Prevalence,molecular fingerprinting and drug resistance profile of enterovirulent <Emphasis Type="Italic">Escherichia coli</Emphasis> isolates from free-ranging yaks of Tawang district,Arunachal Pradesh,India

Of 273 samples (rectal swab) collected from free-ranging yaks of Tawang district, Arunachal Pradesh, 42 Shiga toxin-producing Escherichia coli (STEC), six enteropathogenic E. coli (EPEC) and 27 enterotoxigenic E. coli (ETEC) strains were isolated. All the STEC and EPEC strains were further investigated for respective stx variants (for STEC only) and additional putative virulence factors. The 27 ETEC strains were also screened for characteristic enterotoxin gene(s) and colonization factors. Occurrence of ETEC was significantly (p < 0.05) higher in the diarrheic yaks and yaks of less than 1 year of age. Majority of enterovirulent E. coli isolates were resistant to amikacin, azithromycin, chloramphenicol, colistin, doxycycline, furazolidone, nalidixic acid, nitrofurantoin, streptomycin and tetracycline. Dendrogram, constructed with molecular fingerprinting profiles obtained from RAPD (Randomly Amplified Polymorphic DNA) and ERIC (Enterobacterial Repetitive Intergenic Consensus) PCR, placed the isolates in different clusters irrespective of their serotypes, virulence gene and drug resistance pattern. Collectively, the study indicates that yaks, being a potential reservoir of multidrug resistant STEC and EPEC, may represent significant risk to public health in this region. Higher recovery of ETEC isolates from yaks with diarrhea points out that ETEC may be a major determinant for repeated occurrence of diarrhea in yaks.     

Rumen development and growth of Balouchi lambs offered alfalfa hay pre- and post-weaning

The consumption of solid feed is essential for successful transition from a pre-ruminant to a functional digestive tract. Lambs fed starter rations containing highly fermentable carbohydrates often experience dramatic changes in concentrations of rumen and blood metabolites. The optimal amount of roughage required in the diet of pre-ruminant animals is still unclear. The objective of this study was to determine the effect of feeding alfalfa hay on performance and rumen development in young Balouchi lambs. In a completely randomized design, 30 lambs were fed one of three experimental diets consisting of a control, without alfalfa hay (C), a diet containing 7.5% alfalfa hay (A1), and a diet containing 15% alfalfa hay (A2). Lambs fed A1 and A2 diets had lower dry matter intake during the pre-weaning period (P?P?=?0.02), but feed conversion ratio and average daily gain were not affected by feeding alfalfa hay. Concentration of beta-hydroxybutyric acid was higher in C compared with the A1 and A2 groups (P?P?=?0.04) and increased thickness of muscular layer (P?=?0.05). We concluded that including 15% alfalfa hay in the starter diet could reduce thickness of the keratinization layer and increase muscularity of rumen wall without adverse effects on growth and performance of newborn lambs.     

Improvement in the diagnosis of <Emphasis Type="Italic">Brucella abortus</Emphasis> infections in naturally infected water buffaloes (<Emphasis Type="Italic">Bubalus bubalis</Emphasis>) using an ELISA with a Protein-G-based indicator system

Brucellosis caused by Brucella abortus in domestic water buffaloes (Bubalus bubalis) raised under the traditional system of husbandry in northern India was diagnosed using an enzyme-linked immunosorbent assays (ELISA) with a Protein-G-based indicator system (Protein-G ELISA). A total of 1,551 animals that are positive (N = 61), negative (N = 243), and suspected (N = 1,247) for brucellosis were examined. Rose bengal test (RBT) was used to predict the disease, and accordingly, animals were dichotomized in positive and negative population for receiver operating characteristic (ROC) curve analysis to determine the sensitivity, the specificity, and the performance index of Protein-G ELISA. Taking all animals (N=1551) into account, the ROC curve analysis revealed cut off value of 29.6% positivity (%P) with 98.40% and 94.94%, sensitivity and specificity, respectively. The results were compared with ELISA in which anti-bovine conjugate was used. The cut off in ELISA was 37.9%P and sensitivity and specificity were 96.26% and 97.07%, respectively. The performance indexes of both the assays were almost equal and were 193.34 for Protein-G ELISA and 193.33 for ELISA. The cut off values of both the tests changed, if only known positive (N = 61) and known negative (N=243) animals were used for ROC curve analysis, and accordingly, changes in sensitivity and specificity were observed with significant decrease of performance indexes of both the tests. The high optical density (P<0.0001) background signal with negative serum control and high %P (P<0.0001) in sera from negative population were noticed in ELISA in comparison to Protein-G ELISA.     

In vitro inhibitory effect of trichostatin A on canine grade 3 mast cell tumor

Mast cell tumor (MCT) is one of the most prevalent neoplasms that affect skin and soft tissue in dogs. Because mast cell tumors present a great variety of clinical appearance and behavior, their treatment becomes a challenge. Trichostatin A (TSA), an antifungal antibiotic, has shown inhibitory effects on the proliferation and induction of apoptosis in various types of cancer cells. In order to evaluate the potential of trichostatin A as a therapeutic drug, cells of grade 3 MCT were cultured and treated with concentrations of 1 nM to 400 nM of TSA. MTT assay and trypan blue exclusion assays were performed to estimate cell growth and cell viability, and cell cycle analysis was evaluated. TSA treatment showed a reduction in numbers of viable cells and an increase of cell death by apoptosis. The cell cycle analysis showed an increase of hypodiploid cells and a reduction of G0/G1 and G2/M –phases. According to these results, trichostatin A may be an interesting potential chemotherapeutic agent for the treatment of canine MCT.     

Characterization of Doayo and Kapsiki taurine cattle breeds of Cameroon in their natural environment

Data were collected on live weight (LW), heart girth (HG), height-at-withers (HW), trunk length (TL), age, sex, and coat color of 207 taurines cattle—122 of the Doayo (Namchi) breed and 85 of the Kapsiki (Kirdi) breed. The animals, aged 1 to 20 years, were selected from 60 herds randomly selected from villages of Poli of Faro and Mokolo of Tsanga, divisions of the North and Far North Regions of Cameroon. The data were analyzed using the SAS program with a linear model, applying standard tests. Results indicated no breed effect (P > 0.05) in the growth trends of LW, HG, HW, and TL. HG and TL were highly significantly (P < 0.0001) related to LW. The growth pattern for the two breeds was the same since the linear contrast of least square means for the traits at various age groups did not differ (P > 0.05) significantly. The breeds attained maturity as from 4 years. In the absence of breed effect (P > 0.05), a single regression equation was established for the estimation of live weight as thus LW = - 244.42 ( ±22.57 ) kg + 2.49 ( ±0.23 ) HG + 1.04 ( ±0.25 ) TL {\hbox{LW}} = - {244}.{42 }\left( {\pm {22}.{57}} \right){\hbox{ kg}} + {2}.{49 }\left( {\pm 0.{23}} \right){\hbox{ HG}} + {1}.0{4 }\left( {\pm 0.{25}} \right){\hbox{ TL}} , with HG contributing up to 70% of total variation and TL, 2%. This equation could be used to develop a measuring band useful in the rural environment for commercial and clinical veterinary purposes.     

High-frequency ultrasonography of the skin of clinically normal dogs

OBJECTIVE: To assess the applicability of high-frequency diagnostic ultrasonography for evaluation and accurate measurement of the skin thickness of clinically normal dogs. ANIMALS: 26 healthy dogs (12 sexually intact males, 13 sexually intact females, and 1 spayed female) of various breeds and ages. PROCEDURE: Ultrasonographic examination of the skin and histomorphometric analysis of skin biopsy specimens obtained from the same site were performed. A 13-MHz linear-array transducer was used to obtain a series of ultrasonographic images of the skin in the flank region; images were analyzed and measured by use of imaging software. Cutaneous biopsy specimens were placed in fixative and then stained with H&E and Masson trichrome stains. Histomorphometric analysis was performed by use of an image analyzer. Thickness of the epidermis and dermis of each specimen was evaluated by use of a semiautomatic procedure of quantification. Data obtained from ultrasonographic and histologic measurements were compared by use of the Pearson correlation test. RESULTS: The ultrasonographic pattern of canine skin was consistently characterized by 3 distinct, defined echogenic layers corresponding to the epidermal entry echo, epidermis and dermis, and subcutaneous tissues. A positive correlation was found between ultrasonographic and histologic measurements of skin thickness. CONCLUSIONS AND CLINICAL RELEVANCE: Comparison between ultrasonographic and histologic appearance of the skin revealed that layering of canine skin (ie, epidermis and dermis) and the subcutaneous tissues may be recognized and measured by use of high-frequency ultrasonography. Thus, diagnostic ultrasonography may be a useful tool for the noninvasive evaluation of cutaneous disorders in dogs.     

Growth,feed efficiency and blood profile of buffalo calves consuming high levels of fluoride

Twelve male buffalo calves of 10 to 12 months of age were divided into 3 groups of four each. They were fed wheat straw+concentrate mixture +3 Kg greens. The chemical composition of the diet was same in all the three groups except fluoride which was added (as NaF) in concentrate mixture of group B and C to make the final fluoride concentration 30 ppm and 60 ppm respectively. The animals were kept on scheduled diet for a period of 90 days. Body weights were recorded at the start of the experiment and at fortnightly interval thereafter. Analysis of data revealed that the dry matter intake decreased non significantly in group B and C as compared to control group. A significant decrease in serum calcium and a significant increase in phosphorus concentration were observed in group C animals. A significant increase was observed in alkaline phosphatase activity in group C animals. A non significant decrease was observed in T₄ values in group C animals. On the basis of these results it could be concluded that fluoride in the diet of buffalo calves @ 30 ppm is a safe level whereas 60 ppm has affected the blood metabolites.     

Dynamics of natural bovine herpesvirus-1 (BoHV-1) infection in a dairy herd

In this study, natural cycling of BoHV-1 infection was investigated in two groups of dairy cattle containing 2120 head. Group 1 comprised 127 animals and they were monitored for BoHV-1 infection virologically and serologically in six consecutive sampling periods. It consisted of naive heifers between 6 and 8 months of age, while in group 2, age, sex and the BoHV-1 serostatus of the animals were disregarded. The animals in group 1 were found to have seroconverted at the second sampling. Results of the serological study showed slight antibody response after natural BoHV-1 infection in the herd and neutralizing titres fell below protective levels in the 6–8 months after the peak. During the 2-year study period, one recurrence was detected after primary infection. Virus isolation studies revealed a cytopathic effect indicative of BoHV-1 in two nasal swabs taken during the fifth sampling period from animals with mild upper respiratory tract symptoms. As the study was carried out under natural conditions, it is not known whether the viruses isolated were from recurrences or re-infections. Data from cross-neutralization tests with herd isolates showed higher antibody response than those with the reference virus. The dynamics of BoHV-1 in both groups were found to be statistically similar.     

Frequent use of colistin-based drug treatment to eliminate extended-spectrum beta-lactamase-producing <Emphasis Type="Italic">Escherichia coli</Emphasis> in backyard chicken farms in Thai Binh Province,Vietnam

Reports of livestock infections with extended-spectrum beta-lactamase-producing Escherichia coli (ESBL-E) are increasing. Based on interviews conducted over a 6-month period, we found that veterinarians in the Vietnamese province of Thai Binh prefer to prescribe colistin-based drugs (CBD) in chicken farms. We aimed to clarify whether CBD use selects for strains of colistin-resistant ESBL-E. With the cooperation of seven local households, we detected ESBL-E in chickens’ feces after treating chickens with CBD. Phylogenetic groupings and the presence of CTX-M/AmpC genes were determined, and the multi-antibiotic susceptibility of isolates was analyzed. Our results showed that ESBL-E presented in seven chickens’ feces from two households. Seventy-two percent of ESBL-E isolates harbored CTX-M9 and the phylogenetic group A; the colistin minimum inhibitory concentration (MIC) of all isolated ESBL-E ranged from 0.064 to 1 μg mL^?1. Moreover, ESBL-E isolates were used to experimentally select for colistin resistance, and the effect of commercial CBD on ESBL-E was investigated. The results showed that an ESBL-E strain with a colistin MIC of 4 μg mL^?1 was able to grow in media with CBD. Although CBD treatment was effective, in vitro experiments demonstrated that ESBL-E can easily acquire colistin resistance. Therefore, restrictions on colistin use are necessary to prevent the emergence of colistin-resistant bacteria.     

Effect of herbicides with different modes of action on physiological and cellular traits of Anabaena fertilissima

Cyanobacteria are important components of the lowland rice ecosystem. Therefore, it is important to examine the effect of herbicides (commonly used against weeds of rice crop) on the performance of cyanobacteria. We studied the toxic effects of three herbicides often used in rice field, viz. propanil, pretilachlor and glyphosate, on the performance traits of Anabaena fertilissima C.B. Rao. Pretilachlor [0–40 active ingredient (ai) mg/L] and glyphosate (0–80 ai mg/L) exhibited toxicity to A. fertilissima at higher doses than propanil (0–1.5 mg/L). Propanil had severe damaging effects on cellular characteristics of A. fertilissima when compared to pretilachlor or glyphosate. Propanil treatment of A. fertilissima resulted in the leakage of protoplast from the heterocyst due to the breakage of the plasma membrane and surrounding wall. Our study shows that photosystem II herbicides such as propanil could have deleterious effects on phototrophic (cyanobacterial) communities, which are an integral part of the rice ecosystem.