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951.
Large quantities of specific egg antibodies can be produced with little effort by immunization of laying hens. Several antibody containing egg preparations were subjected to a tenacity test against digestive activity taking piglets with artificial jejunum fistulas as a model. Even with high doses of orally administered yolk lyophilisate no antibody activity could be found in the distal jejunum. The additional feeding of egg white, however, showed a significant protective effect on the yolks antibodies during the digestive act. No difference between egg white of immunized hens and egg white of unimmunized hens could be detected. Buffering the acidic gastric environment with sodium bicarbonate increased the antibody activity in the intestine by an average of 40%. Eggs administered in hot (70 degrees C) beef stock had higher antibody titers than eggs that were boiled for 4 minutes. Tenacity in antibodies fed in pellets was significantly lower than in powdered feed.  相似文献   
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Oviduct epithelial cell co-culture of early porcine embryos.   总被引:1,自引:0,他引:1  
One- to 16-cell porcine embryos were cultured in either Whittens medium supplemented with bovine serum albumin and fetal calf serum (WM) or in the same medium with porcine oviduct epithelial cell co-culture (WM-Poec). All stages of embryos cultured in WM-POEC had higher cell counts after 144-168 h of development than did embryos in WM. There was however, no significant difference in blastocyst formation rate of embryos cultured in WM-POEC over those cultured in WM. A high proportion of the embryos entering culture at the 1-2-cell were able to pass the 4-cell block stage in both WM and WM-POEC, 81% and 77%, respectively. In both media, most of the 1-2-cell embryos arrested their development at the compacted morula stage and failed to blastulate while embryos initiating culture at the 4- and 8-16-cell embryos formed blastocysts in culture at a rate of 80-90%.  相似文献   
956.
The pathogenic effect of enterotoxogenic E. coli is mainly to be found in the jejunum. Hence, an effective immunoprophylaxis should be focussed at this site. This can be done effectively by an oral application of specific antibodies. The present study describes the effectiveness of specific antibodies against E. coli. The antibodies were gained from the yolk of E. coli immunized hens and tested for their in vitro activity. The tests showed a significantly reduced adhesion of enterotoxogenic E. coli onto isolated pig enterocytes as long as the bacteria had been incubated with the specific yolk antibodies beforehand. For this reason, yolk immunoglobulins from immunized hens prove to be an effective and handy source of specific antibodies which offers good protection against adhesion of E. coli onto pig enterocytes.  相似文献   
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We compared estrous and farrowing traits in 274 Duroc X Yorkshire sows penned either in individual gestation stalls or in groups (four or five sows/group) during the intervals from weaning to breeding and from breeding to 30 to 35 d after breeding. Sows were assigned to treatment by parity (primiparous vs multiparous), checked twice daily for estrus from 3 to 10 d after weaning and artificially inseminated (AI) twice during estrus. Ovaries of anestrous sows were examined at laparotomy. No major treatment effects on estrous response were detected and 88% (45/51) of anestrous sows had only small ovarian follicles. Litter traits were not affected by penning treatments. However, penning sows in groups postbreeding resulted in a 50% reduction (P less than .05) in early pregnancy losses as indicated by low serum progesterone 19 to 23 d after AI or return to estrus by 23 d after AI. This resulted in a 12 percentage point higher (P less than .05) farrowing rate for group-penned (78%) than for individually penned sows (66%).  相似文献   
959.
The early development of the gonads, and the ontogenesis of the rete testis and tubuli seminiferi recti in the chicken (Gallus domesticus) The primordium of the gonads can be discerned in the 4-day chick embryo by the elevation of the celomic epithelium to form germinal epithelium, and by the arrival of the primordial germ cells. Already in the 4½ day chick embryo there appears on the left side of the body, as a result of the first proliferation of the germinal epithelium, a subepithelial mesenchymelike cell conglomeration, which has been erroneously labelled in the literature a “urogenital union”. In contrast to the opinion expressed in the literature such a union does not appear until the 10th day, when the mesenchymal cells change to forerunners of rete cells which after hatching differentiate into rete-epithelial cells. The rete testis consists of intra and extratesticular transverse cisterns and of an intercalated and partically subdivided longitudinal cistern. The tubuli seminiferi contori end on the intracapsular lingitudinal cisterns either directly, or indirectly by intercalated tubuli siminiferi recti or intratesticular transverse cisterns.  相似文献   
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