Effect of Maleic Acid on Nutritive Value, Carotenoids Content and In vitro Digestibility of Maize Silage

This study aimed to determine the effects of supplementation of maleic acid (MA) on the silage characteristics, nutritive value, carotenoids contents, and in vitro digestion attributes of maize silage. Maize herbage was ensiled either without (control group: MA0) or with three different doses of 1.0 (MA1), 2.0 (MA2), and 3.0 (MA3) percent (w/w) of the fresh material for 60 days. Supplementation of MA did not change the dry matter (DM), ash, crude protein (CP), ether extract (EE), acid detergent fibre (ADFom), acid detergent lignin (ADL) or TDN contents of the silage. In addition, neutral detergent fibre (aNDFom) content decreased (P<0.001) linearly by the increasing dose of maleic acid dose. However, relative feed value, relative forage quality and non-structural carbohydrate of maize silage increased linearly (P<0.001) by MA. Neither the in vitro total gas and methane production nor the nutritive value of the silage in terms of metabolisable energy (ME), net energy lactation (NEL) and organic matter disappearance (OMd) changed due to maleic acid supplementation. However, the supplementation of MA to maize herbage at ensilaging stage decreased (P<0.01) its α-carotene, β-carotene, γ-carotene, lycopene and zeaxanthin contents in a linear manner with a concomitant increase (P<0.01) in its lutein and total carotenoids contents. It is concluded that maleic acid addition to maize forage at ensiling stage increased the total carotenoids content of the silage without influencing any of the nutrient characteristics.