Carmen Arnal

Squalene-enriched diet fed rabbits displayed large plasma APOB100-containing particles enriched in non-esterified cholesterol and hepatic steatosis mainly due to squalene.

Summary: In Europe, more than 60 breeds are described by the national associations of rabbit breeders. However, these breeds are scarcely used in the commercial production of rabbit meat in Europe, which is based mainly on commercial strains. A European programme, coordinated by the I. N. R. A., has been initiated to realise the inventory of all these breeds and to evaluate the zootechnical value and the genetic characteristics of some of them. Through the European association of rabbit breeders and the FAO national focal points, all the European countries have been asked to fill out a questionnaire describing their populations of rabbits. A data bank is being set up, which will be included in the FAO (DAD-IS) and EAAP data banks. A sample of 10 breeds has been chosen (Flemish Giant, French Lop, Belgian Hare, Vienna White, Champagne Argente, Thuringer, Fauve de Bourgogne, Chinchilla, Himalayan, British). Their zootechnical value (reproduction, growth and carcass traits) is being evaluated on three experimental farms, in comparison with a control breed. At the same time, their genetic polymorphism and the genetic distances between these 10 breeds are calculated on the basis of microsatellites, mitochondrial DNA, other genetic markers and protein polymorphism. Finally, a bank of frozen embryos from these 10 breeds is being constituted.

Background: The objective of the present study is to investigate the migration pattern of the splenic dendritic cell of the chicken named the ellipsoid‐associated cell (EAC) from the site of initial location at the periphery of the ellipsoid to the splenic T‐ and B‐dependent areas. Methods: Bovine serum albumin bound to biotin and conjugated to gold particles was used as a histochemically identifiable antigen detected as a peroxidase reaction. The antigen was intravenously injected, and subsequently its pattern of distribution in a time sequence and within the tissue was examined at the light and electron microsocopy levels. In addition, an hour prior to sacrifice, the chickens received a single injection of the thymidine analogue 5‐bromo‐2′‐deoxyuridine, in order to quantify the number of DNA synthesizing cells and to establish a relationship between the migrating EAC and the rate of mitosis in the white pulp. Results: The observations showed that between 12 hours and 3 days after the second antigen administration the labeled EAC, which was first located around the ellipsoid, progressively reached further areas with time towards the periarteriolar lymphoid sheaths, where newly formed germinal centers appeared. Furthermore, the rate of cell proliferation within the white pulp was associated with the arrival of the antigen‐transporting EAC. Conclusions: The results suggest that migrating EAC have a role as both antigen‐transporting cell and antigen‐presenting cell in the T‐ and B‐dependent areas, as a result of which migrating EAC is transiently found in periellipsoidal white pulp, then periarteriolar lymphoid sheaths, and finally germinal centers, where it may function as an interdigitating cell or as a follicular dendritic cell, depending on its location. Thus, we conclude that the EACs are precursors of both interdigitating and follicular dendritic cells.