Resumen:
BACKGROUND: The effect of the inclusion of sunflower oil (SF) and quebracho tannin (QT) in a sheep diet was evaluated. Nutrient
digestibility and nitrogen (N) utilization, as well as in vitro ruminal degradation kinetics, were evaluated at three levels [0, 20 and
40 g kg
−1
of diet dry matter] of SF and QT in a 3
2
arrangement. The treatments were 0 (control); 20 and 40 g of QT and/or SF kg
−1
of the diet. Four intact male sheep (45 ± 1.3 kg) for each treatment were used in the digestibility trial and kept individually in
metabolic cages.
RESULTS: Nutrient digestibility and N balance were not affected by SF. However, QT at 40 g kg
−1
of dry matter decreased (P < 0.05)
nutrient digestibility and also increased the proportion of absorbed N. Both SF and QT reduced (P < 0.05) the slowly degraded
fraction and rate for organic matter and N. Even though the QT had a negative (P < 0.05) effect on nutrient digestibility, this effect
was mild (P > 0.05) when SF was included in the QT-added diets. Moreover, an interaction (P < 0.05) of SF × QT was observed on
the synchronization index as an indicator of the efficiency of rumen microbial protein synthesis.
CONCLUSION: Supplementation of either SF or QT to sheep diets reduced ruminal organic matter and N degradability, reflecting
the compensatory digestion in the post-ruminal track for organic matter feed utilization.
© 2019 Society of Chemical Industry