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United States Department of Agriculture

Agricultural Research Service

Title: Effects of Bovine Growth Hormone (Posilac) on Growth Performance, Body Composition, and Igfbps in Two Strains of Channel Catfish

Authors
item Peterson, Brian
item Small, Brian
item Bosworth, Brian

Submitted to: Aquaculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 14, 2003
Publication Date: March 1, 2004
Citation: Peterson, B.C., Small, B.C., Bosworth, B.G. 2004. Effects of bovine growth hormone (Posilac) on growth performance, body composition, and IGFBPs in two strains of channel catfish. Aquaculture 232:651-663.

Interpretive Summary: Research was conducted to examine the effects of recombinant bovine growth hormone (rbGH; Posilac), on growth rate, feed efficiency, body composition, and insulin-like growth factor binding proteins (IGFBPs) in Norris and NWAC103 strains of channel catfish. Feed consumption increased 15% with rbGH treatment in the Norris strain while a 6% nonsignificant increase in feed consumption was observed in rbGH treated NWAC103 catfish. Compared to sham controls, rbGH increased final weights but no overall improvement in feed conversion ratio (FCR) was observed in NWAC103 fish. In the Norris strain, rbGH increased final weights but no improvement in FCR was observed when compared to sham controls. rbGH treatments increased total length in both strains, but no difference in condition factor, hepatosomatic index, protein or fat was observed. On day 63, levels of approximately 45 kDa IGFBP (catfish-IGFBP-3) were similar between treated and untreated fish in both strains. Results of this study indicate that rbGH increased weight gain through enhanced linear growth and not through changes in the amount of fat or protein in both strains. Similar levels of cf-IGFBP-3 between treated and untreated fish may reflect "steady state" levels of cf-IGFBP-3 in growing fish. Identifying other endogenous growth factor(s) responsible for the observed increase in growth rate will be crucial in our understanding of improving growth in cultured channel catfish.

Technical Abstract: Research was conducted to examine the effects of recombinant bovine growth (rbGH; Posilac), on growth rate, feed efficiency, body composition, and insulin-like growth factor binding proteins (IGFBPs) in Norris and NWAC103 strains of channel catfish. Three hundred and twenty fish from each strain were assigned randomly to four treatments with four replicates each. The treatments were 1) Sham injected control (needle puncture/3 wks); 2) Low (30 mg/g BW/3 wks, Posilac); 3) Medium (60 mg/g BW/3 wks, Posilac); and 4) High (120 mg/g BW/3 wks, Posilac). Fish were reared in 381 tanks supplied with 26.0 degrees Celsius flow-through well water for nine weeks. Fish were fed a 36% CP commercial diet twice each day to apparent satiation. Feed consumption increased (P < 0.05) 15% with rbGH treatment in the Norris strain while a 6% nonsignificant increase in feed consumption was observed in rbGH treated NWAC103 catfish. Compared to sham controls, all treatments (average weight)(Low, Medium, and High) increased final weights (168 +/- 13.2 g vs. 144 +/- 10.0 g), but no overall improvement in feed conversion ratio (FCR) was observed in NWAC103 fish. In the Norris strain, the High treatment increased (P < 0.05) final weight (135 +/- 6.2 g vs. 106 +/- 8.7 g) but no improvement in FCR was observed when compared to sham controls. rbGH treatments increased (P < 0.05) total length in both strains, but no difference in condition factor, hepatosomatic index, or body composition was observed. On day 63, levels of approximately 45 kDa IGFBP (catfish-IGFBP-3) were similar between treated and untreated fish in both strains. Results of this study indicate the Low treatment was as effective in promoting growth as the High treatment in the NWAC103 strain. Results of the body composition analysis suggest the increase in weight gain was not due to an increase in fat deposition. The observed increase in length suggests rbGH enhances linear growth in channel catfish. Similar levels of cf-IGFBP-3 between treated and untreated fish may reflect "steady state" levels of cf-IGFBP-3 in growing fish. Identifying other endogenous growth factor(s) responsible for the observed increase in growth rate will be crucial in our understanding of improving growth in cultured channel catfish.

Last Modified: 4/18/2014
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