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Indexed/Abstracted in: EMBASE, Science Citation Index Expanded (SciSearch), Scopus
Impact Factor 0,246
Online ISSN 1827-160X
Guillén I. 1, Estrada M. P. 1, Morales R. 1, Melamed P. 2, De La Fuente J. 1
1 Mammalian Cell Genetics Division, Centro de Ingeniería Genética y Biotecnología, Havana, Cuba;
2 Tel Aviv University, Department of Zoology, Tel Aviv, Israel
Serum growth hormone (GH), prolactin (PRL) concentrations and GH and insulin-like growth factor (IGF) mRNA levels were followed in growing tilapia (O. aureus) from hatching to juvenile stages under normal husbandry conditions and under natural conditions of temperature and photoperiod, water oxygen content and water temperature. The increment in body length and weight showed biphasic kinetics with a slow curve in the initial stages of growth (up to 10 g of weight) and an elevation in months 6-8 of life with an increase in the body weight from 10 to over 100 g. Circulating serum GH and PRL levels and GH and IGF mRNA levels showed a pulsatile pattern, consistent with the induction of IGF synthesis by GH and the existence of a negative feedback of IGF on GH expression in tilapia. Furthermore, low GH serum levels generally correlated with a higher relative condition factor of the fish. Our results suggest that low changing GH circulating levels are sufficient to sustain growth in early stages of development in tilapia.