Journal Article
Dietary phytase and xylanase improves growth performance, intestinal morphometric properties, and metabolic gene expression in rainbow trout (Oncorhynchus mykiss)
Mustafa Yildiz; Samuel Ofori-Mensah; Shahram Golzar Adabi; Ömer Metin; Vahap Eldem; Victor E. Kaiza; Muhammed Ali Baltacı
Aquaculture International · Vol. 33, Issue 5 · 2025
Abstract
The aim of this study was to investigate the effects of phytase and xylanase enzymes in diets with high plant proteins on growth, nutritional composition, intestinal morphology, and metabolic gene expression in rainbow trout, Oncorhynchus mykiss . A total of 900 fish were randomly assigned in triplicates (50 fish weighing 31.61 ± 0.32 g per tank) to each of the 6 experimental diets. Dietary treatments included two positive control (PC) groups: PC1, formulated with 40% fish meal (FM), and PC2, formulated with approximately 60% plant proteins (PPS) and 1% monocalcium phosphate (MCP). The negative control (NC) was prepared with 60% PPS. The other three experimental groups were prepared as follows: PC2 + EPU (6000 EPU xylanase), NC + MIX1 (1500 OTU phytase + 6000 EPU xylanase), NC + MIX2 (3000 OTU phytase + 6000 EPU xylanase). At the end of the experiment, weight gain in PC2 + EPU, NC + MIX1, and NC + MIX2 was significantly increased by 11.30%, 8.22%, and 4.96% compared to PC1, respectively ( P P P SLC4 A11 and ATP1 A3 A , and phospholipid hydrolysis genes PG12 A ( P