Effects of recombinant bovine somatotropin on growth and abundance of mRNA for IGF-I and IGF-II in channel catfish (Ictalurus punctatus).

摘要: Research was conducted to examine growth rates, circulating concentrations of IGF-I, and mRNA abundance levels IGF-I IGF-II in channel catfish (Ictalurus punctatus) given recombinant bovine ST (rbST; Posilac, Monsanto Co., St. Louis MO). In the first study, juvenile (5.5 +/- 0.5 g) were randomly assigned one three treatments: 1) sham-injected control (one needle puncture per week); 2) rbST (30 microg x g BW(-1) wk(-1); Posilac); 3) nonhandled (control). At end 6-wk fish weighed, measured for length, G:F determined. Compared with sham treatments, rbST-treated had 48% greater final BW, 14% total 52% (P < 0.001). second (41.1 1.5 two or rbST. Eight treatment sampled on d 0, 1, 2, 7, 14, 21 blood, muscle, liver. Relative expression determined by real-time PCR plasma using a validated fluoroimmunoassay. Circulating increased (37.9 5.5 vs. 22.0 6.6 ng/mL; P 0.05) rbST-injected compared controls 14. Liver 4.3-and 14.4-fold, respectively, 1 0.05); however, liver did not differ from 21. Abundance muscle throughout study. Results study demonstrated that improves performance catfish. showed growth-promoting effects mediated muscle. Instead, results suggest promotes stimulating release, possibly through its direct effect local tissues synthesize IGF-I. The changes support role regulation