EFFECTS OF NUTRITIONAL REGIME ON CORRELATES OF GROWTH-RATE IN JUVENILE ATLANTIC COD (GADUS-MORHUA) - COMPARISON OF MORPHOLOGICAL AND BIOCHEMICAL MEASUREMENTS

The effects of both long-term (35 d of daily feeding, feeding every second day, or starvation) and short-term (up to 15 d of refeeding following starvation) nutritional regimes on morphological (tissue-somatic indices) and biochemical measurements (RNA concentration, RNA/protein ratio, RNA/DNA ratio, and cytochrome c oxidase activity (CCO)) were investigated for a variety of Atlantic cod (Gadus morhua) tissues. Liver-somatic index was the morphological index most sensitive to both the long- and short-term nutritional regimes. The majority of the tissue RNA measurements demonstrated positive linear relationships with growth rate, although stomach, intestine, and white muscle were the most sensitive tissues for all the treatments. Most of the tissues examined also showed positive linear relationships with growth rate, although stomach, intestine, and white muscle were the most sensitive tissues for all the treatments. Most of the tissues examined also showed positive linear relationships between CCO specific activity and long-term growth rate. However, tissue CCO specific activity was relatively insensitive to the short-term alterations in nutritional regime.