Sorghum could be a potential substitute to maize in Mediterranean buffaloes feed in order to improve sustainability of buffalo-based agriculture, due to its reduced water and nitrogen requirements compared with maize, which is currently fed primarily. The aim of this study is to obtain information on rumen degradability of fiber fraction of maize and sorghum silages and to investigate the relationship between degradability and rumen microbial populations. As such four cannulated buffalo milking cows were fed ad libitum two different iso-energetic and iso-proteic diets based on: maize silage (MS diet) and sorghum silage (SS diet). Based on plate counts, cellulolytic bacteria values showed of being higher within the rumen of SS fed buffaloes compared to MS fed buffaloes (4.4*109 vs. 1.9*109 cfu/mL, P < 0.05), on the contrary xylanolytic bacteria (3.2*109 vs. 1.3*109 cfu/mL, P < 0.01) were higher in maize silage due possibly to the different fiber degradability. Real-time PCR of total bacteria, Fibrobacter succinogenes, Ruminococcus albus and Ruminococcus flavefaciens revealed no statistical difference between diets in their 16S rDNA concentrations. Maize silage and sorghum silage alone were subsequently utilized for a degradability experiment. For this trial three cannulated Mediterranean dry buffalo cows were used (body weight 580 ± 8.5 kg). The maize silage was found to have an effective degradability of acid detergent fiber, hemicelluloses and cellulose which were always lower than sorghum silage. Maize neutral detergent fiber degradability and slowly degradable fraction were significantly higher (P < 0.01), on the contrary the immediately degradable fraction was found to be significantly lower (P < 0.001) compared with sorghum. The better sorghum relative feed value (P < 0.001) compared to maize was related to the major content of fiber fraction. As recommended by the IPCC (2006), Tier 2 was chosen to estimate the enteric CH4 emission factor. The estimate of methane production is significantly lower in animals eating sorghum rather than maize (63.48 and 103.00 kg CH4/head/yr respectively, P < 0.001). In conclusion, as no difference was observed in animal weight gain and milk yield, rumen microbiota (excluding fiber-degrading bacteria) or degradability, it should be possible to substitute maize silage with sorghum silage in buffalo diet.
|Autori:||Sarubbi, F.;Chiariotti, A.;Baculo, R.;Contò, G.;Huws, S. A.|
|Data di pubblicazione:||2014|
|Titolo:||Nutritive value of maize and sorghum silages: Fibre fraction degradation and rumen microbial density in buffalo cows|
|Rivista:||CZECH JOURNAL OF ANIMAL SCIENCE|
|Appare nelle tipologie:||1.1 Articolo in rivista|