Title: Evaluating a quantitative methionine requirement for juvenile Pacific white shrimp Litopenaeus vannamei Authors
Submitted to: Book of Abstracts Aquaculture America
Publication Type: Abstract Only
Publication Acceptance Date: January 9, 2013
Publication Date: February 21, 2013
Citation: Velasquez, A., Rawles, S.D., Cummins, V.C., Thompson, K.R., Webster, C.D. 2013. Evaluating a quantitative methionine requirement for juvenile Pacific white shrimp Litopenaeus vannamei [abstract]. Book of Abstracts Aquaculture America 2013: Strike a Chord for Sustainable Aquaculture, February 21-25, 2013, Nashville, Tennessee. p.1123. Technical Abstract: A 10-wk feeding trial was conducted as a third study (all conducted in our laboratory) to determine a quantitative requirement of juvenile Litopenaeus vannamei for sulfur amino acid methionine. Juvenile shrimp (mean weight 0.61 +/- 0.13 g) were reared in 110-L aquaria in a seawater recirculating system. Eight practical diets (4 replicates each) were formulated to contain the same dry ingredients and crude protein level of 35%. Each diet differed only by having increasing levels of crystalline methionine (0.1 to 1.22% of total diet). Neither cysteine nor lecithin was added to the diets in this feeding trial. Choline chloride was added at 0.03%. Experimental diets were formulated with a mixture of casein-gelatin, wheat flour (WF), and crab meal (CM) as protein sources and supplemented with crystalline amino acids to obtain a balanced amino acid profile except for methionine. To prevent leaching of amino acids, these were further pre-coated with binding agent carboxymethylcellulose. Dietary pH was neutralized with 6 N NaOH to levels ranging from 7.5-8.0. Shrimp were fed diets at a 20-6% of their biomass 5 times daily (07:30, 10:30, 13:30, 16:30; 19:30 h). At harvest, growth parameters were determined including final average weight, percent weight gain, specific growth rate, feed conversion efficiency, and percent survival. Methionine requirement was determined by a saturation kinetics model to analyze a minimum level for optimum growth and a dietary level at which highest growth rate were achieved. Final results from this study are pending and will be obtained upon completion of data interpretation.