Metabolic effects on growth and muscle of soya-bean protein feeding in cod (Gadus morhua).
The aim of the present study was to investigate the effect of soya-bean protein on growth and muscle metabolism in fish. Cod, Gadus morhua, were fed on a fish-feed formula with the high-quality fish-meal protein being replaced by 100, 200 or 300 g soya-bean protein/kg fish-meal protein. The feeding experiment lasted for 43 d at a water temperature of 7-8 degrees and a sea water salinity of 3.5%. At the 200 g/kg level of soya-bean protein, food intake and growth rate were similar to those of the controls. At the 300 g/kg level of soya-bean protein, food intake was diminished by 6% and growth by 67% relative to control levels. In muscle, sarcoplasmic protein (/g wet weight) was significantly decreased by 14%. Myofibrillar protein (/g wet weight) was unchanged. Levels of RNA in the myofibrillar fraction decreased at all three levels of soya-bean protein, and that of the sarcoplasmic fraction decreased at the highest level of legume-protein. With increased levels of soya-bean protein, RNA:DNA declined by 18% from 1.88 to 1.54. The contractile protein myosin heavy chain (/mg protein and /g wet weight) and myosin heavy chain-specific mRNA (/mg RNA) were not significantly affected by dietary conditions. Expressed per g wet weight, the decline by 21% of the specific mRNA depended on the total RNA content which decreased with the increase in soya-bean protein. Acid proteinase activity was lowest at the 200 g/kg level, showing a decrease of 23%.(ABSTRACT TRUNCATED AT 250 WORDS)
von der Decken
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A
Wenner-Gren Institute for Experimental Biology, University of Stockholm, Sweden.
Lied
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E
D000818:Animals; D004044:Dietary Proteins / Q000008:administration & dosage*; D004797:Enzyme-Linked Immunosorbent Assay; D005399:Fishes / Q000254:growth & development / Q000378:metabolism*; D009132:Muscles / Q000737:chemistry / Q000378:metabolism*; D009218:Myosins / Q000032:analysis; D013025:Glycine max
D004044:Dietary Proteins; D009218:Myosins