https://orcid.org/0000-0003-3332-0396
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ABSTRACT
A 60-day feeding trial was conducted to determine the effects of different levels of grape seed oil (GO) on growth performance, digestive enzyme activity, fillet proximate and fatty acid composition of rainbow trout (Oncorhynchus mykiss) juveniles (40.17 ± 0.04 g). Five experimental diets were formulated where fish oil (FO) was replaced with 0 (D1), 25 (D2), 50 (D3), 75 (D4) and 100 (D5) % GO. The growth performance was significantly improved with increasing GO levels up to 50% after which fish growth declined (P < .05). Fillet fatty acid composition was showed significantly highest n-6 PUFA levels with increasing GO in diets, while n-3 HUFA levels especially EPA and DHA were significantly decreased (P < .05). Fish fed on diets containing higher levels of GO revealed a decrease in α-amylase activity, whereas trypsin, total alkaline protease, and lipase activities increased significantly with increasing GO levels up to 50% and then decreased. Based on the findings of the present study, it could be concluded that GO could be included in diets up to 50% where it had the best performance over the other diets tested in the present experiment.
Abbreviations
| FO | = | Fish oil |
| GO | = | Grape seed oil |
| SGR | = | Specific growth rate |
| FCR | = | Feed conversion ratio |
| VSI | = | Viscero somatic index |
| HSI | = | Hepato somatic index |
| IW | = | Initial weight |
| FW | = | Final weight |
| WG | = | Weight gain |
| LER | = | Lipid efficiency ratio |
| PER | = | Protein efficiency ratio |
| FER | = | Feed efficiency ratio |
| CF | = | Condition factor |
| PUFA | = | Polyunsaturated fatty acid |
| HUFA | = | Highly unsaturated fatty acid |
| EPA | = | Eicosapentaenoic acid |
| DHA | = | Docosahexaenoic acid |
| TAP | = | Total alkaline protease |
| LC, | = | Long chain |
| ARA | = | Arachidonic acid |
| VO | = | Vegetable oil |
| LA | = | Linoleic acid |
| LNA | = | Linolenic acid |
| PC | = | Pyloric caeca |
| I, | = | intestine |
| FA | = | Fatty acid |
| BHT | = | Butylated hydroxyl toluene |
| FAME | = | Fatty acid methyl esters |
| FID | = | Flame ionization detector |
| BAPNA | = | N-α-Benzoyl-DL-arginine-4-nitroanilide hydrochloride |
| ANOVA | = | Analysis of variance |
| SPSS | = | Statistical package for social sciences |
| MUFA | = | Mono unsaturated fatty acid |
| SFA | = | Saturated fatty acid |
| PA | = | Palmitic acid; SA, Stearic acid |
| OA | = | Oleic acid |
| MCFA | = | mid chain fatty acid |
Acknowledgments
The authors want to express their appreciation for supporting this work by Research Institute for Grape & Raisins and Vice-Chancellors of Research & Technology from Malayer University, Hamedan, Iran under Project No. 84/5-1-501.
Disclosure statement
No potential conflict of interest was reported by the authors.