Influence of Variety and Plant Fractions on Oxalate Content and Nutritional Composition of Pennisetum purpureum, Indigofera tinctoria, and Trichanthera gigantea Siti Nur Haslina Mamat1, Mohammad Mijanur Rahman2*, Renny Fatmyah Utamy3, Md Safiul Alam Bhuiyan2, Rovina Kobun2, Yuli Frita Nuningtyas4, Candyrine Su Chui Len2, Rohaida Abdul Rasid2
1) Faculty of Agro based Industry, Universiti Malaysia Kelantan, Jeli 17600, Kelantan, Malaysia
2) Faculty of Sustainable Agriculture, Universiti Malaysia Sabah, Sandakan 90509, Sabah, Malaysia
*mijanur.r[at]ums.edu.my
3) Department of Animal Production, Faculty of Animal Science, Hasanuddin University, Jl. Perintis Kemerdekaan KM. 10, Makassar 90245, South Sulawesi, Indonesia.
4) Faculty of Animal Science, Universitas Brawijaya, Jl. Veteran, Kota Malang, Indonesia
Abstract
Napier grass (Pennisetum purpureum) is one of the most important tropical forages due to its high biomass yield and favourable carbohydrate that supports efficient rumen fermentation. However, its utilisation is limited by the presence of anti-nutritional factors, particularly oxalic acid, which occurs at higher levels in Napier grass compared to other tropical forages. Excessive oxalate intake can disrupt calcium and magnesium metabolism, leading to metabolic disorders and kidney dysfunction in animals. This study aimed to determine the effects of variety and botanical fractions on oxalate content and proximate composition in Napier grass and selected non-Napier forages. Seven Napier grass varieties (Dwarf, Taiwan, Zanzibar, King, Purple, Pakchong, and Indian) as well as Indigofera tinctoria and Trichanthera gigantea were collected from farms in Kedah and Kelantan, Malaysia. For each plant type, leaves and stems were analysed separately for soluble oxalate, total oxalate, and proximate components contents. Among Napier grass varieties, Dwarf Napier grass exhibited the highest crude protein content, but also contained relatively high levels of soluble oxalate, particularly in the leaves. Overall, oxalate contents were consistently higher in leaves than in stems, mirroring the distribution of nutrients such as crude protein. These findings highlight the importance of considering both varietal selection and plant fractions when formulating feeding strategies to optimise nutritional value while minimising oxalate-related risks in ruminant diets. Selecting appropriate varieties and balancing leaf-to-stem ratios in rations could help reduce oxalate intake without compromising feed quality.
