-
Na +
Cl-
Supplemenation before smoltification may be of benefit
-
K function
control of osmorality and pH
-
K def. induced?
chemically defined diets or certain pathological conditions that could promote K excretion
-
changes in [K]
- fresh -> sea = increase in [K]
- head -> tail = increase in [K]
- -due to smaller cells
- -increase in CT (have less [K])
-
K def. signs
muscle weakness
-
[Ca] in sea water vs. fresh water
- sea water:
- -have an abundance in [Ca] but low in [P], therefore req is readily met
- -excess is secreted, dietary Ca:P should be 1:1
- fresh water:
- -have less [Ca] vs. sea water, Ca dietary req is low
-
What affects Ca absorption?
- Magnesium
- Barium
- Stronium
- Zinc
- Copper
-
Phosphorus function
- bone mineralization
- structural component of soft tissues
- products of energetics and PRO synthesis
-
Phosphorus sources
not readily absorbed in the water, therefore must be dietarily provided
- animal-based feeds have sufficient [P]
- plant-based feeds need inorganic supplementation of P
-
Phytin
- mixed salt of phytin acid + Ca + Mg
- source of P and Mg however it is not readily available
- is broken down by phytase - endogenous to GI tract or synthesized by MO
- decreases bioavailability of Zn, Cu, Co, Mg, Mn, Ca, Fe, and PRO
-
Phosphorus def. signs
- reduced growth
- poor feed conversion
- poor bone mineralization
-
Mg function
- bone mineralization
- neuromuscular transmission
-
[Mg] in sea water vs. fresh water
- sea water:
- meets Mg req unless [Ca] is high, Ca affects Mg absorption. high [Ca] creates a lower threshold for Mg def.
- fresh water:
- do not supply Mg, must be provided dietarily: animal based. (plant based is not as readily available - phytin)
-
Zn function
- enzyme chemical structure
- activator of enzymes
- important for CHO, PRO, lipid metabolism
-
Mg def. signs
- decreased growth rate
- lethargy
- decreased appetite
- nephrocalcinosis
- convulsions
- cataracts
- degeneration of muscle fibers
- spinal curvature
- poor mineralization
- mortality
-
Zn def. signs
- lenticular cataracts*
- shrot-body dwarfism
- fin & skin erosion
- decreased growth rate
- decreased appetite
- mortality
-
what affects Zn absorption?
- phosphatase
- carbonate of Ca, Na, K
-
Change in Mn req?
smaller fish needs more Mn compared to bigger fish
-
Mn def. signs
- short-body dwarfism
- loss of equilibrium
- cataracts
- abnormal tail growth
- poor hatchability
- poor growth rate
-
Fe function
important for heme proteins, hemoglobin, myoglobin
-
Fe def. sign
hypochromic & macrocytic anemia
-
Cu functions
- blood formation
- stability of CT and elastin
-
Cu def. signs
- aortic rupture
- bone deformation
-
Se in regards to Vit E
- have similar def. signs w/ Vit E
- affected by presence of antioxidants and sulphur AA
-
Se def. sign
pancreas disease
-
Iodine source
met readily by the water
-
induced Iodine def
goitre either by lack of iodine or unidentified goitrogen that reduces availability of iodine
-
Fluoride function
protection against dental caries
-
Fluoride sources
met by water and diet
-
Cobalt
no requirement but is in association with B12.
- benefits:
- -increased growth
- -increased hemoglobin and hematocrit value
- -increased synthesis of B12 by MO
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