Efficiency of Bark Extract of Azadirachta indica on Improving Ruminal Ammonia – Nitrogen Utilization in Ruminants: An In vitro Study

Aims: An in vitro gas protocol was performed to assess the potential of Commercial bark extract of Azadirachta indica (BEA) on improving ruminal ammonia (NH3) utilization in ruminants.

Study Design: The experiment consisted with three (3) treatments, each made up with 16 incubation bottles i.e. four (4) replicates for control (no addition of BEA, contained mixed contents of basal diet, rumen fluid and buffer solution), four (4) replicates (mixture of basal diet, rumen fluid, buffer solution and 100 mg/l of BEA), four (4) replicates (mixture of basal diet, rumen fluid, buffer solution and 200 mg/l of BEA) and four (4) replicates (mixture of basal diet, rumen fluid, buffer solution and 400 mg/l of BEA).

Methodology: All three (3) treatments were incubated at a temperature of 39oC. Treatment 1 was incubated for 12 hours, treatment 2, (24 hours) and treatment 3 (48 hours). During in vitro incubation, gas production was measured using pressure transducer after 3, 6, 9, 12, 24 and 36 hours and also pH by using pH meter after 12, 24 and 48 hours in order to assess fermentation process. After pH measurement, incubation was stopped and samples were collected from each replicate across each treatment and stored in the refrigerator for some days before were analysed for NH3 determination using microtiter plate reader. GenStat 15th edition (version 15.1) software was used to analyze the data and statistical method of analysis of variance (ANOVA) i.e. one – way ANOVA was preferred to compare means between treatments.

Results: No statistical differences (p >.05) in ammonia production after 12, 24 and 48 hours of in vitro fermentation. Additionally, there was no pH variation after 12 hours of in vitro incubation, however pH at level of 200 mg/l was higher (p < .05) compared to other treatment levels. After 48 hours, pH at level of 400 mg/l was lower (p < .05) than the rest levels. Nonetheless, after 6, 9, 12, 24 and 36 hours of fermentation, BEA reduced gas production in all levels except at the level of 400 mg/l in which gas production were statistically similar with control after 24 and 36 hours of in vitro fermentation.

Conclusion: Concentrations of 100, 200 and 400ml/g of BEA, cannot enhance ruminal ammonia utilization but can affects fermentation in vitro. This might be caused by the presence of bioactive ingredients in Azadirachta indica which cannot affects hyper ammonia-producing bacteria but can limits growth of other ruminal microbes which digest fiber.