Preliminary investigations of the physiological adjustments associated with compensatory growth in juvenile brook charr (Salvelinus fontinalis)

ABSTRACT

Various physiological factors suspected to govern or be influenced by growth or feed intake of brook charr (80–120 g) were examined under long and short fasting periods during the year. A control (fed to satiation) was included. During winter, fasting (14 and 28 days) followed by refeeding led to a complete compensation. In summer, longer fasting (39 and 61 days) was applied to exacerbate the physiological response. Compensatory growth was observed in the restricted groups, and overall, adjustments/variations in growth and physiological indicators (feed conversion ratio, organosomatic index, enzymatic activities [CS, TRY, CHY]) were more pronounced. Degree of compensation reached was positively related to the deprivation duration. The summer experiment clearly suggests that compensatory growth takes place in two stages after a long starvation period (61 days): (1) restoration of the digestive system (PSI) followed by enzyme activities (trypsin and chymotrypsin) and (2) rebuilding of somatic tissues.

KEYWORDS:

• Brook charr
• catch-up growth
• enzymes
• feed conversion ratio
• food deprivation
• organosomatic indexes
• Salvelinus fontinalis

Acknowledgments

The authors would like to thank the staff from Aquaculture Gaspésie, Inc., for their collaboration and general technical assistance rearing the fish.

Funding

Research funds used to conduct this experiment were granted to Pierre U. Blier and Nathalie R. Le François by SORDAC, ACRDP-DFO, and PARI-CRSNG.

Notes

1. See sunrise/sunset calculator at www.nrc-cnrc.gc.ca/eng/services/sunrise/index.html.