Plant proteins substitutes of fishmeal in aquafeed are usually lacking in some essential amino acids and fatty acids. The microalgae Chlorella vulgaris has good-quality protein with amino acids rich in methionine, lysine and alanine. Four novel diets having C. vulgaris as the main source of protein were produced for African catfish Clarias gariepinus with an initial average weight of 1.09 ± 0.05 g. The diets were labeled Feed 1 (F1) to feed 4 (F4). The treatment diets were included 25% (F1), 15% (F2), 5% (F3) and 0% (F4) green algae meal. The basal ingredients of the feed were corn (maize) included as F1, 40%, F2, 43%, F3, 53% and F4, 43%; and millet meal, which varied in F1 as 23%, F2, 30%, F3, 30% and F4, 30%. The ingredients were preconditioned at 110 °C and pelleted. Post-fingerling African catfish were stocked at 10 fish per aquarium. There were three replicate aquariums for each feed type and the fish were fed for 60 d. The specific growth rate was best for the catfish fed with 25% C. vulgaris diet 7.86 ± 0% day⁻¹, and worst at 6.77 ± 0.07% day⁻¹ for the control group F4, 0% algal meal. The food conversion ratio (FCR) was lowest (1.88 ± 0.02) for 25% algal meal diet (F1) and highest (2.98 ± 0.01) for the 0% algal meal diet F4. Similarly, catfish had average weight gain of 121.02 ± 0.04 g for those fed with F1 compared to 62.50 ± 0.0 g for those fed with 0% algae F4. Protein efficiency ratio was highest for the F1-fed fish (2.46 ± 0.22) and lowest for those fed with F4 (2.02 ± 0.09). The hepatosomatic index was lowest for F1-fed fish (1.48 ± 0.01) and highest for catfish fed with F4 (2.50 ± 0.59). Based on the results, C. vulgaris is a good protein source for African catfish and can also substitute fishmeal in the catfish diets.

Fishmeal (FM) was substituted with soybean meal (Glycine max) (SBM) and bambaranut meal (Voandzeia subterranea) (BNM) in 10 experimental African catfish, Clarias gariepinus, diets. Feed formulation was designed using mixture model. The inclusion level of the three protein ingredients varied between 0% and 60%. Remaining 40% comprised of basal ingredients kept constant for all 10 feeds. African catfish of average initial weight 35.2 ± 0.9 g were fed with one of the treatment diets for 28 days. The protein:lipid ratios of the diets (range 1.5–3.4:1) were used in evaluating the feed utilization and growth of the fish. We found that catfish performances were mainly depending on ingredients and not the ratio itself. The protein:lipid ratios in the diets made of plant ingredients were high but SGR was low. Specific growth rate (SGR) increased with the increase of feed FM content, being ca. 5% day−1 with 60% FM diet but ca. 2% day−1 at both 60% BNM and 60% SBM diets. SGR was similar (3.5% day−1) with diets of 30% BNM or SBM inclusion with 30% FM. Feed conversion ratio increased from below 0.6 of the 60% FM diet up to 1.5 (60% SBM) and 1.7 (60% BNM). Protein efficiency ratio decreased linearly with increasing FM substitution, but protein productive value (PPV) was similar for catfish fed 60% FM diet and its 50% substitution with BNM or SBM. These results suggest that protein:lipid ratio cannot be used in assessing nutritional performance if the source of feed ingredient vary widely. However, these results suggest that BNM can partly substitute FM and completely replace SBM in the diets of African catfish.

Feed and feed ingredients in the tropics are prone to attacks of mycotoxigenic fungi (myco-fungi) infestation during storage or from the field. The heat applied in feed production destroys only the myco-fungi leaving mycotoxins that eventually end up in the fish. Mycotoxins have negative effects on the growth of fish. It is plausible to reduce or totally eliminate the mycotoxins and myco-fungi by the inclusion of special African bentonite supplement called “Uro’. Five iso nitrogenous and iso energetic feed were made with soybean meal of 12% moisture stored at relative humidity of 78% and temperature 29.45±0.87oC for 30 days. The feed was labelled as F1 to F5 and varied in inclusion levels of bentonite supplement as follows, F1, 34%, F2, 25%, F3, 15%, F4, 5% and F5, 0%. The protein supplement and basal ingredients in the diets were same. Feed ingredients were weighed, mixed, conditioned and pelleted. The feed was dried at 40oC for 24 hours and subjected to mycological analysis. African catfish fingerlings of average weight 6.5±0.36 g were stocked at 15 fish per three replicate aquaria per feed type. Fish were fed to satiation twice daily for 140 days. The catfish fed with F1(35% bentonite) had the best food conversion ratio, 1.63±0.15, highest SGR 5.7±0.05% day1 , weight gain 45.7±3.65g, protein efficiency ratio 1.19±0.10 and highest gut weight 3.46±0.45g. All growth and nutritional parameters were increasing with increasing inclusion of bentonite. Mycological analyses showed that three myco-fungi, namely Aspergilus flavus, Mucor mucedo and Cladosporium cladosporioides were prevalent in the feed. However, feed 1 to feed 3, were completely free from myco-fungi, while feed 4 had traces of M. mucedo and C. Cladosporioides but all myco-fungi were prevalent in F5. African bentonite is calcinated and sequestered feed ANF, myco-fungi and mycotoxins. Bentonite increased digesta viscosity which enabled better digestion of feed, lower FCR, enhanced alkaline intestine for protein and fatty acid absorption. Bentonite increased catfish total glycerides and cholesterol but reduced AST and ALT of the catfish.

The high cost of fish oil and fishmeal has necessitated the search for alternative ingredients. Palm oil and sesame oil are plausible alternatives to fish oil. Palm oil is saturated while sesame oil is unsaturated. Five experimental diets were made with varying inclusion of crude sesame and palm oil extract. The inclusion percentages of crude sesame extract (CSE) and crude palm extract (CPE), CSE: CPE, were as follows; Feed 1, 25:5; Feed 2, 20:10; Feed 3, 15:15; Feed 4, 10:5; Feed 5, 5:25 and Feed 6(commercial feed). African catfish fingerlings were stocked in aquaria tanks in three replication. The fish were fed to satiation for 70 days with the feeds. After 70 days of feeding experiment, results showed that alanine amino transferase and aspartate amino transferase were both lowest for catfish fed feed F1, F2 and F3. The catfish had significantly higher digestibility for crude sesame extract (CSE) (93.34±0.22 %) than for crude palm extract, (CPE) 78.98 ± 0.11%. Consequently, treatment Feed F1 had the highest digestibility of 91.32 ± 0.07%, followed by feed F2, 82.25 ± 0.04%. The least digested feeds were Feed 4, (20% CPE) and feed 5, (25% CPE), 70.12 ± 0.06%and 70.23 ± 0.09% respectively. The fatty acids of CPE are dominated by saturated fatty acids (SFAs), which constitute about 49.9±0.08% of the total fatty acids. Among the SFAs hexadecanoic acid or palmitic acid, comprising 46.0 ±0.02% of the total fatty acid. Oleic acid, C18:1 accounts for 43.4 ±0.08%. The fatty acid of CSE is dominated by monounsaturated C18:1 linoleic acid. Oleic acid forms about 45.44±0.01% of the total lipid of sesame crude extract. Sesame extract also has 39.48±0.14 %, C18:2 polyunsaturated fatty acids linoleic acid. Catfish Fatty acids content resembles the fatty acid content of the feeds. The ∑SFA shows that catfish fed with feed F1 had the lowest somatic SFA of 48.58 %. The catfish fed feed 1 had more PUFA than the MUFA or SFA. Incorporation of sesame seed oil in the diets of C. gariepinus produces fish high in PUFA.

There is need to reduce usage of antibiotics in favor of prebiotics and phytogenic in aquafeed production. The study evaluated effects of mushroom on growth, gut histology and haematological variables of Clarias gariepinus. Five treatment feeds were made to vary in inclusion of solvent extracted oyster mushrooms, Lentinus sajor-caju as follows: Feed 1, 0%; Feed 2, 4%; Feed 3, 8%; Feed 4, 12% and Feed 5, 16%. The diets were made isonitrogenous (42%) and isolipidic (6.0%). The growth performances, gut histology and haematological profile of the fish were estimated using standard procedures. The essential amino acid (EAA) contents of the mushroom and feeds were analyzed following standard methods. Ingredients were mixed according to proportions, preconditioned and steam pelleted. African catfish of average weight 9.48g were stocked in three replicates 20liter aquarium, at 113.76g/aquarium and fed with the experimental diets for 90days. Results showed that mushroom had good array of EAA especially lysine (7%). The haematobiochemical parameters and growth of the catfish were best at 8% mushroom extract inclusion. Histological sections showed significant increase in length and width of the mucosal fold microvilli as mushroom extract inclusion increased up to 8%. Similarly, red blood cell counts, packed cell volume, hemoglobin and total white blood cell counts of the catfish increased up to 8%. Fish fed Feed 3 had the best specific growth rate (3.00±0.06% day-1), food conversion ratio (1.54±0.01), weight gain, (128.67±0.02g) and protein conversion ratio of 0.3±0.04. Catfish fed with higher than 8% inclusion of mushroom had reduced growth rates, hemato-biochemical and histological parameters. This may be probably due to the high polysaccharides and beta-glucans present in mushroom. Thus, mushroom extracts should be included in catfish feed but not beyond 8%.