Demonstration of alternative feeds for the Pacific white shrimp, Litopenaeus vannamei, reared in low salinity waters of west Alabama

AbstractThe replacement of marine proteins with vegetableproteins orterrestrialanimalbyproductsinaquacul-ture diets has been gaining momentum. This studyexamines the viability of replacing ¢sh meal inshrimp production diets with alternative proteinsources (combinations of vegetable proteins) in in-land low salinity waters of west Alabama. The testdiets were formulated to contain 36% protein and8% lipid.Thebasaldietcontained10% ¢sh meal.The¢sh meal was then replaced (on a weight to weightbasis) with poultry meal (PM), pea meal or distiller’sdried grain with solubles (DDGS). Two separate ex-periments (laboratory trial and farm trial) were de-vised to test the e⁄cacy of the diets for Litopenaeusvannamei reared in low salinity waters. The labora-tory trial was conducted at the E.W. Shell FisheriesResearchStationinAuburn,Alabama,USA,whereasthefarmtrialexaminedthesamedietsinanoutdoor£ow-throughsystematalowsalinityshrimpfarm inwest Alabama. Results indicate no signi¢cant diier-encesinshrimpgrowth,weightgain,survivalorfeedconversion ratio among dietary treatments, suggest-ing that PM, pea meal and DDGS can serve as alter-natives to ¢sh meal as a protein source for shrimpreared in lowsalinityenvironments.Keywords: poultry meal, distiller’s dried grainwithsolubles,peameal,lowsalinity,¢shmeal,Lito-penaeusvannameiIntroductionFarmers of the Paci¢c white shrimp Litopenaeus van-nameiin inland lowsalinity wellwaters (LSWW) arefaced with the challenge of rearing animals in lessthan ideal environments (Saoud, Davis & Rouse2003; Roy, Davis, Saoud & Henry 2007a,b). Depend-ingontheirsource,inlandLSWWavailabletocultureshrimp can be of varied ionic composition and sali-nity (Boyd & Thunjai 2003; Saoud et al. 2003). Ionicimbalances, which are often found in LSWW, cangenerallybe solvedthroughadditionsof speci¢c ions(e.g. K and Mg) to culture water (McGraw & Scarpa2003; Roy etal.2007a).CommercialfarmersutilizinginlandLSWWare mitigating theproblemby increas-ing levels of Kand Mg in their pond waters throughthe addition of muriate of potash and/or KMag(McNevin, Boyd, Silapajarn & Silapajarn 2004). Un-fortunately,addinglargeamountsofagriculturalfer-tilizers to ponds is an additional expense to inlandfarmers. Increased production costs, competitionfromforeignmarketsandtheincreasingcostofdieselfuelareadditional burdens onfarmers.The cost of feed generallyaccounts for 50^60% oftotal production costs and, thus, west Alabamashrimpfarmers are interested in reducing feed costs.One strategy to reduce feed costs is by reduction in¢sh meal with alternative plant and animal proteinsources.Fishmealis consideredamongthemostsui-table protein sources for shrimp feeds. In spite of itsimportance, a considerable reduction in the use of¢sh meal is expected in the near future. Among thechief concerns include limited availability, variablesupply and cost. Given the growing demand by ani-mal production industries for ¢sh meal and its lim-ited supply, prices are likely to continue to increase,therefore, restraining future use as the main proteinsource in shrimp feeds. Likewise, emerging environ-mental and safety issues associated with the use of