Effect of non-extracted and extracted pomegranate-peel on in vitro gas production parameters of inoculum of Ghezel sheep

The objective of this study was to determine nutritive value of water extracted pomegranate peel with or without polyethylene glycol on in vitro gas production kinetic and ruminal parameters such as ammonia production, VFA and protozoa population. Water extraction of secondary metabolites decreased the total phenols (P<0.01), total tannins (P<0.01), free gallic acids (P<0.01) and galotannin (P<0.01). Addition of polyethylene glycol to non-extracted pomegranate-peel increased in vitro gas production at 24 h of incubation (P=0.01), in vitro organic matter degradability (P=0.047), metabolizable energy (P=0.018), truly degraded substrate (P=0.006) and asymptotic gas production (P=0.02), but microbial protein production, partitioning factor and gas yield were not affected. Extracting increased partitioning factor at 24 h of incubation. Adding polyethylene glycol to non-extracted pomegranate-peel increased total VFA (P<0.01) and acetate (P= 0.01) concentrations. N-NH3 production was increased with addition polyethylene glycol in non-extracted and extracted pomegranate peel (P<0.01). Inclusion of polyethylene glycol and using extracting increased population of total protozoa (P= 0.01) and subfamily of Entodiniinae (P<0.01), but adding polyethylene glycol increased subfamily of Diplodiniinae (P= 0.05). In conclusion, polyethylene glycol improved nutritive value of pomegranate-peel and extracting had negative effect on nutritive value of pomegranate-peel, but extracting has negative effect on nutritive value. However, suggests that in vivo studies for effect this by-product on the efficiency of protein and energy in ruminant.