Ramesh Chandra Patra

Removing the threat of diclofenac to critically endangered Asian vultures

Veterinary use of the nonsteroidal anti-inflammatory (NSAID) drug diclofenac in South Asia has resulted in the collapse of populations of three vulture species of the genusGyps to the most severe category of global extinction risk. Vultures are exposed to diclofenac when scavenging on livestock treated with the drug shortly before death. Diclofenac causes kidney damage, increased serum uric acid concentrations, visceral gout, and death. Concern about this issue led the Indian Government to announce its intention to ban the veterinary use of diclofenac by September 2005. Implementation of a ban is still in progress late in 2005, and to facilitate this we sought potential alternative NSAIDs by obtaining information from captive bird collections worldwide. We found that the NSAID meloxicam had been administered to 35 captiveGyps vultures with no apparent ill effects. We then undertook a phased programme of safety testing of meloxicam on the African white-backed vultureGyps africanus, which we had previously established to be as susceptible to diclofenac poisoning as the endangered AsianGyps vultures. We estimated the likely maximum level of exposure (MLE) of wild vultures and dosed birds by gavage (oral administration) with increasing quantities of the drug until the likely MLE was exceeded in a sample of 40G. africanus. Subsequently, sixG. africanus were fed tissues from cattle which had been treated with a higher than standard veterinary course of meloxicam prior to death. In the final phase, ten Asian vultures of two of the endangered species(Gyps bengalensis,Gyps indicus) were dosed with meloxicam by gavage; five of them at more than the likely MLE dosage. All meloxicam-treated birds survived all treatments, and none suffered any obvious clinical effects. Serum uric acid concentrations remained within the normal limits throughout, and were significantly lower than those from birds treated with diclofenac in other studies. We conclude that meloxicam is of low toxicity toGyps vultures and that its use in place of diclofenac would reduce vulture mortality substantially in the Indian subcontinent. Meloxicam is already available for veterinary use in India.

Enhanced Erythrocytic Lipid Peroxides and Reduced Plasma Ascorbic Acid, and Alteration in Blood Trace Elements Level in Dairy Cows with Mastitis

Oxidative stress has been associated in several inflammatory conditions and incriminated in the pathogenesis of many diseases. However, little information is available on the status of plasma antioxidant levels, essential components of important antioxidant enzymes such as copper, zinc and selenium in blood, and the end product of oxidative damage to the erythrocytic polyunsaturated fatty acids in inflammatory udder conditions. Blood samples were collected from three groups of dairy cows, with 21 in each group: animals with healthy udder, clinical mastitis, and subclinical mastitis. These animals were randomly selected from a herd on the basis of the California mastitis test, somatic cell count and total bacterial count. The mean plasma ascorbic acid concentration was significantly lower in cows with subclinical (p = 0.004) and clinical mastitis (p = 0.000) and the erythrocytic lipid peroxide levels were significantly (p = 0.000) higher in clinical mastitis as compared to controls. There was a significant decrease in mean blood zinc concentration in subclinical (p = 0.005) and clinical mastitis (p = 0.000), but an increase in mean blood copper level in the clinical mastitis group. It was concluded that the blood antioxidant status declines in inflammatory udder conditions, suggesting that incorporation of antioxidants may help in better management of mastitis in dairy cows.

Erythrocyte lipid peroxides and blood zinc and copper concentrations in acute undifferentiated diarrhoea in calves.

Undifferentiated acute calf diarrhoea is a major concern for the dairy industry and its aetiopathogenesis remains diverse. The present study aimed to examine the role of oxidative stress through estimation of erythrocyte lipid peroxide levels and blood zinc and copper concentrations using natural cases of diarrhoea in calves aged 15–30 days old. The calves were kept under identical managemental conditions and were provided with pooled whole colostrum during the first three days and thereafter with only whole milk until they were 1 month old. Diarrhoeic (n = 11) and normal calves (n = 11) of the same age group (15–30 days old) were randomly selected from an organized dairy farm for the study. The mean blood zinc concentration (50.01±2.45 μmol/L vs 66.06±3.06 μmol/L) was significantly (p < 0.05) lower and copper concentration was significantly (p < 0.05) higher in diarrhoeic calves (12.90±0.31 μmol/L vs. 9.44±0.16 μmol/L) than in the healthy calves. The erythrocyte lipid peroxides level was higher (p < 0.05) in diarrhoeic calves (6.88±0.23 nmol malondialdehyde (MDA) per mg of haemoglobin (Hb)) than healthy calves (6.27±0.07 nmol MDA per mg Hb). From the results of the study it is concluded that oxidative stress and antioxidant minerals (zinc and copper) might play important roles in the aetiopathogenesis of bovine calf diarrhoea.

A Comparative Study on Oxidative Stress in Dogs Infected with Ehrlichia canis with or without Concurrent Infection with Babesia gibsoni

Free radicals and other reactive oxygen species (ROS) have been implicated as playing an important role in tissue damage in a variety of pathological processes (Nohl et al., 1996). Overproduction of ROS in diverse pathological conditions leads to oxidative damage to macromolecules, resulting in enhanced lipid peroxidation, DNA strand breaks and protein damage (Halliwell, 1994). Lipid peroxides are self-generating in a chain reaction and are involved in many pathological processes (Del Maestrs, 1980). Oxidative stress has been reported in conditions such as Leishmania chagasi infection (Oliveria and Cecchini, 2000), Thieleria annulata infections in calves (Sahoo et al., 2001) and babesiosis in dogs (Murase et al., 1996). Concurrent infections with Ehrlichia canis and Babesia gibsoni are not uncommon in dogs (Varshney and Dey, 1998). Murase and co-workers (1996) documented oxidative damage and enhanced erythrophagocytosis associated with B. gibsoni infection in blood from infected dogs. However, there seem to have been no reports on the role of oxidative stress in canine ehrlichiosis, with or without concurrent infection of B. gibsoni.

Sequence characterization and polymerase chain reaction-restriction fragment length polymorphism of the mitochondrial DNA 12S rRNA gene provides a method for species identification of Indian deer

Characterization of species-specific molecular markers and development of a method for identification of Indian deer species is necessary to monitor illegal trade of parts and products for better conservation and management of the endangered species. In this investigation, we characterized the 12S rRNA gene sequence for differentiation of Indian deer species and developed a polymerase chain reaction–restriction fragment length polymorphism (PCR–RFLP)-based method for their identification. Universal primers were used for the amplification of the mitochondrial 12S rRNA gene from genomic DNA of chital or spotted deer, hog deer, barking deer, sika deer, musk deer and sambar. PCR products of chital, hog deer and Himalayan musk deer were cloned and sequenced for the first time. Among the Indian deer species, more than 90% similarity was observed in the mitochondrial 12S rRNA gene. The sequences of the above deer species were restriction mapped with the help of Lasergene (DNAstar Inc., Madison, WI, USA). PCR amplicon of these deer species were subjected to restriction digestion with Rsa1, Dde1, Bsr1 and BstSF1 endonucleases that showed a species-specific RFLP pattern. This technique provides a reliable and efficient tool for identification of deer species using a variety of biomaterials.