| The mechanisms of anti-microbial properties of fertile eggs during incubation are not clear, recently. In this paper, a comparison research was carried on to determine the anti-microbial activity of fertile eggs and infertile eggs using a inoculation method of immersion during incubation. The anti-microbial activity of albumen and eggshell and shell membranes of fertile and infertile eggs were also taken into a comparison. Above all, the content of lysozyme and ovotransferrin, the two main types of anti-microbial proteins, were compared.In order to clear the anti-bacterial mechanism of fertile eggs during incubation, the fertile and infertile eggs were used to identify the anti-Salmonella enteritidis differences during different stages of incubation. They were put into inoculation in a SE suspension of approximately 1×105cfu/mL. Egg shell and membrane, albumen, yolk were sampled respectively. The results showed that it was significantly that fewer of the fertile eggs' shell and membrane, albumen samples were contaminated on days 4 (P<0.05), the yolk samples of the two kinds of eggs were clear. There were no significant differences between fertile an infertile eggs in all the sample tested on days 8 and 12 of incubation (P >0.05). However, On days 17, it was significantly that fewer of the fertile eggs' albumen and yolk samples were contaminated (P<0.05), moreover,13.78% of the chick rinses samples from fertile eggs were positive,45.16% of the albumen samples from infertile eggs were positive. By measuring the dry weight and water content of the albumen changes during incubation, a concentration was found and the fertile egg albumen was concentrated more. Meanwhile, the pH values of the albumen were determined to know how it changed, we found that the pH values of fertile eggs' albumen first increase and then decrease, the pH values of infertile eggs' albumen increase all the time. The pH effect will set obstacle for the growing of SE.The incubated albumen of fertile and infertile eggs were set as media, a comparison of the anti-microbial activity was done. The inhibition of all the strains in this experiment was found and there were some differences. The 2d's incubation albumen had the strongest inhibition effect for both the gram-positive and gram-negative bacteria. Then, the inhibition effect would decrease. For the gram-negative bacteria, the inhibition effect was almost the same for the albumen incubated for 0-2 days. When albumen incubated for 3 or 4 days, the inhibition effect of fertile eggs's albumen was weaker then the infertile eggs. For the gram-positive bacteria, the inhibition effect was almost the same for the albumen incubated for 0-3 days. On the 4th day of incubation, the inhibition effect of fertile eggs's albumen was stronger then the infertile eggs.In the chapter 2, we found that on the 4th day of incubation, the anti-SE properties of fertile eggs were stronger than infertile eggs. In the chapter 3, we found that the anti-SE properties of fertile eggs' albumen were weaker than infertile eggs' albumen. Therefore, in the chapter 4, the eggshell penetration of fertile and infertile eggs was discussed. The results showed that:The anti-SE properties of eggshell of fertile eggs were decreased in the early incubation, the resistant time was changed from 81.6h to 60.0h, and there are significant differences(P<0.05); as for the infertile eggshell, the properties were almost the same (P>0.05), the resistant time was remain 58-63h. Most importantly, the average resistant time of fertile eggs'shell was longer than the infertile eggs on the same day of incubation 19.2h (0d),5.4h (1d),5.4h (2d),6.5h (3d),1.2h (4d).In addition, the study also using spectrophotometry to determine the content of two main antimicrobial egg white protein (lysozyme and ovotransferrin). The results showed that the content of lysozyme in albumen first increase then decrease, for the fertile eggs it changed from 3.78mg/mL(0d) to 5.23 mg/mL (2d) when it reached the maximum; for the infertile eggs it changed from 3.86 (0d)mg/mL to 4.71(3d) when it reached the maximum. After that, the content of lysozyme in the infertile eggs's albumen decrease during the whole time of incubation. On the 3-4 days, the content of lysozyme in the fertile eggs'albumen was higher than infertile eggs, because the lysozyme played the major role in inhibiting the gram-positive bacteria, it means that on the 3-4 days, the albumen of fertile eggs have higher ability to inhibit growing than infertile eggs, which is consistent with the results in chapter 3. The content of ovotransferrin is just the same as lysozyme, on the Od of incubation, the content was 4.17 mg/mL and 4.31 mg/mL, respectively. then it commit a increase, on days 2, it reaches the maximum,6.57 mg/mL,6.28 mg/mL, respectively. There must be a relationship between the anti-microbial activity of albumen and the changes of lysozyme and ovotransferrin content. When the content of lysozyme and ovotransferrin increase, the anti-microbial activity gets stronger, when the content of lysozyme and ovotransferrin decrease, the anti-microbial activity gets weaker. |
