In vitro Study of Neem Bark Extract on Rumen Fermentation and Biohydrogenation of Polyunsaturated Fatty Acids

Aim: An In vitro gas production technique was conducted to assess effects of commercial Neem (Azadirachta indica) bark extract (NBE) on rumen fermentation and biohydrogenation (BH) of selected polyunsaturated fatty acids (PUFAs).

Study Design: There were three (3) treatments, each made up of a total of 32 incubation bottles i.e. 8 bottles for control (contained basal diet, rumen fluid and buffer solution), 8 bottles (basal diet, rumen fluid, buffer solution and 100 mg/l of NBE), 8 bottles (basal diet, rumen fluid, buffer solution and 200 mg/l of NBE) and 8 bottles (basal diet, rumen fluid, buffer solution and 400 mg/l of NBE).

Methodology: All three (3) treatments were incubated at a temperature of 39oC for 12 hours (treatment 1), 24 hours (treatment 2) and 48 hours (treatment 3). During incubation procedure, gas production was measured by using pressure transducer after 3, 6, 9, 12, 24, and 36 hours. Consequently, pH was measured by using pH meter after 12, 24 and 48 hours of fermentation and then incubation was stopped. During this time, digested samples in gas medium were collected for analysis of PUFAs by using gas chromatography. GenStat 15th edition (version 15.1) software was used to analyse collected data in which statistical method of analysis of variance (ANOVA) i.e. one – way ANOVA was used to compare means between treatments.

Results: Results showed that no differences in gas production, pH, changes in concentration and BH of selected PUFAs after 48 hours of in vitro fermentation. However, concentrations (g/100g FA) of linolenic acid at levels of 200 and 400 mg/l of NBE i.e. 0.8 and 0.8 respectively were increased (p< .05) compared to control (0.7). Moreover, NBE at level of 400 mg/l inhibits (p<.05) BH of linolenic acid (92.1%) and docosahexaenoic acid (75.0%) compared to control (92.8%) and (80.3%) respectively.

Conclusion: These findings demonstrated that, NBE possesses bioactive compounds which affect BH of docosahexaenoic and linolenic acids and has little effect on improving fermentation and modifying ruminal BH of PUFAs.