Antioxidant levels in tissues of young and adult camels (Camelus dromedarius)

Housing Management of Male Dromedaries during the Rut Season: Effects of Social Contact between Males and Movement Control on Sexual Behavior, Blood Metabolites and Hormonal Balance

Simple Summary

The effect of different housing management systems on the behavior, metabolites and hormonal balance in male dromedaries during the rutting season was evaluated. Male dromedaries that were housed in groups and allowed to walk around had significantly higher frequencies of ruminating, standing, walking and sexual-related behaviors than those housed individually or tied. Movement control had significant effects on blood serum metabolites and hormone concentrations. Fenced and exercised male dromedaries had higher (p < 0.05) concentrations of blood serum transaminases, free radicals, glucose, cholesterol and testosterone and lower (p < 0.05) concentrations of cortisol and triiodothyronine (T3) than tied male dromedaries. Animal social interaction is of particular importance for maintaining physical; psychological and sexual behaviors. Allowing walking-around exercise for captive animals improves their metabolic status and decreases captive stress effects. Housing systems that guarantee social interaction and physical activity are being the most suitable housing management systems for male dromedaries during the rutting season.

Abstract

The current study aimed to evaluate the effect of different housing management systems on behavior, blood metabolites and hormonal balance in male dromedaries during the rutting season. Forty-eight adult male dromedaries were stratified in a two by three factorial experiment design, testing effects of social contact (single and group) and movement control (tied, fenced and exercise). During a ten-week experimental period, male dromedaries were filmed weekly for 20 min three times per day to evaluate their behaviors. Blood samples were collected and analyzed for serum metabolites and hormones. Both animal social contact and movement control significantly affected maintenance, posture and sexual behaviors. Male dromedaries housed in groups expressed higher frequencies of sexual desire-related behaviors (teeth grinding, open legs, tail flapping, dulla “soft palate exteriorization”, blathering and urination) than those individually housed. Animal movement control significantly affected sexual behavior; fenced and exercised male dromedaries expressed higher frequencies of sexual desire-related behaviors than tied ones. Male dromedaries housed in groups and allowed to walk around had significantly higher frequencies of ruminating, standing, walking and sexual-related behaviors than those housed individually or tied. Movement control had significant effects on blood serum metabolites and hormone concentrations. Fenced and exercised male dromedaries had higher (p < 0.05) concentrations of blood serum transaminases, free radicals, glucose, cholesterol and testosterone (2.91 and 2.09 ng/mL, respectively) and lower (p < 0.05) concentrations of cortisol (44.12 and 53.52 nmol/L, respectively) and triiodothyronine (1.68 and 1.91 ng/mL, respectively) than tied male dromedaries. In conclusion, animal social interaction is of particular importance for maintaining physical, psychological and sexual behaviors. Allowing walking-around exercise for captive animals improves their metabolic status and decreases captive stress effects. Housing systems that guarantee social interaction and physical activity are the most suitable housing management systems for captive male dromedaries during the rutting season.

Molecular cloning, characterization and gene expression of an antioxidant enzyme catalase (MrCat) from Macrobrachium rosenbergii

In this study, we reported a full length of catalase gene (designated as MrCat), identified from the transcriptome database of freshwater prawn Macrobrachium rosenbergii. The complete gene sequence of the MrCat is 2504 base pairs in length, and encodes 516 amino acids. The MrCat protein contains three domains such as catalase 1 (catalase proximal heme-ligand signature) at 350-358, catalase 2 (catalase proximal active site signature) at 60-76 and catalase 3 (catalase family profile) at 20-499. The mRNA expressions of MrCat in healthy and the infectious hypodermal and hematopoietic necrosis virus (IHHNV) challenged M. rosenbergii were examined using quantitative real time polymerase chain reaction (qRT-PCR). The MrCat is highly expressed in digestive tract and all the other tissues (walking leg, gills, muscle, hemocyte, hepatopancreas, pleopods, brain and eye stalk) of M. rosenbergii taken for analysis. The expression is strongly up-regulated in digestive tract after IHHNV challenge. To understand its biological activity, the recombinant MrCat gene was constructed and expressed in Escherichia coli BL21 (DE3). The recombinant MrCat existed in high thermal stability and broad spectrum of pH, which showed over 95% enzyme activity between pH 5 and 10.5, and was stable from 40 °C to 70 °C, and exhibited 85-100% enzyme activity from 30 °C to 40 °C.

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.

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.