Fermentation characteristics and nutritional value of Opuntia ficus-indica var. Fuscicaulis cladode silage

[摘要] English: A laboratory study was under taken to investigate the nutritional value of different Opuntia varieties from chemical analysis. One year old cladodes from six different varieties of Opuntia ficus-indica namely Castello, Chicco, Fusicaulis, Montery, Morado and Rubasta were randomly harvested in five replicates. The highest (P<0.05) average dry matter (DM) content was observed for the Chicco variety and was the average for all varieties generally low (9.13%). There were no significant difference (P>0.05) in ash content. Significant (P<0.05)differences among varieties were recorded for crude protein (CP) (3.7 to 8.1%), acid detergent fibre (ADF) (13.6 to 17.4%), neutral detergent fibre (NDF) (19.9 to 38.5%), cellulose (2.4 to 14.8%), hemicellulose (4.5 to 12.7%), lignin (2.51 to 21.5%), non fibre carbohydrates (NFC) (33.4 to 48.6%), ether extract (EE) (1.9 to 2.4%). The average mineral composition were as follows, phosphorus (P) 0.18%, potassium (K) 3.02%, calcium (Ca) 2.3%, magnesium (Mg) 3.6% and sodium (Na) 0.04%. It was concluded that in general cladodes could be classified as a high moisture energy source with an energy level between that of roughages and concentrates with a low CP and high Mg, K and Ca content. In a second study the influence of dry matter (7.12 to 27.6 %) and molasses (0 to 24%) content on the fermentation characteristics of Fusicaulis cladode silage was investigated. One year old cladodes was ensiled in three litre square plastic bottles (six replicates). A higher DM content were characterized with a lower (P<0.05) ADF, NDF, CP and EE content. The inclusion of molasses resulted in a lower (P<0.05) ADF, NDF and EE content. An increased (P<0.05) acetic acid (AA) content in Fusicaulis silage was observed as the level of DM and molasses increased. A higher silage DM content resulted in a lower (P<0.05) propionic acid (PA) and butyric acid (BA) content. No significant (P>0.05) influence of molasses on PA and BA occurred. Lactic acid (LA) content and pH of cladode silage was increased (P<0.05) by higher DM and molasses levels. It was concluded that the content of cladode silage could have detrimental effect on intake and animal performance. In a third study, the effect of DM (35.5 and 37.4%) and molasses (0 and 24%) content of ensiled cladodes on dry matter intake (DMI) and apparent digestibility by sheep was investigated. Twentyfour merino wethers were randomly divided into 4 groups of 6 each. No statistical significant (P>0.05) influence of DM and molasses levels in Fusicaulis silage on the apparent digestibility of DM and CP as well as metabolizable energy (ME) content occurred. The inclusion of molasses resulted in a reduction in the ADF (P=0.08) and NDF (P=0.05) digestibilities. Apparent EE digestibility was reduced (P<0.05) by a higher DM level. DM content of cladode silage had no influence (P=0.42) on DMI by sheep. The inclusion of molasses influenced DMI favourably (P=0.54). In contrast with molasses, a higher DM level (37.4%) in silage resulted in a higher (P<0.05) metabolizable energy intake (MEI). Cladode silage supplied more or less in the ME requirements of 30 kg wether lambs. Weight losses were decreased (P=0.07) by the inclusion of 24% molasses. It was concluded that the laxative effect of cladode silage resulted in a higher rate of passage through the digestive tract. Accordingly the digestibility and ME content of cladode silage is relatively low. Accompanied by a low DMI, cladode silage as a sole energy source supplied only in the maintenance requirement of sheep, especially when molasses was included at ensiling.

[发布机构] University of the Free State