The dentex (Dentex dentex L.) is a fast-growing sparid which represents a possible candidate forMediterranean mariculture. As the basic nutrient requirements of this species are unknown, twofeeding trials were carried out to identify suitable protein and lipid (energy) levels to be used informulating practical diets for dentex. The experiments used groups of 30 specimens (each fishweighing 17 or 20.7 g) which were kept in 12 flow-through 160 1 tanks supplied with seawater at 2 1min-’ (temperature 205 1°C; salinity 33 ppt). An initial 4-week trial was conducted to obtain apreliminary estimate of the optimal protein level. Triplicate groups were fed four practical diets withincreasing levels of protein (44.3,49.3, 55.7 and 58.9% dry matter (DM), over 90% of which wassupplied by white fish meal) and a constant lipid content ( 17.3% DM; mostly supplied by fish lipids)to satiation. An analysis of the nutrient-weight gain relationship indicated that the optimal dietaryprotein level was 49.3% DM. In a second 60 day experiment, duplicate groups of fish were fed sixdiets with three protein levels (44.4,49.5 and 55.8% DM) and two lipid contents ( 12.0 and 17.3%DM) within each protein level, nearly to satiation. Growth performance was lowest in fish given dietscontaining 44.4 or 49.5% protein and 12% lipid and was improved (P<O.O5) either with dietssupplying 55.8% protein (regardless of dietary lipid) or 49.3% protein and 17.4% lipid. The resultsobserved in the second trial suggest that when protein efficiency or retention are considered evendietary levels of 44.3% protein and 17.2% lipid (i.e. 24.3 g protein k.-’ calculated available energy)could be assumed as suitable levels for formulating practical diets for this species, providing highquality fish meal and oil are used.
|Anno di pubblicazione:||1996|
|Titolo:||Growth response of juvenile dentex (Dentex dentex L.) to varying protein level and protein to lipid ratio in practical diets|
|Autori:||E. Tibaldi; P. Beraldo; L.A. Volpelli; M. Pinosa|
|Appare nelle tipologie:||Articolo su rivista|
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