Browsing by Author "Rutaisire, Justus"

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    Effectiveness of African Catfish Pituitary extracts, Dagin and Water flow for optimising Egg Production, Fertilisation and Hatchability in Artificial Spawning of Barbus Altianalis
    (Uganda Journal of Agricultural Sciences, 2016) Aruho, Cassius; Mwanja, Mathew Tenywa; Bugenyi, Fred; Rutaisire, Justus
    Fish inducing hormones are widely used in commercial aquaculture to facilitate continuous supply of sufficient seed required on regular basis by the farmers. The objective of this study was to optimise production of viable eggs for improved hatchability during artificial spawning in Barbus altianalis. Two experiments were conducted, namely (i) experiment I evaluated the efficiency of using catfish pituitary extracts in spawning of second generation broodstocks compared to that of Dagin and water flow. (ii) experiment II examined ripe running females facilitated to spawn by running water only. Fish treated with pituitary extracts performed much better than those treated by Dagin with respect to fertilisation rates at 80.27 ± 39.57% (U = 66.5, p < 0.001) and working fecundity at 2314.40 ± 882.04 (U = 59.5, p < 0.05). However, the difference in hatchability was not significant (p > 0.05). In experiment II, hatchability and working fecundity were significantly higher when fish were striped after 4 hours (100 degree hours at 25 oC) of running water than those striped after 10 hrs (250 degree hours) but fertilization rates were not different. The findings indicate that catfish pituitary extracts are more effective in inducing B. altianalis to spawn than those treated with Dagin. However, the observations made on ripe running females in both experiments suggest that they should not be induced with any hormone. Hence, the cost of spawning could further be reduced using running water, especially in wet seasons when the majority are ripe.
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    Gonadal Recrudescence and Induced Spawning in Barbus Altianalis
    (Aquaculture Research, 2015) Rutaisire, Justus; Levavi-Sivan, Berta; Aruho, Cassius; Ondhoro, Constantine Chobet
    Gonadal recrudescence in Barbus altianalis from River Nile, Jinja (33°05E; 0°45N) Uganda was studied prior to induced spawning. Oocytes in B. altianalis were found to develop in cohorts suggesting batch spawning throughout the year with pronounced spawning activities coinciding with rainfall peaks of April and September. There was a strong positive correlation between rainfall and gonadosomatic index (rS = 0.75, P = 0.008). B. altianalis had low fecundity (6.0 ± 2.0 per gram) and large-sized eggs (2.97 ± 0.1 mm). Induced spawning was successful with exogenous hormones and water current. Results from this study suggested that total striping may not be appropriate, but larger eggs would confer high survival of offsprings under optimal conditions. The success registered in induced spawning of B. altianalis provides a breakthrough in seed production for multiplication and culture of this economically important fish species.
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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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    Histo-Morphological Description of the Digestive System of the Rippon Barbel Barbus Altianals (Boulenger 1900): A Potential Species for Culture
    (Uganda Journal of Agricultural Sciences, 2016) Aruho, Cassius; Tibenda, Victo Namulawa; Bugenyi, Fred; Kato, Charles Drago; Kisekka, Magidu; Rutaisire, Justus
    Morphology of the digestive system can help define the feeding adaptation habits of a given fish species in a given environment. In a study to describe the nature and functionality of the digestive system of Barbus altianalis, samples of B. altianalis were taken from River Nile. Their Lengths and weights were measured and the gut structure preserved. The structure of the digestive tract of the B. altianalis was described using simple morphological observations and standard histological procedures. The digestive tube of B. altianalis is stomachless and valveless, progressively and uniformly reducing in size from the proximal to distal end. The digestive tract is on average 2.22 ± 0.37 times longer than its body length. The mouth is terminal and protrusible and pharyngeal palatal organ is well developed. The last gill arch is modified into pharyngeal teeth and the eosophagus is short and muscular. Histological sections revealed the presence of taste buds from the lips to the cranial eosophagus and these regions of the digestive tract are lined by a stratified squamous epithelium. The intestines are lined by simple or pseudo stratified columnar epithelial layer which is highly folded. Goblet cells containing both acidic and neutral mucins are present throughout the entire digestive tract and are more numerous in the pharynx and the proximal part of the intestine. Lobes of pancreatic acini are discrete and scattered among liver cells, around the intestine and few are seen in the spleen surrounding blood vessels. Thus, the liver could most accurately be termed a hepatopancreas structure.
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    Morphology and Functional Ontogeny of the Digestive Tract of Barbus Altianalis Larvae
    (African Zoology, 2019) Aruho, Cassius; Walakira, John K.; Bugenyi, Fred; Rutaisire, Justus; Reading, Benjamin J.
    The ontogenetic development of digestive structures in Ripon barbel (Barbus altianalis) larvae was investigated using standard histological and histochemical procedures from hatching up to 60 days after hatching (DAH). The study was conducted to determine the best period of exogenous feeding and the stage when the digestive tract is able to digest processed microdiets. Results indicated that at hatching, the digestive tract, mouth and anus were closed. The opening of the mouth and anus were observed 3–4 DAH, whereas complete separation of the entire gut was observed on 5 DAH. Exogenous feeding started 5–6 DAH, but complete yolk exhaustion occurred 7–8 DAH, indicating a period of mixed feeding. Mucosal epithelial folds were first noted 3 DAH in the anterior intestine and became profound with some goblet cells (mucous cells) by 6 DAH. At 7 DAH the mucous cells had started secreting both neutral and acid glycoconjugates. The first intestinal single loop occurred at 28–30 DAH and a double loop at 45–50 DAH. Each coiling was proceeded by larval weight increase. By 7 DAH the buccopharyngeal cavity was lined by a layer of squamous epithelial cells with scattered goblet cells and tastebuds that became numerous by 15 DAH. At hatching, the liver and the pancreas were undifferentiated, but on 3 DAH the hepatocytes and zymogen granules of the pancreas became clear. By 7 DAH both organs enlarged, making extensions into the posterior. Intestines coiling at 28–30 DAH coincided with the beginning of external dressing of the scales, a period when B. altianalis started transforming into a juvenile. By 7–8 DAH the digestive structure showed all the necessary digestive features that could enable the larvae to digest any compound diet suggesting that it may be feasible to substitute or offer a complete microdiet during larvae nursing with reduced larval mortality.
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    National Investment Policy for Aquaculture Parks in Uganda
    (TrustAfrica, 2014) Mugabira, Michael; Borel, Philip; Mwanja, Wilson; Rutaisire, Justus; Balirwa, John; Wadanya, Jackson; Aliyo, Andrew; Kivunike, Godfrey
    According to the National Development Plan (NDP), fish farming in Uganda presents immense opportunities for socio-economic development, in terms of livelihood, income, and employment. The need for the National Investment Policy for Aquaculture Parks in Uganda arose out of public demand for guidance on the investment in commercial scale aquaculture. Stakeholders in aquaculture demanded public guidance and support for implementation of the Aquaculture Parks Concept that is prioritized in Development Strategy and Investment Plan (DSIP) within the Ministry of Agriculture, Animal Industry and Fisheries (MAAIF). This is the main thrust for increasing aquaculture productivity and production in order to achieve an annual 300,000 tonnes by 2016.
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    Optimizing Selection of Sexually Mature Barbus Altianalis For Induced Spawning: Determination of Size at Sexual Maturity of Populations from Lake Edward and Upper Victoria Nile in Uganda
    (Fisheries and Aquatic Sciences, 2018) Aruho, Cassius; Ddungu, Richard; Nkalubo, Winnie; Ondhoro, Constantine Chobet; Bugenyi, Fredrick; Rutaisire, Justus
    Sexual maturity (L50), the length at which 50% of fish in a size class are mature, is a key aspect of domestication of new fish species because it guides the procedure for identification of appropriate broodstock size for artificial spawning. In this study, the L50 was determined for 1083 Barbus altianalis samples obtained from Lake Edward and the Upper Victoria Nile. Gonads of freshly killed samples were examined macroscopically and verified with standard histological procedures for the maturation stages that were used to determine L50. Oocytes and spermatogenic cell sizes were compared for fish obtained from both water bodies. Results indicated that there were no variations in macro gonad features observed for fish from Lake Edward and Upper Victoria Nile. Similarly, there were no significant differences in oocyte sizes (P > 0.05) between the two populations but significant differences in spermatogenic cell sizes were noted (P < 0.05) except for spermatozoa (P > 0.05). This however did not suggest peculiar differences between the two populations for staging the gonads. Consequently, no staging variations were suggested for both populations in determination of L50. Sexual maturity was found in the same class size of fork length (FL) 20–24.9 cm and 35–39.9 cm for males and females from both water bodies, respectively. At this FL, however, males were too small, and for good selection of vigor broodstocks for spawning and conservation purposes, they are better picked from class size of 30–34.9 cm FL and above. These findings were crucial for integration of appropriate breeding size in spawning protocol by farmers and fisheries scientists conserving wild B. altianalis populations.