Effects Of Egg Yolk Antibody Supplemented In Diets On Growth Performance,Diarrhea And Faecal Bacterial Communities Of Post-weaning Piglets

Enterotoxigenic Escherichia coli (ETEC) are the major pathogenic E coli causing diarrheal diseases in post-weaning piglets. In the present study, polymerase chain reaction (PCR) technology was developed to detect different fimbrial genes of ETEC, established by Wang Jie in our laboratory, to investigate the distribution of fimbrial genes of ETEC in commercial pig farm of Zhong Liang Food Product Co., Ltd. in Wu Han city, Hubei province, K88 and F18 were confirmed as the predominant pilin genes associated with post-weaning diarrhea. Induced egg yolk antibodies of faeG-fedF fusion protein in E coli, established by our laboratory, was proved to have the effect on preventing and curing diarrheal diseases in post-weaning piglets, furthermore, on growth performance and fecal bacterial community of piglets. The results were as follows:1. ETEC's epidemiologic survey was carried on pig farm of Zhong Liang Food Product Co., Ltd. in Wu Han city, Hubei province. Polymerase chain reaction (PCR) technology was developed to detect fimbrial antigens, detection of reference stains with special primers showed target bands. In 2008, 348 feceal samples from neonatal (76), suckling (87) and post-weaning (185) piglets with diarrhea were tested for the presence of the fimbrial antigen K88, K99, F18, F41 and 987P of ETEC by PCR. 154 (44.25%) of the 348 samples carried at least one of the ETEC fimbrial antigens. F18 antigen was detected for a dominative pilin gene in 120 (77.92%) of 154 positive samples, K88 antigen was 27 (17.53%), F41 antigen was 15 (9.74%), K99 antigen was 3 (1.95%), 987P antigen was 1 (0.65%). Meanwhile, there were 12 samples known to carry two fimbrial antigens, and 7 samples contained K88 and F18; 2 samples contained K88 and F41; 2 samples contained K99 and F18; 1 sample contained F18 and 987P. Results showed that K88 and F18 are the most common fimbrial antigens of ETEC associated with diarrhea, thus, it is logical to assume that adding induced egg yolk antibodies may be benefited to alleviate piglet diarrhea.2. Effects of hyperimmun spray dried egg protein (SDEP) of faeG-fedF fusion protein, adding in amino acids balance diet, on incidence of diarrhea and growth performance of post-weaning piglets was proved on trial. 180 pigs weaned at 24±2d of age were randomly assigned to three dietary treatments, each including three duplicates with twenty pigs per pen. Diet supplemented with 3% spray dried plasma protein (SDPP) and with 1.5% SDEP was control, and the treatment was supplemented with 1.5% hyperimmune SDEP of faeG-fedF fusion protein. Results showed that three dietary treatments played a significant role in diarrhea diseas (P<0.01). During 0-14d post weaning, incidence of piglet diarrhea in group fed with hyperimmune SDEP and SDEP was significantly lower than that of SDPP group (P<0.01), while there was no significant difference between hyperimmune SDEP group and SDEP group in this early phase. During 15-28d post weaning, incidence of piglet diarrhea in group fed with hyperimmune SDEP and SDPP was significantly lower than that of SDEP group (P<0.01), while there was no significant difference between hyperimmune SDEP group and SDPP group in the late phase. In total, 0-28d post weaning, incidence of piglet diarrhea in group fed with hyperimmune SDEP was significantly lower than that of SDPP and SDEP groups (P<0.01), while there was no significant difference between SDPP group and SDEP group. There was significant difference among all the treatments (P<0.01), and diet with hyperimmune SDEP could relieve diarrhea disease.There was no significant difference among all the treatments (P<0.05), piglets had a high growth velocity and average body weight was above 15kg at 7-week-old. During 0-14d post weaning, there was no significant difference in average daily gain (ADG) and Feed/Gain (F/G) among all the treatments, suggesting supplement of SDEP and hyperimmune SDEP can improve growth performance and increased feed conversion ratio of post-weaning piglets, consistent with SDPP. During 15-28d post weaning, diet with SDPP or SDEP was displaced with the same diet. Results indicated ADG in SDPP and hyperimmune SDEP was significantly higher than that of SDEP group (P<0.05), and SDPP group reached a significant level (P<0.01). In this phase, there was significant difference in F/G among all the treatments, F/G in SDPP and hyperimmune SDEP was significantly lower than that of SDEP group (P<0.01). Throughout the experiment, F/G in SDPP and hyperimmune SDEP was significantly lower than that of SDEP group (P<0.05), and there was no significant difference in feed intake among all the treatments. 3. Effects of hyperimmun SDEP, adding in amino acids balance diet on fecal bacterial community of post-weaning piglets were proved on trial. PCR and denaturing gradient gel electrophoresis (DGGE) were used to monitor the development of bacterial community in faeces of 0, 7 and 21d post-weaning piglets of SDPP control, SDEP control and hyperimmune SDEP treatment. The regions V₆ to V₈ of the 16S rDNA of faecal bacteria were amplified. DGGE profiles of the PCR products were compared by similarity analysis. Results revealed there were less bands on DGGE profiles from fecal samples of 0d post-weaning piglets, no significant differences among all the treatments (P>0.05). The diversity in SDPP group was significantly higher than that of SDEP and hyperimmune SDEP groups, and similarity analysis of fecal samples showing lower than 30% among treatments, suggested some bacteria owned by all piglets before weaning, however, with differences in diversity and quantity of bacterial community. The bands and diversity of DGGE profiles from fecal samples of 7d post-weaning piglets was significantly higher than that of 0d post-weaning piglets (P<0.05) in hyperimmune SDEP group, meanwhile, there were no significant differences in SDPP and SDEP group (P>0.05). Similarity analysis of DGGE profiles from fecal samples of 7d post-weaning piglets indicated 3 marked clusters, hyperimmune SDEP, SDEP and SDPP group respectively, with 78%, 80% and 83% of similarity respectively. The diversity index of bacterial community in hyperimmune SDEP and SDPP group was significantly higher than that of SDEP group (P<0.05), suggesting the diet had a noticeable effect, with the same tendency in the diversity, on bacterial community of post-weaning piglets. With the same treatment, the diversity of DGGE profiles from fecal samples of 21d post-weaning piglets was significantly lower than that of 7d post-weaning piglets (P<0.05) in hyperimmune SDEP and SDPP group, meanwhile, there were no significant differences in SDEP group (P>0.05). In these regards, adding hyperimmune SDEP to the piglets dietary in early weaning made DGGE profiles more complicated and diverse.