February 15-18, 2009 Washington State Convention Center Seattle ...

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EVALUATION OF SOY LECITHIN IN PLANT-BASED DIETS FOR Litopenaeus vannamei
CULTURED IN OUTDOOR TANKS
Timothy C. Morris*, Tzachi M. Samocha, D. Allen Davis, Josh S. Wilkenfeld and Kelsey Holmes
AgriLife Research Mariculture Laboratory
4301 Waldron Rd.
Corpus Christi, TX 78418 USA
tilapiamorris@juno.com
Plant-based feeds present a more environmentally-sustainable alternative to fishmeal-based diets, but require further nutritional
optimization prior to commercial acceptance. Phospholipids (PL) play an important role in maintaining cellular function and
structure. They also enhance cholesterol transport, increase lipid retention, and may facilitate the pelleting process by acting as
a lubricant. Soy lecithin, a primary source for PL, has the potential to improve the lipid component of plant-based feeds. This
study evaluated the response of shrimp to increasing levels of dietary lecithin (0 to 2%) in conjunction with decreasing levels
of fish oils designed to minimize shifts in lipid content of the diets.
The 10-week trial was conducted with juvenile (1.37 ± 0.05 g) Pacific white shrimp, Litopenaeus vannamei, previously conditioned
to a commercial diet (35% crude protein, Rangen, Buhl, Idaho). Shrimp were stocked in a recirculating system
consisting of thirty-six 800-L HDPE tanks (0.65 m 3 water volume) at a density of 26 shrimp/tank (40/m 3 or 31/m 2 ). Water
was recirculated at 1.9 L/min/tank. Naturally-induced primary production was present, aeration was provided by two airstones
(7-10 Lpm/stone), and no external biofiltration was provided. Five plant-based diets were formulated to contain 35%
protein, 6% lipid, and five lecithin levels: 0, 0.25, 0.50, 1.00, and 2.00%. The conditioning feed also served as a reference diet.
Rations were determined based on an assumed growth rate of 1.5 g/wk, an FCR of 1.4, and 100% survival. Feed was offered
three times daily. The study was terminated when shrimp averaged more than 20 g. A one-way ANOVA showed significant
differences between treatments; with average weight, growth, yield, and FCR values ranging from 21.5-22.7 g, 1.9-2.0 g/wk,
0.84-0.90 kg/m 3 , and 1.3-1.4, respectively. Survival was not significantly different between treatments. Results of the present
study indicate a general increase in performance up to 1% inclusion of lecithin.