博士 / 國立臺灣海洋大學 / 水產養殖學系 / 98 / Yucca schidigera also known as the Mojave yucca is a plant native to the southwestern USA and Mexico. This yucca plant extract (YUPE) has been used successfully in the livestock industry to control ammonia accumulation, ammonia concentration and fecal odor in animal excreta. Its application in aquaculture is very promising although the research done up to date has been limited. Those studies have been aimed at water treatment to reduce ammonia, and to enhance the nitrogen/protein metabolism for reduction of ammonia excretion in fish only. Therefore this study aims to provide a better understanding of the applications of YUPE in shrimp culture.
As a first step, in chapters 3 and 4 the potential and effectiveness of YUPE for ammonia reduction in freshwater and seawater, respectively, was investigated. A concentration-response experiment was conducted to determine the effect of different concentrations of YUPE at 0, 18, 36, 72 and 108 mg L-1 on total ammonia nitrogen (TAN) at 0, 1, 3 and 9 mg L-1. The effectiveness analysis showed that at higher YUPE concentrations, higher TAN reduction was observed. Increase in elapsed time also increased TAN reduction. TAN reduction was highest in the first 12-24 h, and decreased thereafter presumably due to exhaustion of YUPE’s efficacy. An empirical model involving TAN, YUPE concentration and time was successfully constructed with high R2. Practical applications of this model on ammonia management strategies were formulated and exemplified for Nile tilapia Oreochromis niloticus and for tiger prawn Penaeus monodon rearing conditions. After assessing YUPE’s efficacy for ammonia reduction (chemical-source), in chapter 5 YUPE effect on ammonia from biogenic source (shrimp excretion) was studied. YUPE at 0, 18, 36 and 72 mg L-1 was added to seawater containing 30, 50 and 100 Kuruma shrimp Marsupenaeus japonicus postlarvae (PL) per liter with or without aeration for 24 h. Even at the lowest YUPE addition level and the highest PL density, no ammonia accumulated in both aeration and no-aeration setups for up to 12 h. Ammonia accumulated only in the controls. In chapter 6, the study was to find out how YUPE supplemented in feed at 300 mg kg-1, 600 mg kg-1 and 1200 mg kg-1 could affect the palatability of juvenile M. japonicus and on water quality and production parameters in an 8-week rearing trial. YUPE at 300 mg kg-1 already enhanced shrimp’s feeding in the first hour. YUPE at 600 mg kg-1 started to reduce ammonia accumulation in water since the second week and YUPE at 300 mg kg-1 since the fourth week. Despite dietary YUPE was favorable for feed consumption and water quality maintenance, it did not affect survival, growth, feed conversion and protein efficiency. The last study in chapter 7 was to find out the potential of using YUPE to reduce the environmental impact of shrimp farming by assessing YUPE’s TAN reduction in marine shrimp culture systems, and its effect on the TAN leaching from aqua-feeds. YUPE at the concentrations previously mentioned was added to water from shrimp culture systems, and to an aqua-feed with 50% crude protein, respectively. YUPE at all concentrations reduced ammonia accumulated in shrimp culture systems. Likewise, the supplementation of YUPE to feed reduced TAN leaching between 50% and 83% when compared to the control.
In conclusion, YUPE addition at 18 mg L-1 for TAN reduction and/or control in shrimp culture systems, and dietary YUPE supplement at 300 mg kg-1 feed for TAN leaching reduction from feed are recommended. Furthermore, YUPE is identified as a natural, safe, and effective solution for ammonia reduction in mariculture.
| Identifer | oai:union.ndltd.org:TW/098NTOU5086025 |
| Date | January 2009 |
| Creators | Roberto Adrián Santacruz-Reyes, 尚瑞柏 |
| Contributors | Yew-Hu Chien, 陳瑤湖 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | en_US |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 208 |
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