Vegetation and condition of arid rangeland ecosystem in Central Saudi Arabia.

Saudi Arabia rangeland ecosystems have undergone intense processes of degradation for many decades because of extreme climate and human activities such as overgrazing and socioeconomic changes. In this study, Hail and Qassim Regions of Saudi Arabia covering an area about 79610.73 km2 were selected to study the rangeland vegetation and condition. Haloxylon salicornicum was the most dominant species, covering more than 56% of the total area. The second prominent community was Acacia-Lycium shawii, which covers about 21% of total area. It was found that about 65% of vegetation in the surveyed area is in good or very good condition compared with about 31% in poor or deteriorated condition. Effective measures such as determination of carrying capacities and development of grazing systems have to be implemented to ensure resources sustainably.

Stress associated with road transportation in desert sheep and goats, and the effect of pretreatment with xylazine or sodium betaine.

The present work investigates some clinical, endocrinological, biochemical and haematological variables in desert sheep and goats stressed in the course of individual road transportation, and the influence thereon of pretreatment with an established anti-stressor drug, xylazine HCl, and a test compound, sodium betaine (trimethylglycine). Road transportation for 2h resulted in variable and statistically insignificant increases in heart, pulse and respiratory rates in both control and experimental animals. Transportation stress significantly increased the concentrations of plasma cortisol, and glucose, and decreased that of magnesium. The endogenous thiocyanate concentration was unaffected. The stress also insignificantly decreased the haematocrit (PCV), and the number of lymphocytes, and increased the concentration of haemoglobin. Pretreatment of sheep and goats with xylazine at a single dose of 0.01 mg/kg by the intravenous route significantly ameliorated the effects induced by the stressful stimulus. The effects of pretreatment of the two species with sodium betaine (10 mg/kg) produced variable and insignificant effects.

Infertility in the dromedary bull: a review of causes, relations and implications.

Research into infertility in the dromedary bull, as reported during the last two decades, is reviewed with emphasis on causes and effects. Reproductive activity of such animals is naturally limited by a breeding season, though with enough encouragement some may mate with oestrous females out of season but a full fertilization potential can in no way be expected. It is essential that any female presented to a bull is capable of reproducing. The presentation of a subfertile or infertile female due to infection or physiological abnormality will adversely affect the female's ability to conceive and, therefore, the apparent fertility rates of the bull she was put to. The average number of successful services a bull could be expected to perform is two per day. Dromedary bulls with large testes have larger sperm outputs and can cope with more than two females per day providing that they are given adequate periods of rest, 1-2 days every 10 days or so, in conjunction with appropriate nutrition throughout the season. Anabolic steroids or testosterone therapies, which are sometimes used in an attempt to improve male characteristics and bull libido, are not recommended for dromedary bulls in breeding work. Such steroids result in a decrease in testicular size and weight with fewer sperm per gram of testicular tissue being found and the sperm produced also have lower motility rates. Pain associated with the act of mating a she-camel, due to injuries or inflammation in the scrotum, testes, prepuce and sheath, can cause a permanent reduction in bull libido. Camel bulls achieving pregnancy rates more than 60% have had consistently higher spermatozoal concentrations and kinematic variables derived by the computerized cell motion analyzer (CMA) system. As far as physical capabilities are concerned, 3-year-old dromedary bulls, which have reached puberty, have been shown to be perfectly capable of fertilizing a female, but they have a limited sperm production to perform consistently throughout the season in a large herd. By 4.5-5.0 years of age, they are capable of producing adequate numbers of sperm to mate as many as females as an adult bull but fertilizing capacity is not attained until 6 years of age on average. Hyperoestrogenaemia, associated with autoimmune thyroiditis and trypanosomiasis, suppresses the secretion of testicular testosterone and augments the release of testicular histamine, which appears mandatory for quantitative reduction/loss of advanced spermatogenic cells in infertile dromedary bulls.

The ameliorative effect of dates (Phoenix dactylifera L.) on ethanol-induced gastric ulcer in rats.

The present work aimed at testing, in a rat model of ethanol-induced gastric ulceration, a local folk medicinal claim that dates are beneficial in gastric ulcers in humans. Aqueous and ethanolic undialyzed and dialyzed extracts from date fruit and pits were given orally to rats at a dose of 4 ml/kg for 14 consecutive days. On the last day of treatment, rats were fasted for 24 h, and were then given ethanol, 80% (1 ml/rat) by gastric intubation to induce gastric ulcer. Rats were killed after 1 h of ethanol exposure, and the incidence and severity of the ulceration were estimated, as well as the concentrations of gastrin in plasma, and histamine and mucus in the gastric mucosa. A single group of rats that were fasted for 24 h, was administered orally with lansoprazole (30 mg/kg), and was given 80% ethanol as above, 8 h thereafter, served as a positive control. The results indicated that the aqueous and ethanolic extracts of the date fruit and, to a lesser extent, date pits, were effective in ameliorating the severity of gastric ulceration and mitigating the ethanol-induced increase in histamine and gastrin concentrations, and the decrease in mucin gastric levels. The ethanolic undialyzed extract was more effective than the rest of the other extracts used. It is postulated that the basis of the gastroprotective action of date extracts may be multi-factorial, and may include an anti-oxidant action.

Immobilization (restraint) stress in desert sheep and goats, and the influence of pretreatment with xylazine or sodium betaine thereon.

Some behavioral, clinical, biochemical and haematological parameters were studied in Desert (Najdi) sheep and goats subjected to the acute and unavoidable stressful stimuli of immobilization. The effect of pretreatment with xylazine (n = 6) or sodium betaine (n = 6) on the responses of these animals has also been investigated. The immobilization stress resulted in increased vocalization and in variable and statistically insignificant increases in heart pulse and respiratory rates. In the two species, immobilization stress significantly elevated the plasma concentration of cortisol (from about 35.2 to about 83.8 mmol/L) and glucose (from 3.1 to 4.6 mmol/L), and decreased the concentration of magnesium (from 0.81 to 0.65 mmol/L). The endogenous thiocyanate concentration was unaffected. The immobilization stress also insignificantly decreased the haematocrit (PCV), and the number of lymphocytes, and increased the concentration of haemoglobin. Pretreatment of sheep and goats with xylazine at a dose of 0.01 mg/kg, via the intravenous route significantly alleviated the effects induced by the stressful stimulus. Pretreatment of the two species with sodium betaine (10 mg/kg/day for 3 days), however, produced variable and insignificant effects. There were no significant differences between sheep and goats in the responses to the immobilization stress, except in vocalization, which was more pronounced in sheep than in goats.

Isolation stress in desert sheep and goats and the influence of pretreatment with xylazine or sodium betaine.

We studied some behavioural, clinical, biochemical and haematological variables in Desert (Najdi) sheep and goats subjected to the acute stressful stimulus of isolation from the flock, and the influence of pretreatment with xylazine (n = 6) or sodium betaine (n = 6). The isolation stress resulted in increased vocalization and in variable and statistically nonsignificant increases in heart, pulse and respiratory rates. Isolation caused significant increases in the plasma concentrations of cortisol (from about 35.2 to about 83.8 mmol/L) and glucose (from 3.1 to 4.2 mmol/L), and a decrease in that of magnesium (from 0.82 to 0.65 mmol/L). The endogenous thiocyanate concentration was unaffected. The isolation stress also significantly decreased the haematocrit (PCV), and the number of lymphocytes, and increased the concentration of haemoglobin. Pretreatment of sheep and goats with xylazine at a dose of 0.01 mg/kg by the intravenous route significantly ameliorated the effects induced by the stressful stimulus. The effects of pretreatment of the two species with sodium betaine (10 mg/kg) produced variable and nonsignificant effects. There were no significant differences between sheep and goats in the responses to the isolation stress, except in vocalization, which was greater in sheep than in goats.

Trypanosomiasis-induced infertility in dromedary (Camelus dromedarius) bulls: changes in plasma steroids concentration and semen characteristics.

The effect of Trypanosomiasis on concentrations of plasma steroids and semen characteristics was studied in 24 dromedary bulls. Based upon the parasitological and serological diagnosis, 18 bulls were found infected with Trypanosoma evansi (Group 2) and six were found to be free from infection and served as controls (Group 1). The infected animals exhibited signs of anaemia indicated by the decrease of packed cell volume (PCV) and haemoglobin concentration (Hb), pale mucus membranes, weight loss, lethargy, weakness and dullness. However, five animals (27.8%) of the infected group revealed elevated rectal temperatures and three animals (16.7%) revealed testicular degeneration upon palpation of their scrotal contents. Concentrations of plasma oestradiol-17beta (86.5 +/- 8.6 pg/ml versus 232.5 +/- 74.4 pg/ml) and testosterone (4.8 +/- 0.7 ng/ml versus 2.7 +/- 1.5 ng/ml) were significantly different (P < 0.05) between the control and infected bulls. Evaluation of the semen collected by electroejaculation and evaluated by a computerized cell motion analyzer revealed normal semen characteristics in the control animals compared to deteriorated ones in the infected bulls. There were highly significant (P < 0.01) decreases in sperm count (12.2 +/- 1.3/ml versus 6.5 +/- 4.9 x 10(6)/ml), motility percentage (68.2 +/- 6.7% versus 27.4 +/-15.6%), percentage of live spermatozoa (73.2 +/- 8.3% versus 35.8 +/- 8.2%) and increases in percentage of morphological abnormalities (3.3 +/- 0.6% versus 15.9 +/- 1.0%) in the infected group. An examination of the plasma hormonal profiles and semen characteristics in the infected bulls indicated that altered Sertoli cell function due to formation of immune complexes in four bulls (Group 2A), pituitary dysfunction in six bulls (Group 2B), testicular degeneration in three bulls (Group 2C) and finally trypanotolerancy in five bulls (Group 2D) are possible factors responsible for poor semen characteristics and infertility induced by T. evansi infection in dromedary bulls.

Intratesticular morphometric, cellular and endocrine changes in dromedary bulls exhibiting azoospermia.

Twenty bulls, aged 7-12 years and selected from six dromedary farms were used in this study. Fifteen previously fertile animals were divided into fertile (controls) and infertile groups on the basis of abnormal scrotal contents following palpation and azoospermic ejaculates collected by electroejaculation. An examination of the clinical and histological findings as well as the testicular patterns of oestradiol-17beta, testosterone and histamine indicated that three bulls displayed normal ranges comparable to the controls but with bilateral spermatocoeles in the caput epididymides in conjunction with the soft texture of the testicles. Seven bulls showed moderate testicular firmness and springiness, a marked increase in testicular oestradiol-17beta and histamine concentrations, and increases in surface area, density of mast cells and percentages of seminiferous tubules containing premeiotic spermatogenic cells as well as decreases in testicular testosterone concentrations, surface area of Leydig cells and diameter of the seminiferous tubules. The remaining five infertile animals had small hard testicles, supranormal testicular testosterone concentrations, baseline values of testicular oestradiol-17beta and histamine, decreased numbers of Sertoli and mast cells, with a predominance (98.2%) of seminiferous tubules containing spermatogonia resting on a thickened tubular basement membrane. The results provide information on the relationship between gonadotrophin, testicular oestrogen, androgens and histamine as well as spermatogenesis in normal and azoospermic dromedary bulls.

Comparative plasma pharmacokinetics and tolerance of florfenicol following intramuscular and intravenous administration to camels, sheep and goats.

Florfenicol, a monofluorinated analogue of thiamphenicol, has a broad antibacterial spectrum. The pharmacokinetics of florfenicol was studied following a single intravenous (i.v.) or intramuscular (i.m.) injection at a dose of 20 mg/kg body weight in healthy male camels, sheep and goats. The concentration of florfenicol in plasma was determined using a microbiological assay. Pharmacokinetic analysis was performed using a two-compartment open model. Following i.m. administration, the maximum plasma concentration of florfenicol (Cmax) reached in camels, sheep and goats was 0.84 +/- 0.08, 1.04 +/- 0.10 and 1.21 +/- 0.10 microg/ml, respectively, the the time required to reach Cmax (t(max)) in the same three respective species was 1.51 +/- 0.14, 1.44 +/- 0.10 and 1.21 +/- 0.10 h. The terminal half-life (t(1/2)beta) and the fraction of the drug absorbed (F%) in camels, sheep and goats were 151.3 +/- 16.33, 137.0 +/- 12.16 and 127.4 +/- 11.0 min, and 69.20% +/- 7.8% , 65.82% +/- 6.7% and 60.88% +/- 5.9%, respectively. The MRT in the same three respective species was 4.01 +/- 0.45, 3.42 +/- 0.39 and 2.98 +/- 0.32 h. Following i.v. administration, the terminal half-life (t(1/2)beta) and total body clearance (Clbeta) in camels, sheep and goats were 89.5 +/- 9.2, 78.8 +/- 8.3 and 71.1 +/- 8.9 min and 0.33 +/- 0.04, 0.30 +/- 0.03 and 0.27 +/- 0.03 L/h per kg, respectively. The area under the curve (AUC(0-infinity)) and the mean residence time (MRT) in the same three respective species were 60.61 +/- 6.98, 62.45 +/- 6.56 and 74.07 +/- 7.85 microg/ml per h, and 2.71 +/- 0.31, 2.34 +/- 0.25 and 2.11 +/- 0.23 h. These data suggest that sheep and goats absorb and clear florfenicol to a broadly similar extent, but the rate and extent of absorption of the drug tends to be higher in camels. Drug treatment caused no clinically overt adverse effects. Plasma enzyme activities and metabolites indicative of hepatic and renal functions measured 1, 2, 4 and 7 days following the drug treatment were within the normal range, indicating that the drug is safe at the dose used.

Variations in the normal activity of esterases in plasma and liver of camels (Camelus dromedarius), cattle (Bos indicus), sheep (Ovis aries) and goats (Capra hircus).

Esterases are a large group of enzymes found in plasma (or serum) and tissues, which hydrolyse a number of xenobiotics. Some of these enzymes have not yet been measured in tropical domestic animals. In the present work, we have measured the activities of three esterases, viz. aspirin esterase, cholinesterase and nitrophenylacetate esterase in the plasma and livers of male and female camels, cattle, sheep and goats. The results indicate that the enzyme activities are highest in the goat, followed by sheep and cattle (which showed broadly similar activities), and lowest in camels. Gender had no statistically significant effect, although males exhibited about 5-8% more enzyme activity in each of the four species, than females.

The effect of treatment with gum Arabic on gentamicin nephrotoxicity in rats: a preliminary study.

In the present work we assessed the effect of treatment of rats with gum Arabic on acute renal failure induced by gentamicin (GM) nephrotoxicity. Rats were treated with the vehicle (2 mL/kg of distilled water and 5% w/v cellulose, 10 days), gum Arabic (2 mL/kg of a 10% w/v aqueous suspension of gum Arabic powder, orally for 10 days), or gum Arabic concomitantly with GM (80mg/kg/day intramuscularly, during the last six days of the treatment period). Nephrotoxicity was assessed by measuring the concentrations of creatinine and urea in the plasma and reduced glutathione (GSH) in the kidney cortex, and by light microscopic examination of kidney sections. The results indicated that concomitant treatment with gum Arabic and GM significantly increased creatinine and urea by about 183 and 239%, respectively (compared to 432 and 346%, respectively, in rats treated with cellulose and GM), and decreased that of cortical GSH by 21% (compared to 27% in the cellulose plus GM group) The GM-induced proximal tubular necrosis appeared to be slightly less severe in rats given GM together with gum Arabic than in those given GM and cellulose. It could be inferred that gum Arabic treatment has induced a modest amelioration of some of the histological and biochemical indices of GM nephrotoxicity. Further work is warranted on the effect of the treatments on renal functional aspects in models of chronic renal failure, and on the mechanism(s) involved.

Effects of malathion plus superphosphate or urea on Najdi sheep.

The effects of p.o. administration of the combination of malathion + superphosphate or urea on Najdi sheep were evaluated in sheep dosed as untreated controls, malathion-treated at 25 mg/kg/d, superphosphate-treated at 450 mg/kg/d, urea-treated at 450 mg/kg/d, malathion-treated at 25 mg/kg/d + superphosphate treated at 450 mg/kg/d, or malathion treated at 25 mg/kg/d + urea treated at 450 mg/kg/d. Oral doses of malathion alone were lethal after 6 d, and malathion + urea were fatal after 6-8 d. Malathion + superphosphate caused death after 2-3 d. Malathion, but not superphosphate or urea, inhibited serum cholinesterase activity. Hepatonephropathy correlated with changes in serum AST, ALP, cholesterol, triglyceride, bilirubin, urea, total protein and albumin. Neither malathion nor its combination with superphosphate or urea caused peripheral neuropathy.

Effect of combination of Capsicum frutescens and Citrullus colocynthis on growth, haematological and pathophysiological parameters of rats.

The toxicity of diet containing 10% of Capsicum frutescens or 10% of Citrullus colocynthis fruits or their 1:1 mixture (5% + 5%) to rats treated for 6 weeks was evaluated. Body weight loss, inefficiency of feed utilization, diarrhoea, and enterohepatonephropathy characterized C. colocynthis toxicosis in rats. Despite impairment of rat's growth neither nephropathy nor diarrhoea was detected in rats fed the 10% C. frutescens diet. Feeding the mixture of C. frutescens and C. colocynthis caused more pronounced effects and death of rats. Vital organ lesions accompanied by anaemia and leucopenia were correlated with changes in serum ALP, AST and ALT activities with alterations in concentrations of total protein, albumin, urea and other serum constituents. Serum bilirubin concentration did not change.

Gastrointestinal transit in mice treated with various extracts of date (Phoenix dactylifera L.).

Dates are commonly consumed, especially in the Middle East, but their effect on gastrointestinal transit (GIT) has not been quantified. The effect of water and ethanol extracts from date flesh and date pits on the GIT in mice was studied. Fasted unanaesthetized male mice received by gavage either the vehicle (0.02 m/kg), or the extracts at doses of 0.01, 0.02 or 0.04 ml/kg. Two separate groups received either clonidine (1 mg/kg) or yohimbine (2 mg/kg). Two hours later, all animals were given a test meal containing charcoal and gum arabic in water. Thirty min thereafter, they were killed and the distance the charcoal column had traveled along the small intestine was measured. Compared with the control, the animals that received the ethanol and water extracts of both date flesh and pits emptied, in a dose-dependent manner, more of their gastrointestinal content. The increase in the GIT ranged from 4 to 22%. However, water extract from dialyzed date flesh induced a dose-dependent decrease in GIT that ranged from 4 to 24%. Clonidine exerted a significant decrease (68%), and yohimbine a significant increase (30%) in the GIT. Depending on the method of extraction, the date extracts may exert an increase or a decrease in GIT.

The effect of calcium load and the calcium channel blocker verapamil on gentamicin nephrotoxicity in rats.

Gentamicin (GM) is used against serious and life-threatening Gram negative infections. However its use is limited by the occurrence of nephrotoxicity. Reports on the interaction between GM nephrotoxicity and calcium (Ca(2+)) or Ca blockers are conflicting. Therefore, in the present work we assessed the effect of treatment of rats with graded doses of calcium carbonate, CaCO(3) (0.25, 0.5 or 1.0 g/kg) orally, or the Ca(2+) channel blocker verapamil (1.75, 3.5 or 7.0 mg/ kg) intramuscularly (i.m.), on the nephrotoxicity induced by concomitant i.m. treatment with GM (80 mg /kg/day for 6 days). Nephrotoxicity was evaluated histopathologically by light microscopy and biochemically by measuring the concentrations of urea and creatinine in plasma, reduced glutathione (GSH), lipid peroxidation and superoxide dismutase (SOD) activity in kidney cortex. The results indicated that the administration of CaCO(3) produced a dose-dependent amelioration in the biochemical indices of nephrotoxicity in plasma and renal cortex, which was significant at the two higher doses used. The histological picture of the renal proximal tubules followed a similar pattern. Treatment with verapamil induced a dose-dependent potentiation in the biochemical parameters of nephrotoxicity that was significant only at the highest dose used (7 mg/kg). This dose also exacerbated the GM-induced histological necrosis. The above interactions may be clinically relevant in patients treated concurrently with these agents.

Use of a new computerized system for evaluation of spermatozoal motility and velocity characteristics in relation to fertility levels in dromedary bulls.

Three ejaculates from each of 14 dromedary bulls were collected at 7-day intervals and diluted to 50 x 10 (6) spermatozoa per ml with sodium citrate (2.9%) seminal extender. Spermatozoal concentrations, motility percentages and velocity measures were evaluated by a new computerized cell motion analyzer (CMA, medical Technologies Montreux SA, Switzerland) for assessing fertility rates in such animals. Greatest variability in concentrations and motility percentages was generally attributed to animal effect within the first ejaculate. Spermatozoal concentrations and kinematic variables in particular percentages of progressive motility, amplitude of lateral head displacement (ALH) and linearity (LIN) percentage were strongly correlated (P<0.01) with fertility rates of dromedary bulls. The CMA-derived measurements of velocity straight line (VSL), velocity curve line (VCL), and velocity averaged line (VAP) were significantly affected by the type of spermatozoal tracks. The present results evidenced that the CMA is a reliable system for determining spermatozoal concentrations, motility percentages and velocity measures and is considered as an accurate and rapid method for evaluating and predicting fertility in the one-humped camel bulls.

Liquorice (Glycyrrhiza glabra) and the adrenal-kidney-pituitary axis in rats.

The effect of oral administration of a water freeze-dried extract of Glycyrrhiza glabra (liquorice) has been studied at doses of 100, 250 and 500 mg/kg in rats on the plasma concentration of cortisol, adrenocorticotrophic hormone (ACTH), aldosterone, renin, sodium (Na) and potassium (K). The results indicated that treatment induced dose-dependent and mostly significant decreases in the concentration of cortisol, ACTH, aldosterone and K. There were concomitant dose-dependent increases in the concentrations of renin and Na. The results suggest a strong and dose-dependent suppression of the adrenal-pituitary axis, accompanied by stimulation of renin production from the kidney.

Effect of freeze dried extract of Olea europaea on the pituitary-thyroid axis in rats.

The effect of an aqueous extract of olive (Olea europaea) leaf on the thyroid activity was studied. The results suggest a stimulatory action of the extract on the thyroid, unrelated to the pituitary.

Response of broiler chicks to dietary Rhazya stricta and Nigella sativa.

1. Rhazya stricta leaves and Nigella sativa seeds were fed to 7-d-old Hibro broiler chicks at 20 and 100 g/kg of the diet for 7 weeks. Although 20 and 100 g/kg N. sativa seed diets did not adversely affect growth, a decrease in body weight and feed efficiency and hepatonephropathy were observed in the chicks fed on the 100 g/kg R. stricta diet. 2. These changes, associated with macrocytic hypochromic anaemia, were correlated with alterations in serum aspartate transaminase' (AST) and alanine transaminase (ALT) activities and concentrations of total protein, albumin, globulin, cholesterol, calcium and other serum constituents. 3. The effect of 20 g/kg R. stricta diet on chicks was not associated with development of biliary hyperplasia or catarrhal enteritis after 7 weeks of treatment.

Effect of lead exposure on the erythrocytic antioxidant levels in goats.

Fifteen adult female goats were orally exposed to 5.46 mg lead (as lead acetate) per kg body weight daily for 2 weeks to study the antioxidant enzymes of the erythrocyte, lipid peroxide level, total thiol groups and total antioxidant status (TAS) in plasma. Ten goats served as unexposed control. Blood samples were collected before exposure (day 0) and on days 7 and 14. Ten per cent erythrocyte haemolysate was prepared and analysed for glutathione peroxidase (GPx), superoxide dismutase (SOD), catalase (CAT), total thiol groups and lipid peroxide. TAS was determined in plasma. There was a significant (P < 0.05) increase of erythrocytic GPx, SOD, CAT, total thiol groups and TAS on day 7 which was followed by a significant (P < 0.05) decrease of all these parameters on day 14. Lipid peroxide level increased significantly (P < 0.05) and the maximum level was attained by day 14. The results obtained indicate a possible role of free radicals in lead poisoning pathogenicity.