Socioeconomic factors associated with the perception and attitude of consumers toward traced meat in Contagem, Minas Gerais, Brazil

The aim of this study was to analyze knowledge related to bovine traceability and to profile the perception and attitude of consumers toward traced beef in Contagem, Minas Gerais, Brazil; in addition to verifying which socioeconomic factors are related to purchasing decisions regarding traced meat. The variables were described and a multiple model Generalized Estimating Equations (GEE) logistic regression was elaborated to identify possible associations between the socio-economic characteristics of consumers and the key attributes of meat that influence their decision to purchase it. Data were accumulated through interviews of 400 consumers in April 2012. The presence of the stamp of the Brazilian Federal Inspection Service (SIF) on the product was the attribute that most influenced the consumers’ purchasing decisions. The majority of the interviewed people had never heard about beef traceability. Among those who had heard about it, most were willing to pay more for traced meat. However, there are disadvantages associated with traceability, mainly in relation to increased meat price. Consumers with higher levels of education and income had a better understanding of this type of certification; moreover, higher monthly incomes were associated with greater consumer willingness to pay more for traced meat

Neue Erkenntnisse über virale Faktoren, die am Lebenszyklus der Marek-Krankheit beteiligt sind

The Marek’s disease virus (MDV) is an alphaherpesvirus of chickens, causing various clinical symptoms including: immunosuppression, paralysis, neurological disorders and terminal lymphomas. Interestingly, in contrast to most herpesviruses, MDV integrates its genome into the telomeres of latently infected host cells. While it’s known that telomere sequences in the virus genome are essential for this process, the actual mechanism and factors influencing this process remain poorly defined. MDV is relatively closely related to the human virus herpes simplex virus 1 (HSV-1) and they possess genes that are functionally conserved. Both virus genomes contain two genes called UL12 and UL29, which encode for a 5’-3’ exonuclease and a single stranded DNA binding protein (ICP8), respectively. For HSV-1, pUL12 and ICP8 interact with each other and promote DNA recombination, a process likely involved in virus replication. Studies have showed that HSV-1’s UL12 when abrogated leads to a severe virus replication defect of 100-1000 fold, which makes it very important for virus replication. On the other hand, UL29 has been shown to be an essential gene for HSV-1 replication. Moreover, the 5’-3’ exonuclease activity of pUL12 has been shown to enhance single strand annealing during HSV-1 replication, whilst ICP8 is dispensable. Despite so many advances in understanding the HSV-1 UL12 and UL29 genes, little is known about their orthologues in MDV. The first aims of this project were to address the role of UL12 and UL29 in MDV replication, verify if these two genes are involved in DNA recombination, and if the recombination complex formed by UL12 and UL29 could help MDV integration into telomeres. To address the roles of UL12 and UL29 in lytic MDV replication, aa 6 and 7 in UL12 and aa 1 in UL29 were replaced for stop codons, abrogating both proteins’ expression individually. After transfecting these UL12 mutant viruses, we could confirm that the stop mutations in UL12 did not completely abrogate virus replication, although reduced the size and number of plaques formed. Next, we mutated the second methionine in UL12 located at aa 136 to a stop codon. Transfection of this mutant virus showed that it could not replicate, indicating that the c-terminus of UL12 is important for replication. In accordance with the data on HSV-1, mutation of UL29 completely blocked virus replication. After addressing the importance of UL12 and UL29 in MDV replication, we assayed their recombination activity in the four main DNA repair recombination pathways in eukaryotic cells: single strand annealing (SSA), homologous recombination (HR), non-homologous end-joining (NHEJ) and alternative non-homologous end-joining (A-NHEJ). Using a cell-based assay and viral protein expression vectors, we could show that UL12 can aid in SSA DNA repair, whilst UL29 was not active for SSA. As UL12 can aid repair of homologous DNA, we investigated the role of UL12 and UL29 in MDV integration using an integration assay with an immortalized chicken T-cell line. We generated shRNAs to knockdown UL12 and UL29 and tested the effect on virus integration. This analysis showed that the absence of these two genes did not interrupt virus integration into T cells. The second main aim of this work was to address whether MDV DNA replication is important for virus integration in T cells. We focused on the UL30 gene, which encodes the MDV DNA polymerase, and generated a mutant virus containing a destabilization domain-UL30 fusion (vUL30DHFR). This destabilization domain fusion enabled inducible control of the viral DNA polymerase. Our results showed that when the DNA polymerase is blocked and virus DNA replication is abrogated, there was no virus genome maintenance in T cells at 14 days post-infection. Moreover, this defect was of a similar magnitude to MDV mutants lacking the viral telomere repeats, which are essential for integration. This evidence is the first to suggest that virus replication is involved in the establishment of the latent MDV genome. Taken together, the work presented in this thesis has shown that MDV encodes essential viral factors for virus replication and that are active in SSA DNA repair but are not essential for MDV telomere integration. Lastly this work has built a foundation for further studies on the links between virus DNA replication and MDV integration into telomeres

Efeito da hidrólise alcalina sobre a compostagem da cama obtida durante a terminação de ovinos

Objetivou-se com este estudo avaliar o efeito da hidrólise alcalina sobre o comportamento da temperatura e as reduções dos sólidos e da fração fibrosa no processo de compostagem da cama obtida durante a terminação de ovinos. O experimento foi conduzido em delineamento inteiramente casualizado com três tratamentos e cinco repetições (leiras) e com os seguintes tratamentos experimentais: 1 - apenas cama da criação de ovinos; 2 -  cama da criação de ovinos acrescida de 0,8% dos sólidos totais (ST) de cal hidratada; tratamento 3: cama da criação de ovinos acrescida de 1,6% dos ST de cal hidratada. A eficiência do processo de compostagem foi avaliada pelas reduções de ST, sólidos voláteis (SV), fibra em detergente neutro (FDN), fibra em detergente ácido (FDA) e hemicelulose, além da temperatura. Foram observadas diferenças (P<0,05) entre os tratamentos para as características mensuradas durante o processo de compostagem, com exceção da temperatura e o FDA que não diferiram entre os tratamentos testados. Foram observadas reduções (P<0,05) de 28,10 e 35,32% de ST e 34,32 e 42,48 % de SV para as doses 0 e 1,6% de cal hidratada, respectivamente. As maiores reduções (P<0,05) observadas foram de hemicelulose, sendo encontrados valores de 29,07 e 44,14% para as doses de 0 e 1,6% de cal hidratada, respectivamente. Concluiu-se que a hidrólise alcalina com 1,6% de cal hidratada foi eficiente no tratamento da cama de ovinos, permitindo um aumento significativo nas reduções de sólidos totais, sólidos voláteis e fibra durante o processo de compostagem

Anaerobic co-digestion of animal manure at different waste cooking oil concentrations

<div><p>ABSTRACT: This study aimed to obtain the best dose of waste cooking oil inclusion for the co-digestion of substrates prepared with dairy cattle and swine manure in order to maximize solids reductions and biogas yield. Analyses of total solids (TS), volatile solids (VS), and neutral detergent fiber (NDF) were performed during the loading and unloading of digesters, while biogas yield was measured twice a week. The maximum reduction in VS (51.4%) was reached with the inclusion of up to 54.6g waste cooking oil.kg manure-1. Maximum NDF degradation occurred with inclusions of up to 69.4g waste cooking oil.kg manure-1. Inclusions of up to 64g of waste cooking oil.kg manure-1 provided specific biogas yield of 291.4 and 251.0L biogas.kg VS-1 added to substrates with swine and cattle manure, respectively. Adding oil at doses between 45.1 and 69.4g waste cooking oil kg manure-1 to substrates composed of cattle or swine manure maximizes reductions of solids and fibrous constituents and enhances specific biogas yield. Furthermore, swine manure supports higher doses of waste cooking oil.</p></div