Roberto Montes de Oca Jiménez

Effects of different doses of Salix babylonica extract on growth performance and diet in vitro gas production in Pelibuey growing lambs

Twenty Pelibuey 3-4 month old and 23.7±3.3 kg body weight male lambs were used in a randomised design to study the effects of daily oral administration of Salix babylonica (SB) extract on dry matter (DM), water intake, average daily gain (ADG), and feed efficiency for 72 days. Animals were divided into four groups fed the same total mixed ration with different doses of SB: 0 (Control), 20 (SB20), 40 (SB40) and 60 (SB60) mL/lamb/d. In vitro gas production (GP) of the same diet fed to lambs as a substrate was measured with different doses of SB (0, 0.3, 0.7, 1.0 mL/g DM). Daily administration of SB to lambs had no effects (P=0.05) on growth performance and DMI (linear effect, P=0.2805; quadratic effect, P=0.3747). Both low and moderate doses of SB (SB40>SB20) tended to increase (linear effect, P=0.4010; quadratic effect, P=0.9166) ADG. The asymptotic GP quadratically increased (P<0.001) with decreased GP rate and with increasing SB extract doses. In vitro GP increased (P<0.05) with advancing of incubation time in all SB doses. During the first 24 h of incubation, 0.3 mL SB/g DM had the highest GP, whereas 1.0 mL SB/g DM quadratically increased (P<0.001) GP. The low dose of SB extract increased ME (linear effect, P=0.024) and short chain fatty acids (SCFA) (linear effect, P=0.023). However, the highest dose quadratically decreased (P=0.02) DM degradability. In conclusion, administration of SB extract at 40 mL/lamb/d tended to increase DM intake, improve daily weight gain in growing lambs with increasing asymptotic in vitro ruminal GP and SB dose.

Influence of Salix babylonica extract in combination or not with increasing levels of minerals mixture on in vitro rumen gas production kinetics of a total mixed ration

The aim of this study was to determine the effects of increasing levels of two feed additives composed of Salix babylonica (SB) extract and minerals mixture (MM) or their combination on in vitro gas production (GP) and dry matter (DM) degradability of total mixed ration (TMR; 50 concentrate: 50 corn silage, on DM basis). Combinations of four levels of SB extract (0, 0.6, 1.2 and 1.8 mL/g DM) with four levels of MM (0, 0.5, 1.5 and 2.5 g/100 g DM) were evaluated in a completely random design. Samples of TMR (1 g) were weighed in 120 mL serum bottles with addition of SB extract and/or MM. Then, 10 mL of particle free ruminal fluid were added followed by 40 mL of the buffer solution. The GP was recorded at 2, 4, 6, 8, 10, 12, 24, 48 and 72 h of incubation. Addition of SB extract, without MM, increased (P<0.05) asymptotic GP (mL/g DM), the rate of GP (/h), GP and DM degradability (DMD). Addition of MM, without SB, increased (P<0.05) b and decreased c and ruminal pH. Increasing the levels of SB increased (P<0.05) b, c, L, and GP in addition to linearly increase (P<0.001) DMD. Increasing levels of MM increased (P<0.05) b and c while decreased pH. An interaction occurred between different SB extract and MM levels: the most effective levels of SB extract and MM on ruminal fermentation and kinetics were 1.8 mL SB extract/g DM and 2.5 g MM/100 g DM.

First report of isolation and molecular characterization of the pathogenic Corynebacterium pseudotuberculosis from of sheep and goats in Mexico

The pathogenic bacteria of Corynebacterium pseudotuberculosis caused a chronic contagious infectious disease of the caseous lymphadenitis or pseudotuberculosis. Globally, isolates obtained from different injuries that affect sheep and goats, have been identified by fully or partially gene sequencing. However, in Mexico there is no complete study to identify by molecular and phylogenetic techniques the circulating isolates as well as its virulence factors. Therefore, in the present study we reported the identification of 57 isolates of C. pseudotuberculosis by bacteriological tests and the amplification of 16S rRNA, rpoB and pld genes, as well as, genes involved in virulence and pathogenicity: Fag A, Fag B, Fag C, Fag D and hsp60. Phylogenetic analysis was performed based on the partial sequence of the rpoB gene. Genes involved in virulence and pathogenicity were identified in the 98.2% of the isolates. Regarding the phylogenetic analysis, were identified the species and subspecies to which they belong of all the tested isolates. The phenotypic and genotypic characterization will allow to establish preventive and prophylactic measures aimed to the creation of effective immunogens against Corynebacterium pseudotuberculosis.

Horse fecal methane and carbon dioxide productions and fermentation kinetics influenced by Lactobacillus farciminis supplemented diet

ABSTRACT The effect of equine fecal inocula on the in vitro gas, methane (CH4), and carbon dioxide (CO2) production was elucidated in the present study. Fecal inocula were obtained from four Azteca horses (aged 5–8 years, 480 ± 20.1 kg). In vitro fermentation (up to 48 hours) was performed with substrate consisting of 50% (w/w) oat straw and 50% (w/w) of a commercial concentrate in the presence of a commercial Lactobacillus farciminis product (0–6 mg/g DM of substrate). Incorporation of L. farciminis resulted in increased levels of asymptotic gas (GP), CH4, and CO2 production (P < .05). The lag time and the rate of GP were shown to be independent from L. farciminis addition (linear, P > .05; quadric, P > .05). Furthermore, a slight reduction in fermentation pH (linear, P = .029) and higher metabolizable energy values (P = .001) were obtained with L. farciminis supplementation in a dose‐dependent manner. No significant impact of L. farciminis on dry matter degradability values was estimated (P > .05). In vitro gas, CH4, and CO2 production were increased (linear, P ≤ .001) in the presence of L. farciminis from 6 hours of incubation onward. In conclusion, addition of L. farciminis at a dose‐dependent manner (2–6 mg/g DM of diet) was observed to be persuasive in terms of attaining amicable hindgut fermentation by improving fecal gas kinetics viz. gas, CH4, and CO2 production without any side effect. HighlightsLactobacillus farciminis at 2–6 mg/g dry matter of diet improved asymptotic gas production.Methane and carbon dioxide production increased up to 48 hours at higher doses of additive.Significant reduction in fermentation pH and higher metabolizable energy were reported.Consequences of L. farciminis on fecal gas emission in horse feeding were emphasized.

Detection of Quinolone Resistance in Salmonella typhimurium Pig Isolates Determined by gyrA Gene Mutation Using PCR- and Sequence-Based Techniques within the gyrA Gene

BACKGROUND The emergence of reduced susceptibility to fluoroquinolones among Salmonella enterica serotype Typhimurium isolates leading to clinical failure of treatment poses a great therapeutic challenge. METHODS The current study is focused on the evaluation of the minimum inhibitory concentration (MIC) of quinolones in 29 Salmonella typhimurium of 86 Salmonella spp. strains, obtained from pigs from the State of Mexico. The MIC was performed with the Kirby-Bauer method. On the other hand, the GyrA gene was sequenced. The present study was undertaken to describe the resistance profiles and fluoroquinolone resistance mechanism of Salmonella Typhimurium. RESULTS The DNA sequence of the gyrA genes from Salmonella enterica serovar typhimurium revealed strong similarity between gyrA and its counterpart in Escherichia coli. The sequencing of quinolone resistance-determining region (QRDR) of the gyrA gene showed the presence of mutation at either S83 or at D87 in almost all the Salmonella typhimurium isolates. CONCLUSION This mutation, although phenotypically expressed as decreased susceptibility to fluoroquinolones goes undetected by the disk diffusion method using the present method of Kirby-Bauer. Hence, it can increase morbidity and mortality due to delay in appropriate antibiotic treatment.

Antibiotics susceptibility of quinolones against Salmonella spp. strains isolated and molecularly sequenced for gyrA gene

Drug-resistant Salmonella is frequently detected in most parts of the world, and its rate of resistance has increased significantly in recent years. However, this study aimed to evaluate the minimum inhibitory concentration (MIC, determined with the Kirby-Bauer method) of quinolones in 86 Salmonella spp. strains isolated from pigs. Both the inside and outside of the QRDR region of strains were sequenced. The DNA sequence of the QRDR region of Salmonella spp. revealed the mutations S83F, D87N and S83Y. The region outside the QRDR showed a mutation in L582G. Forty-five isolates of Salmonella ssp. were categorized as quinolone-resistant; out of these, 16 corresponded to Salmonella enterica and isolates showed intermediate resistance (6.25%) to nalidixic acid. Three isolats (18.6%) were resistant to ampicillin; two (12.5%) were resistant to carbenicillin. Moreover, three (18.7%) isolates were resistant to gentamicin, nitrofurantoin and pefloxacin, and 8 (50%) were resistant to trimethoprim/sulfamethoxazole. Six percent of Salmonella spp. strains showed less resistance to antimicrobial agents compared to S. Thyphimurium (18%). The resistance to individual quinolones varied by serotypes. For S. anatum and S. Reading, it was 12.25%, and for S. choreaeaesuis, S. typhimurium monofasica, 6.25%. In contrast, S. agona, S. bredeney and S. london were sensitive to these antibiotics. In conclusion, quinolones have become the drugs of choice for the treatment of severe Salmonella infections. The study of mutations outside the QRDR region opens up new insights about the resistance of Salmonella to fluoroquinolones.

Distribution of lymphocytes, immunoglobulin-containing cells, macrophages, and dendritic cells in the accessory sex glands of rams experimentally infected with Actinobacillus seminis

A distribuicao das celulas envolvidas na resposta imune em glândulas sexuais acessorias de carneiros experimentalmente infectados com Actinobacillus seminis foi estudada. Doze carneiros de um ano de idade foram experimentalmente infectados via intrauretral (IU) (n=4) e via intraepididimal (IE) (n=4) e quatro animais controles (CON) foram utilizados. Os animais foram abatidos 35 dias apos a inoculacao, amostras foram retiradas das glândulas sexuais acessorias e testes bacteriologicos e histopatologicos foram realizados. A presenca de linfocitos CD4, CD8 e TCRγδ (WC1), celulas CD45RO, macrofagos (CD14), celulas dendriticas (CD1b) e celulas contendo IgA, IgG and IgM (IgCC) foi determinada. Os animais do grupo IE desenvolveram epididimite clinica. Nao foram visualizadas lesoes nos carneiros do grupo IU, dois dos CON inoculados intraepididimalmente desenvolveram pequenas lesoes no epididimo. Isolados de A. seminis foram obtidos de 6:16 (37,5%) nas glândulas sexuais acessorias no grupo IE mas nao nos grupos IU e CON. No grupo CON celulas contendo IgA and IgM predominaram nas glândulas bulbouretrais e na prostata e foram escassas ou ausentes nas vesiculas e na ampola. Um incremento significativo de celulas contendo IgA, IgG and IgM foi confirmado nas vesiculas seminais, na ampola e nas glândulas bulbouretrais no grupo IE. Nos grupos IE e IU foi evidenciado um aumento em CD4, CD8, WC1, CD45RO e CD14 nas vesiculas e ampola. As celulas dendriticas CD1b estavam presentes na ampola e nas vesiculas com processo inflamatorio. A. seminis induziu uma resposta imune local nos grupos IE e IU. Estes resultados indicam um padrao diferente de celulas imunes infiltrantes nas glândulas sexuais acessorias de carneiros infectados por A. seminis.