Improve nutritive value of silage based on prickly pear peel by-products

Prickly pear (Opuntia ficus-indica L. Mill) is widely cultivated in arid regions of every continentfor its nutritious fruits and various commercial applications, cactus pear cladodes are used asforage in the most arid regions, while recently prickly pear by-products are studied as ruminantfeed. They are characterised by a high moisture and sugar content; therefore, it is necessary tostudy suitable conservation methods. The aim of this study was to verify the effectiveness of sil-age to preserve prickly pear peels (PP) in a mixture with other by-products at different inclusionlevels (5% straw and 6% or 12% wheat bran). For each treatment, six under vacuum micro-siloswere prepared and, after 40 d of storage, the state of preservation was evaluated. Subsequently,the aliquots were analysed for chemical composition and incubated with sheep rumen fluid toevaluate the fermentation kinetics. The use of wheat bran and straw added to PP resulted in anincrease in dry matter (DM); PP silage with wheat bran was found to have higher protein con-tent and nutritional value. The greater presence of lactic acid was found in PP, such as aceticacid, therefore the lactic/acetic ratio was 2.33, significantly lower than silages with the additionof wheat bran. Silage with 5% straw showed the lowest level of organic matter disappearance(OMD) and the cumulative volume of gas (OMCV) produced during the incubation. The PPshowed the fastest fermentation rate achieved after 12 h of fermentation, while those containingwheat bran, presented a higher maximum fermentation rate (Rmax), which need longer time tobe achieved. Canonical discriminant analysis (CDA) showed clear discrimination of differentsilages based on their chemical characteristics and parameters detected during in vitro incuba-tion. Overall, the silages with the addition of wheat bran can be considered the best and, of thetwo, those produced with the addition of 12% bran. Finally, ensilage represents a conservationtechnique suitable for preserving the nutritional characteristics of PP.