Evaluation of the effects of Keratinase-treated feather meal as a replacement for fishmeal on growth performance, liver function, and intestinal health in juvenile largemouth bass (Micropterus salmoides)
The enzymatic hydrolysis method was considered highly effective in hydrolyzing indigestible feathers into digestible proteins, however the practice of feather meal remained limited in aquafeed. Here, we evaluated the effects of hydrolyzed feather meal by keratinase (KFM), which breakdown keratin of...
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| Main Authors: | , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Elsevier
2025-03-01
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| Series: | Aquaculture Reports |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S2352513425000225 |
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| Summary: | The enzymatic hydrolysis method was considered highly effective in hydrolyzing indigestible feathers into digestible proteins, however the practice of feather meal remained limited in aquafeed. Here, we evaluated the effects of hydrolyzed feather meal by keratinase (KFM), which breakdown keratin of feather to improve the protein utilization. Six diets were formulated. They respectively replaced fishmeal (FM) at 0 % (CON), 20 % (D1), 40 % (D2), 60 % (D3), 80 % (D4) and 100 % (D5) levels with KFM, and fed to 360 uniform-sized juvenile largemouth bass (initial weight, 14.84 ± 0.01 g) for 8 wk. According to analysis on weight gain rate (WGR), specific growth rate (SGR) and feed conversion ratio (FCR), we found that the largemouth bass had the best growth performance when dietary KFM replaced 25.19 %-26.25 % of FM, and the highest feed utilization when replacing 9.38 % of FM. Besides, the expression of fatty acid synthetase (fas) gene presented a linearly increased difference with the increasing KFM concentrations (P = 0.001), whereas the expression of adipose triglyceride lipase (atgl) gene was linearly decreased (P = 0.000), resulting in hepatic lipid accumulation in largemouth bass. Furthermore, there was a significant enhancement of antioxidant capacity along with oxidative stress in liver of largemouth bass with the increasing KFM concentration (P < 0.05). We concluded that no more than 55 % of FM replaced by KFM could benefit the metabolism of largemouth bass via the IGF/PI3K/AKT/TOR pathway. Moreover, when all dietary FM was replaced by KFM, the predominant intestinal flora was significantly inverted, resulting in histological abnormalities and low feed utilization of largemouth bass. Collectively, we suggested that approximate 25 % of FM replaced by KFM could benefit the growth and reduce fishmeal reliance in largemouth bass. |
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| ISSN: | 2352-5134 |