Growth yield, carcass traits, biochemical and non- specific immune parameters in grey mullet, Mugil cephalus Linnaeus, 1758 under cyclic starvation and L- carnitine supplementation

The main objective for the present research was to assess the effect of cyclic starvation and L- carnitine supplementation on growth (body final weight, hepatosomatic index (HSI), daily growth rate (DGI), feed conversion ratio (FCR) and voluntary feed intake (VFI)), body composition (crude protein, crude lipid, ash and moisture), biochemical (plasma total protein, glucose, cholesterol, triglyceride and liver glycogen) and immunological (lysozyme activity) parameters in grey mullet. To satisfy the foregoing end, a total of 240 fish with an average weight of 1.33±0.26 g were randomly divided into four groups (three replicates, 20 fish per tank). Two groups were fed on a daily basis and the other two ones were kept starved for 7 days once in 2 weeks. Two groups were fed a carnitine free basal diet and the remaining were fed a diet with 800 mg carnitine kg-1. Cyclic starvation led to significantly decreased body final weight, DGI, FCR, total protein, triglyceride and cholesterol. On the contrary, no significant differences were found across all groups for FCR, HSI, glucose, liver glycogen and lysozyme concentrations. At the same time, the combined effects of cyclic starvation and carnitine supplementation were manifested in DGI and VFI parameters. In light of the above results, it can be noted that in both feeding regimes, growth, feed utilization and carcass quality in grey mullet increased upon adding 800 mg carnitine kg-1 diet.