|Rawles, Steven - Steve|
Submitted to: Book of Abstracts World Aquaculture Society
Publication Type: Abstract Only
Publication Acceptance Date: 1/25/2001
Publication Date: 1/25/2001
Citation: Rawles, S.D., Lochmann, R., Bryant, R.J. Amylopectin: amylose ration in semipurified diets influences growth and body composition of sunshine bass morone chrysops m. saxatilis.. Book of Abstracts World Aquaculture Society. 2001. p.278. Interpretive Summary: Starch is natural compound made up of molecular "chains" of the sugar glucose. Starch complexity is determined by the degree of glucose chain branching. In animal feeds, starch complexity can effect growth, liver size, and the accumulation of body fat. Large livers in fish sometimes indicate poor health or nutrition. A 10-week feeding trial was conducted at the HKD Stuttgart National Aquaculture Research Center to determine the effect of changing the ratio of highly-branched starch (amylopectin) to less complex starch (amylose) on the growth of hybrid striped bass fingerlings. Fish were fed semipurified diets containing 25% carbohydrate in which protein, energy, and fat levels were held constant. Carbohydrate in the diets was composed of either glucose, dextrin (acid-treated starch composed of unbranched glucose chains),or corn starch with different ratios of amylopectin and amylose. Growth of fish fed diets containing corn starch of the highest (70%) and lowest (0%) amylose content was not statistically different from that of fish fed the diet with simple starch (dextrin), but was greater than those of fish fed either the diet of intermediate (30%) amylose content or the diet containing glucose. Feed conversions were greatest in fish fed diets with the highest amylose content. In addition, the highest fillet yields were found in fish fed the diet with the highest amylose content. Liver size decreased as starch complexity in the diet increased and was smallest in fish fed the diet containing the greatest amount of complex starch (amylopectin). However,
Technical Abstract: A 10-week feeding trial was conducted to determine the effect of dietary amylopectin:amylose ratio on growth performance of advanced sunshine bass fingerlings (60 g, initial weight). Fish were fed semipurified iso- nitrogenous, isocaloric, isolipidic diets containing 25% carbohydrate. Carbohydrate in the diets was composed of glucose, dextrin, 30% amylo- pectin:70% amylose, 70% amylopectin:30% amylose, or 100% amylopectin:0% amylose. Diets were fed to fish in quadruplicate 60-L tanks (7 fish/tank) connected to a brackish water recirculating culture system with filtration Weight gain of sunshine bass at the end of the trial ranged from 195 to 236% of initial weight and was greater (P < 0.05) for fish fed the diet containing dextrin than for fish fed the diet containing glucose. Weight gains of fish fed diets containing corn starch of the highest (70%) and lowest (0%) amylose content were not statis-tically different from that of fish fed the diet with dextrin, but were significantly greater than those of fish fed either the diet of inter-mediate (30%) amylose content or the diet containing glucose. Feed efficiency ranged from 0.52 to 0.61 and was lower in fish fed the diet containing glucose. Hepatosomatic index decreased with increasing carbohydrate complexity in the diet. Fish fed diets containing complex starch exhibited smaller HSI values than fish fed diets containing glucose or dextrin. Intraperitoneal fat was significantly lower in fish fed diets containing some amylose. The highest mean muscle ratio was found in fish fed the diet with the highest amylose content. These results suggest that feeding diets in which a large portion of the carbohydrate is amylose starch may reduce energy storage in body depots without affecting growth or fillet yield.