Tannin treatment for protecting feed protein degradation in the rumen in vitro

Abstract

This experiment was conducted to evaluate the effect of tannin extract addition for protecting feed protein from microbial degradation in the rumen in vitro. Design of experiment employed a factorial 5 × 2 randomized complete block design with 3 replicates. The first factor was tannin extract addition, i.e., control without tannin (T0), addition of 2% tannic acid (T1), addition of 2% tannin chestnut (T2), addition of 2% tannin extract from Calliandra calothyrsus (T3), and addition of 2% tannin extract from Clidemia hirta (T4). The second factor was two feed ingredients rich in protein contents, consisted of soybean meal and Indigofera zollingeriana forage. Results showed that there was no interaction between tannin treatment and different protein sources. Tannin addition from various sources significantly decreased degradation of dry matter and rumen degradable protein (P<0.05), but had no significant effects on pH, dry matter digestibility and crude protein digestibility. Comparing among different tannin sources, the best tannin to protect protein degradation was chestnut tannin. Indigofera zollingeriana forage had higher undegradable protein than soybean meal after being added with tannin (P<0.05). It can be concluded that tannin treatment is able to reduce feed protein degradation.