Evaluation of degradability and ruminal kinetics of soybean meal subjected to strategies to maximize protein escape from the rumen

Abstract

The objective of this experiment was to evaluate the in situ dry matter degradability and in situ crude protein degradability of soybean meal subjected to different treatments (thermal, chemical, tannins or saponins). The treatments were: conventional soybean (CON); soybean expeller (EXP); lignosulfonate-treated soybean meal (LIGS); condensed tannin-treated soybean meal (CTAN); hydrolysable tannin-treated soybean meal (HTAN) and Yucca schidigera extract-treated soybean meal (YUC). Samples of 5 g soybean meal were packed in nylon bags and incubated in the rumen of 2 fistulated cattle for seven incubation times (0, 3, 6, 9, 12, 18 and 24 hours), in sequence were washed, dried and weighed. The ruminal kinetics parameters were calculated, and the experiment was completely randomized, with six treatments, four replicates each, with duplicates. The EXP and LIGS treatments showed lower crude protein disappearance (CPD) within 12 hours, the CON, HTAN and YUC treatments had the highest CPD, and the CTAN presented an intermediate value (41.84%) (P < 0.05). EXP had the lowest fraction “a” (soluble) of crude protein (CP) (10.1%) followed by LIGS and CTAN (average of 14.82%). EXP and LIGS had the highest rumen undegradable fraction of CP (57.35 and 51.62%), respectively. In addition, ruminal disappearance rates of dry matter and CP of the treatments ranged from 2.17 to 1.36% h-1 and from 2.63 to 1.2% h-1, respectively. The most efficient treatments to reduce ruminal protein degradation were EXP, LIGS and CTAN.