تاثير روتيفر آب شيرين غني شده با ويتامين C برشاخصهاي رشدلاروتاسماهي ايراني (Acipenser persicus)

ماهيان خاوياري از قديمي ترين مهره دارن بوده و از ديدگاه تكاملي نسبت به ماهيان استخواني قدمت بيشتري دارند(Gaumnitz et al.,2001). تاس ماهي ايراني گونه بومي كشورمان است كه ا ز نظر ميزان تفريخ بالاترين نرخ را داشته و سهم بسيار بالايي از تركيب رهاسازي مراكز تكثير شيلاتي راتشكيل ميدهد (سالنامه آماري شيلات، 1391). متاسفانه اين گونه درصد تلفات لاروي بالا يي در روزهاي نخست تغذيه و در هنگام رها سازي به دريا دارا ميباشد. بنابر اين به منظور بهره برداري مداوم از ذخاير تاسماهيان يافتن راه حلهايي براي افزايش بازماندگي، ازدياد نسل و بهبود كارايي تكثير و پرورش ضروري بنظر مي رسد(Burtsev et al., 2001).

Acipenser persicus is the most important sturgeon species in the south Caspian Sea, showing high mortality during larval culture. The aim of this study was to use the freshwater rotifer, Brachionus calyciflorus to feed A. persicus larvae to improve survival rates and enhance resistance. Three experimental treatments were used in this study; Treatment 1, similar to the feeding protocol of the hatchery was initially fed decapsulated cysts of artemia and then fed daphnia; Treatment 2, was fed a mixed diet of decapsulated artemia cysts, daphnia and freshwater rotifers and Treatment 3, was fed freshwater rotifers enriched with vitamin C (ascorbic acid 6- palmitate). A total of 45 larvae were stocked in each experimental tank (100 l capacity) filled with 30 l of water. Three replicates were used for each experimental group. Larvae were fed at the rate of 30% of body weight per day for 8 days. Mean dissolved oxygen, pH and water temperature throughout the experimental period were 9.58±0.2 mg/l, 8.5±0.1 and 22.5±0.5 ?C, respectively. Results showed significant differences in specific growth rate (SGR), percentage weight gain (WG), feed conversion ratio (FCR), and condition factor (CF) of experiment treatment 1 and treatment 3 and survival ratio were significantly different among treatment 3 and other treatments .This study demonstrated that Brachionus calyciflorus is a suitable live food for larval feeding.