RESUMO: Este estudo foi conduzido para avaliar os efeitos de aditivos nas características de fermentação, composição química e digestibilidade in vitro do gafanhoto preto tetraplóide (TBL). A silagem de folhas TBL não foi tratada (controle) ou foi tratada com 1 × 106 ufc / g FM Lactobacillus plantarum (L), 1% glicose (G), 3% melaço (M), uma combinação de 1% glicose e Lactobacillus plantarum ( L + G), ou uma combinação de 3% de melaço e Lactobacillus plantarum (L + M). A qualidade da fermentação, a composição química e a digestibilidade dos nutrientes foram analisadas. As concentrações de etanol e ácido acético foram os produtos de fermentação dominantes em todas as silagens, com exceção da silagem L + M. Os tratamentos L, G e L + G não influenciaram na fermentação. O tratamento com M aumentou (P<0,05) a concentração de ácido láctico e diminuiu (P<0,05) o pH, quando comparado com a silagem controle. As melhores propriedades de fermentação foram observadas na silagem L + M, como indicado pela dominância do ácido lático sobre o etanol nos produtos de fermentação. As silagens M e L + M apresentaram maior teor de matéria seca (P<0,05), e a silagem M apresentou maior carboidrato solúvel em água residual que o controle. A ensilagem aumentou (P<0,05) a matéria seca in vitro, a fibra em detergente neutro e a degradabilidade da fibra em detergente ácido de TBL. Entre as silagens, a silagem M apresentou os maiores teores de matéria seca, fibra em detergente neutro e degradabilidade da fibra em detergente ácido. Os resultados obtidos sugerem que a aplicação de bactérias lácticas em conjunto com 3% de melaço pode ser uma estratégia eficaz para evitar a ocorrência de fermentação alcoólica e melhorar a qualidade da fermentação da silagem TBL. A adição de açúcares fermentáveis à TBL aumenta a disponibilidade de nutrientes para ruminantes.

ABSTRACT: This study was conducted to evaluate the effects of additives on the fermentation characteristics, chemical composition and in vitro digestibility of tetraploid black locust (TBL). The TBL leaves silage was either untreated (control) or treated with 1 × 106 cfu/g FM Lactobacillus plantarum (L), 1% glucose (G), 3% molasses (M), a combination of 1% glucose and Lactobacillus plantarum (L+G), or a combination of 3% molasses and Lactobacillus plantarum (L+M). Fermentation quality, chemical composition and nutrient digestibility were then analyzed. Ethanol and acetic acid concentrations were the dominant fermentation products in all silages except L+M silage. The L, G and L+G treatments failed to influence the fermentation. The M treatment increased (P<0.05) the lactic acid concentration and lowered (P<0.05) the pH when compared with control silage. The best fermentation properties were observed in L+M silage, as indicated by the dominance of lactic acid over ethanol in fermentation products. The M and L+M silages exhibited higher (P<0.05) dry matter, and M silage showed higher residual water-soluble carbohydrates than the control. Ensiling increased (P<0.05) the in vitro dry matter, neutral detergent fiber and acid detergent fiber degradability of TBL. Among the silages, M silage had the highest levels of dry matter, neutral detergent fiber and acid detergent fiber degradability. The obtained results suggested that application of lactic acid bacteria together with 3% molasses could be an effective strategy to prevent the occurrence of ethanol fermentation and improve fermentation quality of TBL silage; addition of fermentable sugars to TBL improves nutrient availability to ruminants.

RESUMO: O objetivo do presente estudo foi investigar a dinâmica de mudança na fermentação e perfis de ácidos graxos em silagens de alfafa de alta humidade durante a ensilagem a 45°C, 30°C e 15°C. Após a ensilagem por 1, 3, 7, 21, 39 e 65 dias, as amostras foram amostradas e examinadas. A fermentação láctica mudou para a fermentação butírica em silagens ensiladas a 30°C e 45°C. Estas ocorreram em ensilamento durante 21 e 65 dias, respectivamente, acompanhado de alto teor de amônia-N (>150g/kg N), o que resultou em um aumento súbito de pH (P < 0,05). Em contraste, o aumento do teor de ácido láctico foi observado na silagem ensilada a 15°C durante a ensilagem durante 65 dias (P < 0,05). À medida que a temperatura de ensilagem aumentou, as perdas consideráveis na FA total, C18: 2n6 e C18: 3n3, aumentaram após a ensilagem durante 1 dia, em comparação com a alfafa antes da ensilagem (P < 0,05), principalmente devido à termolabilidade da FA poliinsaturada e à multiplicação de bactérias do ácido lático. Os conteúdos de FA total, C18: 2n-6 e C18: 3n-3, foram flutuação na silagem armazenada a 30°C e 45°C durante a ensilagem de 3 a 65 dias (P < 0,05), mas diminuiu a 15°C devido à intervenção de bactérias aeróbias, leveduras e lipoxigenase.

ABSTRACT: The objective of present study was to investigate the dynamics of change in fermentation and fatty acid profiles in high moisture (DM=232g/kg FW) alfalfa silages during ensiling at 45°C, 30°C and 15°C. After ensiling for 1, 3, 7, 21, 39 and 65 days, silages was sampled and examined. Lactic fermentation changing into butyric fermentation in silage ensiled at 30°C and 45°C occurred on ensiling for 21 and 65 days, respectively, as accompanied with high ammonia-N content ( >150g/kg N), which subsequently resulted in a sudden increase of pH (P < 0.05). In contrast, the increase of lactic acid content was observed in silage ensiled at 15°C during ensiling for 65 days (P<0.05). As the ensiling temperature rose, considerable losses in total FA, C18:2n6 and C18:3n3 increased after ensiling for 1 day as compared with alfalfa before ensiling (P < 0.05) mainly due to thermolability of polyunsaturated FA and multiplication of lactic acid bacteria. Contents of total FA, C18:2n-6 and C18:3n-3 fluctuated in silage stored at 30°C and 45°C during ensiling from 3 to 65 days (P < 0.05), but decreased at 15°C due to the intervention of aerobic bacteria, yeasts and lipoxygenase. Therefore, after ensiling for 65 days, high moisture alfalfa silage ensiling at 15°C had better fermentation quality than at 30°C and 45°C. Temperature had significant influence on dynamics of change in FA profile in alfalfa silage during ensiling.

RESUMO: Ensilagem é uma estratégia simples e de baixo custo que habilita a preservação de sub-produtos agrícolas por longo tempo e com mínimo impacto ambiental, tal como a preservação de palha de arroz e resíduos da destilação de grãos (DG) para uso na alimentação de ruminantes. O objetivo deste estudo foi avaliar o efeito de incluir diferentes proporções de DG e palha de arroz (i.e. 0, 10, 20 or 30% of DG) com ou sem inclusão de 5% de melaço sobre variáveis da fermentação e composição química do material ensilado. O estudo foi conduzido em blocos casualizados em um esquema fatorial 4 × 2, com três repetições, utilizando mini-silos de 1L de capacidade (n=24). Embora a interação entre DG e melaço foi significativa (P<0,01) para a maior parte das variáveis, em geral a adição de DG diminuiu linearmente o pH e as concentrações de ácido acético, ácido butírico e amônia (P<0,01), e aumentou linearmente a concentração de ácido láctico (P<0,01). Exceção foi a concentração de ácido propiônico que diminuiu linearmente sem a adição de melaço enquanto aumentou linearmente com a adição de melaço, à incrementados níveis de inclusão de DG (P<0,01). Em ambos casos, com ou sem adição de melaço, a adição de DG aumentou linearmente o teor de matéria seca, de carboidratos solúveis em água e de proteína bruta, e diminuiu o teor de fibra em detergente neutro do material ensilado the NDF content (P<0,01). Baseado na perspectiva de máxima utilização de palha da arroz, recomenda-se a mistura de 10% de DG associado com 5% de melaço no processo de ensilagem.

ABSTRACT: Ensilage is a simple and low-cost strategy to enable long term preservation and environmentally friendly utilization of agricultural by-products, such as straws and distiller's grains (DG) for ruminants. Effect of mixing different proportions of DG and rice straw (i.e. 0, 10, 20 or 30% of DG) with or without 5% molasses addition on fermentation and chemical variables of silages was evaluated. The study was conducted as a randomized blocks design in a 4 × 2 factorial arrangement, with three replications, using laboratory silos of 1L capacity (n=24). Despite a significant interaction (P<0.01) between DG and molasses addition was observed for most variables, in general the increased addition of DG linearly decreased the pH value, acetic acid (AA), butyric acid (BA) and ammonia N concentration (P<0.01), and increased the lactic acid (LA) concentration (P<0.01). Exception was the propionic acid concentration which linearly decreased without molasses addition and linearly increased with molasses addition at increased proportion of DG (P<0.01). In both silages with or without molasses the addition of DG increased the dry matter, water soluble carbohydrates and crude protein (P<0.01), and decreased the NDF content (P<0.01). Based on the perspective of maximum utilization of rice straw, the mixture of 10% of DG associated to 5% molasses at ensilage process is recommended.

Background: Cold-active endo-1, 4-β-glucanase (EglC) can decrease energy costs and prevent product denaturation in biotechnological processes. However, the nature EglC from C. farmeri A1 showed very low activity (800 U/L). In an attempt to increase its expression level, C. farmeri EglC was expressed in Escherichia coli as an N-terminal fusion to protein S (ProS) from Myxococcus xanthus. Results: A novel expression vector, pET(ProS-EglC), was successfully constructed for the expression of C. farmeri EglC in E. coli. SDS-PAGE showed that the recombinant protein (ProS-EglC) was approximately 60 kDa. The activity of ProS-EglC was 12,400 U/L, which was considerably higher than that of the nature EglC (800 U/L). ProS-EglC was active at pH 6.5-pH 8.0, with optimum activity at pH 7.0. The recombinant protein was stable at pH 3.5-pH 6.5 for 30 min. The optimal temperature for activity of ProS-EglC was 30°C-40°C. It showed greater than 50% of maximum activity even at 5°C, indicating that the ProS-EglC is a cold-active enzyme. Its activity was increased by Co2+ and Fe2+, but decreased by Cd2+, Zn2+, Li+, methanol, Triton-X-100, acetonitrile, Tween 80, and SDS. Conclusions: The ProS-EglC is promising in application of various biotechnological processes because of its cold-active characterizations. This study also suggests a useful strategy for the expression of foreign proteins in E. coli using a ProS tag.

ABSTRACT Objective: Enterococcus faecalis is the dominant microbial species responsible for persistent apical periodontitis with ability to deeply penetrate into the dentin. Exopolysaccharides (EPS) contribute to the pathogenicity and antibiotic resistance of E. faecalis. Our aim was to investigate the antimicrobial activity of calcium hydroxide (CH), camphorated parachlorophenol (CMCP), and chlorhexidine (CHX) against E. faecalis in dentinal tubules. Material and Methods: Decoronated single-canal human teeth and semicylindrical dentin blocks were incubated with E. faecalis for 3 weeks. Samples were randomly assigned to six medication groups for 1 week (n=10 per group): CH + 40% glycerin-water solution (1:1, wt/vol); CMCP; 2% CHX; CH + CMCP (1:1, wt/vol); CH + CMCP (2:3, wt/vol); and saline. Bacterial samples were collected and assayed for colony-forming units. After dentin blocks were split longitudinally, confocal laser scanning microscopy was used to assess the proportion of viable bacteria and EPS production in dentin. Results: CMCP exhibited the best antimicrobial activity, while CH was the least sensitive against E. faecalis (p<0.05). CHX showed similar antimicrobial properties to CH + CMCP (1:1, wt/vol) (p>0.05). CH combined with CMCP inhibited EPS synthesis by E. faecalis, which sensitized biofilms to antibacterial substances. Moreover, increasing concentrations of CMCP decreased EPS matrix formation, which effectively sensitized biofilms to disinfection agents. Conclusion: The EPS matrix dispelled by CH paste with CMCP may be related to its bactericidal effect; the visualization and analysis of EPS formation and microbial colonization in dentin may be a useful approach to verify medicaments for antimicrobial therapy.

ABSTRACT This study was designed to find the effect of vitamin E supplementation on growth, serum antioxidant enzymes, and some trace elements in Japanese quail (Coturnix coturnix japonica) under low ambient temperature. A total of 180 day-old Japanese quails were randomly divided into four groups and provided with 0 (group A), 50 (group B), 100 (group C), and 150 IU/kg (group D) vitamin E (dl-α-tocopherol acetate) under an average temperature of 9±0.5 °C for an experimental period of 42 days. The result showed that feed intake per day, body weight, weight gain per day, and feed conversion ratio did not differ significantly between the groups. Serum concentrations of superoxide and glutathione peroxidase were significantly high in birds supplemented with 150 mg/kg of vitamin E. The concentration of aspartate aminotransferase was not significantly affected between the control and treated groups; however, alanine transaminase concentration significantly reduced in group D. Zinc concentration in the blood increased significantly in group D, with no significant effect on copper and manganese between the control and treated groups. Vitamin E at the level of 150 IU/kg of feed improves the blood antioxidant status and zinc concentration, with no effect on the performance traits of quail reared under low ambient temperature.

Background: Zymomonas mobilis, as a novel platform for bio-ethanol production, has been attracted more attention and it is very important to construct vectors for the efficient expression of foreign genes in this bacterium. Results: Three shuttle vectors ( pSUZM 1, pSUZM2 and pSUZM3 ) were first constructed with the origins of replication from the chromosome and two native plasmids (pZZM401 and pZZM402) of Z. mobilis ZM4, respectively. The three shuttle vectors were stable in Z. mobilis ZM4 and have 3,32 and 27 copies, respectively. The promoter Ppdc (a), from the pyruvate decarboxylase gene, was clonedinto the shuttle vectors, generatingthe expressionvectors pSUZM1(2, 3)a. The codon-optimized glucoamylase gene from Aspergillus awamori combined with the signal peptide sequence from the alkaline phosphatase gene of Z. mobilis was cloned into pSUZM1(2, 3)a, resulting in the plasmids pSUZM1a-GA, pSUZM2a-GA and pSUZM3a-GA, respectively. After transforming these plasmids into Z. mobilis ZM4, the host was endowed with glucoamylase activity for starch hydrolysis. Both pSUZM2a-GA and pSUZM3a-GA were more efficientatproducingglucoamylase thanpSUZM1a-GA. Conclusions: These results indicated that these expression vectors are useful tools for gene expression in Z. mobilis and this could provide a solid foundation for further studies of heterologous gene expression in Z. mobilis.