Browsing by Author "KASSAHUN KOYSHA OYATO"

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    EFFECTS OF PROBIOTIC SUPPLEMENTATION ON GROWTH AND HEALTH PROMOTION OF THE NILE TILAPIA, Oreochromis niloticus (Linnaeus, 1758)
    (HAWASSA UNIVERSITY, 2023-10) KASSAHUN KOYSHA OYATO
    Probiotics have emerged as promising feed additives in aquaculture, offering potential benefits for fish growth and health promotion. This study was intended to evaluate the efficacy of three probiotic strains, Bacillus subtilis subtilis (p1), Bacillus subtilis inaquosorum (p2), and Saccharomyces cerevisiae (p3), on the growth and health of Oreochromis niloticus fingerlings. A total of 300 fingerlings with an average weight of 7.7 ± 0.103g and length of 7.46 ± 0.073cm were randomly divided in to five experimental groups: control (p0), p1, p2, p3, and a combination of all three probiotics (p4). The fish were fed a diet containing 30% crude protein (CP) at 5% of their body weight either with a basal feed (control group, p0) or with probiotic-supplemented feed (p1, p2, p3, and p4 groups at a dosage of 1.5*10⁸ CFU/mL) for 90 days. Water quality parameters, including dissolved oxygen (DO), pH, and temperature, were measured every 15 days, three times a day. Growth performance parameters, including body weight gain (BWG), specific growth rate (SGR), daily weight gain (DWG), feed conversion ratio (FCR), protein efficiency ratio (PER), and survival rate (SR), were assessed at the end of the experimental period. Additionally, gut microbiota analysis, hematological parameters, and proximate composition of fish were evaluated. The results indicated that water quality parameters remained stable throughout the experiment, except for DO, which showed significant differences (P < 0.05) among the groups. The probiotic-supplemented groups (p1, p2, p3, and p4) exhibited significantly higher growth performance parameters compared to the control group (p0). The group fed with Bacillus subtilis inaquosorum (p2) demonstrated the most remarkable growth performance, with the highest BWG (128.4 ± 0.146 g), SGR (2.66 ± 0.015% day⁻¹), DWG (1.43 ± 0.001 g day⁻¹), and PER (4.28 ± 0.004), and the lowest FCR (1.04 ± 0.003) and SR (100 ± 1.291%). Additionally, the probiotic diet effectively eliminated pathogenic microflora, including Salmonella spp., Escherichia coli, and Candida albicans, from the gut of O. niloticus compared to the control group. Hematological examination revealed significantly improved packed cell volume, RBC, hemoglobin, WBC, and differential leukocyte counts in the probiotic-fed groups. Proximate composition revealed better Crude protein, Dry matter and Carbohydrate content in probiotic diet and decreased Moisture, Crude fat, Ash and Crude fiber. In conclusion application of probiotics in aquaculture is crucial to improve growth and health of O. niloticus as well as to improve water quality