International Journal of Aquaculture, 2025, Vol.15, No.3, 155-164 http://www.aquapublisher.com/index.php/ija 162 4 Discussion At the onset of the experiment, the mean weight of O. andersonii was 3 g. Both treatments exhibited slow growth during the initial three weeks, likely due to acclimatization. Subsequently, growth rates increased, with Treatment 1 and Treatment 2 achieving final mean weights of 14.79 g and 13.74 g, respectively. Despite Treatment 1's numerically higher weight gain, the difference was not statistically significant (P = 0.110), indicating comparable performance between the commercial and on-farm-formulated feeds. This result is consistent with findings by Basiita et al. (2022), who reported similar growth patterns for O. niloticus under controlled conditions, with no significant differences in growth when fed either commercial or on-farm-made feeds. While weight gain did not differ significantly between treatments, a notable difference was observed in fish length. Treatment 1 fish reached a mean length of 8.98 cm, whereas Treatment 2 fish averaged 8.33 cm (P = 0.007). This disparity suggests that factors beyond feed type, such as water quality parameters influenced by diet composition, may have impacted somatic growth. Environmental variables like temperature, pH, and dissolved oxygen are known to affect fish morphology and growth efficiency. A study by Abd El-Hack et al. (2022) found similar results, where variations in water quality, particularly temperature and oxygen levels, contributed to differences in fish length and growth efficiency, even under identical feeding conditions. Despite Treatment 1’s higher overall weight, its lower meat yield may be attributed to a greater proportion of non-edible components. These results align with a study by Opiyo et al. (2014), which observed that fish fed on-farm-formulated feeds often exhibited higher meat yield due to better nutrient utilization from locally sourced ingredients. Feed conversion efficiency was better in Treatment 2, with an FCR of 1.5, compared to 1.9 in Treatment 1. Lower FCR values indicate more efficient feed utilization. Both treatments demonstrated acceptable FCRs, falling below the threshold reported in similar studies on tilapia species. For instance Mengistu et al. (2020) reported an FCR of 1.71 for tilapia fed in cage environments, emphasizing the efficiency of such diets in promoting optimal growth while minimizing feed wastage. No mortality was observed in either treatment, indicating that the fish were reared under favorable conditions throughout the trial. The 100% survival rate underscores the effectiveness of the culture system and husbandry practices employed. This finding is consistent with studies on tilapia, such as those conducted by Ahir et al. (2023), who reported a 100% survival rate in tilapia on farm enriched feed, highlighting the effectiveness of optimized feeding and rearing practices. The specific growth rate ranged from 2.5% in Treatment 2 to 2.6% in Treatment 1. Elevated SGRs are often associated with optimal environmental conditions, including suitable temperature and dissolved oxygen levels. Regular water changes and aeration likely contributed to these favorable conditions in the present study. Makori et al. (2017) found similar growth rates in tilapia when dissolved oxygen and temperature were maintained within optimal ranges, highlighting their importance in achieving high SGRs in aquaculture. Water temperature ranged from 24.46 ± 0.82 °C to 26.56 ± 0.51 °C, aligning with the optimal range for tilapia culture. Dissolved oxygen levels varied between 5.59 ± 1.17 mg/L and 6.01 ± 1.03 mg/L, exceeding the minimum threshold required for optimal growth. pH levels were within the recommended range, averaging between 8.39 ± 0.06 and 8.50 ± 0.03, further supporting healthy growth conditions. These results are consistent with findings from Makori et al. (2017), who recommended maintaining a temperature range of 25 °C~30 °C and dissolved oxygen levels above 5 mg/L for optimal tilapia growth. 5 Conclusions In conclusion, the study highlights that on-farm-made feed can effectively support the growth performance and carcass composition of Oreochromis andersonii reared in indoor tanks. While there was no significant difference in growth performance or carcass composition between fish fed on commercial feed and those fed on the on-farm-made diet, the results suggest that on-farm-made feed can be a viable alternative in aquaculture,
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