Effects of oral administration of dried purslane (Portulaca oleracea) extract on some growth indices, carcass quality and intestinal microbial flora of rainbow trout (Oncorhynchus mykiss) fry

In the present study, the effect of dried purslane (Portulaca oleracea) extract was evaluated on some growth indices, and carcass quality and intestinal microbial flora in rainbow trout (Oncorhynchus mykiss) fry. For this purpose, 600 rainbow trout fry with an average weight of 3.30 ± 0.1 grams in a completely randomized design with 5 levels including 0% (control, T0), 0.5% (T1), 1% (T2), 1.5% (T3), and 2% (T4), dried purslane extract/kg of feed, and three replicates in 15 tanks of plastic 300 liters (40 fish/tank). Sampling of fish in treatments after 60 days of the experiment period was performed randomly. After sampling, some growth indices were measured such as final weight and length, feed conversion ratio (FCR), body weight percentage (BWP), specific growth ratio (SGR), condition factor (CF), survival rate (SR), protein precipitation in the body, the protein efficiency ratio, intestinal microbial flora and carcass quality. The results of this study showed that dried extract of purslane at 1% level increased body weight and reduced feed conversion ratio compared to other treatments (p <0.05).  The survival rate of fry in the treatment of 0.5% increased compared to other treatments (p <0.05). Also, the condition factor decreased significantly in 2% dried purslane extract. The treatments showed that dried purslane extract at 1% level is suitable for improving the growth performance of rainbow trout. The carcass protein content in all treatments increased except 2% dried purslane extract (P <0.05). The amount of carcass fat in all experimental treatments decreased significantly (p <0.05) in the control treatment, especially in the treatment of 1.5% drird purslane extract (P <0.05). The carcass moisture content was respectively treatments of 0.5% and 0% dried purslane extract that were higher than other treatments (p <0.05). Also, the amount of carcass ash in treatments with 1.5% and 2% dried purslane extract was higher than other treatments (p <0.05). The other positive results of dried purslane extract were increased intestinal bacteria in 1% treatment (P <0.05). Overall, the results of this study show that a 1% dried puslane extract in combination with food can be used to improve the growth performance and improve nutritional efficiency in aquatic animals.