Effects of different fatty acid supplements on rumen fermentation parameters and microbial population in vitro condition

The aim of this study was to determine effects of different fatty acid profiles on rumen digestion coefficients, some of rumen metabolism parameters and rumen microbial populations. Different oils were used as source of fatty acids such as, Oleic, Linoleic, Linolenic, DHA and EPA. Palmitic acid supplemented from a commercial product (BergaFat T-300) containing high Palmitic acid percentage. Results showed that supplementation of unsaturated fatty acids led to reduction in nutrient digestibility and rumen population of protozoa, anaerobic fungi and cellulolytic bacteria (P˂0.05). Fish oil resulted in higher population of proteolytic and amilolytic bacteria in expense of cellulolytic and major biohydrogenating population (P˂0.05). Palmitic acid source reduced population of two of major cellulolytic bacteria, but there were no effects on cell wall digestibility, total and profile of rumen VFA (P>0.05). All of the oil supplements except for Palmitic acid supplement reduced methanogeinic archaea (P˂0.05). Unsaturated fatty acid sources including fish oil greatly reduced rumen biohydrogenating bacteria population (P˂0.05). Rumen total VFA and acetate concentration but not propionate decrease as PUFA sources supplemented. Fish oil resulted in greatest reduction in VFA concentration compared with control (103.9 vs. 74.0 mM/L, respectively).