WWW.WAS.ORG • WORLD AQUACULTURE • DECEMBER 2017 37 (CONTINUED ON PAGE 38) TABLE 2. Recommended feeding rates of fermented soybeans to shrimp. The daily total quantity should be divided into three to four portions. SHRIMP SIZE (g) FEEDING RATE (PERCENT BODY WEIGHT) 1 – 5 5 – 4 5 – 10 4 – 3 10 – 20 3 – 2 20 – 30 2 – 1 in water quality, production of live feeds that are consumed by shrimp and the pretreatment of SBM to improve its nutritional value and palatability. Copepods are a natural food source of shrimp, containing astaxanthin, amino acids and fatty acids, such as omega-3 fatty acids, that are not found in terrestrial plant-based ingredients, such as soybean meal. Therefore, the consumption of live foods by shrimp is essential, inasmuch as soybean meal is nutritionally inferior to fishmeal in the diets of crustaceans (Taher et al. 2017). In addition to deficiencies in certain nutrients, plant proteins often contain high amounts of antinutritional factors, including phytic acid, non-starch polysaccharides, protease inhibitors and tannins that disrupt nutrient utilization and can impart a bitter taste to the shrimp. It has yet to be determined whether pretreatment reduces antinutritional factors and/or improves the nutritive value of soybean meal. Some species of Bacillus can produce amino acids, lipids or pigments from the degradation of plant proteins (Eaksuree et al. 2016) and reduce some antinutritional factors (Yuan et al. 2017). Shrimp with full intestines have been routinely observed to actively seek out and consume FSY (Fig. 4) and some farmers even insist that shrimp prefer FSY over commercial pellets. To better understand this and potentially optimize the pretreatment method, can be found at Romano (2017) and at www.bioshrimp.com. After the copepod bloom, early post-larvae are stocked at 20/m2, a density that is substantially lower than intensive farms. The exact stocking density depends on pond size, growth rates, water quality and market demand. After stocking, FRB is added daily at 1 ppm throughout the culture cycle to serve two important functions. First, this will create some biofloc to help maintain water quality, but at a much lower scale (< 25 mL/L as measured by an Imhoff cone) than an established biofloc-based system. Second, FRB will support pond zooplankton and act to provide supplemental nutrition to the shrimp. In addition to the post-larvae directly feeding on live feeds, it is believed that the larger and more benthic shrimp consume copepod eggs when they sink to the pond bottom. Once shrimp reach 40-50 g (around 180 days of culture), the crop should be partially harvested to ensure that stocking densities do not become excessive. To create FSY, soybean meal crumble is fermented with additional ingredients in smaller amounts. An example of this formulation is shown in Table 1 and can be done in simple containers (Fig. 3) or in cement mixers. Other farms use variations of this formulation, based on experience and availability of ingredients. For example, fermented soy sauce can substitute for salt and wheat bran can substitute for rice bran. When applying this mixture to ponds, feeding trays should be used to gauge and adjust feeding rates. Table 2 shows a general feeding schedule, but as a rule, underfeeding is preferred to overfeeding to minimize the negative effects of excess FSY decomposing in the pond. Reasons for Success Based on reports from farmers applying this management system, shrimp growth reportedly can be up to 0.5 g/d and survival over 80 percent with no serious disease outbreaks. There are several contributors to the success of this protocol, including improvement FIGURE 3. Fermenting soybean meal with other ingredients to be used as feeds in a black tiger shrimp pond. TABLE 1. Ingredients and quantity to create fermented soybeans. INGREDIENTS AMOUNT Soybean meal (defatted) 5 kg Rice bran 2 kg Wheat bran 2 kg Roasted soybeans 1 kg Calcium carbonate 100 g Fermented soy sauce One tablespoon Probiotic * 1 g Egg 1 Water 20 L * The probiotic can be Bacillus sp. or their hydrolytic enzymes.
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