| 1. |
- Abro, Rani
(författare)
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Digestion and metabolism of carbohydrates in fish
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis deals with the digestion and metabolism of carbohydrates in Arctic charr, Eurasian perch and tilapia. Two sources of carbohydrates, native starch (wheat) and chitin (zygomycete biomass), were evaluated. Gut tissue of Arctic charr displayed significant chitinase activity, of both endo- and exo-chitinase forms. Moreover, the distribution pattern along the gastrointestinal tract of Arctic charr differed between endo-chitinase and exo-chitinase. The endo-chitinase activity in stomach tissue and in the distal intestine was several hundred-fold higher than the exo-chitinase activity in stomach tissue. The greatest exo-chitinase activity was found in the distal intestine fed a zygomycete-based diet. Disturbed intestinal integrity and increased uptake rate of the amino acid lysine were observed in the distal, but not proximal, intestine of fish fed the zygomycete-based feed. A ¹HNMR metabolomics approach revealed no differences in metabolic profile in liver tissues of Arctic charr fingerlings fed a zygomycete-based diet and a fish-meal based diet. The inclusion of wheat starch did not affect α-amylase activity in gut tissue of Arctic charr and Eurasian perch. Overall, α-amylase activity was correlated with the trends obtained for starch digestibility. The apparent digestibility (AD) of crude protein, starch, crude fat and energy differed between the fish species, with on average higher values for all parameters in Eurasian perch than in Arctic charr. Within fish species, dietary starch level had no effect on AD of dry matter, crude protein, crude fat and energy. Studies of the metabolic response to wheat starch inclusion in Arctic charr and tilapia using ¹HNMR base metabolomics indicated metabolic effects in tilapia, while inclusion of starch in the diet of Arctic charr resulted in partial or negligible metabolism effects. Thus there are species-related differences in the metabolic response to dietary starch inclusion.
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| 2. |
- Abro, Rani, et al.
(författare)
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Effect of Dietary Starch Inclusion Rate on Digestibility and Amylase Activity in Arctic charr (Salvelinus alpinus) and Eurasian perch (Perca fluviatilis)
- 2013
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Ingår i: Journal of Aquaculture Research and Development. - : OMICS Publishing Group. - 2155-9546. ; 5
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Tidskriftsartikel (refereegranskat)abstract
- This study investigated digestibility and amylase activity in Arctic charr and Eurasian perch fed different dietary levels of wheat starch. Eurasian perch (190 ± 0.5 g) and Arctic charr (102 ± 0.5 g) were fed one of six iso-nitrogenous diets containing 0, 10, 15, 20, 25 and 30% wheat starch. Each diet was fed to four replicate groups of fish to determine the impact of diet on the apparent digestibility (AD) of dry matter (DM), crude protein, starch, crude fat and energy. At the end of the experiment, tissue samples were collected for assessment of amylase activity in the proximal and distal intestine. The AD of DM, crude protein, starch, crude fat and energy differed between fish species (P<0.001), with on average higher values for all parameters in Eurasian perch than in Arctic charr. Within fish species, there was no effect (P>0.05) of dietary starch level on the AD of DM, crude protein, crude fat and energy. Overall, α-amylase activity correlated with the trends obtained for starch digestibility. The inclusion of wheat starch did not affect amylase activity within species.
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| 3. |
- Abro, Rani, et al.
(författare)
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Evaluation of chitinolytic activities and membrane integrity in gut tissues of Arctic charr (Salvelinus alpinus) fed fish meal and zygomycete biomass.
- 2014
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Ingår i: Comparative Biochemistry and Physiology - Part B: Biochemistry & Molecular Biology. - : Elsevier BV. - 1096-4959 .- 1879-1107. ; 175, s. 1-8
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Tidskriftsartikel (refereegranskat)abstract
- Chitinolytic activity, nutrient uptake and intestinal barrier functions were investigated in gut tissues of Arctic charr (Salvelinus alpinus) fed iso-nitrogenous diets based on fish meal, with or without inclusion of zygomycetes (Rhizopus oryzae). We found that gut tissue of Arctic charr had significant chitinase activity, of both endo- and exo-chitinase iso-forms. Moreover, the distribution pattern along the GI tract of Arctic charr differed between endo-chitinase and exo-chitinase. The endo-chitinase activity in stomach tissue and in the distal intestine was several hundred-fold higher than the exo-chitinase activity in stomach tissue. The greatest exo-chitinase activity was found in the distal intestine. The zygomycete-based diet resulted in higher chitinolytic activity in gut tissue compared to the fish meal-based diet. Disturbed intestinal integrity and increased uptake rate of the amino acid lysine were observed in the distal, but not proximal, intestine of fish fed the zygomycete-based feed.
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| 4. |
- Abro, Rani, et al.
(författare)
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Metabolic insights in Arctic charr (Salvelinus alpinus) fed with zygomycetes and fish meal diets as assessed in liver using nuclear magnetic resonance (NMR) spectroscopy
- 2014
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Ingår i: International Aquatic Research. - : Springer Science and Business Media LLC. - 2008-4935 .- 2008-6970. ; 6, s. 1-11
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Tidskriftsartikel (refereegranskat)abstract
- Fish meal is the major source of animal protein in feed for cultured salmonid fish, but its availability is limited and it must eventually be replaced by alternative protein-rich feed ingredients. Zygomycetes (Rhizopus oryzae) is a fungus with protein-rich biomass that could replace fish meal protein in fish feed. Using a 1H NMR spectroscopy approach, we studied the metabolic pattern in Arctic charr (Salvelinus alpinus) fed a commercial diet with unknown composition (ST), a diet with all protein from fish meal (FM) and a diet with most of the protein from zygomycetes biomass (FZ). No significant difference (p≥0.05) was found in spectral data between FM and FZ using the OPLS-DA fitted model. However, other models showed that diet ST clearly differed significantly (p˂0.05) from diets FM and FZ. Signals for acetate, β-alanine, choline, creatine, formate, glucose, inosine, lysine, SN-glycero-3-phosphocholine and two unknown metabolites were higher in fish fed diets FM and FZ than in fish fed diet ST. These results show that the metabolic profile in liver of Arctic charr will remain unchanged if fish meal protein is replaced with zygomycete protein, suggesting similar physiological responses to both feed ingredients. In contrast, feeding a commercial diet altered the metabolic fingerprint compared with diets FZ and FM, suggesting important differences in ingredient composition and the physiological response to this diet.
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