Ingestion of Milk Containing Very Low Concentration of Antimicrobials: Longitudinal Effect on Fecal Microbiota Composition in Preweaned Calves.

Although antimicrobial drugs are central to combat disease in modern medicine, the use of these drugs can have undesired consequences for human and animal health. One consequence is the post-therapy excretion of pharmacological agents, such as the elimination of drug residues at very low concentrations in the milk of lactating mammals. Limited information is currently available on the impact from the exposure of the gut microbiota to drug residues using in vivo natural models. The objective of our study was to address this knowledge gap and evaluate the effect on the fecal microbiota composition from feeding preweaned dairy calves raw milk with residual concentrations of ampicillin, ceftiofur, penicillin, and oxytetracycline from birth to weaning. At birth, thirty calves were randomly assigned to a controlled feeding trial where: 15 calves were fed raw milk with no drug residues (NR), and 15 calves were fed raw milk with drug residues (DR) by adding ceftiofur, penicillin, ampicillin, and oxytetracycline at final concentrations in the milk of 0.1, 0.005, 0.01, and 0.3 μg/ml, respectively. Fecal samples were rectally collected from each calf once a week starting at birth, prior to the first feeding in the trial (pre-treatment), until 6 weeks of age. Sequencing of the microbial 16S rRNA genes was conducted using the Illumina MiSeq, which provides a high resolution of the microbiota down to the genus level. Discriminant analysis showed that, except for pre-treatment samples, calves fed milk with drug residues and calves fed milk without drug residues easily discriminated at the genus level on their weekly microbial profile. However, analysis comparing the abundance of taxon between NR and DR showed significant differences only at the genus levels, and not at the phylum, class, order or family levels. These results suggest that although drug residues can result in clear discriminate gut microbial communities, they do not result in disruption of taxonomic levels above the genus

Isolation and characterization of Faecalibacterium prausnitzii from calves and piglets.

The goal of our study was to isolate and characterize Faecalibacterium prausnitzii from fecal samples of healthy calves and piglets, in order to develop a novel probiotic for livestock animals. We identified 203 isolates of Faecalibacterium sp., which were clustered in 40 genetically distinct groups. One representative isolate from each cluster was selected for further characterization. The concentrations of the short chain fatty acids (SCFA) acetate, butyrate, propionate and isobutyrate in the culture media were measured by gas chromatography. We observed reduction in the concentration of acetate followed by concomitant increase in the concentration of butyrate, suggesting that the isolates were consuming acetate present in the media and producing butyrate. Butyrate production correlated positively with bacterial growth. Since butyrate has many benefits to the colonic epithelial cells, the selection of strains that produce higher amounts of butyrate is extremely important for the development of this potential probiotic. The effect of pH and concentration of bile salts on bacterial growth was also evaluated in order to mimic the conditions encountered by F. prausnitzii in vivo. The optimal pH for growth ranged between 5.5 and 6.7, while most isolates were inhibited by of the lowest concentration of bile salts tested (0.1%). Antimicrobial resistance profile showed that most isolates of Faecalibacterium sp. were resistant against ciprofloxacin and sulfamethoxazole-trimethoprim. More than 50% of the isolates were resistant to tetracycline, amikacin, cefepime and cefoxitin. A total of 19 different combinations of multidrug resistance were observed among the isolates. Our results provide new insights into the cultural and physiological characteristics of Faecalibacterium prausnitzii illustrating large variability in short chain fatty acid production, in vitro growth, sensitivity to bile salts, and antibiotic resistance and suggesting that future probiotic candidates should be carefully studied before elected for in vivo studies

Shedding light on net neutrality: The Brazilian case

The recently enacted 'Civil Rights Framework for the Internet' (Marco Civil), is a Law that has set the grounds for different Internet related rights in Brazil. Among its provisions are the ones related to network neutrality. Due to the importance of the topic, as well as its relevance for the Internet ecosystem, this paper aims at analyzing net neutrality as per established on Marco Civil. In order to do so, it utilizes the theory of Chris Marsden, who has classified neutrality into the "backward-looking" and 'forward-looking' models and also defends a co-regulatory institutional model. Moreover, this paper also draws insights from the recent debate over net neutrality United States, which are also re-evaluating it's regulatory approach to the topic

Short communication. Effects of antibiotics (oxytetracycline, florfenicol or tulathromycin) on neonatal calves’ faecal microbial diversity.

In this study, we used barcoded pyrosequencing of the 16S rRNA gene to characterise the effects of antibiotic treatment upon the faecal microbiota of neonatal calves. Eleven pre-weaned calves were treated for pneumonia or otitis using one of three antibiotics (oxytetracycline, florfenicol or tulathromycin) and were matched for age /date of birth and sex with eleven control calves. All calves were born and reared at the same farm. Faecal microbial diversity data were obtained by barcoded pyrosequencing of the 16S rRNA gene one week pre-treatment, and one and two weeks post treatment for both treated and control calves. Using multivariate discriminant analysis we were able to show that antibiotic treatment has a substantial effect on faecal samples’ microbial composition one week after administration; this effect was no longer observed two weeks after administration. The effect of oxytetracycline treatment on Lactobacillus spp. was shown to be significant but many other important species appeared to be unaffected. The small number of calves used in the study prohibited quantitative comparisons of the effects of individual antibiotics compared to others on Chao1 richness index; despite this, however, some interesting numerical differences were apparent. In conclusion, our study serves to illustrate that change occurs in the gut microbiome of the young ruminant in response to antimicrobial administration. Given the limitations of our study we suggest that further similar studies are necessary

Scheduling of a hydro producer considering head-dependency, price scenarios and risk-aversion

In this paper, a mixed-integer quadratic programming approach is proposed for the short-term hydro scheduling problem, considering head-dependency, discontinuous operating regions and discharge ramping constraints. As new contributions to earlier studies, market uncertainty is introduced in the model via price scenarios, and risk aversion is also incorporated by limiting the volatility of the expected profit through the conditional value-at-risk. Our approach has been applied successfully to solve a case Study based on one of the main Portuguese cascaded hydro systems, requiring a negligible computational time

A prospective cohort study of digital cushion and corium thickness, Part 1: associations with body condition, lesion incidence and proximity to calving

Claw horn disruption lesions (CHDL) are a major cause of lameness in dairy cattle and are likely a result of excessive forces being applied to the germinal epithelium that produces claw horn. The digital cushion is a connective tissue structure, containing depots of adipose tissue, that sits beneath the distal phalanx and has been shown to be thicker in fatter cows. Body condition score (BCS) loss is a risk factor for CHDL, and one possible explanation is that fat is mobilised from the digital cushion during negative energy balance, causing the digital cushion to thin and lose force dissipating capacity, leading to disruption of claw horn growth. This prospective cohort study investigated the association between measures of body fat and sole soft tissues (SST) thickness (a combined measure of the corium and digital cushion beneath the distal phalanx) in a longitudinal manner. SST of 179 cows in two high yielding dairy herds were measured at five assessment points between 8 weeks prior to and 35 weeks post calving. BCS, back fat thickness (BFT) and lesion incidence were recorded. Data were analysed in a 4-level mixed effects regression model, with the outcome being SST thickness beneath the flexor tuberosity of the distal phalanx. Data from 827 assessment points were available for analysis. The overall mean of SST was 4.99 mm (SD: 0.95). SST was thickest 8 weeks prior to calving (5.22 mm, SD: 0.91) and thinnest one week post-calving (4.68 mm, SD: 0.87), suggesting that there was an effect of calving on SST. BFT was positively correlated with SST in the model with a small effect size (a 10 mm decrease in BFT corresponded with a 0.13 mm decrease in SST), yet the nadir of BFT was 11.0 mm at 9-17 weeks post calving (when SST was ~4.95 mm), rather than occurring with the nadir of SST immediately after calving. SST also varied with other variables, e.g. cows that developed a sole ulcer or severe sole haemorrhage during the study had thinner SST (-0.24 mm), except when a sole ulcer was present, when it was thicker (+0.53 mm). Cows that developed lesions had a thinner digital cushion prior to the lesion occurrence, which became thickened with sole ulcer presence, perhaps representing inflammation. Further, whilst BFT was correlated with SST over time, SST may also have been influenced by other factors such as integrity of the suspensory apparatus, which could have a major effect on CHDL. Measures of body fat likely contributed to having thin SST, but other factors including calving, herd and lesion presence also had an effec

Faecalibacterium prausnitzii : from microbiology to diagnostics and prognostics

We thank Dr Xavier Aldeguer and MD David Busquets from the Hospital Dr Josep Trueta (Girona, Spain) and M.D Míriam Sabat Mir from the Hospital Santa Caterina (Salt, Spain) for their help and critical discussion concerning clinical aspects. This work was partially funded by the Spanish Ministry of Education and Science through the projects SAF2010-15896 and SAF2013-43284-P, which has been co-financed with FEDER funds. Dr Sylvia H Duncan acknowledges support from the Scottish Government Food, Land and People program.Peer reviewedPostprin

Faecalibacterium Prausnitzii: Isolation, Characterization And Effects On Dairy Calves

FAECALIBACTERIUM PRAUSNITZII: ISOLATION, CHARACTERIZATION AND EFFECTS ON DAIRY CALVES Replacement heifers are extremely important for the success of a dairy farm. Strategies to improve performance while maintaining welfare, health and expenses at optimal levels are the focus of many research groups. Results from a previous study showed that young calves with a higher relative abundance of Faecalibacterium prausnitzii had a better weight gain and decreased incidence of diarrhea during the preweaning period. Our hypothesis was that the administration of F. prausnitzii could improve gastrointestinal health and performance of preweaned heifers. The first objective of this thesis was to advance our knowledge on the anaerobic bacterium F. prausnitzii and its in vitro characteristics. The second objective was to test its effects in vivo, administering it to newborn calves. In order to achieve our first objective, 203 isolates of F. prausnitzii were isolated from the feces of calves and piglets. Forty genetically distinct F. prausnitzii isolates were selected for further characterization. A large variability was observed among isolates for in vitro short chain fatty acid metabolism, growth, antibiotic resistance, and sensitivity to low pH and bile salts. Based on this data, 4 isolates with desirable characteristics were selected and used as part of a probiotic cocktail in the subsequent in vivo studies. To accomplish our second objective two trials were completed. First a safety trial was conducted using 30 newborn bull calves. Since no adverse effects of the oral and rectal administration of F. prausnitzii to neonatal calves were observed, a large field trial was performed in a commercial farm. This last study demonstrated that the oral administration of F. prausnitzii reduced the incidence of severe diarrhea and related mortality rate and increased weight gain in preweaned dairy heifers. The results presented in this thesis contribute to the knowledge about F. prausnitzii characteristics. Moreover, our studies demonstrated that F. prausnitzii administration to newborn calves is safe and proved the concept that this commensal bacterium is a promising probiotic for newborn calves. Further research is needed to evaluate in vivo mechanisms of action and interactions between this microbe, the gut microbiota and the host