Skeletal muscle growth dynamics and the influence of first-feeding diet in Atlantic cod larvae (Gadus morhua L.).

Dynamics between hypertrophy (increase in cell size) and hyperplasia (increase in cell numbers) of white and red muscle in relation to body size [standard length (SL)], and the influence of the first-feeding diets on muscle growth were investigated in Atlantic cod larvae (Gadus morhua). Cod larvae were fed copepod nauplii or rotifers of different nutritional qualities from 4 to 29 days post hatching (dph), Artemia nauplii from 20 to 40 dph and a formulated diet from 36 to 60 dph. The short period of feeding with cultivated copepod nauplii had a positive effect on both muscle hyperplasia and hypertrophy after the copepod/rotifer phase (19 dph), and a positive long term effect on muscle hypertrophy (60 dph).

Live feed is not a major determinant of the microbiota associated with cod larvae (Gadus morhua).

The gastrointestinal (GI) tract of newly hatched fish is probably colonized by bacteria present in the water, but how environmental and internal factors affect the development of the GI microbiota is poorly understood. In this study, we investigated the effect of diet and of rearing in separate tanks on the cod larval microbiota. Cod larvae were fed three different live feed diets.