Physico-Chemical Properties and In Vitro Fermentation Evaluation of Ensiled Guinea Grass (Panicum Maximum) With Different Protein Additives

Abstract

Preservation of guinea grass with protein additives as silage for dry-season feeding makes it possible to preserve and improve its nutritional composition. Consequently, research was carried out to investigate the nutritive values of Guinea grass (Panicum maximum) ensiled with different protein additives. Guinea grass was ensiled with Tephrosia bracteolata, cassava tops, soybean meal, poultry litter, and urea to obtain the following silages: Guinea grass only (Gg) control, Gg + Tephrosia bracteolata (Gg + Tb), Gg + cassava tops (Gg + Sbm), Gg + poultry litter (Gg + Pl), Gg + urea (Gg + U), and Gg + soybean meal (Gg + Sm) respectively) and designated as follows: T1, T2, T3, T4, T5 and T6. The guinea grass was ensiled with 10% protein additives except urea, which was added at a 3% level, and each treatment was replicated four times. After nine months (9 months) of fermentation, the silages were opened, and physical characteristics, chemical composition, and in vitro fermentation evaluation were determined using standard techniques. The silages were characterised by a greenish-yellow colour, a firm and dry texture, a pleasant and fruity odour, and not being mouldy. All these characteristics indicate that the silage was preserved well. The temperature (0 C), pH (3.41–5.69), percentage moisture content (62.39–71.79%), and dry matter (28.01–37.86%) of the silages were significantly (P 0.05) different across the treatments. Furthermore, the results of the chemical analysis showed that all the nutrients in the silages were significantly (P 0.05) different except the EE, which was similar across the treatments. The crude protein (CP) contents (10.91–21.78%) and crude fibre (CF) levels (24.47–27.00%) of silages varied significantly (P 0.05) across the treatments. Fibre fractions (neutral detergent fibre (NDF) 58.03–61.47% and acid detergent lignin (ADL) 13.23–15.53%) were significantly (P 0.05) different, while acid detergent fibre (ADF), cellulose, and hemicellulose were similar across the treatments. There were significant (P 0.05) differences in in vitro fermentation means of methane (5.00–6.00%), total gas volume (9.00–15.00 ml), metabolisable energy (4.20–4.92 KJ/DM), short chain fatty acid (0.16–0.31 ml), dry matter degradability (32.35–42.36%), organic matter digestibility (35.35–42.36%), and fermentation efficiency (2.78–4.24). The results obtained from this study indicate that all the protein additives used in ensiled guinea grass improved the protein contents significantly, and in vitro fermentation gas production indicates a low level of methane (CH4) production, an indication of a reduction in energy loss.