication clinique a été rarement décrite chez le dromadaire, mais dans les travaux présentés ici, l'apport continu en Se s'est traduit par un tableau pathognomonique traduisant une sélénose de type chronique. L'ensemble de ces travaux a permis de proposer des recommandations pratiques de complémentation pour une espèce qui s'avère au final relativement sensible à en apport excessif à des teneurs plus faibles que chez les bovins. Le taux sérique de Se maximal été de 638.7 mg/ml chez les femelles gestantes avec une concentration de 273.2 ± 48.0 mg/ml chez les nouveau-nés, cependant des concentrations de 302 ± 94.60 mg/ml dans le colestrum et 167.1 ± 97.3 mg/ml dans le lait ont été notés
Variability of vitamin E concentration in camel plasma
No full textIn the present study, variability of plasma a-tocopherol was reported in different groups of camels (non-lactating and non-pregnant, pregnant, lactating and their new-born, young, selenium intoxicated young camels). The mean values in the different groups were 1.13 ± 0.61 pg/ml (non-lactating and non pregnant),1.12 ± 0.81 pg/ml (pregnant),1.20 ± 0.80 pg/ml (lactating), 0.82 ± 1.06 pg/ml (new-born), 0.56 ± 0.22 pg/ml (young) and 0.68 ± 0.36 pg/ml (intoxicated young). There was no significant change in the time. Those values appeared lower than in plasma of other ruminants, but the effect of vitamin E supplementation was not known in camel
Maternal transfer of selenium by blood and milk in camels
Full text linkTen pregnant female camels were divided into two groups. The control group received no supplement; the experimental (treated) group received a daily oral supplement of 2 mg Se as selenite for the last three months of pregnancy and the first month of lactation. The Se concentration in serum increased significantly in the supplemented group and was threefold higher (305.9 ± 103.3 ng/mL) than in the concentration control group (109.3 ± 33.1 ng/mL). Blood values in camel calves were similar to those of the dams. The selenium concentration increased in similar proportions in milk (167.1 ± 97.3 ng/mL vs 86.4 ± 39.1 ng/mL in the supplemented and control groups respectively). In the colostrum, Se concentration was higher in both groups, but with a similar difference: 108.2 ± 43.9 ng/mL vs 302 ± 94.60. Significant correlations were reported between dam serum Se, camel calf serum Se, milk Se and GSH-Px both in dams and calves
Trace elements and heavy metals in healthy camel blood of United Arab Emirates
No full textIn the present paper, 240 camels were sampled for the determination of trace elements and different heavy metals. The variation factors included age, sex and physiological status which were assessed for some parameters. On the average, the mineral contents were 190.3 [mu]g/100ml (iron), 60.1 [mu]g/100ml (copper), 44.0 [mu]g/100ml (strontium), 22.5 [mu]g/100ml (arsenic), 20.0 [mu]g/100ml (zinc), 19.7 [mu]g/100ml (selenium), 19.3 [mu]g/100ml (boron) and 14.6[mu]g/100ml (barium). Other minerals like aluminium (3.7 [mu]g/100ml), molybdenum (2.9 [mu]g/100ml), chromium (2.0 [mu]g/100ml), nickel (1.8 [mu]g/100ml), lead (1.5 [mu]g/100ml), manganese (0.16 [mu]g/100ml), cobalt (0.08 [mu]g/100ml) and cadmium (0.07 [mu]g/100ml) were in very small concentration
Meta-analysis of the interactions between selenium status and haematological, biochemical and mineral parameters in camel blood
No full textFrom several experiments on selenium metabolism in order to measure the effect of selenium supplementation (0, 2, 4, 8, 12 and 16 mg daily under selenite form), haematological, biochemical and mineral parameters were studied and their interactions with selenium status and dietary selenium were analyzed. Considering the increasing level of supplementation, important changes in blood parameters were observed: significant decreasing of PVC, haemoglobin and iron concentration attesting the sign of anaemia from 8 mg level. An important decrease of blood albumin and a drastic fall of uraemia expressed the loss of appetite in intoxicated animals receiving at least 12 mg selenium daily. At reverse, the enzymes attesting cell damage increased significantly. The decreasing of zinc and the increasing of copper from 8 mg showed inflammation process in target organs. It was concluded that se selenium supplementation could not overpass 4-8 mg per day for adult animals or 0.5-1 ppm in the diet
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Trace elements and heavy metals statuts in Arabian camel
No full textIn the desert, camel rearing is an important cultural fact. In the present paper, 240 Arabian camels from Emirates were sampled for the determination of trace elements and different heavy metals. The following elements were tested: copper, zinc, iron, aluminium, arsenic, boron, barium, cobalt, chromium, cadmium, manganese, molybdenum, nickel, selenium, strontium and lead. The variation factors included age, sex and physiological status. On the average, the mineral contents were 190.3 µg/100 ml (iron), 60.1 µg/100 ml (copper), 44.0 µg/100 ml (strontium), 22.5 µg/100 ml (arsenic), 20.0 µg/100 ml (zinc), 19.7 µg/100 ml (selenium), 19.3 µg/100 ml (boron) and 14.6 µg/100 ml (barium). Other minerals like aluminium (3.7 µg/100 ml), molybdenum (2.9 µg/100 ml), chromium (2.0 µg/100 ml), nickel (1.8 µg/100 ml), lead (1.5 µg/100 ml), manganese (0.16 µg/100 ml), cobalt (0.08 µg/100 ml) and cadmium (0.07 µg/100 ml) were in very small concentration. Age, sex and physiological effects were assessed for some parameters. According to the lack of references in camel species, it is difficult to link those results to polluting context. But those data could contribute to understand the heavy metal status in camel confronted to pollution
- …
