The use of Daphnia magna and Artemia nauplii in the early feeding of Acipenser guldenstaedtii Brandt and Ratzeburg, 1833 larvae

A 28-day feeding trial was conducted on the A. guldenstaedtii larvae during the early stages of active feeding, using three live foods, namely Daphnia magna, Artemia urmiana and a mixture of both (Daphnia 50% w/w and Artemia50% w/w) with a feeding frequency of 6 times per day. The healthy larvae of A. guldenstaedtii were provided from the sturgeon center of Marjanii. Having three replicates (100 fish per tank), the fish larvae in three treatments (A, D and D) were scheduled and fed based on 30 percent of the body weight in a day by Artemia urmiana nauplii, Daphnia sp. And a mixture of both, respectively. The initial mean body weight of fish larvae was 35.332.50 mg and its density was 2 individuals per liter. This experiment was conducted in a completely randomized design. The fish were weighed individually at the beginning and end of the experiment. The proximate composition of the fish samples (the beginning and end of the experiment), Artemia nauplii, Daphnia and a mixture of them were determined. Maximum protein retention efficiency (72.29%), lipid retention efficiency (14.61%) and energy retention efficiency (44.81%) were obtained in treatments D (fish larvae fed with a mixture of Artemia nauplii and Daphnia), while the minimum of protein efficiency ratio (6.18) and energy efficiency ratio were showed in treatments of D and A, respectively. The results of the present observations demonstrated that the exploitation ability of A. guldenstaedtii larvae in using live food was different.