Optimization Of Plant Based Diets For Pacific White Shrimp (Litopenaeus vannamei)
Type of Degreedissertation
Fisheries and Allied Aquacultures
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Supplies of marine ingredients are finite and their prices are high, fluctuating and the price is expected to continue to rise. The aquaculture industry has long recognized that the viable utilization of plant feedstuffs formulated in aquafeeds is essential for the sustainable development of aquaculture. Soybean meal is regarded as economical and nutritious feedstuffs with moderate crude protein content and a reasonably balanced amino acid profile, which can function as the primary protein source in practical shrimp feeds. To facilitate the continued development of plant based feed formulations, a series of studies were conducted to determine the impact of utilizing high level of soybean meal on feed formulations. Traditional sources of soybean meal have certain characteristics including the presence of several antinutritional factors and a high carbohydrate concentration which may limit the quantity that can be used in the aquafeeds. New strains of selectively bred non-genetically modified (non-GM) soybeans can reduce level of trypsin inhibitors, oligosaccharides, and/or enhance protein levels. The first study evaluated the efficacy of six new varieties of soybean meal in practical feed formulations by evaluating the biological response of shrimp in terms of growth and in vivo digestibility in high soy feed formulations. Results of this study demonstrated that new lines of soybean could be used to improve growth and digestibility coefficients in shrimp feed and the commercialization of nutritionally improved soybean should be encouraged. Soybean meal is an inexpensive ingredient. To help reduce the shrimp feed cost, soybean meal can be replaced with other less expensive ingredients such as Dried Distillers Grains with Solubles (DDGS) from sorghum (S-DDGS). Furthermore, the use of pelleted or extruded feeds may result in shifts in performance as the processing conditions are considerably different. Hence, the second component of this research was to evaluate the biological response to practical diets containing grade level of S-DDGS in extruded and pelleted shrimp feeds. Results of this study revealed that S-DDGS can be included in practical diets without negative effects on growth, survival, and feed conversation ratio (FCR). Hence the use of S-DDGS (up to 40%) should be encouraged as an alternative protein in shrimp feed formulations. As fishmeal is replaced with plant based protein sources, there are a number of nutrients that will change, including minerals such as copper, zinc and iron etc. Copper is essential for the survival of all organisms, including shrimp. Three trials in this study were conducted to evaluate growth and tissues response to two copper sources (copper sulfate pentahydrate and tri-basic copper chloride) for L. vannamei in a practical feed formulation. Results in this study demonstrated that tri-basic copper chloride (TBCC) was a safe, effective and highly available source of copper in shrimp diet formulations for L. vannamei. Overall, results from these studies reveal that the use of new varieties of soybean meal should be encouraged for use in shrimp feed formulations. Meanwhile, it also indicated the use of high level of soybean meal as main protein source in combination with S-DDGS in formulated diets formulation as long as essential nutrients in diets are properly balanced to meet shrimp nutritional requirements. In addition, TBCC could be used as alternative copper source in shrimp diet formulations for L. vannamei.