Effects and interactions between phytase, xylanase and β-glucanase on growth performance and nutrient digestibility in Nile tilapia

Exogenous enzyme pretreatment improves utilization of high-carbohydrate diets in rainbow trout (Onchorhynchus mykiss): effects on growth, digestibility, fillet quality, and gene expression

Exogenous enzymes are used to enhance ingredient digestibility, overall fish growth, and feed utilization; however, different administration methods have not been extensively studied. In this study, a mixture of carbohydrases (α-amylase, cellulase, xylanase, and β-glucanase) was applied before (at B3, B6, B12, and B24 hours), during (D), or after (A) the production of high-carbohydrate diets (33% carbohydrates) to assess their effects on the growth and feed utilization of rainbow trout. The enzymes were added to the diets at the minimum required levels, determined by a reducing sugar test with dinitrosalicylic acid (DNS) based on the available wheat flour and soybean meal in the diet. Seven isoenergetic (21 kJ/g) and isonitrogenous (40%) diets were formulated and fed to fish (n = 210, 17.41 ± 1.76 g) for 8 weeks. Overall growth parameters improved in the B6 and B3 groups, which also showed the lowest FCR values (0.84 and 0.85, respectively) and significantly higher weight gain, PER, and SGR compared to the other treatments. The apparent digestibility of protein, lipid, ash, and dry matter was significantly enhanced in the B3 group. Additionally, DHA and omega-3 fatty acid content increased in B3 (p < 0.05), although no significant differences were observed in fillet contents of EPA and ARA (arachidonic acid) between treatments (p > 0.05). The pretreatment of ingredients (B3 and B6) likely induced a protein-sparing effect, as indicated by higher PER and increased amino acid retention in the fillets (p < 0.05). Moreover, higher metabolizable energy and glucose levels led to significant upregulation of the ghrelin hormone (GHRL), growth hormone (GH), and insulin-like growth factor (IGF-I) genes in the B3 and B6 treatments (p < 0.05). In conclusion, pretreatment of ingredients (soybean meal and wheat flour) with optimized multienzyme doses improved digestibility and activated regulatory genes, resulting in enhanced growth, feed utilization, and fillet quality in high-carbohydrate diets for rainbow trout.

The multi-enzymes and probiotics mixture improves the growth performance, digestibility, intestinal health, and immune response of Siberian sturgeon (Acipenser baerii)

The inclusion of exogenous digestive enzymes and probiotics is well established in the aquafeed industry. The mixture of multienzymes and probiotics improves the feed utilization and wellbeing of aquatic animals than the individual supplementation. Herein, we evaluated the exogenous multi-enzyme mixture (beta-glucanase, cellulase, alfa-amylase, protease, xylanase, and phytase) at 250 mg/kg and multi-species probiotic (Bacillus subtilis, Lactobacillus acidophilus, L. delbrueckii, L. rhamnosus, L. plantarum, and Pediococcus acidilactici; 1 × 1010 CFU/g for each bacterial strain) at 2 g/kg on the performances of Siberian sturgeon. The final weight, weight gain, SGR, and PER were markedly enhanced while the FCR was reduced in fish fed multienzyme and probiotics premix (P<0.05). Multi enzymes and probiotic mixture significantly increased the total body protein content (P˃0.05). Multi enzymes and probiotic mixture also improved the digestibility of crude protein, dry matter, and crude lipids nutrients (P<0.05). The count of Goblet cells, microvilli diameter, microvilli length, outer muscle wall diameter, and enterocyte total absorptive surface were markedly increased (P<0.05) by dietary multienzymes and probiotics mixture. The WBCs and neutrophils showed marked improvements (P<0.05). The levels of glucose, triglycerides, blood urea nitrogen, and total bilirubin were markedly higher in fish fed the control than fish fed the multienzymes and probiotics mixture (P<0.05). Significantly, Siberian sturgeon-fed dietary multienzymes and probiotics had improved lysozyme activity, total immunoglobulin, and total protein in the skin mucus and serum samples (P<0.05). Further, the serum complement C3 and C4 was higher in fish-delivered multienzymes and probiotic mixture than in control (P<0.05). In conclusion, dietary probiotics synergistically enhanced the activity of multienzymes and resulted in increased feed utilization, nutrient digestibility, and health status of Siberian sturgeon.