Evaluation of ruminant diets containing lime-hydrolyzed feather meal substituted with soybean meal using in vitro gas production technique

This study was performed aimed at evaluating the effect of substitution of calcium hydroxidehydrolyzed feather with soybean meal (SBM) in ruminant diet using the in vitro gas production technique. Treatment 1 (control) consisted of 70% concentrate + 30% alfalfa hay. In treatment 2, untreated (raw) feather was substituted with SBM. In treatments 3, 4, and 5, feather hydrolysate obtained following hydrolysis with calcium hydroxide in a reactor at 1400 rpm and 100ºC for 100, 200, or 300 min was replaced with SBM. By increasing the reaction time from 100 to 300 min, the feather solubility increased from 50.8 to 90.7%. Diets containing solubilized feather had greater in vitro digestibility (72.9, 79.0 and 69.3%) compared to the diet containing untreated feather (59.2%), but the increase was not directly correlated with pretreatment duration. No significant difference was recorded in ruminal NH3-N between control treatment (7.82 mg/100 mL) and the treatment containing feather pretreated for 200 min (7.64 mg/100 mL), but significant differences were found between untreated feather (4.17 mg/100 mL) and the control treatment. Microbiological evaluation of the pretreated feather samples showed that hydrolysis conditions were effective in controlling microbial contamination. The results showed that feather pretreated for 200 min could be a promising alternative for replacing a portion of proteins in the ruminant diet; however, the actual value of the hydrolyzed feather for ruminants must be determined in in vivo studies.