Growth Performance of Giant Gourami Osphronemous goramy Juvenile to Recombinant Growth Hormone by Immersion and Different Aquarium-rearing Period.
Kinerja Pertumbuhan Benih Ikan Gurame yang Diberi Perendaman Hormon Pertumbuhan Rekombinan dengan Masa Pemeliharaan Berbeda di Akuarium.
Abstract
Slow growth of giant gourami became the main problem in cultivation of this commodity. Long rearing period surely would increase the risk and cost of production. Therefore, a technology is required to enhance growth rate of giant gourami. The aims of this experiment were to analyse growth performance of giant gourami to the recombinant giant gourami growth hormone (rOgGH) immersion at a dose of 120 mg/L for 60 minutes at juvenile stage and to evaluate the proper aquarium-rearing period. After immersed, fish were reared in aquarium for 2 weeks, 3 weeks and 4 weeks before moved to fish pond (aquarium-rearing period became the second factor on this experiment, in term to design a proper method to apply this technology). There were 3 replications for every treatment. RT-PCR analysis showed that IGF-I mRNA expression level increased just after rOgGH immersion about 208,3% compared with control. However, lipase analysis showed no differences between treated fish and control fish that is 0,055 unit/minute.g body weight and 0,053 unit/minute.g body weight for each group. Furthermore, treatment of rOgGH also altered the utilization of dietary and stored lipid, protein and carbohydrates. The results showed significant differences (P<0,05) for nutrient retention between treated fish and control fish. Fish that immersed by rOgGH had higher fat retention (15,92±0,37%) if compared with the control BSA fish (6,52±0,38%). Immersion treatment with rOgGH also had a higher protein retention that was 23,58±2,33% compared with BSA control fish 19,75±1,00%. Immersion treatment with rOgGH had a lower carbohydrate retention that was 2,86±0,21% if compared with BSA control 10,63±0,92%. Observation to feed efficiency value showed that immersion in rOgGH had no statistically significant affect (P>0,05) compared with BSA control for 3 types of feed. For tubifex worms, the feed efficiency value that reached was 14,8±5,6% (rOgGH) and 12,7±5,0% (BSA). So that crumble feed, 51,6±17,8% (rOgGH) and 41,9±13,6% (BSA), for small feed (2mm) 66,8±9,0% (rOgGH) and 54,8±10,0% (BSA). Treatment that gave a significant affect was aquarium-rearing period, it showed that fish which reared in aquarium for 2 weeks had a higher feed efficiency value for tubivex worm and crumble feed that were ,7±2,8% and 60,5±7% if compared with fish which reared in aquarium for 3 and 4 weeks with efficiency value for each were 15,6±2,1% and 7,9±4,4% for tubifex worms and 30,7±5,0% and 49,0±16,5% for crumble feed. Growth acceleration were expected in this immersion treatment, but results showed that there were no differences between rOgGH treated fish and BSA control fish (8,7±0,3% and 8,4±0,3%). Aquarium-rearing period seemed to be the effecting-factor which gave significant affect (P<0,05) to fish growth, it showed that fish that reared in aquarium for 2 weeks had a faster growth that was 8,7±0,2% if compared with fish that reared in aquarium for 3 and 4 weeks (8,3±0,1% and 8,6±0,5% for each group). Results also showed that immersion in rOgGH had no significant affect (P>0,05) if compared with BSA control for survival rate (58,9±17,9% and 57,9±14,6% for each group). Aquarium-rearing period seemed to have significant affect (P<0,05) for survival rate which fish that reared in aquarium for 2 weeks had a higher survival rate (75,5±10,2%) if compared with fish that reared for 3 and 4 weeks (55,4±5,8% and 44,4±11,0% for each group). By the results it was suggested that immersion in rOgGH with dose at 120 mg/L once at the early rearing-time could increase the IGF-I expression level and influences metabolic pathways towards higher use of carbohydrates for energy production and lipid synthesis, and increasing utilization of lipids and proteins for retention. Results also showed that giant gourami juvenile could be reared in aquarium for 2 weeks after treatment (16 days after first feeding) and then moved to fish pond for next rearing stage.
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