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Effects of the recombinant fungal phytase enzyme PhyA derived from Pichia pastoris on growth factors and phosphate content in the feces of rainbow trout (Oncorhynchus mykiss)
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Sayed Kamel Ghadirzadeh   , Ehsan Nasr , Najmeh Sheikhzadeh * , Marziyeh Heidarieh |
| Department of Food Hygiene and Aquatic Animals, Faculty of Veterinary Medicine, University of Tabriz, Tabriz, Iran. , ns76032@gmail.com |
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Abstract: (215 Views) |
This research examined the effects of lysed yeast supplemented with a recombinant phytase enzyme derived from Pichia pastoris on the growth performance of rainbow trout (Oncorhynchus mykiss) and the resultant phosphorus concentrations in their fecal matter, utilizing acid-insoluble ash as a marker for phosphorus measurement. The experiment was conducted with three replicates for each treatment group, utilizing a total of 30 fish (average weight 20 ± 1.54 g) allocated randomly across 12 tanks. The study included three treatment cohorts that were administered varying dosages of recombinant phytase at 1000, 2000, and 3000 IU/kg of feed while a control group received no treatment. The group with 2000 IU/kg showed the best growth performance, achieving the highest final weight (81.98 g), weight gain (62.13 g), and average daily growth (5.59 g). The treatment achieved a significant specific growth rate of 4.61 ± 0.12 and a food conversion ratio of 0.41 ± 0.02, both of which were statistically distinct from the control and other treatments by the second week (P<0.05). Survival percentages in both the control and treatment groups showed no significant differences (P > 0.05). Additionally, this group had the lowest acid-insoluble ash percentage at week eight and the highest phosphorus digestibility index (55.6%) at week six (P > 0.05). The control group exhibited the highest phosphate concentration (0.622 mg/l) during week six, while the phytase-treated group had a lower concentration (0.312 mg/l). Overall, the findings suggest benefits of the 2000 IU/kg phytase treatment for trout growth and phosphorus utilization, although changes in phosphate levels reach statistical significance.
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| Keywords: : recombinant phytase, rainbow trout, Pichia pastoris, acid-insoluble ash, digestibility |
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Full-Text [PDF 828 kb]
(83 Downloads)
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Type of Study: Research |
Subject:
Special
Received: 2025/01/29 | Accepted: 2025/02/28 | Published: 2025/03/30
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