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Abstract: This study determined the chemical composition and metabolizable energy (ME) value for ruminants of seeds and pulps from grape pomaces (GP), which were produced from white and red Vitis vinifera cultivars in Italy and California (USA). Six Italian (i.e., three white and three red) and five California red cultivars were collected after the crush of grape juice had been completed and were ensiled in micro-silos for 45d. Fresh and ensiled samples were manually sieved to separate seeds from the pulp plus skin fraction and an overall inventory of 44 samples was obtained from the 24 Italian and 20 California samples (i.e., seeds and pulp fractions, fresh or ensiled from 6 or 5 cultivars, respectively). Both in seeds and pulp, the red Italian samples had higher organic matter (P<0.01), ether extract (P<0.05), neutral detergent fiber (aNDF, P<0.01), acid detergent fiber (ADF, P<0.01), lignin(sa, P<0.01) and Cu (P=0.02 and P<0.01, respectively) relative to the California red samples. In addition, K (P<0.01), Fe (P<0.01) and Zn (P=0.03 and P<0.01, respectively in seeds and pulps) were higher in red samples from California versus those from Italy. Italian white samples had higher saponins in pulp (SAP, P<0.05) and tended to have higher total extractable phenolics both in seeds and pulps (P=0.07 and P=0.10, respectively) than did Italian reds. Both in seeds and pulps, ensiling increased concentrations of aNDF (P<0.01 and P=0.08, respectively), ADF (P<0.01) and lignin(sa) (P<0.01 and P=0.03, respectively), had no impact on mineral levels and decreased concentrations anthocyanins (P=0.05) and SAP (P=0.01), respectively in seeds and pulp. Samples were fermented in diluted rumen fluid to measure in vitro rumen fermentability in terms of gas production, which was used to predict ME. Gas production from seeds of different origin were similar, with the exception of higher values at 48h in red California cultivars with respect to those from Italy (19.2ml versus 18.0ml, P<0.05). In pulps, Italian reds did not differ from Italian whites, but had lower gas production than the red California samples (9.2ml versus 12.2ml, 16.6ml versus 21.3ml, 26.3 versus 32.7, P<0.01, at 4, 24 and 48h respectively). Ensiling reduced gas production in seeds at 24 and 48h of incubation (P<0.01) and in pulps at 48h (P=0.09). Seeds from Italian red samples were lower (P<0.01) in ME than Italian whites (6.23MJ/kg DM versus 6.89MJ/kg DM, P<0.01) and higher (P<0.01) than the California samples (5.58MJ/kg DM). There were no differences between ME of the groups of pulps, but ensiling reduced estimated ME content in seeds (5.94MJ/kg DM versus 6.54MJ/kg DM, P<0.01), but not in pulps. On the basis of our results, and in agreement with other recent papers and/or textbook data, the potential to use de-seeded GP as a feed in diets of high producing ruminants is limited. [Copyright &y& Elsevier]

Abstract: The experiment compared reductions in the level of N fertilisation of corn crop (i.e., no N fertilisation; 0-N, or 150kg of N/ha; 150-N) with those currently adopted in the Po valley of North Italy (i.e., 300kg of N/ha; 300-N) on chemical and nutritional characteristics of grain, stalks and leaves in corn hybrids selected for whole plant silage production (i.e., FAO 700 maturity). Grain composition and starch availability for digestion was examined at three stages of maturity of the kernels (i.e., ½ milk line, ¾ milk line and black layer). One hybrid had a lower grain yield (15.2 versus 16.0–16.8tonnesDM/ha; P<0.05), while all hybrids were similar in whole plant yield. Levels of N fertilization of 150-N and 300-N resulted in similar yields of grain and whole plants, which were 17 and 33% higher, respectively (P<0.01) than 0-N plots. Hybrids were similar in chemical composition. Reduction of N fertilisation from 300-N to 0-N lowered (P<0.01) the crude protein content in grains, leaves and stalks (P<0.05 in apical part of stalks) and reduced the zein content in grains from 43 to 33g/kg DM (P<0.01). Vitreousness of grains was not influenced by N fertilisation, while the highest (P<0.01) gas production was at the short incubation time of 2h for grains with 300-N. Reduction of fertilisation levels (i.e., 150-N and 0-N versus 300-N) lowered (P<0.01) NDF degradation in the basal stalks (0.385 and 0.392 versus 0.412) and leaves (0.604 and 0.620 versus 0.622). Stage of maturity of grain did not interact with the N level of fertilization, and advanced maturity was associated with a marked increase (P<0.01) in zein content from 36 to 49g/100g CP and in grain vitreousness from 31 to 40g/100g endosperm and with a reduction of the gas production, which had the lowest values at 2 and 48h (P<0.01) of incubation. Overall, reductions in N fertilisation of corn crop slightly lowered the crude protein content and fiber degradation of different part plants. In grains, the lowest N fertilisation (i.e., 0-N) reduced the zein contents and increased rumen fermentability. [Copyright &y& Elsevier]