Assessing the efficacy of graded levels of Azolla (Azolla pinnata) on nutritive value and methane production: An in vitro rumen fermentation study

Abstract

This study aimed to investigate the effect of dried Azolla (Azolla pinnata) graded levels on nutritive value and methane production using the rumen in vitro gas production technique. The experiment consisted of three treatments. The first treatment (T1) was a mix of 30% alfalfa hay and 70% concentrate feed mixture (CFM) as a control. The second (T2) and third treatments (T3) were the same as the control group, but 50% and 100% of soya bean meal (part of CFM) were replaced with dried Azolla for T2 and T3, respectively. The data showed that the inclusion of gradually levels of Azolla in the experimental rations didn’t show negative effects on fermentation and nutritive value. Total gas production (GP) after incubation for 24 hours, in vitro dry matter degradation (IVDMD), in vitro organic matter degradation (IVOMD) and neutral detergent fiber degradation (NDFD) had similar values among the tested rations, but without significant differences. On the other hand, graded levels of Azolla resulted in a significant (P<0.05) reduction in metabolizable energy (ME), total digestible nutrients (TDN) and methane production. TDN decreased by 2.63 and 3.50% for T2 and T3 compared to T1, respectively. Methane production was reduced by 31.92 and 47.30% for T2 and T3 compared to T1 respectively. Generally, increasing Azolla levels had no deleterious effects on nutritive value and resulted in a higher reduction in methane production.