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Influence of soybean meal supplementation with tannins extracted from pistachio hulls on performance and feed efficiency of Holstein bulls
The objective of this study was to examine the effects of soybean meal (SBM) supplementation with pistachio concentrated extract (PEC) on performance and feed efficiency of Holstein bulls. The sun dried pistachio hulls was grounded through a 0.5 mm screen and soaked with ratio of 1:10 in (pistachio: water). Filtered extract was concentrated by heating at 95 ̊C. The SBM was treated with PCE containing 11.14 % total phenol and 7.13% total tannin /DM of extract. The experiment duration was 14 weeks and involved 28 growing young bulls (256±56 kg BW) in a completely randomized design. The study lasted 94 d (10 d adaption). Treatments included: (1); control (SBM without PEC) (2); SBM with 5% PEC (3); SBM with 10% PEC and (4); SBM treated with 15% (kg PEC/100kg DM SBM). Diets were formulated to meet nutrient requirements according to NRC (1996) and to be isocaloric and isonitrogenous, with forage concentration ratio of 30:70. The TMRs were supplied ad-libitum to bulls in two equal meals (08.00 and 17.00) and bulls had free access to fresh water. Body weight (BW) of each calf was recorded every 28 days before the morning feeding. Results indicate that, tannin supplementation did not affect (P<0.05) final BW and dry matter intake but there were significant differences among treatment 15% and control in average daily gain (1.25 Vs. 1.06 consequently, P<0.01) and feed efficiency (gain: feed) (6.62 Vs. 7.82 consequently, P<0.05). So it seems that the high level of PCE can improve performance and feed efficiency of Holstein bulls.
Keywords: Holstein bulls, pistachios hulls, Soybean Meal, tannin