Effect of β-Glucans in Diets on Growth, Survival, Digestive Enzyme Activity, and Immune System and Intestinal Barrier Gene Expression for Tropical Gar (Atractosteus tropicus) Juveniles

Abstract

Abstract:The application of β-1,3/1,6-glucan derived from yeast at five concentrations (0%, 0.5%, 1.0%, 1.5%, and 2.0%) in formulated diets was evaluated in juveniles for its effects on the growth, survival, digestive enzymatic activity, and expression of genes associated with the immune system (interlukin-10 (IL-10), transforming growth factor (TGF), occludin (OCC), mucin2 (MUC2), lysozyme (LYS), and nucleotide-binding and oligomerization domain 2 (NOD2)) in tropical gar (Atractosteus tropicus). For the experiment, three replicates of 30 fish per experimental unit (70 L) were cultivated for 62 days. The growth results showed no statistically significant differences in relation to weight and total length between treatments. The activity of digestive enzymes (alkaline proteases, trypsin, leucine aminopeptidase, and amylase) did not show significant differences between treatments, except for chymotrypsin activity, where fish fed 1.0% and 1.5% of β-glucans showed higher activities compared with the rest of the treatments. On the other hand, the analysis of gene expression did not show significant differences between treatments, although a tendency of increase in the expression of IL-10, TGF, MUC2, and OCC was observed with an addition of 1.5% of the prebiotic, but there was a decrease in the fish fed with 2% of the prebiotic. It is possible to include concentrations of between 0.5% and 1.5% of β-glucans in the diets for A. tropicus, with no detectable adverse effects on growth, survival, digestive enzyme activity, or specific gene expression. β-glucan 1,3/1,6 added at 1.0% and 1.5% in the diet significantly increases chymotrypsin activity.

Fructooligosaccharide supplementation in diets for tropical gar ( Atractosteus tropicus ) juvenile: Effects on morphophysiology and intestinal barrier function

“…However, Nieves‐Rodríguez et al. (2018) only observed an increase in chymotrypsin activity using 10 and 15 g/kg β‐glucans. In agreement with our results, in the Wuchang bream ( M. amblycephala ), the main intestinal enzymes' activity increased with FOS addition (Wu et al., 2013).…”

Analysis of the Productivity, Immunity, and Health Performance of Nile Tilapia (Oreochromis niloticus) Broodstock-fed Dietary Fermented Extracts Sourced from Saccharomyces cerevisiae (Hilyses): A Field Trial

“…Midhun et al [ 32 ] reported that dietary probiotics could modulate MUC-2 gene expression in O. niloticus . Additionally, Nieves-Rodríguez et al [ 47 ] showed that the expression of MUC-2 in Atractosteus tropicus tended to increase with the addition of a prebiotic, β-1,3/1,6-glucan derived from yeast at 1.5%, while there was a decrease in the fish fed 2% of the prebiotic, which indicated that high concentrations of this immune stimulant inhibited the expression of MUC-2. The elevated IGF-1 RNA levels in the liver and intestine of the Hilyses-treated group confirmed its potential growth-promoting effect.…”

“…Essential amino acids, such as glutamic acid, play a substantial role in tissue proliferation and regeneration that consequently improve nutrient digestion and feed utilization [ 62 ]. Modulation of intestinal microbiota by MOS increases villus integrity and resistance to pathogenic bacteria, which increases digestion and absorption efficiency [ 17 , 47 , 63 ]. β-glucans stimulate the proliferation of beneficial gut flora and eliminate pathogenic gut flora, resulting in increased weight gain [ 64 ].…”

Immunomodulatory activity of β‐glucans in fish: Relationship between β‐glucan administration parameters and immune response induced

“…On top of that, mucus and antibacterial peptides can be secreted by the goblet cells to trap and eliminate pathogens at the intestinal mucosal layer (Pirarat et al, 2015). Fish that received β‐glucan orally was also shown to highly express mucin, the main glycoprotein that made up the mucus layer coating on the intestinal wall; thereby maintains the protective capability of the fish intestinal barrier (Nieves‐Rodríguez et al, 2018).…”