The effect of sodium hydroxide and alkaline hydrogen peroxide on chemical composition of wheat straw and voluntary intake, growth and digesta kinetics in store lambs

Wheat straw was treated with alkaline hydrogen peroxide (AHP) by either spraying (spray AHP, E) 250 ml of AHP solution containing 20 g H2O2 and 8.3 g NaOH kg(-1) straw dry matter (DM) or by soaking (dip AHP, F) straw in 2% AHP solution to give a final concentration of 57 g H2O2 and 19 g NaOH kg(-1) DM, The AHP-treated straws were compared with A, B, C and D straws treated respectively with 0, 8.3, 25 and 50 g kg(-1) DM of NaOH alone in a feeding trial using 36 Dorset Down x Mule store lambs. A digestibility trial using 7 wethers, selected from the feeding trial, in a 7 x 4 incomplete Latin square was also conducted to examine the effects of these treatments on the extent of nutrient digestion and rates of passage (k(1) and k(2)). Neutral-(NDF), Modified acid-(MADF), Acid-detergent fibre (ADF) and Acid-detergent lignin (ADL) in the straw organic matter (OM) changed quadratically with increasing NaOH alone from 0 to 50 g kg(-1) DM. AHP had different effects on composition depending upon the mode of application. Spray treatment (E v B) did not alter composition but the dip treatment F had less NDF and more MADF, ADF and especially ADL than treatment C. Voluntary straw intake (VSI), liveweight gain (LWG), LWG/W-0.75 and digestibility increased linearly (P < 0.001) with the increase in NaOH alone from 0 to 50 g kg(-1). Spray AHP did not affect VSI, LWG or digestibility compared with either untreated straw or straw treated with the same amount of NaOH alone. Dip AHP tended to increase (P > 0.05) VSI, LWG and LWG/W-0.75 but decreased DM, MADF (P < 0.05), OM (P < 0.01) and NDF (P > 0.05) digestibility compared with untreated control and reduced VSI, LWG and LWG/W-0.75 (P < 0.05) and all digestibility parameters (P < 0.001) compared with treatment with NaOH alone (C), Spray AHP treatment increased (P < 0.05) rate of passage (k(1) measured with Yb) compared with NaOH-treated control. Dip AHP treatment showed a similar trend (P > 0.05). AHP did not result in any gross ill effects on animal health.