Effects of administration of probiotic strains on GALT of larval gilthead seabream: Immunohistochemical and ultrastructural studies

Abstract

Two bacterial strains Lactobacillus fructivorans (AS17B), isolated from adult seabream (Sparus aurata L.) gut, and Lactobacillus plantarum (906), isolated from human faeces, were administered contemporaneously during seabream development using Brachionus plicatilis and/or Artemia salina and dry feed as vectors. Experimental group A received the probiotic strains already via rotifers from day 5 post-hatch (ph), whereas treatment of group B began with Artemia feeding from day 27 ph. Fish were sampled at day 28 ph (group A and control) and day 99 ph (groups A, B and control) for electron microscopy, histology and immunohistochemistry with the polyclonal antiserum ORa against homologous serum Ig and the mAb G7 specific for seabream acidophilic granulocytes. In all groups, timing and pattern of differentiation of the digestive tract did not differ. Furthermore, neither tissue damage nor manifest inflammation was provoked by probiotic administration. At day 28 ph, the developing GALT already housed mucosal leucocytes, including Ig(+) cells but no acidophilic granulocytes. No differences were seen between experimental groups. At day 99 ph, the density of Ig(+) cells (+51%) and acidophilic granulocytes (+284%) was significantly higher (p<0.05) in group A than in controls. Also group B had a higher density of Ig(+) cells (+17%) and acidophilic granulocytes (+130%) compared with controls, although less pronounced. Light and electron microscopy observations detailed the occurrence of heterogeneous populations of lymphocytes and granulocytes in the developing intestinal mucosa, and highlighted the net expansion of G7(+) acidophilic granulocytes (A +536%, B +292% vs. control) due to probiotic administration. Evidence is provided that early feeding with probiotic-supplemented diet increased the number of Ig(+) cells and acidophilic granulocytes in seabream gut and that the effects were more pronounced when administration started during gut metamorphosis. These results point to a stimulatory effect of probiotics on the gut immune system that correlates with improvement of fry survival.

Elucidating the Probiotic Potential of Malaysian Paenibacillus pabuli Against Vibrio alginolyticus in Artemia Culture

“…Several publications have disclosed the application of probiotics supplemented via live carriers such as rotifers and Artemia to be able to stimulate the immunity of fish and shrimp, thus improving their growth and survival (Picchietti et al, 2009(Picchietti et al, , 2007Rengpipat et al, 1998). Our study discovered, the higher pathogen load in the culture water would result in a lower survival rate of Artemia.…”

Bacillus cereus and Bacillus subtilis used as probiotics in rotifer (Brachionus plicatilis) cultures

“…The control of bacterial load by the addition of probiotic bacteria, most frequently sought for the elimination of pathogenic bacteria, has been shown to be an effective treatment to increase the productivity and health status of cultured fish [27][28][29].…”

Immunocytochemical Tools Reveal a New Research Field Between the Boundaries of Immunology and Reproductive Biology in Teleosts

“…Especially in the gilthead seabream, numerous antibodies have been obtained in the recent years, particularly those specific for studying the endocrine regulation of multiple biological processes such as reproduction, growth, metabolism, etc. (Abad et al, 1992;García-Ayala et al, 2003;Modig et al, 2008;Morgado et al, 2007;Picchietti et al, 2007;Pinto et al, 2009;Pirone et al, 2008;Radaelli et al, 2003Radaelli et al, , 2005Santos et al, 2001;Villaplana et al, 1997). Regarding the gilthead seabream immune response, an array of monoclonal and polyclonal antibodies have been developed for leukocyte markers (Sepulcre et al, 2002), immune molecules ( Corrales et al, 2010;García-Castillo et al, 2004;Pelegrín et al, 2004) or immunoglobulins (Picchietti et al, 2006).…”