Evaluation of Azolla (Azolla pinnata) and Its Supplementary Effect on in Vitro Digestibility and Metabolizability of Crop Residues

A study was conducted for nutritional evaluation of Azolla pinnata and its supplementary effect on digestibility and metabolizable energy (ME) value of the crop residues by in vitro techniques. Different crop residues viz., paddy straw, finger millet straw, maize stover, maize husk, sorghum stover and Bengal gram husk were supplemented with 0 (control), 3, 6 or 9% azolla. The CP, CF, EE, TA, NFE contents of azolla were found to be 21.66, 15.15, 4.41, 17.84 and 40.79%, respectively. The in vitro dry matter digestibility (IVDMD) and the ME content of azolla was 54.49% and 5.44 MJ/kg DM, respectively. There was significant (P<0.05) decrease in ME and IVDMD values for finger millet straw, maize stover and maize husk supplemented with 3–9% azolla as compared to control indicating negative influence of azolla on nutritive value of crop residues. Hence, azolla can only serve as good source of protein, amino acids and minerals with no beneficial effect on digestibility or energy density of crop residues.