Browsing by Author "Tadesse, Abebe (PhD)"

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    Comparison of Nutritional and Sensory Quality of Vegetables Grown on Aquaponics Technology and Conventional Produces
    (Addis Ababa University, 2019-06) Wolde, Dereje; Getachew, Paulos (PhD); Tadesse, Abebe (PhD)
    Aquaponics is one of a sustainable and alternative food production sector that integrates aquaCUlture with hydroponics. It is an emerg.ing part of aquaculture that uses the natural interaction between bacteria, fish and plants to change waste into clean water. Compared to soilbased agriculture and aquaculture production methods, aquaponics has many benefits including re-use of the wastewater from the growing fish, production of two commodities from a single system and expanded food production by urban residents. For the sustainability of aquaponics, the nutritional and sensory quality of the produces should be equivalent or better than the conventional produces. Thus, this study was aimed to compare the nutritional quality and customer preference of lettuce (Lacnlca sativa L.) and kale (Brassica carinata) grown on aquaponic system with that of conventionally grown in soil-based system. Proximate composition of lettuce and kale was determined using standard methods of AOAC and mineral content was determined by Inductively Coupled Plasma Optical Emision Spectroscopy. Sensory test was also determined by using discriminatory, preference and rating acceptance test methods. Accordingly, the aquaponic lettuce from Shewa Robit site had a significant (p
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    Effects of Niger Cake Inclusion in Fish Feed as a Major Protein Source on Anion Dynamics in Nile Tilapia-Lettuce Aquaponics System
    (Addis Ababa University, 2018-05-04) Amare, Liyuwork; Getahun, Abebe (Professor); Tadesse, Abebe (PhD)
    The aquaponics systems culture different organisms that are dependent on nutrients generated from feed. Most of the time the major protein source of this system is fish meal. However, the availability of fish meal is very scarce and the cost is not affordable for developing countries. So, this study was carried out to examine Niger seed cake as replacement of fish meal and also to compare the anion dynamics of Niger seed cake with fish meal. The experiment was conducted in five treatments, each treatment in duplicate, with the proportion of Niger seed cake; 0% (Control), 12.5% (TA), 25% (TB), 37.5% (TC), 42.5% (TD). Also a hydroponic treatment (H) was included to examine performance of each treatment on anion dynamics. Samples of fish, lettuce and water were collected every week for about five weeks. Both phosphorus and nitrogen groups (ammonia, nitrite and nitrate) were analyzed by spectrophotometer. The result of the experiment had shown that as the Niger seed cake inclusion increased in the fish feed (43%), TD, the increment of anion in the system was observed, which was comparable with the control diet. However, it had low anion loading than the hydroponic solution. In the lettuce, as percentage of the alternative feed increased, the concentration of anion became higher and comparable with the control fish feed. In general, the result of the experiment had shown little difference with the fish meal. Therefore, higher percentage of alternative feed from plant sources such as Niger seed cake could be taken as supplementary source of feed.