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Individually reared female Nile tilapia ( Oreochrornis niloticus ) can grow faster than males
Author(s) -
Schreiber S.,
Focken U.,
Becker K.
Publication year - 1998
Publication title -
journal of applied ichthyology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.392
H-Index - 62
eISSN - 1439-0426
pISSN - 0175-8659
DOI - 10.1111/j.1439-0426.1998.tb00612.x
Subject(s) - biology , nile tilapia , oreochromis , zoology , body weight , tilapia , fish <actinopterygii> , fishery , endocrinology
Summary It has often been claimed that male tilapia appear to grow faster than females, which may be caused either by a sex‐specific physiological growth capacity, female mouth‐brooding or the more aggressive feeding behaviour of males. To test for differences in the physiological growth capacity of both sexes, 45 Oreochromis niloticus were reared individually for 109 days in aquaria or respirometric boxes connected to recirculating systems. During this time, body mass increased from 38.2 ± 6.5 g to 130.9 ± 39.5 g for males and 34.5 ± 5.5 g to 163.2 ± 29.8 g for females. In contrast to results for previous studies on group rearing reported in the literature, body mass gain, metabolic growth rate, feed conversion and productive protein value (PPV) were significantly ( P < 0.05) better for females than for males in our experiment under individual rearing. Energy retention (K 101 ), heat dissipation and non‐utilized energy were also slightly more favorable for females than for males. The superior female growth performance in this study is due to lower metabolic costs, i.e. oxygen consumption is lower for females than for males. The growth superiority of males reported in other studies is therefore probably caused by behavioral rather than physiological factors.