عنوان مقاله [English]
Enzymes and food attractants are the ingredients used to improve the nutritional status of fish in recent years. In this experiment, the effect of dietary administration of betaine and Natozim multi-enzyme on growth indices (Weight gain, SGR and FCR) and growth hormone gene expression (GH) in Great sturgeon (Huso huso) were investigated. For this purpose, 126 fish with an average weight of 32±3 gr, were fed diets supplemented with 3 different levels of 0, 1 and 1.5% in combination with 0, 250 and 500 mg/l for 8 weeks. At the end of the feeding trial, growth indices were assessed. RNA extracted from brain a liver, cDNA synthesized using Supreme script RTase kit and Real-time PCR were done using GH an IGF primers. Results showed no significant difference in growth indices and GH and IGF expression gene in fish fed betaine (P>0.05). However, with increasing the amount of Apsozyme multi-enzyme from 250 to 500 mg in the non-betaine condition, there was a significant increase (p < 0.05) in the weight gain, specific growth factor, and growth gene expression, as well as the Food Conversion Rate. The best growth performance indices and growth gene expression were in combination treatments (500 mg of apsazymeand 1 and 1.5% betaine) (p < 0.05). Regarding the results, it seems that the use of apsazymeand betaine can help to improve growth by eliminating the effects of anti-nutrients and attracting fish to foods.