Effect of dietary alginic acid on juvenile tilapia (Oreochromis niloticus) intestinal microbial balance, intestinal histology and growth performance

Abstract

The aim of the present study was to assess the effect of a commercial alginic acid source (Ergosan) on tilapia Oreochromis niloticus intestinal microbial balance, intestinal morphology, and growth parameters. Fish were fed a basal control diet or the basal diet plus a source of alginic acid (5 g kg(-1) Ergosan; Schering-Plough Aquaculture, UK) for 9 weeks. At the end of the trial, light and electron microscopy demonstrated that the morphology of the intestinal tract at the gross and ultra-structural level was not affected by dietary alginic acid inclusion. Both groups of fish displayed healthy, normal morphology with no signs of disease, cell or tissue damage. Intestinal epithelial leucocyte infiltration was not affected by dietary alginic acid. Molecular bacterial profiles derived from PCR-DGGE illustrated highly similar microbial communities (both within the lumen and associated with the intestinal mucosa) in the respective treatment groups. Microbial ecological parameters (e.g. species diversity and richness) also remained unaffected. Although not significant, trends towards elevated survival and body protein content were observed in the alginic acid-fed fish. These results are suggestive that alginic acid does not adversely impact the indigenous gastrointestinal microbial balance and subsequently does not impact upon the epithelial brush border integrity. Validation of non-detrimental impacts of immunostimulatory products on gastric microbiota and epithelial integrity should be pursued in future studies as maintaining microbial balance and epithelial integrity is essential for proper gut functionality.

Preparation and anatomical distribution study of 67Ga-alginic acid nanoparticles for SPECT purposes in rainbow trout (Oncorhynchus mykiss)

“…Also, Ergosan increased the density of the intestinal goblet cells, villus and fold length in rainbow trout [9] and villus, fold and enterocyte height in tilapia [22]. The results of the current study prove the positive effects of Ergosan (alginic acid) on imaging of the fi sh gastrointestinal morphology.…”

The effect of supplementation with polysaccharides, nucleotides, acidifiers and Bacillus strains in fish meal and soy bean based diets on growth performance in juvenile turbot (Scophthalmus maximus)

“…Whole body composition of turbots remained unaffected by additive inclusions in both, high and low FM diets as in earlier studies comparing FM-or PP-based diets supplemented with some additives Heidarieh et al, 2012;Kühlwein et al, 2014;Merrifield et al, 2011;Ng et al, 2009). The observed growth decline of fish fed high levels of soy bean and wheat proteins cannot be explained by reduced development of fillet muscles caused by lower protein retention or reduced fat storage.…”

“…Research demonstrated that b-glucan or MOS enriched diets did not improve growth in dentex (Dentex dentex), tilapia, Asian catfish (Clarias batrachus), channel catfish (Ictalurus punctatus), hybrid tilapia (O. niloticus ♀ × O. aureus ♂) and Atlantic salmon (Efthimiou, 1996;Grisdale-Helland et al, 2008;He et al, 2009;Kumari and Sahoo, 2006;Lara-Flores et al, 2003;Welker et al, 2007;Whittington et al, 2005). Moreover, supplementation with brown algae extracts, yeast nucleotides and potassium diformate did not support growth compared to the unsupplemented diets in red drum (Sciaenops ocellatus) and tilapia (Li et al, 2005;Merrifield et al, 2011;Zhou et al, 2009). Refstie et al (2010) proved that supplementation with MOS (2 g kg −1 diet) in a FM reduced diet, containing soy bean and sunflower meal (SBM + SFM) as substitutes, improved growth performance in salmon.…”

“…The reduction of FM to 32% was chosen as studies showed that growth performance in turbot was significantly decreased with a FM Table 1 Ingredients, nutrient composition in g kg −1 dry matter (DM) and gross energy in MJ kg CT = control, GM = b-glucan/MOS, AC = alginic acid, NR = nucleotides/RNA, PDF = potassium diformate and BS = Bacillus spp. Additive concentrations were recommended by manufacturers and literature (Burrells et al, 2001a,b;Lückstädt, 2008;Merrifield et al, 2011 C-HF = high fish meal control, C-LF = low fish meal control, GM = b-glucan/MOS, AC = alginic acid, NR = nucleotides/RNA and BS = Bacillus spp. Additive concentrations were recommended by manufacturers and literature (Burrells et al, 2001a,b;Merrifield et al, 2011 content below 40% and a PP level above 30%, respectively (Bonaldo et al, 2011;Day and Plascencia González, 2000).…”

“…Additive concentrations were recommended by manufacturers and literature (Burrells et al, 2001a,b;Lückstädt, 2008;Merrifield et al, 2011 C-HF = high fish meal control, C-LF = low fish meal control, GM = b-glucan/MOS, AC = alginic acid, NR = nucleotides/RNA and BS = Bacillus spp. Additive concentrations were recommended by manufacturers and literature (Burrells et al, 2001a,b;Merrifield et al, 2011 content below 40% and a PP level above 30%, respectively (Bonaldo et al, 2011;Day and Plascencia González, 2000). The other four experimental diets were formulated on the basis of control diet C-LF and were supplemented with commercially available feed additives: (1) GM, (2) AC, (3) NR and (4) BS (for details see 2.2).…”