Animal Nutrition and Feed Technology

This study was taken up to assess nutritional worth of floating aquatic macrophytes like Azolla pinnata (family: Azollaceae), Lemna minor (family: Lemnaceae), Spirodela polyrhiza (family: Araceae) and Salvinia molesta (family: Salviniaceae); and evaluated the best one as the goat bucks feed supplement. The DM content was very low in the above macrophytes (3.0 to 9.0%). Azolla had the highest (P<0.01) concentration of CP, water-soluble sugars, reducing sugars and true protein. All the aquatic macrophytes were rich in macro and micro minerals. Salvinia had the highest (P<0.01) concentration of heavy metals like arsenic, lead, chromium, and tin. The lowest concentration of arsenic and lead was observed in spirodela, chromium in azolla and tin in lemna. The concentration of all the tested heavy metals was well below the maximum tolerance limit. The in-vitro gas production studies revealed that the Azolla had the second highest net gas production and lowest methane production potential. Azolla was therefore, supplemented to the TMR fed to goat bucks at 5% on DM basis. The dietary supplementation of azolla improved DM intake, digestibility of nutrients and N-retention in goat bucks. It did not have any adverse impact on the health of animals. It was concluded that the tested floating aquatic macrophytes were rich in CP, macro and micro minerals. Heavy metals were well below the maximum tolerance level. Azolla having an edge over other macrophytes was supplementing to the TMR of goat bucks. The nutrient utilization and N-retention were not affected, except the digestibility of ADF, which was improved significantly in goat bucks.