Masters Degrees (Animal Sciences)

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Browsing Masters Degrees (Animal Sciences) by Subject "African catfishes -- Growth"

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    Comparisons of growth performance of African catfish (Clarias gariepinus BURCHELL, 1822) fingerlings fed different inclusion levels of black soldier fly (Hermetia illucens) larvae meal diets
    (Stellenbosch : Stellenbosch University, 2016-03) Talamuk, Raphael; Pieterse, Elsje; Salie, Khalid; Stellenbosch University. Faculty of Agrisciences. Dept. of Animal Sciences.
    ENGLISH ABSTRACT: Fish food are a good source of quality protein and other essential nutrients required in human diets. The health benefits of eating fish have been extensively reported. Fish provide the global population with 17% of animal protein intake. However, fish supply from capture fisheries is believed to be stagnant or declining and is not likely to increase in the future. Aquaculture is widely acknowledged as having the potential to fill this gap in food fish production for the human population. One of aquaculture’s drawbacks is heavy reliance on non-sustainable protein sources for aqua feed. The search for alternative and sustainable protein sources has rendered insects as an attractive option in fish diets, since fish naturally consume insects. Insects have a satisfactory amino acid profile and are rich in fats, minerals and vitamins. This study investigated the effects of different inclusion levels of black soldier fly (BSF) larvae meal in the diet of African catfish (Clarias gariepinus) fingerlings. The production parameters and feed utilisation of fish that received the control diet and the BSF supplemented diets were compared. Moreover, the influence of these different diets on water quality parameters, gut histology and body composition of the experimental fish were investigated. Four experimental diets were formulated containing 0% (control), 10%, 20% or 30% BSF larvae meal. A total of 720 fingerlings (5 – 6 g) were randomly allocated to four treatments with six replicates per treatment. The trial was terminated after a 91 day feeding period. Proximate analyses were performed on the experimental diets on a dry matter basis. Although the experimental diets were prepared to be similar iso-nitrogenous and iso-caloric, the proximate analysis showed crude protein content ranged from 41.50% - 44.24%, and crude fat ranged from 11.16% - 16.49%. The gross energy ranged from 19.10 – 20.06 MJ/kg. For statistical analysis, the level of significance used was at p-value 0.05. Treatment effects with p-values less than 0.05 were considered significant. Alternatively, treatment effects with p-values more than 0.05 were not significantly different. If the ANOVA test was found less than 0.05, then Bonferroni post hoc test for least square means was used for multiple comparisons. The results showed that water quality parameters fluctuated within the acceptable range for African catfish and did not compromise the growth of fish between treatments. The growth of fish that received the control diet and 10% BSF diet were not significantly different (P >0.05); however, both were significantly different (P < 0.05) from fish that received BSF 30% larvae meal diet. The fish fed BSF 10% and BSF 20% larvae meal diets were not significantly different from each other. No significant difference in feed utilisation between treatments in terms of average daily gain, feed conversion ratio, protein efficiency ratio and specific growth rate were observed. No differences (P > 0.05) were found in dressing percentages between treatments. The proximate composition of the catfish showed no difference (P > 0.05) in percentage moisture, protein, lipids and ash between treatments. This study shows that BSF larvae meal did not affect the proximate body composition of the African catfish at any tested inclusion levels compared to the control diet. Gut histology of fish that fed on the control diet, 10% BSF, 20% BSF and 30% BSF were compared. No significant differences were found in height of mucosal folds and mucosal folds area between treatments. Significant differences were found in thickness of muscular layer between treatments. The results suggest that BSF larvae meal did not negatively affect intestine morphology in African catfish fingerlings, at least for the 91 day feeding period. This study showed that BSF larvae meal is a viable protein source in the diet of African catfish. Furthermore, this investigation suggests that if unprocessed BSF larvae meal should be used for catfish production, the inclusion level should not exceed 10%. Moreover, this study recommends the defatting of BSF larvae to enable high inclusion levels in the diet of African catfish.