Browsing by Author "Kasozi, Nasser"
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Item Antibacterial Activity of Lactobacillus spp and Lactococcus spp Isolated from Various Parts of Pebbly Fish, Alestes baremoze(British Microbiology Research Journal, 2016) Kato, Charles D.; Kahuma, Carol E.; Namulawa, Victoria T.; Kasozi, NasserThe study sought to identify microbial communities and potential probiotics in one of the popular fish species, Alestes baremoze. A total of 15 samples were collected from Lake Albert and swabs of the skin, gills and gut were made, and cultured on general purpose and selective media. The bacteria isolated were confirmed using morphological and biochemical tests while probiotic screening was done using the agar spot method. The prevalent potential pathogenic bacteria were Staphylococcus aureus (100%) and Escherichia coli (67.7%). The highest total microbial load was generally recorded for samples from the skin. Staphylococcus spp had the highest total microbial load recorded from all the samples (skin, 8.50±22.1x102 cfu/g and gills, 8.00±24.3x102 cfu/g). When the effect of potential probiotic genera (Lactobacillus spp and Lactococcus spp) isolated from skin, gills and gut was investigated, Lactobacillus spp showed the highest overall activity against all test pathogens. The highest activity for Lactobacillus spp was demonstrated against E. coli (15.4±0.19 mm) and S. aureus (14.0±0.17 mm). The highest activity for Lactococcus spp was demonstrated against S. aureus (8.7±0.12 mm) and E. coli (7.2±0.1 mm). Furthermore, no probiotic activity was recorded against Streptococcus spp and Pseudomonas spp. No significant (p> 0.05) differences in antimicrobial activity were noted using Lactic acid bacteria isolated from the different fish body parts. Based on the positive results from this study, Lactobacillus spp. should be further characterised and studied in challenge experiments in fish to explore its probiotic effects.Item The complex microbiome in aquaponics: significance of the bacterial ecosystem(Annals of Microbiology, 2021) Kasozi, Nasser; Abraham, Benjamin; Kaiser, Horst; Wilhelmi, BrendanAquaponics is a technology that has minimal impact on the environment and which is often promoted as a solution for sustainable food production. Developing aquaponics sustainably requires a thorough understanding of the biological components of the system. Recent reports on the bacterial populations of aquaponics systems using new DNA sequencing technologies are revealing a complex and diverse microbial ecosystem. The purpose of this review is to present information on microbial composition and various factors affecting bacterial activity in aquaponics systems. Approaches for establishing a bacterial ecosystem during the setup of an aquaponics system, and microbiological safety of aquaponics products are also highlighted. Methods: This review was developed by evaluating and synthesising current literature of peer-reviewed publications related to aquaponics and microbial communities. Based on the results from credible academic journals, publications were categorised into five groups: methods used to characterise microbiomes, biofiltration microorganisms, bacterial diversity, biofilter establishment, and safety of aquaponics products. Results: The microbial ecosystem is essential for biological filtration of water through the mineralisation of nutrients required for plant growth in an integrated system. The aquaponics microbiome is complex, and bacterial composition varies between the different compartments of these systems. Establishing these bacterial ecosystems is essential for optimal functioning of aquaponics. At the phylum level, Proteobacteria and Bacteroidetes are dominant in aquaponics systems. Despite bacteria being fundamental to aquaponics, there are currently no reports of human pathogens in aquaponics products.Item Dietary amino acid requirements of pebbly fish, Alestes baremoze (Joannis, 1835) based on whole body amino acid composition(Aquaculture Reports, 2019) Kasozi, Nasser; Iwe, Gerald; Sadik, Kassim; Asizua, Denis; Tibenda Namulawa, VictoriaAlestes baremoze is a valuable food fish with a wide geographical distribution in East, North and West Africa. Currently, the nutritional requirements of A. baremoze have not yet been determined, which hinders attempts towards developing appropriate feed formulations for its culture. This study was thus conducted to estimate essential amino acid (EAA) requirements of A. baremoze using the A/E ratio method, as a guide in formulating its diet. Fish samples used in the study were categorised into four classes according to their fork lengths (1–12 cm; 13–24 cm; 25–36 cm and 37–48 cm), with each class consisting of 10 fish. Results from the amino acid composition analysis revealed significant difference (P<0.05) in the concentration of tryptophan, lysine, methionine, threonine, phenylalanine, isoleucine and valine amongst the different class sizes of A. baremoze. The A/E ratios of A. baremoze muscle tissue were in the same range with those obtained from other fish species, except for tryptophan. When expressed as a percentage of dietary protein, the EAA requirements of A. baremoze, were however not significantly different (P > 0.05) within the four classes. The EAA requirement profiles for A. baremoze were found to be similar to those observed in other omnivorous fish species. Considering the importance of A. baremoze as a potential species for freshwater aquaculture, the present data provides guidance to the development of test diets with appropriate amino acid inclusions until dose response treatments are carried out.Item Effect of Bacillus spp. on Lettuce Growth and Root Associated Bacterial Community in a Small-Scale Aquaponics System(Agronomy, 2021) Kasozi, Nasser; Kaiser, Horst; Wilhelmi, BrendanThe integration of probiotics in aquaponics systems is a strategy for mitigating environmental impacts and for promoting sustainable agriculture. In order to understand the role of probiotics, we investigated the effect of a commercial probiotic mixture of Bacillus subtilis and B. licheniformis on the growth of lettuce (Lactuca sativa L.) under deep-water culture integrated with Mozambique tilapia (Oreochromis mossambicus). We determined plant growth, water quality parameters, and leaf mineral analysis, and assessed the influence of a probiotic mixture on the microbiota. Bacterial communities were analyzed by high-throughput 16S rRNA gene sequencing. Compared to the control systems, the addition of the probiotic Bacillus significantly increased the concentration of nitrate and phosphate in deep water culture solution, which contributed to improved lettuce growth. In both the growth trials, the Fv/Fm, the mean shoot dry weight, and the mean fresh weight of the harvested shoots from the Bacillus treatment were significantly higher than those observed for the control plants. Higher concentrations of phosphorus, potassium, and zinc in the lettuce leaves were found in systems that received the Bacillus. Although differences were observed at the phylum level, Proteobacteria and Bacteroidetes were predominant in both the Bacillus-treatment and the control systems. At the genus level, however, the communities present in the two types of systems were heterogeneous with Bacillus-treated systems, containing significantly higher numbers of Chryseobacterium, Bacillus, Nitrospira, Polynucleobacter, and Thermomonas. The results indicate that Bacillus supplementation can effectively alleviate nutrient deficiencies, improve water quality, and modify the composition of bacterial communities in aquaponics systems.Item Effect of Stocking Density on the Growth Performance of Sex Reversed Male Nile Tilapia (Oreochromis niloticus) Under Pond Conditions in Tanzania(World, 2014) Kapinga, Imani; Mlaponi, Enock; Kasozi, NasserA study was conducted to compare the growth potential of monosex Nile tilapia at two different stocking densities. Fish of 2.6±0.1g average weight were stocked in ponds at the stocking density of 3fish/m2 (low stocking density ‘LD’) and 13fish/m2 (high stocking density ‘HD’) respectively. Locally feed (CP; 25 %) was administered at 5% of body weight three times a day for five months. Monthly sampling was conducted to assess growth by measuring weight and length of 30 fish from both systems to obtain the average weight and length for specific growth rate (SGR), feed conversion ratio (FCR), average daily gain (ADG), weight gain (WG) and Biomass (BM). There was significantly higher (p<0.05) fish growth performance in LD ponds; SGR (3.47%), ADG (0.57g), WG (83.5g) compared to HD; SGR (2.71%), ADG (0.27g) and WG (40.8g). BM in HD was significantly higher (565.3g) compared to LD (258.3). There was no significant difference (p>0.05) in FCR, although lower value was in HD (2.46) than LD (2.71). The differences in performance of Tilapia in the two stocking densities could have been attributed to stress, competition for food and living space. However, HD gave significantly higher biomass yield per area than LD and can be very useful to give good returns for local consumption and where resources like land, water and capital are inadequate. There is therefore need to determine the optimum management levels necessary to boost fish growth of under high-density systems.Item Fatty acid profile of pebbly fish, Alestes baremoze (Joannis, 1835) from Lake Albert, Uganda: Implications for its feed requirements(Uganda Journal of Agricultural Sciences, 2020) Kasozi, Nasser; Degu, Gerald Iwe; Walakira, John; Tibenda Namulawa, VictoriaThe objective of this study was to establish the fatty acid profile of Alestes baremoze, with a view of establishing its dietary fatty acid requirements. Fish samples from Lake Albert were categorized into four classes according to fork lengths (1–10 cm, 11–20 cm, 21–30 cm, and 31–40 cm), with each class comprising of six fish. In addition, eggs were collected from six sexually mature females. A total of 35 fatty acids were identified and categorized into saturated fatty acids (SFAs), monounsaturated acids (MUFAs), and polyunsaturated fatty acids (PUFAs). SFAs accounted for 5.07% to 37.05%, MUFAs and PUFAs constituted 20.65% to 53.78%, and 10.34% to 66.10% respectively, of total fatty acids in all studied fish size classes. The results from this study indicated that fatty acid composition in A. baremoze varied significantly with size classes. The findings may provide guidance on the fatty acid inclusions for diets formulated for this fish under culture conditions.Item Histomorphological Description of the Digestive System of Pebbly Fish, Alestes baremoze (Joannis, 1835)(The Scientific World Journal, 2017) Kasozi, Nasser; Iwe Degu, Gerald; Mukalazi, Julius; Kato, Charles D.; Kisekka, Majid; Owori Wadunde, Akisoferi; Kityo, Godfrey; Namulawa, Victoria T.Histomorphological studies of the digestive system of Alestes baremoze captured from Lake Albert, Uganda, were done using standard procedures. These revealed that A. baremoze has a fleshy-lipped terminal small mouth, large molar, short oesophagus, a three-lobed liver, pouch-like stomach, a nine-fingered caeca, and a long tubular intestine. A stratified squamous epithelium with numerous mucus-secreting cells lined the lips with no taste buds. Stratified squamous epithelia lined the oesophagus in the anterior portion which turned into a columnar epithelium towards the stomach. The lamina propria had numerous tubular glands throughout the entire oesophageal length.The stomach consisted of three distinct regions (cardiac, fundic, and pyloric) with distinguished lamina propria glands.The intestinal mucosa was thrown into villi of varying heights, with the tallest in the anterior part, lined with a simple columnar epithelium with numerous lymphocytes-like infiltrations. Numerous goblet cells appeared in the intestinal lamina epithelialis; these increased uniformly towards the anal opening. The liver was divided into lobules, with a central vein. Hepatocytes were visibly arranged closely, forming irregular cords, and the scattered tubular acinar glands formed the exocrine pancreas (hepatopancreas). Stomach content analysis indicated that the fish eats plankton, mollusks, crustaceans, and insects as the main proportion of its diet.Item In vivo Efficacy of Ethanolic Extract of Cassia nigricans (Vahl) Against Gastro-Intestinal Nematodes (GIN) of Goats in West Nile Region, Uganda(Am J Clin Exp Med, 2016) Oba, Peter; Asizua, Denis; Komuntaro, Godwin; Kasozi, Nasser; Kalenzi, Moses; Apamaku, Michael; Kateregga, John; Okwee-Acai, James; Ndukui, Jimmy G.; Kabasa, William; Benda, Katali K.Several plants are used by farmers for the treatment of gastrointestinal nematodes (GIN) in goats. However, their phytochemical properties, efficacy and safety is largely unknown. A trial was therefore designed to determine in vivo efficacy of ethanolic extract of Cassia nigricans against gastrointestinal nematodes (GIN) in goats. Cassia nigricans leaves were collected from Arua District, Uganda. Ethanolic extraction method was to prepare extracts and the experimental goats were dosed accordingly. Treatments were assigned to five (5) groups of goats (n=9) as follows: Group A, the negative control (30ml of distilled water; group B, the positive control (Albendazole 10%, 8mg/kg). Groups C, D and E received extracts at 50, 100 and 150mg/kg, respectively. Live weights (LWs kg), faecal samples (for faecal egg count reduction (FECR) based on eggs per gram (EPGs) of faeces, packed cell volume (PCV %), total protein (TP g/dL), body condition scores (1-5) and Faffa Malan Chart (FAMACHA scores 1-5) were taken on day 1 of the experiment and subsequently at 7-day intervals for 4 weeks. Results revealed that a significant increase in LWs by 2nd week was observed in goats treated with Albendazole from 20.8 ± 1.9 to 21.9 ± 1.8 (p ≤ 0.05). No change in LWs and in TP was observed in all other groups (p ≥ 0.05). Only Albendazole treated group exhibited a significant increase of PCV in the 2nd week (p ≤ 0.05). EPGs were observed to significantly drop in those treated with Albendazole by the 2nd week from 300 ± 91 to 0 ± 0 and extract at 150 mg/kg dose from 740 ± 236 to 60 ± 25 (p ≤ 0.05). The FECR for Albendazole, 50, 100 and 150 mg/kg doses of the extract were found to be 100%, 37.3%, 66.6% and 83.8% respectively. Only at 150 mg/kg dose did the extract show moderate efficacy in reducing mixed Strongyle spp faecal egg counts in goats. Strongyles spp. were the most predominant genera of nematodes found in goats. Further evaluations of leaf extracts and other plant parts is necessary to establish its potential as a source of local effective remedy against gastro-intestinal nematodes in goats.Item Iron supplementation and management in aquaponic systems: A review(Aquaculture Reports, 2019) Kasozi, Nasser; Tandlich, Roman; Fick, Martin; Kaiser, Horst; Wilhelmi, BrendanIron is one of the essential micronutrients for plant development and fish growth in aquaponic systems. Iron is an essential element for photosynthesis, DNA synthesis, and many other cellular functions for plants. With regard to fish, it is an integral component of proteins involved in cellular respiration and oxygen transfer. Aquaponic systems are often iron deficient due to low amounts of iron in commercial fish feeds. Therefore, iron needs to be supplemented to ensure optimal plant performance. Adding these supplements requires close management of the system, and careful selection of chelating substances as the Fe-chelate bioavailability is environment dependent. Reports of iron supplementation and management in aquaponic systems are limited. This review critically examines iron supplementation strategies, different sources of iron and factors influencing iron uptake for optimal biomass production. The effectiveness of different iron chelates is also discussed. Furthermore, optimum ranges of dissolved iron concentrations for different components in an aquaponic system are reported. This review aims to provide a better understanding of iron optimisation strategies to minimise iron deficiency and enhance biomass growth.Item Metabarcoding Analysis of Bacterial Communities Associated with Media Grow Bed Zones in an Aquaponic System(International journal of microbiology, 2020) Kasozi, Nasser; Kaiser, Horst; Wilhelmi, Brendan)e development of environmentally sustainable plant and fish production in aquaponic systems requires a complete understanding of the systems’ biological components. In order to better understand the role of microorganisms in this association, we studied the bacterial communities in the dry, root, and mineralized zones of a flood-and-drain media bed aquaponic system. Bacterial communities were characterized using metabarcoding of the V3-V4 16S rRNA regions obtained from paired-end Illumina MiSeq reads. Proteobacteria, Actinobacteria, and Bacteroidetes accounted for more than 90% of the total community in the dry zone and the effluent water. )ese phyla also accounted for more than 68% of the total community in the root and mineralized zones. )e genera Massilia, Mucilaginibacter, Mizugakiibacter, and Rhodoluna were most dominant in the dry, root, and mineralized zones and in the effluent water, respectively. )e number of shared operational taxonomic units (OTUs) for the three zones was 241, representing 7.15% of the total observed OTUs. )e number of unique OTUs in samples from dry zone, root zone, mineralized zone, and effluent water was 485, 638, 445, and 383, respectively.)e samples from the root zone harbored more diverse communities than either the dry or mineralized zones. )is study is the first to report on the bacterial community within the zones of a flood-and-drain media bed. )us, this information will potentially accelerate studies on other microbial communities involved in the bioconversion of nitrogen compounds and mineralization within these types of aquaponic systems.Item Nutrient composition of fish protein powder developed from Brycinus nurse (Rüppell, 1832)(Food Science & Nutrition, 2018) Kasozi, Nasser; Asizua, Denis; Iwe, Gerald; Namulawa, Victoria T.A new product in the form of edible fish powder was developed from small pelagic fish (Brycinus nurse) which constitutes one of the major commercial fisheries in Lake Albert, Uganda. The objective of the study was to determine the proximate and mineral composition of the newly developed fish powder and also to compare it with Nile tilapia powder already on market. Results indicated that the changes in the amount of protein and ash were found to be significantly higher (p < 0.05) in fish powder than in fried samples. The increase in fat content of fried fish samples was found to be significant compared to other fish samples. No significant changes (p > 0.05) were observed in carbohydrate content for raw, fried, and powdered samples. Vitamin A decreased significantly in powdered samples. Comparing the B. nurse powder and tilapia powder (made from juvenile tilapia as raw material), the results indicated that B. nurse had higher levels of iron and manganese. Extracting proteins from B. nurse provides an opportunity to increase the utilization of harvested catch.Item Profile: adding value to fish: Lovin Kobusingye is not just a successful woman entrepreneur in Uganda but an influential voice in shaping pan-African fisheries policies(2020) Kasozi, NasserLovin Kobusingye is a well-known young woman fish entrepreneur working in Central Uganda’s Wakiso District. For over eight years, she, along with her two partners and over a thousand other fish farmers, has worked on fish processing and value addition. At the same time, she has persistently lobbied the government to support women-led entrepreneurship through an enabling policy framework designed to protect women in fisheries activities both in Uganda and, at a higher level, throughout Africa. Lovin Kobusingye has a string of achievements to her credit. She is the Director and Co-Founder of Kati Farms (U) Ltd, a fish agro-processing enterprise. She is also the President of the Eastern Africa Women in Fisheries and Aquaculture Association (WIFA) that includes representation from eleven countries: Uganda, Kenya, Tanzania, Rwanda, Burundi, Ethiopia, Eritrea, Somalia, southern Sudan, Sudan and Tanzania. She is President of the Uganda National Women’s Fish Organization (UNWFO) and Treasurer of the African Women Fish Processors andItem Site suitability assessment of selected bays along the Albert Nile for Cage Aquaculture in West Nile region of Uganda(International Journal of Fisheries and Aquaculture, 2016) Kasozi, Nasser; Opie, Hellen; Iwe, Gerald; Enima, Christopher; Nkambo, Mujibu; Turyashemererwa, Martin; Naluwayiro, Janet; Sadik, KassimSelection and management of sites are among the most significant elements for the success and sustainability of aquaculture operations. Water quality, water depth and water current are three of the major factors that need to be considered before initiating cage culture in a natural water body. This study was conducted to identify suitable sites for cage farming along the Albert Nile of Uganda by assessing the physical, chemical and topographical characteristics over a three month period. Four bays (Odoi, Fundo, Onere and Isirini) were randomly sampled and the results were compared against the acceptable standards. Basing on the physical and chemical criteria, most of the surveyed points were within the acceptable ranges except for the water depths which were lower and total suspended solids which were higher than the recommended ranges. Regarding topographical characteristics, Odoi and Fundo bays were found to be very prone to floating weeds and submergent macrophytes. All the sampled areas within Odoi, Fundo and Onere fishing bays whose depths were found to be more than 2 m can be manipulated to have Low Volume High Density (LVHD) cages while Isirini, Acaar and Ayilebe fishing bays were found not to be suitable for cage culture because they were very shallow.