Browsing by Author "Geremew, Akewake (PhD)"

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    Effects of Water Hyacinth-based (Eichhornia Crassipes) Vermicompost Tea (Aqueous Extract) Supplement on Growth Performance of Lettuce Under Non-Circulating Hydroponics and Aquaponics System
    (Addis Ababa University, 2020-11-14) Ruth, Upile; Geremew, Akewake (PhD)
    The study was conducted to determine the effects of water hyacinth-based (Eichhornia crassipes) vermicompost tea (aqueous extract) supplement on growth performance of lettuce under the non-circulating hydroponics system. Water hyacinth is nutrient-rich and can undergo vermicomposting and be used in hydroponics or aquaponics production systems. The purpose of this study was to investigate the potential use of water hyacinth-based vermicompost tea material in a hydroponics system for an improved product of lettuce and management of water hyacinth through utilization. The study used a systematic random sampling design to obtain the sample size of a total of 33 plants per unit. To compare the effect of various dilutions of water hyacinth based vermicompost tea and the growth performance of lettuce in non-circulating hydroponic and aquaponic systems leaf area, shoot length, root-shoot ratio, growth rate, moisture content analysis, were used. Ash and digesting methods were used to determine the effect of various dilutions of hyacinth-based vermicompost tea on the concentration of selected nutrients and heavy metals in lettuce. Lettuce dosed with hydroponics nutrient solution were significantly different at (P<0.05) from lettuce supplied with water hyacinth-based vermicompost extract dosed at 30%, 40% and 60%, the plants had a higher growth rate, shoot length and moisture content, large leaf area and a small root-shoot ratio. Lettuce dosed with vermicompost tea was resistant to aphid and fungi attack, while the ones dosed with synthetic solutions were attacked. Yield from hydroponics and aquaponics system was not significant. Lettuce dosed with WHBVCT were short in nutrient content in their solutions while the ones with synthetic solutions had enough nutrient supply. Lettuce dosed with WHBVCT had nutrient and heavy metal concentrations within the permissible limit, except for treatment dosed at 30% and 40% which showed a higher Pd and Zn values. WHBVCT is rich in chitinase, phenols and alcohol which digest the chitin of insects and phenol and inhibit the growth of fungus and spread of insects which made lettuce with WHBVCT more resistant than the others. Therefore, WHBCVT can be used to control aphids and fungus, but it cannot be used for lettuce production non-circulating hydroponics and trials have to be made on fruiting vegetables to observe its performance.
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    Partial Replacement of Fish Meal by a Mixture of Lupin (Lupinus Albus L.) and Grass Pea (Lathyrus Sativus L.) Meal in the Diets of Nile Tilapia (Oreochromis Niloticus L.) Fingerlings in a Recirculating Aquaculture System
    (Addis Ababa University, 2020-06-06) Fisseha, Tsegay; Geremew, Akewake (PhD); Fetahi, Tadesse (PhD)
    Aquaculture is one of the fastest-growing animal production sectors in the world producing near half (47%) of the world total fish production. However, it depends heavily on the expensive fish meal which is a limiting factor for the formulation of optimal fish diet in aquaculture systems. Although several investigators have tried to replace the fish meal with different locally available sources of plant proteins, similar studies on incorporating a mixture of lupin and grass pea meal are non-existent. This study evaluated the effects of fish meal replacement by a mixture of lupin and grass pea meal at inclusion levels of 0, 25, 50, and 75% as potential plant protein sources in the diets of Nile tilapia fingerlings on growth performance, feed utilization, carcass composition, and hematological parameters. The study was carried out in the Center for Aquaponics and Recirculating Aquaculture System, in the College of Natural and Computational Sciences, Addis Ababa University from October, 2019 to December, 2019 for 10 weeks. Experimental diets were formulated to be iso-nitrogenous (36g 100 g-1), iso-lipidic (10g 100 g-1) and iso-energetic (18 KJ g-1), and fed at 6-10% of their body weight day-1. A total of 276 Nile tilapia fingerlings were stocked into four treatments, each in three replicates using a completely randomized design where different dietary treatments were randomly assigned to the experimental aquaria. At the end of feeding trials, results revealed that replacement of 25, 50, and 75% of fish meal by lupin and grass pea mixture meals did not significantly (P > 0.05) affect most of growth and feed utilization parameters. However, fish fed with 25% lupin and grass pea mixture meal revealed enhanced final body weight and improved feed intake. This enhanced growth performance of fingerlings might be attributed to the compensatory effects of mixing plant proteins that improved the amino acid profile and bioavailability. Compared to the control diet, increasing lupin and grass pea mixture meals in the diets significantly increased hepatosomatic index. This might have been associated with higher feed intake and the high energy content in the feed that resulted in increased storage of glycogen or lipid in the liver. Replacement of fish meal by lupin and grass pea mixture meal has also resulted in comparable carcass composition and hematological parameters. These comparable and promising results might have been because of the improved amino acid profile due to the effect of mixing feed ingredients, and reduced antinutritional factors in the experimental diets due to preprocessing of lupin and grass pea by soaking, dehulling, and roasting. However, Hemoglobin, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration and lymphocytes had shown significant increase at higher fish meal replacement levels (75%). From the economic point of view, lowest incidence cost (44.31) and higher profit index (1.58) was obtained in the 75% replaced diet, whereas highest incidence cost (72.5) and lowest profit index (0.96) was recorded from the control diet. In general, there are promising nutritional and economic justifications for replacing fish meal by a mixture of lupin and grass pea protein sources in the diets of Nile tilapia considering growth parameters, feed utilization, carcass composition, hematological parameters, and economic analysis up to 75% level.