Fish stocks as phosphorus sources or sinks: Influenced by nutritional and metabolic variations, not solely by dietary content and stoichiometry.
Sci Total Environ
; 938: 173611, 2024 Aug 15.
Article
in En
| MEDLINE
| ID: mdl-38815832
ABSTRACT
The study provides a descriptive understanding of when fish (Cyprinus carpio model) are the source or sink of phosphorus. Dissolved reactive phosphorus (DRP; PO4-P) losses (51.1 ± 5.9 % of intake-P) increase at excess of bioavailable P (>0.83 g 100 g-1 dry matter, DM fed) or when food (digestible) NP mass ratio (≤4.41) approaches organismal storage threshold (~41). This is known, however, even at a sub-threshold food P content (0.57 g 100 g-1 DM) and food NP mass ratio (7.31), DRP losses (57.8 ± 4.5 % of intake-P) may be extraordinary if two indispensable amino acids are biologically insufficient (lysine ≤1.43 g, methionine ≤0.39 g 100 g-1 DM fed). Given that methionine and lysine are sufficient, DRP losses cease (≈0 %) and even some P from water is absorbed, given there is support from non-protein energy (NPE). Insufficient NPE (<180 kcal 100 g-1 DM fed) may drive DRP losses (81.6 ± 4.3 % of intake-P) beyond expected levels (46-59 % of intake-P) at a given food P content (0.91 g 100 g-1 DM). Natural food seldom fulfills low P, high lysine + methionine, and high NPE contents simultaneously, thus keeping fish in a perpetual P recycling for algae (scaleless carp > scaly carp). Such P recycling ceases only during basal metabolism. During feeding state, the richness of lysine + methionine bound N and lipid + carbohydrate bound C in the food base may enhance the fishes' threshold of P storage. P storage can be diminished when they are insufficient. We show that for fish, the decision of P recycling or not recycling (for algae) may change based on the supply of specific fractions of N or C from the food web or metabolic variations (basal metabolism, presence of scales). NOVELTY STATEMENT The ecological stoichiometry theory is better connected to fish nutritional bioenergetics for better understanding and biomanipulation of eutrophication processes.
Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Phosphorus
/
Diet
Limits:
Animals
Language:
En
Journal:
Sci Total Environ
Year:
2024
Document type:
Article
Country of publication:
Países Bajos