Trace-elements status in camels. A review

Regional and Seasonal Variability of Mineral Patterns in Some Organs of Slaughtered One-Humped Camels [Camelus dromedarius] from Saudi Arabia

Camel products are receiving great interest worldwide because of their high functional properties and nutritive values. Therefore, this study was focused on the variation of copper [Cu], zinc [Zn], manganese [Mn], selenium [Se], iron [Fe], iodine [I], and some heavy metals, cobalt [Co], lead [Pb], and cadmium [Cd], in the blood and tissues of slaughtered camels from five regions in Saudi Arabia [SA] during the summer and winter seasons, because environmental factors vary from region to region. Whole blood, meat, liver, rumen fluid, and rumen tissues were collected from the slaughterhouse in each region during the two seasons. Moreover, samples were prepared and analyzed for trace mineral and heavy metal concentrations using ICP-MS. The data were statistically analyzed as part of a complete randomized design and correlation analysis for season and location using SAS. The findings revealed a pattern in the minerals, with Ca being the only mineral that was unrelated to other minerals in the liver. For lead and cadmium, our mean value in liver [0.40 µg/g] was below the limit of the EU standard for cadmium [0.50 µg/g], while in meat and liver, lead contents [1.62 µg/g and 2.57 µg/g, respectively] were above the limit of the EU standard [0.10 and 0.20 µg/g, respectively]. For meat, the significantly highest positive correlations were observed between P and Mg [R² = 0.928], Fe and Mn [R² = 0.860], and Co and Mn [R² = 0.821]. For rumen tissues, P and Mg were highly correlated [R² = 0.958] as well as Zn and Mg [R² = 0.857], Zn and P [R² = 0.836], and Fe and Ca [R² = 0.802]. As a result, a region and season reflect variations in mineral concentrations in SA during the summer and winter seasons. Further intensive research is needed to investigate the minerals' biological mechanisms in camels under different environmental conditions.

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.

Camel Proteins and Enzymes: A Growing Resource for Functional Evolution and Environmental Adaptation

In less agroecological parts of the Asian, Arabian, and African deserts, Camelus dromedarius play an important role in human survival. For many years, camels have been employed as a source of food, a tool of transportation, and a means of defense. They are becoming increasingly important as viable livestock animals in many desert climates. With the help of camel genetics, genomics and proteomics known so far, this review article will summarize camel enzymes and proteins, which allow them to thrive under varied harsh environmental situations. An in-depth study of the dromedary genome revealed the existence of protein-coding and fast-developing genes that govern a variety of metabolic responses including lipid and protein metabolism, glucoamylase, flavin-containing monooxygenase and guanidinoacetate methyltransferase are other metabolic enzymes found in the small intestine, liver, pancreas, and spleen. In addition, we will discuss the handling of common medications by camel liver cytochrome p 450, which are different from human enzymes. Moreover, camels developed several paths to get optimum levels of trace elements like copper, zinc, selenium, etc., which have key importance in their body for normal regulation of metabolic events. Insulin tolerance, carbohydrate and energy metabolism, xenobiotics metabolizing enzymes, vimentin functions, behavior during the rutting season, resistance to starvation and changes in blood composition and resistance to water loss were among the attractive aspects of camel enzymes and proteins peculiarities in the camels. Resolving the enigma of the method of adaptation and the molecular processes linked with camel life is still a developing repository full of mysteries that need additional exploration.

Effect of Zinc, Selenium, and Vitamin E Administration on Semen Quality and Fertility of Male Dromedary Camels with Impotentia Generandi

This study aimed to investigate the effect of zinc (Zn), selenium (Se), and vitamin E (Vit E) administration on semen quality and fertility in male dromedary camels with impotentia generandi (IG, post-coital infertility). Factors that may affect response to treatment were investigated. Thirty-three IG-affected and five fertile camels were included. Case history was obtained, and breeding sound examination was performed. Semen was collected using electroejaculation. IG-camels were classified according to initial sperm count, body condition score, age, duration of infertility, IG-type, and testicular size. IG-camels were treated with a combination of intramuscular injections of Vit E (α-tocopherol acetate, 1 mg/kg bw) and Se (sodium selenite, 0.088 mg/kg bw) once every week for three successive weeks and by daily oral administration of 360 mg of zinc gluconate for 5 successive weeks. Semen quality was estimated before and after treatment. IG-treated camels were allowed to mate females in estrus, and conception rates were calculated. The results showed that sperm cell concentration, sperm motility, and viability significantly increased, while sperm abnormality significantly decreased after treatment (P < 0.01). Positive correlations were observed between initial sperm cell count and post-treated sperm count (P = 0.001), sperm motility (P = 0.01), and viability (P = 0.002). Other variables and their interactions did not affect response to treatment. Conception rates improved after treatment. In conclusion, Zn, Se, and Vit E administration improved semen quality and fertility in male dromedary camels with impotentia generandi. Initial sperm count can be used to predict the degree of camel response to treatment.

Determination of Zinc in Camel Skin Using Laser-Induced Breakdown Spectroscopy

Zinc plays a major role in skin integrity, which can be affected by dromedary camels' hard life conditions. Deficiencies in some trace elements especially in zinc can explain susceptibility of this species to skin diseases. Compared with ruminants, camel is already known for his relatively low zincemia. In order to assess dromedary camels' skin zinc content, the present study was carried out in several provinces located in the south of Morocco where camel skin diseases are commonly observed. Zinc content in dromedary camel skin was determined using for the first time laser-induced breakdown spectroscopy (LIBS), method considered so far quick and simple with few or no sample processing. Collected data showed that zinc skin contents ranged between 115 ± 60 (for external side) and 94 ± 82 ppm (for internal side) with significant variability according to animals and to skin layers (external side versus internal side). Zinc skin content decreased from external to internal layers. Such preliminary results could be used to compare skin zinc nutritional level in healthy camels with those affected by skin diseases.

Copper, Iron, Manganese, Zinc, Cobalt, Arsenic, Cadmium, Chrome, and Lead Concentrations in Liver and Muscle in Iranian Camel (Camelus dromedarius)

Camel meat as healthy food has received much attention for human consumption. In the present study, liver and muscle from 60 camels (Camelus dromedarius) including 26 males and 34 females were sampled to determine the concentration of As, Cd, Pb, Cr, Cu, Fe, Mn, Zn, and Co using the inductively coupled plasma-optical emission spectrometry (ICP-OES). Based on the obtained results, the average content of essential or toxic elements in the liver and muscle was as follows: 111.2 ± 26.51, 38.57 ± 7.97 (Zn), 3.28 ± 0.79, 2.12 ± 0.49 (Cu), 76.98 ± 14.20, 59.34 ± 11.81 (Fe), 0.87 ± 0.22, 0.48 ± 0.12 (Mn), 0.52 ± 0.27, 0.03 ± 0.01 (Co), ND ± 0.008, 0.012 ± 0.008 (Cd), 7.06 ± 1.58, 3.90 ± 0.86 (Cr), 0.85 ± 0.043, and 0.18 ± 0.02, and 1.12 ± 0.21 (As) mg kg^-1. Pb concentration was lower than the detection limit (ND). The results showed that the liver concentrations of Cu, Zn, Fe, Mn, Co, and Cr were significantly higher than those in the muscle. The association of sex, age, region, and sampling period, with a concentration of these elements, revealed that concentration of zinc in the liver and cobalt in the muscle were significantly higher in the male. Also, significantly higher cobalt and zinc concentrations in muscle were seen in the first 6 months of the year. Age-related differences in muscle concentrations were observed for cobalt. The concentration of trace elements and heavy metals in the liver and muscle samples were not correlated. Comparison of heavy metals concentration in both tissues with European Commission regulation showed that except Cd, the other heavy metals had a higher level than the EU standard. The results of this study showed that camel meat can be contaminated with heavy metals, but more investigations are needed.

Impotentia generandi in male dromedary camels: heavy metal and trace element profiles and their relations to clinical findings and semen quality

The aim of this study was to investigate the profiles of cadmium (Cd), lead (Pb), selenium (Se), zinc (Zn), copper (Cu), molybdenum (Mo), iron (Fe), and manganese (Mn) in serum of dromedary camels with impotentia generandi and their associations with the clinical findings and semen analysis data. Sixteen male dromedary camels with impotentia generandi (IG group) and 5 fertile camels (FERT group) were used. The external and internal genital organs were examined using visual inspection, palpation, and ultrasonography. Semen was collected by electroejaculation and examined for volume, count, motility, viability, and abnormality. Blood was collected from all camels and serum was harvested. All serum samples were digested by concentrated acids and analyzed for heavy metals and trace elements by flame emission atomic absorption spectrophotometer. Results showed that the mean heavy metal and trace element concentrations in serum were in the following descending order Fe > Zn > Cu > Cd > Mo > Se > Mn > Pb. Cd was higher in IG than in FERT males (P = 0.02). Se was greater in FERT than in IG groups (P = 0.003). Zn was higher in in FERT than in IG groups (P = 0.001). There were positive correlations between Zn and sperm count (r = 0.59, P = 0.005) and sperm motility (r = 0.57, P = 0.005) and a tendency for negative correlation between Zn and sperm abnormalities (r = - 0.44, P = 0.05). In conclusion, Cd might be implicated as a cause of infertility in male camels. Deficiencies of Se and Zn may also have adverse impacts on male camel reproduction.

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.

Comparative effects of selenium supplementation on the plasma selenium concentration and erythrocyte glutathione peroxidase activity in cattle and camels

At an experimental farm, five camels and five cows were each given a similar basal diet for 6 months. They received oral trace element supplementation for 3 months (day 22 to 112) which included zinc, copper, selenium, manganese, iodine and cobalt and corresponded to twice the daily requirement generally recommended for cows. Plasma selenium concentrations were significantly lower in the camels (20 (s.e. 2) mg/l) compared with the cows (33 (s.e. 2) μg/l). The mineral supplementation induced a large increase in the plasma selenium concentration in the camels which reached 200 (s.e. 35) fig/l. In the cows, the increase was much smaller and did not go beyond 65 (s.e. 8) μg/l. Before supplementation the red blood cell glutathione peroxidase activity was similar in the camel and the cow varying between 4000 and 6000 IU per 100 g haemoglobin. In both species, this activity increased with mineral supplementation and remained very high even when mineral supplementation was stopped. The results suggested that selenium metabolism in camels is different from that in the cows.

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.

Physiological change in camel milk composition (Camelus dromedarius) 2: physico-chemical composition of colostrum

Eleven samples of dromedary camel colostrum in Kazakhstan, which originated from one farm only, were collected to study the changes in the physico-chemical composition (total fat, total protein, iodine index, lactose, calcium, phosphorus, iron, vitamin C, urea, ammonia, density, Dornic acidity, pH, and skimmed dry matter) all along the first postpartum week. At that time, the fat matter decreased from 25.9% to 3.1% and protein from 17.2% to 4.2%, in contrast to vitamin C which increased. Minerals showed high variations with lower values the first day after parturition and variable changes up to the end of the week where the values were stabilized. The iron concentration decreased from the second day postpartum. No clear changes of the other parameters were observed, notably for the non-protein nitrogen (urea and ammonia).

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.

Effect of different selenium supplementation levels on selenium status in camel

Twelve female camels divided into three groups received, after a 2-week adaptation period, an oral Se supplementation (0, 2, and 4 mg, respectively) under sodium selenite form for 3 months. Feed intake was assessed daily, blood samples and body weight were taken on a weekly basis, and feces and urine samples were collected every 2 weeks up to 1 month after the end of the supplementation period. The Se concentration in serum was increased significantly in supplemented groups. The maximum level was observed in the period of supplementation in the camel receiving 4 mg (492.5 ng/mL), which was fourfold higher than the value at the beginning of the trial (126 to 138.5 ng/mL according to the groups). The selenium concentration increased significantly in urine and feces but to a lesser extent. A similar trend was observed with glutathione-peroxidase (GSH-Px) values varying between 8.4 and 96.5 IU/g Hb. However, no difference occurred between the two groups receiving 2 or 4 mg Se at the supplementation period. Vitamin E (mean 1.13 +/- 0.61 microg/mL with range 0.27-3.09) did not change significantly. Significant correlations were reported between serum Se, GSH-Px, fecal, and urinary excretion or concentration.

Studies on the haematology and trace element status of adult Bactrian camels (Camelus bactrianus) in China

Reference values were established for some haematological and serum biochemical constituents in Bactrian camels (Camelus bactrianus) in China. The contents of seven trace elements in the blood, hair, liver, kidney, heart, spleen, lung, cerebrum, cerebellum, rib, ovary, pancreas and gluteal muscle of Bactrian camels were also measured. Some of these values are reported for the first time for Bactrian camels in China. Most haematological and serum biochemical values were similar to those of cattle, yaks, sheep and dromedary camels, but the mean serum albumin concentration and the albumim/globulin ratio were significantly higher than those in other ruminants and the mean thyroxine concentration was half that in dromedary camels. The liver contained the highest concentrations of copper, zinc, manganese and iron, and the renal cortex contained the highest concentration of selenium. The concentrations of selenium, cobalt, zinc, manganese and molybdenum in the tissues were within the reference ranges for other ruminants, but the mean iron and copper concentrations in the liver were significantly higher than those in other ruminants.

Purification and partial characterization of camel (Camelus Dromedarius) ceruloplasmin

Adult and young camel ceruloplasmin (Cp) were isolated and purified using the single-step chromatography on amino ethyl-activated sepharose. There are no differences between the adult and the young camel protein. The molecular mass of the protein, as estimated by SDS-PAGE (denaturant conditions), was approximately 130000 Da. The electrophoretic mobility of camel Cp is slightly higher as compared to human and sheep protein suggesting that the camel Cp is homogeneous, compact and more acid. The copper content was estimated to be 5.8+/-0.3 atoms per molecule. The spectroscopic feature includes an absorption maximum at 610 nm, which could be attributed to type 1 copper. The EPR spectrum was completely devoid of any typical signal of the type 2 copper. The kinetic parameters of the adult camel Cp for the specific activity as p-phenylendiamine oxidase were determined as K(m)=0.42 mM and V(max)=0.93 microM NADH/mn/mg Cp. The optimum pH for the activity was 5.7.

Comparative study of copper and zinc metabolism in cattle and camel

At an experimental farm, five camels and five cows were fed a similar basal diet for 6 mo. They received oral trace element supplementation for 3 mo (day 22-112). This supplementation included zinc, copper, selenium, manganese, iodine, and cobalt, and corresponded to twice the requirements generally recommended for cows. Plasma copper and zinc concentrations were significantly lower in the camels (61 micrograms/100 mL for copper and 38 micrograms/100 mL for zinc) than in the cows (111 and 83, respectively). The supplementation had no effect on plasma zinc concentration in the camels in spite of the low observed values in this species. Liver copper concentration at the beginning of the trial was lower in the camels (9 ppm) than in the cows (35 ppm), and stayed at lower levels during the entire supplementation period. There was no clear difference in fecal excretion of copper and zinc between the camels and the cows. The results suggested that trace element requirements are lower in camels than in cows and that camels regulate their plasma zinc concentration at a very low level (< 40 micrograms/100 mL).