EVALUATING NUTRITIVE VALUE OF POULTRY BY-PRODUCT MEAL USING IN SITU AND IN VITRO GAS PRODUCTION TECHNIQUES

This experiment was designed to determine the chemical composition, rumen degradation kinetics using in situ method and fermentation characteristics and energetic value of poultry by-product meal (PBM) by in vitro gas production technique. In the in situ experiment, three ruminally cannulated Ghezel rams were used to determine degradation characteristics of dry matter (DM), organic matter (OM) and crude protein (CP) of PBM. Nylon bags were filled with 3 g dried and ground samples and then incubated in the rumen of rams for the periods of 0, 2, 4, 8, 12, 16, 24, 36 and 48 h. After the removal of bags from the rumen, bags were washed and dried at 60°C for 48 h and then remaining residues were analyzed and calculated for DM, OM and CP degradability’s. In the in vitro experiment, rumen fluid was obtained from three cannulated rams. Approximately 200 mg samples (as DM basis) were placed into syringes contain rumen fluid-buffer and then incubated at 2, 4, 6, 8, 12, 16, 24, 36, 48, 60 and 72 hours. The results showed that DM, OM, CP and ether extract (EE) content of PBM was 87.64, 81.49, 53.71 and 22.35%, respectively. Effective degradability (at 5% out flow rate) for DM, OM and CP of PBM were 49.93, 52.10 and 49.73%, respectively. Gas production volume at 24 h incubation, estimated OM digestibility, short chain fatty acids (SCFA), metabolizable energy (ME) and net energy for lactation (NEL) contents of PBM were 8.83 ml/200mg DM, 53.13%, 0.192 mmol, 10.38 MJ/kg DM and 5.69 MJ/kg DM, respectively. In conclusion about half of the PBM is degradable in the rumen and remaining escaped into intestine. Thus it may provide sufficient protein to maintain microbial protein synthesis in the rumen as well as un-degradable protein supplies amino acids to the small intestine.