DefinePK

Abstract

ABSTRACT The common carp (Cyprinus carpio) is an agastric fish, having digestive tract pH above 6 and cannot digest phytate properly found in plant-based diets. Phytate acts as an anti-nutrient, as it chelates with minerals to form insoluble mineral-phytate complexes and reduce their bioavailability. Therefore, in this study citric acid (CA) and exogenous phytase (PHY) were incorporated with canola meal-based (CM) diets to check their effects on mineral availability and digestibility in C. carpio fingerlings. Four CM-based diets were prepared by substituting CM for fishmeal at 0, 25, 50, and 75% levels, in which PHY (0 and 750 FTU kg-1) and CA (0 and 2.5%) were added at two levels, creating a total of sixteen test diets labelled from T1 to T16. For 8-week, common carp were fed on test diets about 2.5% of their live body weight. Fecal samples were collected from each tank twice daily to assess mineral digestibility. The results showed that the highest apparent digestibility coefficients for minerals were observed in fish fed on T12 diet (50% CM, 2.5% CA and 750 FTUkg-1 PHY), This combination synergistically improved the digestibility of minerals, such as calcium (63%), phosphorus (70%), sodium (60%), potassium (70%), magnesium (68%), iron (73%), copper (73%), manganese (67%), and zinc (63%). These findings suggested that supplementing CM based diets with CA and PHY effectively released chelated minerals from phytate complexes, thereby enhancing their availability for C. carpio. This approach can contribute to improve fish performance and overall nutritional efficiency. Incorporating CA and PHY in CM based diets holds promise for optimizing mineral digestibility in fish.