1Research Centre on Animal Welfare - RECAW, UNESP, Campus Experimental do Litoral Paulista, Unidade São Vicente, Pça. Infante D. Henrique s/nº, São Vicente 11330-900, SP, Brazil.
2Instituto de Neurociencias, CSIC-UMH, Unidad de Neurobiología del Desarrollo, Campus de Sant Joan, Apto 18, 03550 Sant Joan d'Alacant, Alicante, Spain.
3Departamento de Fisiologia, Instituto de Biociências, UNESP, Rubião Jr. s/n, Botucatu 18618-000, SP, Brazil.
*Corresponding author: E-mail: deliciohc@yahoo.com.br
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We tested the correlation between growth rate before and after a food deprivation phase in twelve single held Nile tilapias, Oreochromis niloticus. The experiment was divided into three phases: before food deprivation (phase 1: 15 d), food deprivation (phase 2: 12 d) and refeeding (phase 3: 15 d). The specific growth rate - SGR, food conversion efficiency - FCE and feed ingestion increased significantly during phase 3. Positive and significant correlations were found either to SGR or to feed ingestion between Phase 1 and 3 but not for FCE. The SGR on phase 3, moreover, were positively correlated to FCE and feed ingestion, while on phase 1 SGR was positively correlated to FCE only. Thus, high pre-fasting SGR or feed ingestion reflects in likewise high post-fasting SGR or feed ingestion values. Moreover, since SGR and FCE are correlated to each other in both phase 1 and 3, but phase 3 SGR is also correlated to feed ingestion; we could suppose that hyperphagic behaviour could be the main compensatory mechanism. Accordingly, we suggest that a fish with an elevated growth performance shall display a proportionally raised post-fasting growth response in order to normalize its predetermined growth trajectory and resume its normal growth rate.
Growth, food deprivation, fish, Nile tilapia, Oreochromis niloticus
