ABSTRACT
Antinutritional components must be substantially reduced to ensure better utilization of unconventional feeds in animal nutrition. Among the different methods of processing, soaking represents a simple and inexpensive alternative. This study attempted to determine the nutritional properties of socked Jatropha curcas kernel (JCK) and the effect of its dietary inclusions on Clarias gariepinus (n = 50; mean initial weight = 6.19 ± 0.52 g). Three treatments of JCK (i.e., soaking 24, 48, and 72 h) were tested alongside a control group. The result showed that soaking substantially improved proximate composition and reduced anti-nutrient compared to the control JCK. A similar trend of improved performance was observed when the treated JCK was included in diets composed of 35% crude protein; a total of 315 kcal g-1 energy and fed to C. gariepinus for 56 days. Alongside the improvement observed in growth, it was also noted that carcass protein and haematological variables were improved with the dietary administration of soaked JCK. Histological examination of the intestine and liver tissues also revealed fewer signs of histopathological degeneration in the fish, consequent upon dietary inclusion of soaked JCK (i.e., 72 h) compared to those raised on the raw JCK-included diets. It was, therefore, concluded that soaking could be a much easier method of nutritionally improving JCK for the administration to C. gariepinus.
ABSTRACT
The nutritional value of Jatropha curcas kernel (JCK) can be improved through different processing methods; however, when using a thermal treatment, optimization of the process is needed to prevent denaturation of nutrients. In this study, JCK was toasted for varying durations (0, 10, 20, and 30 min) and nutritionally evaluated. The implication of feeding Clarias gariepinus with dietary inclusions (35% CP; 315 kcal g-1) of the toasted JCK was also reported. The results obtained suggest that prolonged duration of toasting improved the nutritional characteristics of the JCK until the 20th min. Beyond this time, the protein content and essential amino acids are reduced. However, the antinutrients continuously decreased with prolonged processing. The growth, carcass analysis, and haematology of the fish groups fed toasted JCK at varying duration also did better than those fed raw JCK. Importantly, the performance tends to reduce for those fed JCK toasted beyond 20 min. The estimated cost of producing 1 kg of the fish also substantially reduced with feeding the processed JCK than feeding raw JCK. Histological examination of the intestine and liver tissues further revealed fewer signs of histopathological degeneration for fish-fed processed JCK compared to the control. It was concluded that the processing of JCK by toasting should not exceed 20 min to improve the nutritional composition of the feed ingredients and their dietary utilization by fish.
Subject(s)
Catfishes , Hematology , Jatropha , Animal Feed/analysis , Animals , Diet/veterinaryABSTRACT
This study evaluated the effects of cooking for different hydrothermal-treatment durations (10, 20, 30 and 40 min) on the proximate composition, amino acid profile, fatty acid composition and organoleptic parameters of filets of African catfish Clarias gariepinus (Burchell, 1822). Filets of the fish were prepared from market size African catfish with similar breeding history. Parameters of the processed filet under the different hydrothermal durations were also compared against a raw-unprocessed control group except during organoleptic analysis. The results obtained revealed a significant increase in protein, fat and ash content until the 30th minute of hydrothermal processing (p ≤ 0.05). Beyond this processing time, protein and fat significantly reduced while ash remains unaffected. The same trend was observed for most essential/non-essential amino acids isolated as well as the prominent saturated fatty acids, monounsaturated fatty acids and polyunsaturated fatty acids. In all, the raw control group consistently recorded the least values of nutritional components. The perception of assessors was, however, found to be similar (p ≥ 0.05) in terms of organoleptic parameters regardless of the duration of the processing time of the filets. It was concluded that cooking the African catfish filet using the hydrothermal method should not be extended beyond 30 min.
