Spray-dried porcine plasma affects intestinal morphology and immune cell subsets of weaned pigs ☆ M. Nofrarías a, ⁎ , E.G. Manzanilla b , J. Pujols c , X. Gibert c , N. Majó a , J. Segalés a , J. Gasa b a Centre de Recerca en Sanitat Animal (CReSA), Departament de Sanitat i d'Anatomia Animals, Universitat Autònoma de Barcelona, 08193, Bellaterra, Barcelona, Spain b Departament de Ciència Animal i dels Aliments, Universitat Autònoma de Barcelona, 08193, Bellaterra, Barcelona, Spain c Centre de Recerca en Sanitat Animal (CReSA), Institut de Recerca i Tecnologia Agroalimentaria (IRTA), 08007, Barcelona, Spain Abstract The aim of this study was to evaluate the effects of dietary spray-dried porcine plasma (SDPP) on the productive performance, intestinal morphology and leukocyte cell subsets of piglets. Sixteen early-weaned piglets (20 ± 2 d) were distributed into two dietary treatments: 1) free access to control diet or 2) 6% SDPP in the control diet instead of soy-protein concentrate. Intestinal morphometry of the small and large intestine, haematology and immune cell flow cytometric analysis of blood, ileo-colic lymph node and ileal Peyer's patches were performed in all pigs. Although SDPP treatment did not increase growth performance, it improved feed efficiency. We observed that SDPP diminishes blood monocytes, and macrophages (SWC3+), B lymphocytes (CD21+) and γδ T cells (γδTCR+) in gut lymphoid tissues. SDPP-treated piglets also showed lower intraepithelial lymphocyte numbers and lamina propria cell density in the small and large intestine. All these results suggest lower activation of the immune system of the SDPP-piglets during the post-weaning period. Moreover, the use of SDPP can be considered a valid alternative to antibiotic growth promoters. © 2007 Elsevier B.V. All rights reserved. Keywords: Immunology; Intestinal morphology; Nutrition; Spray-dried plasma; Weaning pig 1. Introduction Weaning is a critical period for piglets that involves stressful factors, when the immune and digestive systems are still immature. This situation generally results in a poor growth rate, associated with effects on the intestinal mucosa integrity and with the occurrence of pathological disorders (Pluske et al., 1997; Spreeu- wenberg, 2002). After the banning of in-feed antibiotics, spray-dried porcine plasma (SDPP) have been proposed as an alternative (Coffey and Cromwell, 2001) because it can maintain mucosal integrity and reduce intestinal inflammatory response after weaning, helping the piglet to resist bacterial aggressions (Bosi et al., 2004). An experiment was designed to evaluate the effect of dietary SDPP on intestinal morphology and on leuko- cyte cell subset populations of peripheral blood and gut Livestock Science 108 (2007) 299 – 302 www.elsevier.com/locate/livsci ☆ This paper is part of the special issue entitled “Digestive Physiology in Pigs” guest edited by José Adalberto Fernández, Mette Skou Hedemann, Bent Borg Jensen, Henry Jørgensen, Knud Erik Bach Knudsen and Helle Nygaard Lærke. ⁎ Corresponding author. Tel.: +34 93 5814495; fax: +34 93 5814490. E-mail address: miquel.nofrarias@cresa.uab.es (M. Nofrarías). 1871-1413/$ - see front matter © 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.livsci.2007.01.103