Effect of tea oil and sunflower oil on rumen fermentation, milk composition and rumen microbial population in water buffaloes fed elephant grass-based diets

Abstract Text:

The objective of this study was to investigate the effect of tea oil and sunflower oil on rumen fermentation, milk composition and rumen microbial population in water buffaloes fed elephant grass-based diets. Thirty two lactating water buffaloes were allocated at random to 1 of 4 treatments composed of elephant grass and concentrates containing no additional oil (Control group), or supplemented with 200g of sunflower oil(SF group), 200 g tea oil(TO group), 200 g sunflower oil and tea oil (SF:TO=1:1, ST group). On d 7, 14, 21, 28, samples of milk were collected for milk composition analysis using GC and a MilkoScan FT120. On day 28, rumen fluids was collected by stomach tube and used for pH, VFA, NH₃-N determination and DNA extraction. Total bacteria, Methanogens, fungi, protozoa, R.flavefaciens, F.succinogenes, and Butyrivibrio group were quantified by relative real-time PCR. Compared with the control, dietary supplements of 200 g tea oil or sunflower oil alone or in combination with each other decreased the concentration of NH₃-N and milk production significantly (P < 0.05). Concentrations of milk fat and total solids were greater than control group after oil supplementation (P < 0.05). Oils supplementations have no effect on concentrations of milk protein and lactose. Acetate: propionate ratios were significantly increased after oils supplementation (P < 0.05). Concentrations of acetate, propionate, butyrate and total VFAs were not affected by oils supplementation. C18:2 and c9t11-CLA were increased by sunflower oil or the combination of sunflower and tea oil (P < 0.05). Only Cis9 C18:1 was increased after tea oil supplement alone (P < 0.05). Inclusion tea oil resulted in greater concentration of milk fat, Cis9 C18:1 and total solids and less concentration of NH₃-N and milk production. Methanogens, fungi, protozoa, R.flavefaciens, F.succinogenes, and Butyrivibrio group populations were not influenced by oil supplementation. In conclusion, tea oil or sunflower oil manipulated ruminal fermentation and milk composition without effect on abundance of fibrolytic bacteria and Butyrivibrio group when water buffaloes were fed elephant-grass based diets.

Keywords: water buffalo, rumen, milk composition