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Effect of dietary tryptophan on growth performance, survival and hematological indices of juvenile Siberian sturgeon (Acipenser baerii) at different stocking densities
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Masoumeh Naghibi1   , Mirmasoud Sajjadi1 , Mahmoud Mohseni2 , Bahram Falahatkar1 |
1- University of Guilan
2- International Sturgeon Research Institute |
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Abstract: (18 Views) |
Introduction
According to world's growing population, one of the most important problems is food security. On the other hand, aquaculture is considered one of the important industries for providing protein and food resources worldwide, which has always faced numerous challenges (Pauly and Zeller, 2017). Given the issue of food security, the primary goal of aquaculturists is to achieve higher production. However, one of the most significant problems in aquaculture is the lack of water resources (Falahatkar and Rahdari, 2017). The lack of water resources has led fish producers to use increased stocking density as a solution to improve production. The increase in density can cause stress. One of the ways to achieve much production is to improve formulated diets to enhance the growth and health of fish. Researchers have added tryptophan to the diets of cultured fish to improve growth performance because it has been shown that this amino acid can improve growth performance as a very important economic indicator (Hosseini et al., 2020; Jhon et al., 2024; Zhang et al., 2024). Therefore, the present study was conducted with the hypothesis that growth, survival, and hematological indices in high-density cultured juvenile Siberian sturgeon (Acipenser baerii) would improve with the supplementation of dietary tryptophan.
Methodology
The study was conducted with 12,000 juvenile Siberian sturgeons with an average weight of 10.24±0.10 g in 8 experimental treatments with three replicates in 24 tanks as follows: Treatments 1 and 2 (fish fed with no dietary tryptophan at densities of 1.3 (LD; low density) and 2.6 kg/m² (HD; high density), respectively), Treatments 3 and 4 (fish fed with diets containing 0.2% tryptophan in the protein at densities of 1.3 and 2.6 kg/m², respectively), Treatments 5 and 6 (fish fed with diets containing 0.4% tryptophan in the protein at densities of 1.3 and 2.6 kg/m², respectively), Treatments 7 and 8 (fish fed with diets containing 0.6% tryptophan in the protein at densities of 1.3 and 2.6 kg/m², respectively). The juvenile sturgeons were fed at 3% of their body weight for 12 weeks. At the end of the rearing period, the fish were weighed and growth indices were measured. Blood samples were taken for hematological analysis. To assess the effects of stocking density and tryptophan levels on growth performance, survival, and hematological indices, a Two-way ANOVA test was used, followed by Tukey's test for comparisons at the P≤0.05 significance level.
Results
The analysis of growth performance at the end of the experimental period showed that different tryptophan levels, stocking densities, and their interaction had significant effects on WG, BWI, SGR, and DGR (p≤0.05). In all mentioned factors, tryptophan in LD with diets containing tryptophan showed significant differences compared to control and HD. The highest levels of these parameters were observed at 0.4% tryptophan in LD. Results showed no significant differences between treatments fed with different diets containing tryptophan in feed intake, but stocking densities and their interaction had significant effects (p≤0.05). The interaction effect of different tryptophan levels and stocking densities on PER, CF, and FCR showed significant effects of different tryptophan levels and stocking densities on these growth indices, with no significant interaction effect (p≤0.05). While the impact of diets containing tryptophan in LD showed significant differences, this difference was not observed in HD. The interaction effect of tryptophan and stocking density on SR was not significant, and survival rates were 100% in all treatments (p≤0.05). In hematological indices, different tryptophan levels, stocking densities, and their interaction had significant effects on RBC (p≤0.05), with the best performance in LD fed with 0.4% tryptophan. Tryptophan and stocking density had significant effects on WBC, HB, and HCT, with no significant interaction effects (p≤0.05). WBC and HB levels in both density treatments showed significant differences, with the highest WBC in LD with 0.2% tryptophan and HD with 0.6% tryptophan. The highest HB levels were observed at 0.4% tryptophan in both densities treatments. The highest HCT levels was observed at 0.4% tryptophan in LD, while no significant differences were observed in HCT at different tryptophan levels in HD.
Discussion and conclusion
The results of this study showed the positive impact of using tryptophan on growth performance and increased production in LD. Threre was no significant effect on growth indices in HD. The negative effects of density and stress on growth performance divert the body's micronutrient reserves from their primary function, using for stress response instead of growth, leading to reduced growth (Dabrowski et al., 1996). Additionally, regarding the positive effect of 0.4% tryptophan on hematological indices in juvenile Siberian sturgeon culture, results showed that in LD, using this diet positively affected all hematological indices, promoting the health of Siberian sturgeon. In HD, although tryptophan had no significant impact on RBC and HCT, it positively affected WBC and HB, improving the health of Siberian sturgeon. It appears that improving hematological indices with diets containing tryptophan in HD increases fish tolerance to stress in HD. In general, it can be concluded that providing the necessary amount of tryptophan in the diet is essential for the growth, development and health of Siberian sturgeon at HD by improving hematological indices. Therefore, it is recommended to use 0.4% tryptophan to increase production and improve health conditions in Siberian sturgeon, especially under high density conditions.
Conflict of interest
The corresponding author, on substitute of all authors of this article, announces that in publishing this article, publication ethics, including plagiarism, research misbehavior, data cheating, or both submission and publication, have been completely avoided, and there are no commercial benefits, and the authors have not received any payment for presenting their work. Therefore, the originality of the content of this article is declared. This work has not been previously published elsewhere and has not been submitted to another journal at the same time. Hereby, it grants permission to the publisher to publish the article and its contents, including text, tables, figures, etc.
Acknowledgments
We would like to express our gratitude to the Beluga Caviar Fish Farm, International Sturgeon Research Institute and the Faculty of Natural Resources, University of Guilan.
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| Keywords: Sturgeon, Nutritions, Amino acid, Stress |
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Full-Text [PDF 1195 kb]
(7 Downloads)
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Type of Study: Research |
Subject:
تغذيه
Received: 2025/02/11 | Accepted: 2025/08/1
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