Browsing by Author "Sserwadda, Martin"

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    Growth and Survival of Ripon Barbel (Barbus Altianalis) Larvae and Juveniles Fed Five Experimental Diets in Captivity
    (Aquaculture Reports, 2020) Aruho, Cassius; Walakira, John K.; Owori-Wadunde, Akisoferi; Nuwamanya, Ephraim; Bugenyi, Fred; Sserwadda, Martin; Rutaisire, Justus; Borski, Russell J.
    Mass production of quality seed is vital for commercial culture and requires prior knowledge of appropriate larval diets and their utilization. Four experiments were sequentially conducted at different periods to evaluate the effect of live and a processed microdiet on growth and survival of Barbus altianalis larvae and juveniles. Larvae were fed exclusively on live prey (Moina and Artemia nauplii), microdiet (57 % Crude Protein), decapsulated Artemia cysts and in combination (Moina + microdiet). The effect on growth was further evaluated in subsequent juvenile trial by co-feeding. Green water effect on larval growth was also evaluated. In the final experiment, 15 day old larvae were raised in fertilized outdoor concrete tanks. Results indicated that each diet affected larval growth significantly different (P < 0.05) with the combination diet (152.05 ± 2.51mg) and decapsulated Artemia (141.14 ± 2.43 mg) performing better than microdiet, Moina and Artemia nauplii in that order. In subsequent juvenile experiment, larvae originally fed decapsulated Artemia (510.13 ± 11.93 mg) and those fed a mixed diet (500.20 ± 11.8 mg) performed better than other diets. Ontogenetic pattern of amylase, lipase and protease activity identified larvae maturation age at 14–21 Days after hatching (DAH) (14.93 ± 0.36–31.5 ± 0.61 mg) with the combination diet. When larvae at 15 DAH were nursed in outdoor tanks, final survival and growth performance increased to 95.3 % and 1112 ± 42.70 mg compared to the indoor nursing at 90.9 % and 355.33 ± 6.44 mg respectively by 75 DAH. Therefore we recommend that any microdiet manipulations and or outdoor nursing be done during or after this period. Microalgae had no direct effect on larval growth (P > 0.05). In this study, larvae were confirmed to utilize the microdiet from exogenous stage but co-feeding produced best average weight (152.05 ± 2.51mg), specific growth rates (4.06 ± 0.19) and survival (90.9 %). This study provided guiding strategies for improved rearing of B. altianalis fingerlings in captivity.
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    Ontogenetic development of the gastrointestinal tract of African lungfish larvae Protopterus aethiopicus (Heckel 1851): A light microscopy study
    (Aquaculture Research, 2020) Sserwadda, Martin; Nevejan, Nancy; Ntanzi, Ronald; Cornillie, Pieter; Broeck, Wim Van den; Van Stappen, Gilbert
    The organogenesis of the digestive system was described in the African lungfish (Protopterus aethiopicus) from 6 days post‐hatching (6 DPH) to 17 days post‐hatching (17 DPH) reared at 27°C. To elucidate the position of the gastrointestinal tract in relation to the neural tube, notochord and yolk sac at 6 DPH, and to the vertebral column, lungs and kidneys at 17 DPH, larvae were mapped by means of computer‐assisted 3D reconstructions starting from histological serial sections. The larvae showed a simple digestive tract, which appeared as a straight undifferentiated and closed tube at 6 DPH. Microscopical observation showed that yolk reserves were not completely depleted by 17 DPH. During the endogenous feeding period at least up to 17 DPH, the larval digestive system experienced a fast transformation with almost complete development of most digestive organs (pharyngeal teeth, intestinal vestibule, intestine and liver). Our findings suggest that, by 17 DPH, African lungfish larvae are ready to start exogenous feeding.
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    Spatial Risk Estimation of Parasitic Infestations of Pond and Cage Cultured Nile Tilapia (Oreochromis niloticus) in the Lake Victoria Crescent, Uganda
    (Makerere University, 2023) Luttamaguzi, Abdul N.; Kisakye, John J.; Mudumba, Tutilo; Agoe, Catherine; Sserwadda, Martin; Walakira, John
    A study was conducted to determine the estimated parasitic infestation and associated risk factors (Water quality, Farm management practices and External factors such as Intermediate hosts and Wild fish entry) of farmed Nile tilapia in Pond grow-out, Cage grow-out (lake), Cage grow-out (reservoir) farms and Hatcheries in the Lake Victoria Crescent, Uganda. Sixteen parasite genera and 65%(418/640) infestation rate were obtained. However, Pond grow-out farms and Hatcheries did not only constitute 81% and 63% of the parasite genera, but also had the highest mean number of parasite genera per farm of 1 to 7 and 4 to 8 respectively. Cage grow-out (reservoir) farms and Hatcheries had the highest mean prevalence of> 0.7. Water quality parameters, farm management practices and external factors varied across the 4 farming systems, with Cage growout farms (lake) with the best water quality parameters, farm management practices and control over intermediate hosts and wild fish entry. Using Spatial Areal Unit Modelling with Conditional Autoregressive Priors, out of 16 risk factors, only Intermediate hosts had a significant effect on estimated parasitic infestation. Estimated parasitic infestation of 0.28 (low) or 0.55 (high) prevalence was obtained. All Cage grow-out (reservoir) farms and Hatcheries, and 78%(14/18) of Pond growout farms had high estimated parasitic infestation despite their locations, while 75%(3/4) of Pond grow-out farms that had low estimated parasitic infestation were located in Masaka (an area with many minor and less polluted rivers). Fifty-six percent (5/9) of Cage grow-out (lake) had low estimated parasitic infestation and were located in the Southern part of Wakiso, Southern part of Mukono and Southern part of Jinja but far from the Napoleon Gulf. The Cage grow-out farms with high estimated parasitic infestation were found in the Southeastern part of Buikwe (an area with sugar cane plantations and factories) and Southern part of Jinja in the polluted Napoleon Gulf. Therefore, the type of farming system and its location (spatial component) need to be given at-most importance when coming up with management and sanitary control strategies to encounter parasite infestation.
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    The Brine Shrimp Artemia Survives in DilutedWater of Lake Bunyampaka, an Inland Saline Lake in Uganda
    (Water, 2018) Sserwadda, Martin; Kagambe, Edmond; Van Stappen, Gilbert
    Ugandan aquaculture is in the process of development; however, it requires access to an affordable live food source, such as brine shrimp Artemia. This study fits within a broader feasibility study of domestic Artemia production in salt lakes. Since Uganda is a landlocked country, the only opportunity for live water food sources lies in the salt lakes in the west of the country. This study used saline water from one of these lakes, Lake Bunyampaka (salinity 72 mg L−1). Two Artemia strains, i.e., the Great Salt Lake strain, which is the dominant strain on the market, and the Vinh Chau strain, which is by far the most inoculated strain in the world, were assayed for their survival, growth, and reproduction in diluted Lake Bunyampaka water, using natural seawater as control. The organisms were fed live freshly cultured microalgae Tetraselmis suecica ad libitum. Our study revealed that the Vinh Chau strain performed especially well in Lake Bunyampaka water diluted to 50 g L−1. The data presented in this study generate the first useful information for the future inoculation of Artemia in Lake Bunyampaka in Uganda, and hence domestic Artemia production in the country; however, further larger-scale laboratory work, followed by field trials, is still needed.