Oral recombinant bovine somatotropin improves growth performance in rainbow trout (Oncorhynchus mykiss)

  The aim of this research was to evaluate the effects of oral recombinant bovine somatotropin (RBS) ۱% on growth performance of rainbow trout (Oncorhynchus mykiss). ۶۰۰ rainbow trout weighing ۴۶±۱ grams were randomly allotted in two groups including: ۱) the control group and ۲) RBS treated group, each in three replicates. The fish were hand-fed with commercial pellets. The fish received ۲۰۰g RBS ۱% per ۱۰۰kg BW. The administration method of RBS-mixed feed to fish was once a week for ۴ consecutive weeks, totally ۸ times for ۱۲ weeks of rearing periods. At the end of each rearing periods (on day ۲۸, ۵۶, ۸۴) the means of some of growth characteristics were calculated in the control and RBS treated groups. The obtained results in this research demonstrated that there were no significant differences between appearance growth characteristics in the control and RBS treated groups on days ۲۸ and ۵۶ of rearing periods (p> ۰.۰۵). However, there were significant differences between means of whole body weight (p< ۰.۰ ۵), weight gain (p< ۰.۰۵), average daily growth ( p< ۰.۰۵) , total length ( p< ۰.۰۰۱) , and average daily length ( p<۰.۰۵ ) of the control and RBS treated groups on day ۸۴ of rearing period. In the same period, there was greater ۱۱.۲% comparative growth rate in RBS treated group than the control group. Generally, the obtained data showed that oral administration of RBS ۱% can produce a significant increase in the growth rate of rainbow trout weighing ۴۶±۱ grams on day ۸۴ of rearing period.

Keywords:

Oral recombinant bovine somatotropin , Growth performance , Rainbow trout , Oncorhynchus mykiss