38 SEPTEMBER 2019 • WORLD AQUACULTURE • WWW.WAS.ORG absence of feed in the trays, the next feeding dose can be adjusted by increasing, decreasing or maintaining the feeding dose. In the review of feeding trays, feeders can also evaluate the presence of diseased or dead shrimp and the amount of molts present. In recent years, broadcasting feed multiple times (>6) per day is becoming more widely used and have been one of the most important transitions in shrimp farming in recent years. Shrimp producers are becoming convinced that investment in automatic feeders can improve growth rate, reduce feed conversion ratio and reduce the time necessary to reach harvest size (Table 1). Automatic timed feeders are designed to provide feeding doses according to a schedule established with software or in a specific way according to the experience of each shrimp farmer. The schedule allows flexibility in varying the dosage (quantity), frequency (times per day) and supply schedule of feed. Automatic timed feeding also uses two or three feeding trays located in the feed supply radius. Additional equipment may include oxygen and temperature sensors. Automatic acoustic feeders are designed to provide food according to the sound generated by the “chewing” of feed by shrimp. The sound is perceived by an acoustic sensor (hydrophone) that is linked to computer software that controls the quantity and frequency of feeding. Acoustic feeding systems often include dissolved oxygen and temperature sensors. In the first results with implementation of multi-feeding and automatic feeding, the production variable that is reduced considerably is FCR. In traditional broadcast feeding less than 6 times/day, FCR was 1.8. With feeding multiple times per day, FCR is reduced to 1.7. With timed automatic feeding, FCR was 1.5 and with acoustic feeding was 1.4. The complex situation that the shrimp industry is currently experiencing due to the drop in market prices is leading to the implementation of new production techniques and methodologies that ensure reductions in the production cost of shrimp. Various indicators are used to measure technical efficiency in shrimp farming. These include: • Cost per weight of shrimp produced is the cost of producing a pound of shrimp of a given size (US$/lb). • Productive Efficiency Index (PEI) is the product of weekly growth rate by survival, divided by the Feed Conversion Ratio (FCR). A higher numerical value reflects better PEI. • Economic performance is the production utility that is generated per area of production per unit time (US$/ha per d). • Financial indicators, including earnings before interest, taxes, depreciation, and amortization (EBITDA), return on equity (ROE) and Internal Rate or Return (IRR). Multi-feeding and Automatic Feeding The cost of feeding in shrimp production represents approximately 50 percent of production costs. Therefore, it is extremely important to implement feeding strategies, such as automatic feeding, that result in reduced feed conversion ratio (FCR) and greater growth rate in fewer days of culture, to be more competitive. Conventional feeding is done manually by applying a percentage of the total shrimp biomass in the pond as a function of shrimp size. Workers responsible for feeding use boats filled with feed and broadcast feed as they traverse the pond. Feed is usually applied one to three times daily. Workers also add some feed to trays to evaluate feeding response. Based on the relative presence or Implementation of Feeding Strategies to Improve Technical Efficiency in Shrimp Farming Máximo Quispe Chau TABLE 1. Productive results achieved in 2017 (second semester) in Ecuador, for stocking from nurseries at densities of 11-13/m2. Feed management n Harvest Density FCR Survival Growth Days Biomass weight (g) (#/m2) (%) rate (g/wk) (kg/ha) Acoustic feeder 59 20.9 13.1 1.43 61.3 1.39 105 1,634 Timer feeder 73 19.9 13.1 1.53 66.8 1.31 105 1,721 Multi-feeding (≥6 times/d) 145 19.5 12.6 1.70 64.8 1.34 101 1,582 Broadcast feeding (<6 times/d) 275 20.9 11.8 1.78 56.1 1.34 112 1,379 Multi-feeding (≥6 times/day): Broadcast feeding manually or with a backpack in a specific area of the pond. Broadcast feeding (<6 times/day: Traditional broadcast feeding or with use of feeding trays. n: Number of ponds analyzed.
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