scholarly journals Bacterial Synergism or Antagonism in a Gel Cassette System

2003 ◽  
Vol 69 (12) ◽  
pp. 7204-7209 ◽  
Author(s):  
Eirini Tsigarida ◽  
Ioannis S. Boziaris ◽  
George-John E. Nychas

ABSTRACT The growth and the metabolic activity of Shewanella putrfaciens, Brochothrix thermosphacta, and Pseudomonas sp., when cultured individually or in all possible combinations in gel cassettes system supplemented with 0.1% glucose at 5°C, were investigated. The overall outcome was that the coexistence of the above-mentioned microorganisms affected not only each growth rate but also their type of metabolic end products compared to the control cultures. These effects were varied and depended on the selection of the combination of the tested bacteria. For example, the growth of Pseudomonas sp. strains cocultured with either B. thermosphacta or S. putrefaciens strains resulted in different effects: a promoting one for the first and an inhibitory one for the second. Moreover, the production of formic acid and two unidentified organic acids (peaks a and b) was characteristic in all cases in which S. putrefaciens was cultured.

2019 ◽  
Vol 5 (1) ◽  
Author(s):  
Manuel Gómez-García ◽  
Cinta Sol ◽  
Pedro J. G. de Nova ◽  
Mónica Puyalto ◽  
Luis Mesas ◽  
...  

Abstract Background Accurate screening of new alternative antimicrobial compounds is essential for their use to control pathogens in swine production due to the replacement of antibiotics and zinc oxide. Most in vitro studies have separately reported the antimicrobial activity of organic acids and essential oils (EOs) using diverse methods for susceptibility testing. In addition, in vitro outcomes can help in the selection of the suitable antimicrobial compound and effective combinations of these compounds in the control of pathogens of interest in pork production. Therefore, the aim of this study is to determinate the antibacterial activity of six organic acids and six EOs against Escherichia coli, Salmonella spp. and Clostridium perfringens isolates, some of them multi-resistant to antibiotics, from swine origin. The synergistic effects between the products with higher activity for each bacteria were also calculated. Results All products tested showed activity against at least one bacterial species, except for black pepper EO. The results showed that formic acid with the shortest chain length was the most effective against E. coli and Salmonella spp., while the sodium salt of coconut fatty acid distillates with long chain acids was the most effective against C. perfringens. The susceptibility of isolates tested to EOs was similar, a result that demonstrates a similar activity of these products against phylogenetically unrelated pathogens. In addition, an additive effect was shown for carvacrol-oregano EO for E. coli, formic acid-carvacrol and formic acid-thymol for Salmonella spp. and carvacrol-cinamaldehyde for C. perfringens. Conclusions The susceptibility of isolates to EOs was similar, a result that demonstrates a similar activity of these products against phylogenetically unrelated pathogens in contrast to organic acids. In addition, an additive effect was shown for several combinations of these compounds.


1961 ◽  
Vol 41 (1) ◽  
pp. 30-39 ◽  
Author(s):  
L. A. Charette

The effects of sex and age of castration of males on growth rate, feed efficiency and carcass characteristics in bacon type swine were measured using 16 pigs each as gilts, entire boars, and boars castrated at birth, 6, 12, 16, and 20 weeks of age. Castration at 20 weeks was too late since some pigs reached 200 pounds live weight before that age. Boars consumed less feed daily than barrows and gilts, were thinner in loin fat, and yielded a higher percentage of shoulder than gilts. The carcasses of boars and gilts were longer, had less fat covering over the shoulder and back, a larger area of loin, and a higher iodine number than those castrated late. Acceptability tests showed that sex or age of castration did not affect the flavour, odour, or tenderness of the meat.Purebred breeders can delay castration for better selection of boars without any serious effect on growth, physical carcass characteristics, and feed requirements. Although the market discriminates against boars, it appears questionable whether castration is necessary when boars are slaughtered at 200 pounds before they reach the age of 150 days.


2005 ◽  
Vol 483-485 ◽  
pp. 225-228 ◽  
Author(s):  
Didier Chaussende ◽  
Laurence Latu-Romain ◽  
Laurent Auvray ◽  
M. Ucar ◽  
Michel Pons ◽  
...  

Thick (111) oriented β-SiC layers have been grown by hetero-epitaxy on a (0001) a-SiC substrate with the Continuous Feed-Physical Vapour Transport (CF-PVT) method. The growth rate was 68 µm/h at a pressure of 2 torr and a temperature of 1950°C. The nucleation step of the β-SiC layer during the heating up of the process was studied in order to manage first the a to b heteropolytypic transition and second the selection of the b-SiC orientation. With a adapted seeding stage, we grew a 0.4mm thick layer almost free of Double Positioning Boundaries on a 30mm diameter sample. First observations of the layer by cross-polarised optical Microscopy are presented both in planar view and in cross section geometry.


2021 ◽  
Vol 41 (1) ◽  
pp. 60-67
Author(s):  
E. K. Ndelekwute ◽  
H. O. Uzegbu ◽  
K. U. Amaefule ◽  
C. O. Okereke ◽  
B. I. Umoh

A Six week study was carried out to investigate effect of different organic acids (OAs) fed through drinking water on carcass yield and internal organs weight of broiler chickens. The OAs were acetic acid (AA) butyric acid (BA), citric acid (CA) and formic acid (FA). One hundred and fifty (150) day old AborAcre-plus chicks were used. There were five treatments. Treatment 1 which served as control (CON) consumed water with no organic acid, while treatments 2,3, 4 and5 respectively were offered drinking water treated with 0.25% acetic acid (AA), butyric acid (BA), citric acid (CA) and formic acid (FA). Each treatment was replicated three times each having 10 birds arranged in completely randomized design (CRD). Feed and water were offered ad libitum. Results showed that dressed carcass weight and breast weight were improved by all the organic acids. While only AA positively influenced the thigh weight, all the OAs drinking water fed resulted to smaller drumstick compared to the CON. Feeding of AA, BA and FA through drinking water increased (PSO.05) deposition of abdominal fat. Weight of pancreas, small intestine, caecum and large intestine was significantly (P<0.05) higher in CON. The gall bladder was significantly (P<0.05) bigger in all the OA groups. Conclusively, OAs could be fed through the drinking water for improved percentage carcass yield, breast meat and larger gall bladder and invariably bile volume


2008 ◽  
Vol 14 (4) ◽  
pp. 311 ◽  
Author(s):  
K. PARTANEN ◽  
T. JALAVA

An in vitro gas production technique was used to screen different organic acids (formic, propionic, lactic, citric, and fumaric acid), organic salts (calcium formate, potassium sorbate, and sodium benzoate), and inorganic phosphoric acid for their ability to modulate microbial fermentation in the digestive tract of piglets. For the incubation, 40 ml of culture medium (53% buffer, 45% frozen ileal digesta, and 2% fresh faeces) was dispensed in vessels containing 5 ml of buffer, 0.5 g of feed, and 20 ìl of liquid or 20 mg of solid acidifiers. Gas production was measured every 15 min during the 24 h incubation at 39°C, and a Gompertz bacterial growth model was applied to the gas production data. Formic acid was the only acid that reduced the maximum rate of gas production (ìm) compared to that in the control treatment (P < 0.05). The ìm was slower in vessels with formic acid than in those with calcium formate, citric acid, and potassium sorbate (P < 0.05) Calcium formate increased the ìm compared to the control treatment (P < 0.05). The maximum volume of gas produced and the lag time did not differ between different acidifiers (P > 0.05). When investigating formic-acid-based mixtures that contained 1–5% of potassium sorbate and/or sodium benzoate, the estimated parameters for the Gompertz growth model did not differ from those for treatments with plain formic acid (P > 0.05). However, concentrations of total volatile fatty acids, acetic acid, propionic acid, and n-butyric acid were reduced by all the mixtures (P < 0.05), but not by plain formic acid (P > 0.05). In conclusion, organic acids and salts were found to differ in their ability to modulate microbial fermentation in the digestive tract of piglets. Mixing formic acid with potassium sorbate or sodium benzoate changed fermentation patterns, and the possibility to use them to enhance the antimicrobial effect of formic acid should be investigated further in vivo.;


Author(s):  
I.L. Astapchuk ◽  
◽  
N.A. Marchenko ◽  
G.V. Yakuba ◽  
A.I. Nasonov ◽  
...  

The influence of various culture media on the growth, morphological and cultural characteristics of the fungus F. sporotrichioides was studied. Ten culture media were used in our research. A comparative study of the growth rate of the F. sporotrichioides mycelium made it possible to identify two media that are the most suitable for the cultivation and identification of this species, namely carrot and tomato agar. We took into account such criteria as ensuring the maximum degree of sporulation, rapid growth and development of mycelium (the 7th day), colony diameter (71–78 mm), as well as the ease of preparation. Nirenberg culture medium can be used to obtain a large number of conidia of the fungus. Because of the high variability of cultural characteristics of F. sporotrichioides, we recommend using different composition of media.


1981 ◽  
Vol 61 (4) ◽  
pp. 977-981 ◽  
Author(s):  
S. LEESON ◽  
J. D. SUMMERS

Two trials were conducted with Nicholas strain turkeys. In trial 1, 300 male poults were reared to 49 days using either initial stages of 'large-turkey' feeding regime, or a situation allowing for diet self-selection of protein and energy. Within these programs, diets were supplemented with 10 ppm avoparcin, while a comparable number of controls received no growth promoter. Avoparcin improved growth rate (P < 0.01) irrespective of age, and improved feed utilization to 35 days of age. This effect was not confounded with the form in which diets were offered. In a second trial a 'broiler-turkey' feeding schedule was used, with birds slaughtered at 88 days. Diet treatments consisted of a control diet containing 33 ppm robenz and test diets containing either 33 ppm robenz + 10 ppm avoparcin or 10 ppm avoparcin alone. Avoparcin improved weight gain (P < 0.05) irrespective of coccidiostat inclusion. Feed utilization and carcass grades were not influenced by diet. The 7% improvement in body weight noted here with avoparcin was substantially greater than that previously observed with broiler chickens.


2021 ◽  
Vol 40 (3) ◽  
pp. 80-96
Author(s):  
Vicentiu Covrig ◽  
Daniel McConaughy ◽  
Adam Newman ◽  
Pavan Kumar Nadiminti ◽  
Mary Ann K. Travers

This article presents the first detailed statistical analysis of the volatilities of various commonly encountered financial metrics used in contingent consideration (and earn-out) agreements. The valuation of contingent consideration using an option-based methodology and non-equity volatilities is becoming more common in business valuation. We provide clear evidence that the volatility of five financial metrics—revenue; earnings before interest, taxes, depreciation, and amortization (EBITDA); EBIT, net income, and total assets—is strongly, negatively related to firm size and profitability. However, contrary to common belief, the volatility of these metrics is not related to a firm's financial leverage. We also calculated the volatilities using four different methodologies that are employed in practice. Although no theory guides the selection of methodologies, based upon our work, we have found that the year-over-year growth rate, using a quarterly frequency, provides the most reasonable results.


Parasitology ◽  
1970 ◽  
Vol 61 (3) ◽  
pp. 425-433 ◽  
Author(s):  
Frank Nowell

Suppression ofP. bergheiinfections but not those ofN. rodhainiorT. bruceiin mice on milk diet were noted. The suppression ofP. bergheiwas variable. This was not due to differences of the quality of the milk or to the mice eating faeces, sawdust, etc. which may be rich in PABA. The variability was at least partially due to selection of a strain of parasite probably requiring a lower level of PABA than normal. One such strain was isolated and its pattern of infection compared with the normal strain. The ‘milk diet’ strain caused a higher fatality rate in mice on milk diet but always showed a lower parasitaemia growth rate in mice on normal diet. When repassaged through mice on normal diet, the ‘milk diet’ strain did not revert immediately to the infection pattern of the normal strain.


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