Evaluation of Fermented Mixed Leaf Meal as an Alternate Protein Source in the Diet of Labeo rohita Fingerlings

Abstract

The present study was designed to evaluate the potential of solid-state fermented mixed leaf meals (SFMLM), comprised of Sesbania bispinosa, Glycine max, Leucaena leucocephala, and Eichhornia crassipes leaves as an alternative protein source in the diet of Labeo rohita (Hamilton, 1822) fingerlings. Fermentation was carried out over 7 days using different microbes (Bacillus subtilis, B. megaterium, Lactobacillus plantarum, Chaetomium globosum, Saccharomyces cerevisiae and Aspergillus niger) either individually or in combinations. Nutritional quality of each combination was analysed at every 24 h interval. Fermentation significantly reduced the antinutritional factors such as phytic acid, tannins and saponins, making it superior than that of only mixed leaf meal (MLM). The best nutritional quality was obtained using a combination of B. megaterium, L. plantarum and S. cerevisiae fermented for 3 days. This SFMLM was used in a 60-day feeding trial. Five isonitrogenous (crude protein 30%) and iso-caloric diets (Digestible energy: 346 kcal/100 g) were formulated with 0% (C), 10% (T1), 20% (T2), 30% (T3), and 40% (T4) SFMLM. A total of 225 acclimated L. rohita fingerlings (5.2 ± 0.01 g) were randomly distributed across treatments in triplicate. Among the groups, T2 showed significantly higher (p < 0.05) weight gain, specific growth rate, and lower feed conversion ratio in L. rohita fingerlings. The activities of protease, lipase, and amylase were also significantly higher (p < 0.05) in this group. Hence, it can be concluded that the 20% solid-state fermented mix leaf meal (SFMLM) can effectively replace the traditionally used oil protein source in L. rohita diets without compromising the growth.