The emergence of commercial fish farming has stimulated the establishment of fish feed factories in Uganda. However, no information is available on the safety of the feed, mainly due to lack of mycotoxin testing facilities and weak regulatory systems. A study was carried out to examine fungal colonization and mycotoxin contamination in fish feed samples (n = 147) of different types collected from nine fish farms (n = 81) and seven fish feed factories (n = 66) in the Lake Victoria Basin (LVB). Fungi were isolated in potato dextrose agar, grouped into morphotypes and representative isolates from each morphotype were identified based on the internal transcribed spacer (ITS) region of ribosomal DNA sequences. Aflatoxin B₁ (AFB₁) and total fumonisin (combinations of B₁, B₂ and B₃; hereinafter named fumonisin) levels in feed samples were determined by enzyme-linked immunosorbent assay (ELISA). A wide range of fungi, including toxigenic Aspergillus flavus and Fusarium verticillioides, were isolated from the fish feed samples. AFB₁ was detected in 48% of the factory samples and in 63% of the farm samples, with toxin levels 400 µg/kg, respectively. Similarly, 31% of the factory samples and 29% of the farm samples had fumonisin contamination ranging between 0.1 and 4.06 mg/kg. Pellets and powder had higher mycotoxin contamination compared to other commercially available fish feed types. This study shows AFB₁ as a potential fish feed safety issue in the LVB and suggests a need for more research on mycotoxin residues in fish fillets.

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.

Uganda’s aquaculture sub-sector is rapidly developing, contributing up to 22% of all fish produced in the country. However, the sub-sector still faces challenges related to limited access to extension services, production inputs, post-harvest handling facilities, disease incidences, value-addition skills and weak market linkages. Although there have been isolated interventions at different aquaculture value-chain nodes, the registered challenges continue to recur. To address prioritized issues in Uganda’s aquaculture sub-sector, nine zonal aquaculture innovation platforms were established based on the country’s nine agro-ecological zones. These platforms brought together different stakeholders to identify solutions to common problems in each aquaculture value-chain node. Each innovation platform consisted of fish farmers, hatchery operators, traders, extension workers, researchers, input dealers, local leaders, and financial institutions. During a series of zonal workshops, participants identified constraints to the aquaculture sub-sector in their respective zones. From the findings, there are technical knowledge gaps across the entire aquaculture value chain mainly affecting hatchery operators, input suppliers, and farmers. Therefore, there is need for coordinated interventions to enhance access to production technologies, innovations, knowledge, and skill transfer to promote gender-centered aquaculture development.

The ultrastructure of the gastrointestinal tract of Nile perch was described using Transmission Electron Microscopy standard procedures. Investigations revealed the presence of mucous cells, blood vessels and oil droplets plus several nerve cells and muscle bundles in the oral cavity. Further observations revealed columnar epithelial cells in the oesophagus, with a ragged surface, high electron dense cytoplasm, intercellular spaces, mitochondria and mucus granules. The lamina propria of the oesophagus was composed of loose connective tissue, blood vessels, nerve cells and several leucocytes, while the muscularis externa was composed of striated muscle bundles with the a Z line, A band and I band. The stomach was characterized by mucosal glandular cells with electron dense granules, a prominent nucleus, mitochondria, and secretory canaliculi. The liver had an isotropic parenchyma composed of several hepatocytes with a single spherical euchromatic nucleus. The exocrine pancreatic cells in the liver occurred around large blood vessels, had large centrally positioned nuclei with electron dense nucleolus, electron dense granules, Rough Endoplasmic Reticulum, and mitochondria which dominated the cytoplasm of pancreatic cells.

With increasing aquaculture intensification, emergence of fish ill-health incidents is expected, particularly under hatchery conditions, owing to stress attributed to for instance poor water quality and overcrowding, and improper nutrition. The objective of this study was to explore the ill-health incidents in fish hatcheries in Uganda. This was done using a face-to-face interview using a semi-structured questionnaire. A total of 48% of the 56 sampled hatcheries had experienced fish disease incidents, with African catfish being the most affected species (81.5%). Disease signs and symptoms were mainly observed during the fry (66.7%), fingerling (55.6%) and larva (51.9%) stages. Among 27 hatcheries, the most common disease signs and symptoms observed were cotton-wool growth (20), red spots on skin and fins (12), fish swimming upside down (12), and tail and fin rot (11). The analysis revealed that the level of experience of the farmer, the type of hatchery facility, and water quality monitoring were significantly associated with ill-health incidents in hatcheries. The results inform policy and practice, improving disease prevention and control to safeguard fish health and ensure Uganda’s long-term viability aquaculture.

Aquaculture in Uganda is mainly anchored on two fish species: Nile tilapia ( Oreochromis niloticus ) and the Ugandan African catfish ( Clarias gariepinus ). The Ugandan C. gariepinus is popular among farmers nationwide because of its desirable traits, such as high growth rates, a broad array of trophic levels, and resistance to diseases and parasites. Nevertheless, the species’ productivity is limited by insufficient molecular genetic data that can be used to inform selective breeding efforts. We fill this gap by sequencing the mtDNA D‐loop of 192 C. gariepinus individuals from five major water bodies of Uganda. The results show that the Western Rift Valley lakes (Edward, George, and Albert) are more genetically diverse, with the least being the Central region lakes, particularly the Kyoga basin lakes. Fst values and the haplotype network group the C. gariepinus populations into two genetic clusters: the Western Rift Valley lakes (Albert, Edward, and George systems) and the Lakes Victoria and Kyoga systems. In particular, the current study reveals that Lakes Edward and George are likely a panmictic population. However, we noted genetic heterogeneity in L. Victoria, relatively indicating within‐lake genetic structure. These results present the initial steps for genetically characterizing the Ugandan C. gariepinus populations and are key to guiding the use of the wild stocks in aquaculture for selective breeding programs to propel fish farming in Uganda.