Soybean meal is the dominant protein source in aquaculture feeds. Hence, there is considerable interest in evaluating improved soy based products that could improve performance. Additionally, there is still debate on the efficacy of plant vs animal-based feeds. The goal of this research was to evaluate the impacts of an animal-based diet and soy-based feeds using various processed soy including solvent-extracted soybean meal with low oligosaccharide (SBM-LO) content, soy protein concentrate (SPC), fermented (FerSBM), and expeller-pressed (EPSBM) process on the growth performance, feed utilization efficiency, intestine histology, and gene expression. The first trial was conducted in a green water recirculation system with the stocking density at 30 inds/ tank, at the initial weight of 0.42 ± 0.01 g. Shrimps were fed in eight weeks using four replicate tanks, with eight experimental diets including SBM-LO, SPC, FerSBM at 50% and 100% protein replacement as well as EPSBM at 100% replacement on a protein basis with solvent extracted soybean meal in the basal diet (48 g/100g diet). An animal protein based reference diet contained fishmeal and poultry by-product meal as primary protein source. Trial results revealed significant differences amongst treatments, with the exception of survival (P >0.05), significant difference in performance was observed. Shrimp fed the animal-based diet in the moderate performing group. Concerning histomorphology and gene expression, no statistical changes were observed (p>0.05). The second trial used shrimp with a mean weight of 0.29 ± 0.01 g and evaluated the use of the low oligosaccharide (LO-SBM) and fermented soybean (FerSBM) meals as the primary protein source. Nine different experimental diets were examined. Solvent extracted soybean meal was the primary source of protein of the basal diet, which was replaced with four levels of replacement (40 %, 60 %, 80 %, and 100 %) of each of LO-SBM and FerSBM. All growth metrics in the trial showed no significant differences among diets (p>0.05). Except for phosphorus retention (p<0.001), we observed no significant contrast concerning feeding utilization efficiency (p>0.05). The results of trial two demonstrate that the tested soybean ingredients at various levels had no detrimental effects on the growth response or feed utilization of Pacific white shrimp. The outcome showed the potential of replacing the solvent extracted soybean meal with new variety low oligosaccharide or fermented soybean meals when needed. However, as previously described there are limits to the use of soy protein concentrate. Irrespective of soy source, there were no actionable shifts in gut histology or gene expression that indicate adverse responses to the various soybean meals tested in these studies.
Key works: shrimp, soy-based diets, gut health