COST-EFFICIENT REPLACEMENT OF ESSENTIAL LIPIDS (CHOLESTEROL, n-3 HUFA AND PHOSPHOLIPIDS) IN PRACTICAL GROW OUT DIETS FOR WHITE SHRIMP Penaeus vannamei USING DIFFERENT SOURCES OF PURIFIED BILE SALTS

Alexander van Halteren*, Sam Ceulemans, Allen (Ming-Hsun) Wu and Peter Coutteau
 
Nutriad International NV, Dendermonde, Belgium - a.vanhalteren@nutriad.com

The increased cost and/or limited availability of essential fat sources for shrimp feed, particularly fish oil, cholesterol and/or lecithin, have become a challenge for shrimp nutritionists during recent years. The current study aimed at determining the potential of different sources of bile salts as partial replacement of cholesterol, n-3 HUFA and phospholipids in practical grow out diets for the white shrimp (Penaeus vannamei). Although the use of bile salts in shrimp nutrition has been empirically documented, it is not known to what extent the efficacy of bile salts is affected by its origin, composition or molecular structure.

Five diets were processed using a pilot scale pelletizer (pre-conditioning during 2 min @ 90°C mash temperature; die 2 mm x 40 mm; post- conditioning @ 90 °C, 20 min). A positive control diet (CON HI) and a negative control diet (CON LO)  only differed in terms of levels of essential lipids by reducing the level of fish oil (-0.5%), reducing the level of lecithin (-0.5%) and eliminating the cholesterol supplement in CON LO. Three treatments were designed as follows: LO/LIPO : CON LO diet supplemented with a mixture of bile salts from bovine origin (LIPOGEST, Nutriad);  LO/CHA : CON LO diet supplemented with purified cholic acid from bovine origin;   LO/PG: CON LO diet supplemented with a mixture of bile salts from pig origin.

CON LO versus CON HI showed lower growth (g/wk : -14%), increased feed conversion ratio (FCR : +16%) and lower protein efficiency ratio (PER : -14%), indicating that growth and feed utilization were negatively affected by the reduction of the essential lipids. Supplementation of bile salts to the CON LO diet improved growth and feed conversion, which no longer were significantly different compared to the positive control group CON HI. The supplementation of bile salts significantly improved PER, confirming that the dietary energy was utilised more efficiently, sparing more protein for tissue growth and enhancing the uptake of the dietary lipids. Although the different sources of bile salts did not result in significant differences, the addition of purified cholic acid and the bile salts from bovine origin showed better performance in terms of growth (7-11%), FCR (4-5%) and PER (6%) compared to the bile salts sourced from pigs.