The antibacterial activity of the egg white protein conalbumin

Applications of In Ovo Technique for the Optimal Development of the Gastrointestinal Tract and the Potential Influence on the Establishment of Its Microbiome in Poultry

As the current poultry production system stands, there is a period of time when newly hatched chicks are prevented from access to feed for approximately 48-72 h. Research has indicated that this delay in feeding may result in decreased growth performance when compared to chicks that are fed immediately post-hatch. To remedy this issue, in ovo methodology may be applied in order to supply the embryo with additional nutrients prior to hatching and those nutrients will continue to be utilized by the chick post-hatch during the fasting period. Furthermore, in ovo injection of various biologics have been researched based on the ability of not only supplying the chick embryo with additional nutrients that would promote improved growth but also compounds that may benefit the future health of the chicken host. Such compounds include various immunostimulants, live beneficial bacteria, prebiotics, and synbiotics. However, it is important to determine the site and age of the in ovo injection for the most productive effects. The primary focus of the current review is to address these two issues [the most effective site(s) and age(s) of in ovo injection] as well as provide the framework for the development of the gastrointestinal tract (GIT) of the chick embryo. Additionally, recent research suggests the colonization of the microbiota in the developing chick may occur during the late stages of embryogenesis. Therefore, we will also discuss the potentials of the in ovo injection method in establishing a healthy and diverse community of microorganisms to colonize the developing GIT that will provide both protection from pathogen invasion and improvement in growth performance to developing chicks.

Therapeutic and prophylactic applications of bacteriophage components in modern medicine

As the interactions of phage with mammalian innate and adaptive immune systems are better delineated and with our ability to recognize and eliminate toxins and other potentially harmful phage gene products, the potential of phage therapies is now being realized. Early efforts to use phage therapeutically were hampered by inadequate phage purification and limited knowledge of phage-bacterial and phage-human relations. However, although use of phage as an antibacterial therapy in countries that require controlled clinical studies has been hampered by the high costs of patient trials, their use as vaccines and the use of phage components such as lysolytic enzymes or lysozymes has progressed to the point of commercial applications. Recent studies concerning the intimate associations between mammalian hosts and bacterial and phage microbiomes should hasten this progress.

INFLUENCE OF TEMPERATURE ON BACTERIAL INFECTION OF THE HEN'S EGG

Temperature of incubation had a marked effect on infection of eggs in which the air cells had been inoculated with a washed suspension of Serratia marcescens. There was no evidence of bacterial multiplication or spoilage in eggs held at 10 C for 42 days. Multiplication occurred in the shell membranes of eggs held at 30 or at 37 C when the yolk made contact with these membranes, and continued in the contents of the egg, at which time the first signs of spoilage appeared. In a few eggs, very large populations were present in the shell membranes and in the albumen. In eggs inoculated with Pseudomonas fluorescens and held at 10 C, bacterial multiplication occurred in the shell membranes in the first 7 days of incubation. These populations did not appear to change in size in the 7- to 14-day period of incubation. Renewed multiplication and concomitant spoilage of the contents was observed in many of the eggs thereafter.

Effect of faecal extract on the growth of Salmonella enteritidis in artificially contaminated hens' eggs

1. Salmonella enteritidis PT 4 grew in eggs stored at 25 degrees C, but not at 10 degrees C. 2. The incidence of generalised infection of the egg contents (greater than 10(6) salmonellas/ml) was greater in eggs inoculated with cells suspended in faecal extract compared to those with cells in Ringer's solution. 3. The removal of most of the iron did not decrease the growth-promoting effect of the faecal extract.

Growth of Salmonella enteritidis in artificially contaminated hens' shell eggs

The effect of some factors on the growth of Salmonella enteritidis phage type 4 in artificially contaminated shell eggs was investigated. Salmonella enteritidis was found to be resistant to the antimicrobial properties of the albumen. Growth occurred on storage at 25 degrees C but not at 4 or 10 degrees C. The rate and extent of infection was influenced by the size of inoculum, the site of contamination relative to yolk movement, and the presence of iron in the inoculum.

Molecular heterosis at the conalbumin locus in the ring-necked pheasant (Phasianus colchicus)

Egg whites of Phasianus colchicus containing conalbumin of the heterozygous type show a stronger inhibitory effect on the growth of Saccharomyces cerevisiae than egg whites with conalbumin of the common homozygous type. This fact is interpreted as an example of heterosis at the molecular level.

Factors affecting the growth of Pseudomonas fluorescens in liquid egg white

Pseudomonas fluorescens grew rapidly in fresh egg albumen diluted with water. Growth of the bacteria in egg albumen was stimulated by the addition of carbohydrate and ovomucoid-rich egg exudate. Polyacrylamide-gel electrophoresis for residual egg albumen revealed extensive proteolysis of albumen inoculated with the organism. A fluorescent compound with absorption maximum at 408 nm was isolated from a defined salt medium inoculated with P. fluorescens. It shortened the lag phase and increased the final cell yield of the organism when added to the salt medium (100 mug/ml).

Liesegang-like rings of growth and inhibition of bacteria in agar caused by metal ions and chelating agents

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