Growth, Biochemistry, Quality, and Risk Assessment of Oreochromis nioloticus Influenced by Crude and Processed Chicken Manure

This study aimed to evaluate the effect of crude chicken manure and its processing on growth, biochemistry, quality, and risk assessment of Oreochromis niloticus,as this habit is used in several fish farms, without an adequate knowledge of its effect on fish quality. Fourfeeding regimes were applied, namely (1) crude chicken manure (CM), (2) processed chicken manure, (3) mixed diets [processed CM (45 days) + commercial fish diet (45 days)], and (4) commercial fish diet (control), for 90 days in glass aquaria. The fish fingerlings were acclimatized prior to the start of the experiment, followed by twice daily feeding and regular monitoring of water quality. The growth performance showed a positive trend from crude CM toward the processed CM as fish diets, leading to an increase in final weight and weight gain. The crude CM recorded the lowest final weight of 11.3g and weight gain of 10.2g, and the lowest survival percentage of 85.1%. Furthermore, mosthaematological parameters displayed the similar trend, except RBCs which showed insignificant changes. The immunological indicators such as WBCs showed anelevation starting from the dispersed diet (crude CM) toward the processed CM and mixed diets, then dropped down in the control trial, reflecting the normal trend against strange fish diets. Blood biochemistry, such as total protein and cholesterol, exhibited significant changes in the crude CM, processed CM, and the mixed trial compared to the control group. Regarding fish quality and nutrional values, fish muscle of fish fed crude CM contained the highest ash value of 7.58%, while it was 5.46% for those fed on the processed CM. However, fish muscles for mixed diets contained 5.19% ash and 62.19% protein. Human risk assessment was presented in this investigation by heavy metals determination. Pb value in fish muscles was 4.86mg/ kg for fish fed the crude CM; it was the highest one of all feeding trials. While, it decreased to 4.06mg/ kg after CM processing. The mixed feeding trial exhibited the lowest level of Arsenic (0.06mg/ kg). Processing chicken manure reduces its disadvantages by converting dispersed materials into pellets, thereby decreasing water pollution. It is not recommended to feed fish on pure crude chicken manure and pure processes of CM during the whole fish rearing, since fish need other nutrients and more energy to reduce the heavy metals formed due to chicken manure utilization. Utilizing a mixture of fish diet and processed chicken manure in fish farms, in controlled quantities, can mitigate environmental pollution. It's essential to implement processing procedures and ensure clean sourcing for optimal results.