Changes in Lipid Profiles in Muscle of Farmed shi drum (Umbrina cirrosa) after Starvation and re-feeding 
Suárez, M.D.1, Sáez, M.I.1, Guil-Guerrero, J.L.2, Arizcun, M.3, Hidalgo, M.C. 4, Morales, A.E. 4, Abellán, E.3 and Cardenete, G.4
1Animal Production Division. 2Food Technology Division. 1,2Universidad de Almería, 04120 Almería, Spain. 3 Planta Cultivos Marinos. Instituto Español de Oceanografía. Ctra. De la Azohía, s/n. Puerto de Mazarrón. Murcia  (Spain). 4 Dpto. de Zoología. Facultad de Ciencias. Universidad de Granada.  18071 Granada (Spain).

Starvation is a usual strategy in aquaculture, in which lipid are metabolized, having a beneficial effect on the textural characteristics, however, an excessively prolonged fasting may negatively impact both on their performance parameters such as nutritional composition. After starvation fish are known to show greater growth rates than other fishes normally fed.
In this work, the influence of a 30-days starvation period followed by a 30-days re-feeding period (ad-libitum and paired) on biometric parameters and muscle lipid composition of the shi drum (Umbrina cirrosa) was studied. 
It has been noted that fasting has adversely influenced most of the biometric parameters except fillet yield, which relates muscle weight to the total weight of the fish, indicating significantly higher lipid depletion in visceral area than in the muscle. In fact, shi drum is a lean fish, being the muscle lipid content low (1.87 and 1.33 g/100 g in fed and fasted fish respectively) when comparing with other cultured fish species.
Clear modifications in muscle fatty acid profiles were found as result of the starvation, in which was noticeable a decreasing of MUFA and n-6 PUFA while n-3 PUFA content improves, leading to a n-3/n-6 ratio modification.
Also is noticeable that fish re-fed ad libitum have recovered the muscle, digestive and total body weight. However, in fish re-fed paired weight parameters were lower than in control fish. On the other hand, muscle lipid content has remained at significantly lower values than control regardless re-feeding method (1.49 and 1.43 g/100 g in ad libitum and paired respectively), however, fatty acid profiles were significantly modified, showing similar proportions to control fishes and without differences for both re-feeding methods.
Proyecto de Investigación 15275/PI/10 de la Fundación Séneca, C.A. de Murcia