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

RESPONSE OF PACIFIC WHITE SHRIMP, Litopenaeus vannamei, TO VARYING RATIOS
OF SOYBEAN OIL AND FISH OIL IN PLANT-BASED DIETS OFFERED TO SHRIMP
CULTURED IN OUTDOOR TANKS
Timothy C. Morris*, Tzachi M. Samocha, D. Allen Davis, Josh Wilkenfeld and Kelsey Holmes
Texas 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. Fishmeal substitution strategies have been used successfully in conjunction with
marine oils. However, when all marine fish oil sources are removed, shrimp performances declines due to a lack of essential
fatty acids. Previous experiments have demonstrated that supplementing plant oils with essential fatty acids can be done, but is
quite expensive. A more economical alternative is to minimize the levels of marine oils by diluting them with other oils such
as soybean oil. The objective of this study was to evaluate the response of shrimp to diets with decreasing levels of fish oil as
replaced by soybean oil.
A 10-week trial was conducted with Litopenaeus vannamei juveniles (1.37 ± 0.05 g), previously conditioned to a commercial
shrimp diet (35% CP, Rangen, Buhl, Idaho). Shrimp were stocked in a recirculating system consisting of forty 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 and
aeration was provided by two airstones (7-10 Lpm/stone). Naturally-induced primary production was present and no external
biofiltration was provided. The study evaluated a total of six diets with five replicates per treatment. Diets containing no fishmeal
and targeted crude protein levels of 35% were formulated with soy:fish oil ratios of (100:0, 50:50, 60:40, 70:30, 80:20,
and 90:10) and 6% lipid. A 35% CP diet (Rangen Inc., Buhl, Idaho) served as a reference diet. Feed was offered three times
daily. Rations were determined based on an assumed growth rate of 1.5 g/wk, an FCR of 1.4, and 100% survival. The study
was terminated when shrimp achieved a mean final weight above 20 g. This paper will discuss the results from this study.
231