Effect of different selenium supplementation levels on selenium status in camel

Blood Trace Element Status in Camels: A Review

Trace minerals play an important role in animal health and productivity. They are involved also in many physiological activities, and their deficiency causes a variety of pathological problems and metabolic defects, reducing consequently the animal productivity. The demand for animal products in semi-arid areas is rapidly increasing, and the supply is still below the required level, partially due to low animal productivity. Camels (Camelus dromedarius and Camelus bactrianus) are considered one of the main sources of healthy, high-quality meat and milk for human consumption within most of the countries in the semi-arid regions. Despite their efficient adaptation to their environment, camels can suffer from the growth retardation of newborns, low feed efficiency, anemia, poor fertility, poor reproduction and many other metabolic disorders. It is well known that trace mineral deficiencies and trace mineral toxicities can influence camels' production and reproductive efficiency, as well as many aspects of their growth and metabolism. Evaluating the trace minerals status of camels and their variability is an obvious step toward improving camels' productivity and health. Thus, the present article reviews the data regarding the status of trace minerals (copper, zinc, iron, selenium, manganese, cobalt, iodine, fluorine, molybdenum, sulfur, bromide and nickel) in camel blood and their physiological variability, with a focus on their deficiency and toxicity effects.

Serum vitamin A and E, copper, zinc and selenium concentrations and their relationship with health outcomes in dromedary hospitalized camels (Camelus dromedarius)

The goals of this study were to measure serum vitamin A (retinol) and E (α-tocopherol) and trace elements concentrations (copper, zinc and selenium) during diseases condition and to determine their association with hematological parameters and immune status of hospitalized camels. A total of 95 dromedary camels [healthy (n=65); hospitalized camels (n=30)] were included in this study. Vitamin A and E concentrations were significantly lower in hospitalized camels than apparently healthy ones (P<0.05). Hospitalized camels had lower concentrations of zinc and selenium compared to healthy camels (P<0.05). Vitamin E, copper, zinc and selenium concentrations were positively correlated with phagocytic activity in hospitalized camels (P<0.05). The likelihood of deficiency of vitamin A and E, zinc and selenium concentrations were significant in female hospitalized camels than males and in young age hospitalized camels < 6 years old compared to old ones (P<0.05). Decreased vitamin A and E and trace elements concentrations were associated with hospitalized camels’ phagocytic activity and index. The prevalence of low vitamin A and E, zinc and selenium concentrations were frequent in female hospitalized camels and hospitalized camels of age < 6 years old suggesting severe oxidative stress.

Selenium and copper status of camels in Al-Jouf area (Saudi Arabia)

In order to understand the changes in copper and selenium status in camel dam and calf around the calving period, blood samples were collected in 26 she-camel before delivery and after as well as their calves after birth. The mean values for the mother and their newborn were respectively 70.3 ± 19.8 and 58.6 ± 13.9 μg/100 ml for copper, 5.3 ± 3.7 and 4.6 ± 1.7 μg/100 ml for selenium. No change was observed for copper, but selenium increased after parturition in 81% of the case. The selenium status of camel calf was correlated with those of its mother, but not the copper. As the whole the correlation between selenium and copper was significantly positive. The selenium status was improved in camel receiving diet enriched with barley. The maternal transfer to milk has to be investigated.

Effect of organic selenium supplementation on growth, Se uptake, and nutrient utilization in guinea pigs

Forty weaned male guinea pigs (Cavia porcellus) of 152.6 +/- 7.96 g mean body weight were divided into four equal groups and fed a common basal diet comprised of 25% ground cowpea (Vigna unguiculata) hay, 30% ground maize (Zea mays) grain, 22% ground gram (Cicer arietinum) grain, 9.5% deoiled rice (Oryza sativa) bran, 6% soybean (Glycine max) meal, 6% fish meal, 1.5% mineral mixture (without Se), and ascorbic acid at 200 mg/kg to meet their nutrient requirements along with 0, 0.1, 0.2, and 0.3 ppm of organic selenium (Se) in groups I, II, III, and IV, respectively. Experimental feeding lasted for a period of 10 weeks, during which, daily feed intake and weekly body weights were recorded. Intake and digestibility of dry matter, organic matter, ether extract, crude fiber, and nitrogen-free extract as well as uptake of calcium and phosphorus were similar (P > 0.05) among the four groups. Feed:gain ratio was also similar (P > 0.05) in the four groups. However, digestibility of crude protein was significantly (P < 0.001) higher in group II supplemented with 0.1 ppm organic Se as compared to other three group. Intake and absorption of Se was significantly (P < 0.001) higher in all the Se supplemented groups as compared to control group. Average daily gain (ADG) was significantly (P < 0.05) higher in group II (3.16 g/day) and III (3.38 g/day) as compared to group I (2.88 g/day). However, ADG in group IV (supplemented 0.3 ppm organic Se) was significantly (P < 0.05) lower (2.83 g/day) than group II and III, but comparable (P > 0.05) to group I. Findings of the present experiment suggests that Se requirements of guinea pigs are > or =0.2 ppm, as supplementation of 0.1 ppm organic Se in the diet (having 0.1 ppm Se) not only enhanced their growth rate but also improved the protein utilization.

Selenium distribution in camel blood and organs after different level of dietary selenium supplementation

Eight young female camels shared in four groups of two 2 years received a basal diet enriched respectively with 0, 2, 4, and 8 mg selenium under sodium selenite form for 64 days. Feed intake was assessed daily; blood samples were taken on weekly basis. One camel from each group was killed at the end of the experiment. Se concentration in serum was increased significantly in the supplemented groups with an average of 176.3 +/- 18.0 ng/mL in the control group, 382.7 +/- 107.6 in the group receiving 2 mg Se, 519.8 +/- 168.4 in the group receiving 4 mg Se, and 533.4 +/- 158.6 in the group receiving 8 mg Se daily. For glutathione peroxidase (GSH-Px) activity, the control group (51.0 IU/g Hb) and the group receiving 2 mg (50.5 IU/g Hb) were significantly different than groups receiving 4 and 8 mg (respectively, 65.9 and 76.1 IU/g Hb). No significant variation occurred for vitamin E (mean, 0.56 +/- 0.23 ng/mL). Significant correlation between serum Se and GSH-Px was reported. Kidney was the richest organ in selenium followed by lung, spleen, and liver, but the increase in supplemented groups was more marked in liver and kidney. The hair seemed to be the best indicator of selenium intake in camel.

Effect of selenium supplementation on blood status and milk, urine, and fecal excretion in pregnant and lactating camel

Ten pregnant female camels divided into two groups received, after a 2-week adaptation period, an oral selenium (Se) supplementation (0 and 2 mg, respectively) under sodium selenite form for 6 months from the three last months of gestation up to the three first months of lactation. Feed intake was assessed daily. Blood samples and body weight were taken on a biweekly basis, both in dams and their camel calves after parturition. Feces and urine samples were collected monthly and milk on a biweekly basis. The Se concentration in serum increased significantly in the supplemented group and was threefold higher than the concentration compared to the control group, respectively, 305.9 +/- 103.3 and 109.3 +/- 33.1 ng/mL. The selenium concentration increased in similar proportion in milk (86.4 +/- 39.1 ng/mL in the control group vs 167.1 +/- 97.3 ng/mL in treated group), in urine, and feces. The glutathione peroxidase (GSH-Px) activity varied between 18.1 +/- 8.7 IU/g hemoglobin (Hb) in control group and 47.5 +/- 25.6 IU/g Hb in treated group but decreased after parturition in both groups. Vitamin E did not change significantly and was, on average, 1.17 +/- 0.72 and 1.14 +/- 0.89 ng/mL in the control and treated groups, respectively. Significant correlations were reported between serum Se, milk Se, GSH-Px, and fecal and urinary excretion or concentration. Blood values in camel calves were similar to those of the dams. The results seemed to confirm the sensitivity of camel to Se supplementation with an important increase of selenium in serum and milk.

Selenium in camel--a review

Requirements for trace minerals in camels, particularly selenium, are not well-known. Selenium supplementation using a pharmaceutical form or commercial mineral mixture is common practice in camels to address the cardiomyopathy often attributed to selenium deficiency. This supplementation is often empirical and based on estimated needs for cattle. Nowadays the use of selenium in animal foodstuffs is commonplace and further investigation of its metabolism (ingestion, dynamic of storage-destocking, excretion) in camels is warranted. The present review aimed to synthesize all the experimental research (comparative selenium status in cow and camel, response to different levels of supplementation at different physiological stages, excretion maternal transfer, experimental toxicosis) and field observations (deficiency, supplementation practices) undertaken in camels. The results underline the particularity of the unique metabolic profile of the camel and lead to practical recommendations for supplementation in camels, highlighting its relative sensitivity to excess Se intake at lower levels than in cattle. The maximal tolerable dose is 8 mg and the recommended doses range from 2 to 4 mg.