Effects in air-exposed corn silage of medium chain fatty acids on select spoilage microbes, zoonotic pathogens, and in vitro rumen fermentation.

Medium chain fatty acid (MCFA) treatment (0.75% C6, hexanoic; C8, octanoic; C10, decanoic; or equal proportion mixtures of C6:C8:C10:C12 or C8:C10/g; C12 = dodecanoic acid) of aerobically-exposed corn silage on spoilage and pathogenic microbes and rumen fermentation were evaluated in vitro. After 24 h aerobic incubation (37 °C), microbial enumeration revealed 3 log10 colony-forming units (CFU)/g fewer (P = 0.03) wild-type yeast and molds in C8:C10-treated silage than controls. Compared with controls, wild-type enterococci decreased (P < 0.01) in all treatments except the C6:C8:C10:C12 mixture; lactic acid bacteria were decreased (P < 0.01) in all treatments except C6 and the C6:C8:C10:C12 mixture. Total aerobes and inoculated Staphylococcus aureus or Listeria monocytogenes were unaffected by treatment (P > 0.05). Anaerobic incubation (24 h at 39 °C) of ruminal fluid (10 mL) with 0.02 g overnight air-exposed MCFA-treated corn silage revealed higher hydrogen accumulations (P = 0.03) with the C8:C10 mixture than controls. Methane, acetate, propionate, butyrate, or estimates of fermented hexose were unaffected. Acetate:propionate ratios were higher (P < 0.01) and fermentation efficiencies were marginally lower (P < 0.01) with C8- or C8:C10-treated silage than controls. Further research is warranted to optimize treatments to target unwanted microbes without adversely affecting beneficial microbes.

Effects of thymol and carvacrol, alone or in combination, on fermentation and microbial diversity during in vitro culture of bovine rumen microbes.

Two essential oils (EO), thymol and carvacrol, were used in six ratio (100:00, 80:20, 60:40, 40:60, 20:80 and 00:100) combinations of both EO and in a dose of 0.2 g L-1 in bovine ruminal culture medium, 24-h cultures, to evaluate effects on total gas production (TGP), methane production, in vitro dry matter digestibility (IVDMD) and in vitro culture population dynamics of methanogenic and total bacteria. Total DNA extracted from ruminal microorganisms was subjected to denaturing gradient gel electrophoresis (DGGE)-polymerase chain reaction (PCR) to examine effects on bacterial populations. The effect of EO on TGP and IVDMD were assessed by comparison to untreated control cultures. In general, methane production by the microbial populations appeared to be higher with treatments containing the highest concentration of thymol than with treatments containing more carvacrol resulting in a tendency for greater methane-inhibiting activity achieved as the thymol concentration in the thymol:carvacrol mixtures decreased linearly. The population of total bacteria with a 74.5% Dice similarity coefficient for comparison of DGGE band patterns indicating shifts in bacterial constituents as EO ratios changed. No effects on TGP, IVDMD while only slight shifts in the methanogenic populations were seen with an overall 91.5% Dice similarity coefficient.

Short chain nitrocompounds as a treatment of layer hen manure and litter; effects on in vitro survivability of Salmonella, generic E. coli and nitrogen metabolism.

The current study was conducted to assess the bactericidal effectiveness of several nitrocompounds against pathogens in layer hen manure and litter. Evidence from an initial study indicated that treatment of layer hen manure with 12 mM nitroethane decreased populations of generic E. coli and total coliforms by 0.7 and 2.2 log10 colony forming units (CFU) g-1, respectively, after 24 h aerobic incubation at ambient temperature when compared to untreated populations. Salmonella concentrations were unaffected by nitroethane in this study. In a follow-up experiment, treatment of 6-month-old layer hen litter (mixed with 0.4 mL water g-1) with 44 mM 2-nitroethanol, 2-nitropropanol or ethyl nitroacetate decreased an inoculated Salmonella typhimurium strain from its initial concentration (3 log10 CFU g-1) by 0.7 to 1.7 log10 CFU g-1 after 6 h incubation at 37°C in covered containers. After 24 h incubation, populations of the inoculated S. Typhmiurium in litter treated with 44 mM 2-nitroethanol, 2-nitropropanol, ethyl nitroacetate or nitroethane were decreased more than 3.2 log10 CFU g-1 compared to populations in untreated control litter. Treatment of litter with 44 mM 2-nitroethanol, 2-nitropropanol, ethyl nitroacetate decreased rates of ammonia accumulation more than 70% compared to untreated controls (0.167 µmol mL-1 h-1) and loses of uric acid (< 1 µmol mL-1) were observed only in litter treated with 44 mM 2-nitropropanol, indicating that some of these nitrocompounds may help prevent loss of nitrogen in treated litter. Results warrant further research to determine if these nitrocompounds can be developed into an environmentally sustainable and safe strategy to eliminate pathogens from poultry litter, while preserving its nitrogen content as a nutritionally valuable crude protein source for ruminants.

Effects of repeated-low level sodium chlorate administration on ruminal and fecal coliforms in sheep.

Abstract The objective of this study was to evaluate the efficacy of oral sodium chlorate administration on reducing total coliform populations in ewes. A 30% sodium chlorate product or a sodium chloride placebo was administered to twelve lactating Dorper X Blackbelly or Pelibuey crossbred ewes averaging 65 kg body weight. The ewes were adapted to diet and management. Ewes were randomly assigned (4/treatment) to one of three treatments which were administered twice daily by oral gavage for five consecutive days: a control (TC) consisting of 3 g sodium chloride/animal/d, a T3 treatment consisting of 1.8 g of sodium chlorate/animal/d, and a T9 treatment consisting of 5.4 g sodium chlorate/animal/d; the latter was intended to approximate a lowest known effective dose. Ruminal samples collected by stomach tube and freshly voided fecal samples were collected daily beginning 3 days before treatment initiation and for 6 days thereafter. Contents were cultured quantitatively to enumerate total coliforms. There were no significant differences in total coliform numbers (log10 cfu/g) in the feces between treatments (P = 0.832). There were differences (P < 0.02) in ruminal coliform counts (log10 cfu/mL) between treatments (4.1, 4.3 and 5.0 log10/mL contents in TC, T3 and T9 Treatments, respectively) which tended to increase from the beginning of treatment until the 5th day of treatment (P < 0.05). Overall, we did not obtain the expected results with oral administration of sodium chloride at the applied doses. By comparing the trends in coliform populations in the rumen contents in all treatments, there was an increase over the days. The opposite trend occurred in the feces, due mainly to differences among rumen contents and feces in ewes administered the T9 treatment (P = 0.06). These results suggest that the low chlorate doses used here were suboptimal for the control of coliforms in the gastrointestinal tract of ewes.

Effects of Hops Treatment on Nitrogen Retention, Volatile Fatty Acid Accumulations, and Select Microbial Populations of Composting Poultry Litter Intended for Use as a Ruminant Feedstuff.

Poultry litter is a valuable crude protein feedstuff for ruminants, but it must be treated to kill pathogens before feeding. Composting effectively kills pathogens, but it risks losing ammonia to volatilization or leaching during degradation of uric acid and urea. Hops bitter acids also exert antimicrobial activity against certain pathogenic and nitrogen-degrading microbes. Consequently, the present studies were conducted to test if adding bitter acid-rich hop preparations to simulated poultry litter composts may improve nitrogen retention while simultaneously improving pathogen killing. Results from an initial study, testing doses of Chinook or Galena hops preparations designed to each deliver 79 ppm hops ß-acid, revealed that, after nine days simulated composting of wood chip litter, ammonia concentrations were 14% lower (p < 0.05) in Chinook-treated composts than untreated composts (13.4 ± 1.06 µmol/g). Conversely, urea concentrations were 55% lower (p < 0.05) in Galena-treated than untreated composts (6.2 ± 1.72 µmol/g). Uric acid accumulations were unaffected by hops treatments in this study but were higher (p < 0.05) after three days than after zero, six, or nine days of composting. In follow-up studies, Chinook or Galena hops treatments (delivering 2042 or 6126 ppm of ß-acid, respectively) for simulated composts (14 days) of wood chip litter alone or mixed 3:1 with ground Bluestem hay (Andropogon gerardii) revealed that these higher dosages had little effect on ammonia, urea, or uric acid accumulations when compared to untreated composts. Volatile fatty acid accumulations measured in these later studies were affected by the hops treatments, with butyrate accumulations being lower after 14 days in hops-treated composts than in untreated compost. In all studies, beneficial effects of Galena or Chinook hops treatments were not observed on the antimicrobial activity of the simulated composts, with composting by itself decreasing (p < 0.05) counts of select microbial populations by more than 2.5 log10 colony forming units/g compost dry matter. Thus, while hops treatments had little effect on pathogen control or nitrogen retention within the composted litter, they did lessen accumulations of butyrate, which may prevent adverse effects of this fatty acid on palatability of litter fed to ruminants.

Effect of Select Tannin Sources on Pathogen Control and Microbial Nitrogen Metabolism in Composted Poultry Litter Intended for Use as a Ruminant Crude Protein Feedstuff.

Poultry litter is a good crude protein supplement for ruminants but must be treated to kill pathogens before feeding. Composting effectively kills pathogens but risks loss of ammonia due to uric acid degradation. The objectives of this study were to test the ability of tannins to reduce pathogens and preserve uric acid during poultry litter composting. In two experiments, poultry litter was mixed with phosphate buffer and distributed to 50-ml tubes (three tubes/treatment per sample day) amended with 1 ml buffer alone or buffer containing pine bark, quebracho, chestnut, or mimosa tannins. Treatments achieved 0.63% (wt/wt) quebracho, chestnut, or mimosa tannins in experiment 1, or 4.5% pine bark or 9% quebracho, chestnut, or mimosa tannins in experiment 2. Tubes were inoculated with a novobiocin- and nalidixic acid-resistant Salmonella typhimurium, closed with caps, and incubated at successive 3-day increments at 22, 37, and 42°C, respectively. In experiment 1, bacterial counts in contents collected on days 0, 6, and 9 revealed a treatment by day effect (p < 0.03), with the Salmonella challenge being 1.3 log10 CFU/g higher in quebracho-treated composts than in untreated controls after 6 days of composting. After 9 days of composting, Salmonella, wildtype Escherichia coli, and total aerobes in untreated and all tannin-treated composts were decreased by about 2.0 log10 CFU/g compared to day 0 numbers (3.06, 3.75, and 7.77 log10 CFU/g, respectively). Urea and ammonia concentrations tended (p < 0.10) to be increased in chestnut-treated composts compared to controls and concentrations of uric acid, urea, and ammonia were higher (p < 0.05) after 9 days of composting than on day 0. Despite higher tannin application in experiment 2, antibacterial effects of treatment or day of composting were not observed (p > 0.05). However, treatment by time of composting interactions was observed (p < 0.05), with quebracho- and chestnut-treated composts accumulating more uric acid after 24 h and 9 days of composting and chestnut-, mimosa- or quebracho-treated composts accumulating less ammonia than untreated composts. Results demonstrate that composting may effectively control pathogens and that tannin treatment can help preserve the crude protein quality of composting poultry litter.

Nitro-treatment of composted poultry litter; effects on Salmonella, E. coli and nitrogen metabolism.

Poultry litter is a potentially valuable crude protein feedstuff for ruminants but must be treated to kill pathogens before being fed. Composting kills pathogens but risks losses of nitrogen due to volatilization or leaching as ammonia. Treatment of poultry litter with ethyl nitroacetate, 3-nitro-1-propionate, ethyl 2-nitropropionate (at 27 µmol/g), decreased numbers of experimentally-inoculated Salmonella Typhimurium (>1.0 log10 compared to controls, 4.2 ± 0.2 log10 CFU/g) but not endogenous Escherichia coli early during simulated composting. By day 9 of simulated composting, Salmonella and E. coli were decreased to non-detectable levels regardless of treatment. Some nitro-treatments preserved uric acid and prevented ammonia accumulation, with 18% more uric acid remaining and 17-24% less ammonia accumulating in some nitro-treated litter than in untreated litter (18.1 ± 3.8 µmol/g and 3.4 ± 1.4 µmol/g, respectively). Results indicate that nitro-treatment may help preserve uric acid in composted litter while aiding Salmonella control.

Influence of sodium chlorate, ferulic acid, and essential oils on Escherichia coli and porcine fecal microbiota.

The influence of sodium chlorate (SC), ferulic acid (FA), and essential oils (EO) was examined on the survivability of two porcine diarrhetic enterotoxigenic Escherichia coli (ETEC) strains (F18 and K88) and populations of porcine fecal bacteria. Fecal bacterial populations were examined by denaturing gradient gel electrophoresis (DGGE) and identification by 16S gene sequencing. The treatments were control (no additives), 10 mM SC, 2.5 mg FA /mL, a 1.5% vol/vol solution of an EO mixture as well as mixtures of EO + SC, EO + FA, and FA + SC at each of the aforementioned concentrations. EO were a commercial blend of oregano oil and cinnamon oil with water and citric acid. Freshly collected porcine feces in half-strength Mueller Hinton broth was inoculated with E. coli F18 (Trial 1) or E. coli K88 (Trial 2). The fecal-E. coli suspensions were transferred to crimp top tubes preloaded with the treatment compounds. Quantitative enumeration was at 0, 6, and 24 h. All treatments reduced (P < 0.05) the counts of E. coli F18 at 6 and 24 h. With the exception of similarity coefficient (%SC), all the other treatments reduced (P < 0.05) the K88 counts at 24 h. The most effective treatments to reduce the F18 and K88 CFU numbers were those containing EO. Results of DGGE revealed that Dice percentage similarity coefficients (%SC) of bacterial profiles among treatment groups varied from 81.3% to 100%SC. The results of gene sequencing showed that, except for SC at 24 h, all the other treatments reduced the counts of the family Enterobacteriaceae, while Lactobacillaceae and Ruminococcaceae increased and Clostridiaceae decreased in all treatments. In conclusion, all treatments were effective in reducing the ETEC, but EO mixture was the most effective. The porcine microbial communities may be influenced by the studied treatments.

Efecto de Candida norvegensis sobre la degradabilidad ruminal de rastrojo de maíz y el crecimiento de corderos / Effect of Candida norvegensis on ruminal degradation of corn stover and on growth performance of lambs

Resumen Los probióticos favorecen el desarrollo de microorganismos benéficos en el rumen, lo que incrementa la digestibilidad de los nutrientes y mejora el desempeño productivo de los rumiantes; con esto, se tiene la posibilidad de utilizar ingredientes como el rastrojo de maíz de relativo bajo valor nutritivo, pero altamente disponible en algunos lugares a bajo precio. Convencionalmente, se utilizan como probióticos las levaduras Saccharomyces, aunque existen reportes sobre el uso de cepas autóctonas, como Candida norvegensis. El objetivo de este estudio fue evaluar los efectos del probiótico de Candida norvegensis en la degradabilidad ruminal in situ de rastrojo de maíz y en el comportamiento productivo de ovinos en crecimiento. La levadura Candida norvegensis (cepa Levazoot 15) [0 g (T1) y 5 g (T2)] se usó para determinar la degradación ruminal in situ (DRMS), del rastrojo de maíz, en 3 vacas canuladas ruminalmente por medio de la técnica de la bolsa de poliéster. No hubo efecto de la levadura (P > 0.05) para la fracción (a), (b) y (a+b); pero la degradabilidad efectiva al 1 %/h y 5 %/h de recambio ruminal fue mayor para T2 (P < 0.05). En un segundo experimento, 32 corderos se asignaron al azar a corrales individuales por 105 d para evaluar 4 dietas que difirieron en la proporción de concentrado/ forraje: T1 = 75:25, T2 = 75:25, T3 = 50:50, y T4 = 25:75. A excepción de T1, las dietas fueron suplementadas con Candida norvegensis, a razón de 15 mL/kg de peso vivo, equivalente a 5 g/d de levadura en base seca. Los ovinos en la dieta con 75 % de concentrado más la levadura (T2) presentaron mayor ganancia de peso, y mejor conversión alimenticia (P < 0.05). Se concluye que Candida norvegensis mostró efectos benéficos en la degradabilidad ruminal y en el desarrollo de corderos.

Abstract Probiotics assist in the development of beneficial microorganisms in the rumen that increase digestibility of nutrients and improves the productive performance of ruminants; it also has the possibility of using ingredients as corn stover of relatively low nutritional value, but available in some places at low prices. Saccharomyces yeasts are conventionally used as pro biotics and there are reports that use native strains such as Candida norvegensis. The objective of this study was to evaluate the effects of the probiotic of Candida norvegensis on the in situ ruminal dry matter degradability of corn stover and on the productive performance of growing lambs. In the first experiment, the yeast Candida norvegensis (strain Levazoot 15) [0 g (T1)] and 5 g (T2) was used to determine the in situ ruminal dry matter degradation (RDMD) of the corn stover in 3 cows with cannulas in the rumen, which was determined by the polyester bag technique. There was no effect of yeast (P > 0.05) on fraction (a), (b) and (a+b). However, the effective degradability at 1 %/h and 5 %/h of ruminal turnover was higher in T2 (P < 0.05). In the second experiment, 32 lambs were randomly assigned to individual pens for 105 d to evaluate 4 diets that differed in the proportion of concentrate: forage: T1 = 75: 25, T2 = 75:25; T3 = 50: 50, and T4 = 25: 75. With the exception of T1, the diets were supplemented with Candida norvegensis at 15 mL/kg of live weight, equivalent to 5 g/d of yeast in dry matter basis. The lambs in the diet with 75 % of concentrate plus the yeast (T2) showed greater weight gain and best feed conversion (P < 0.05). It is concluded that Candida norvegensis showed beneficial effects on ruminal degradability and on the growth of lambs.

Comparison of three sampling procedures for evaluating intestinal villi: A swine model / Comparación de tres procedimientos de muestreo para evaluar vellosidades intestinales: Modelo porcino / Comparação de três métodos de amostragem para a avaliação das vilosidades intestinais: Modelo suíno

Abstract Background: Villi morphology and function affect the absorption capacity of the small intestine. Most tissues are fragile and their morphology may change with excessive manipulation and inadequate sampling techniques. Intestinal sampling includes methodologies such as cutting longitudinally or transversely, keeping the intestinal content in it and preserving all in a 10% formalin solution; washing the intestinal sample in saline solution while emptying it by pressing downwards with two fingers, conserving the sample in a 10% formalin solution and knotting both ends of the sample, introducing 10% formalin into it and preserving it in the same solution. Objective: To compare height, area and desquamation caused by washing, pressing, and knotting used in sampling and conservation techniques of small intestine villi of pigs. Methods: Samples (n = 270) from duodenum, jejunum and ileum of 30 Landrace × Yorkshire crossed pigs, aged 7 to 8 months were randomly subjected to washing, soft pressing or knotting procedures, fixed in 10% formalin solution, embedded in paraffin, and stained with eosin and hematoxylin. Intestinal villi in each slide were observed to determine height, surface area and cellular desquamation of each villus. Results: Villi height from duodenum and ileum knotted samples was higher (p<0.05) compared with samples from the other procedures in the same anatomical portion, which were similar to each other (p>0.05). Villi from knotted jejunum samples were the shortest (p<0.05) compared to the other two procedures, which were similar to each other (p>0.05). Knotted samples from ileum had larger villi area compared with the rest of the procedures and intestinal portions (p<0.05). Villi desquamation was similar among procedures and portions of the intestine (p>0.05). Conclusion: Knotting is the recommended procedure for intestinal cell morphometry evaluation, as values of villi height and area are higher. Desquamation in the three procedures may be related to epithelial restoration processes.

Resumen Antecedentes: La morfología y función de las vellosidades afectan la capacidad de absorción del intestino delgado. La mayoría de los tejidos son frágiles y su morfología puede cambiar con una manipulación excesiva y técnicas de muestreo inadecuadas. El muestreo intestinal incluye metodologías tales como el corte longitudinal o transversal, conservando el contenido intestinal y conservando todo en una solución de formol al 10%; lavado de la muestra de intestino en solución salina mientras se vacía, presionándola hacia abajo con dos dedos, conservando la muestra en solución de formol al 10% y anudando ambos extremos de la muestra, introduciendo en ella formol al 10% y preservándola en la misma solución. Objetivo: Comparar la altura, área y descamación causada por el lavado, presión y anudamiento utilizados en la toma de muestras y técnicas de conservación utilizadas en vellosidades intestinales en cerdos. Métodos: Se obtuvieron 270 muestras de duodeno, yeyuno e íleon de 30 cerdos cruzados Landrace × Yorkshire de 7 a 8 meses de edad, y se sometieron aleatoriamente a procedimientos de lavado, prensado suave o anudado y fueron fijados en solución de formol al 10%, procesados por inclusión en parafina y teñidos con eosina y hematoxilina. Se observaron las vellosidades intestinales de cada muestra para determinar su altura, la superficie de cada vellosidad y la descamación celular. Resultados: La altura de las vellosidades de las muestras anudadas de duodeno e íleon fue mayor (p<0,05) que las muestras de los otros procedimientos en la misma porción anatómica, las cuales fueron similares entre sí (p>0,05). Las vellosidades procedentes de muestras de nudos de yeyuno fueron las más cortas (p<0,05) en comparación con los otros dos procedimientos, que fueron similares entre sí (p>0,05). Las muestras anudadas del íleon presentaron mayor área de vellosidades que el resto de los procedimientos y porciones intestinales (p<0,05). La descamación de las vellosidades fue similar en todos los procedimientos y porciones del intestino (p>0,05). Conclusión: El procedimiento de anudamiento es el recomendado para la evaluación morfométrica de células intestinales, considerando que los valores de altura y área de las vellosidades son mayores. La observación de la descamación en los tres procedimientos puede estar relacionada con un proceso de restauración epitelial.

Resumo Antecedentes: A morfologia e função das vilosidades afeta a capacidade de absorção no intestino delgado. A maioria dos tecidos são frágeis e podem mudar sua morfologia com um manuseio excessivo e técnicas de amostragem inadequada. A amostragem de intestino inclui metodologias tais como corte longitudinal ou transversal, conservando o conteúdo intestinal e mantendo tudo em uma solução de formalina a 10%. A amostra do intestino é lavada em solução salina enquanto se esvazia pressionando para baixo com dois dedos, após isso a amostra é submergida em uma solução de formalina a 10% e atam-se as duas extremidades do intestino, mais formalina 10% é introduzida no mesmo e é preservado na mesma solução. Objetivo: Comparar a altura, área e descamação nas vilosidades do intestino delgado em porcos, causada pela lavagem, pressão e colocação do nó y pelas técnicas de conservação. Métodos: Duzentos e setentaa mostras de duodeno, jejuno e íleo de 30 porcos de cruzamento de raças Landrace e Yorkshire de sete a oito meses de idade foram submetidos aleatoriamente a procedimentos de lavagem, prensagem suave ou colocação de nós e foram fixados em solução de formalina a 10%, processados para inclusão em parafina e corados com hematoxilina e eosina. Foram observadas as vilosidades de cada amostra para determinar a sua altura, a superfície de cada célula vilosidade e descamação celular. Resultados: A altura das vilosidades nas amostras de duodeno e íleo com nó foi maior (p<0,05) do que as amostras de outros procedimentos na mesma parte anatómica, as quais foram semelhantes entre si (p>0,05). Amostras de jejunos com nó apresentaram vilosidades menores (p<0,05) em comparação com os outros dois procedimentos, que foram semelhantes entre si (p>0,05). Amostras de íleo com nó apresentaram maior área nas vilosidades do que outros procedimentos e outras porções do intestino (p<0,05). A descamação das vilosidades foi semelhante em todos os procedimentos e porções do intestino (p>0,05). Conclusão: O procedimento de colocação do nó é o recomendado para a avaliação morfométrica das células intestinais, já que os valores de altura e área das vilosidades são mais elevados. A observação da descamação nos três procedimentos poderia estar relacionada com um processo de restauração epitelial.