Effect of ensiling pumpkin (Cucurbita maxima D.) with dried sugar beet pulp on the content of bioactive compounds in silage and its antioxidant potential

• Fresh material and the obtained silages with inoculant and without it were compared.
• Ensiling resulted in increased proportion of SFA and reduction of PUFA in silages.
• Minor losses of carotenoids and e-tocopherol were found in silages with inoculant.
• Ensiling did not decrease significantly the antioxidant potential of silages.

Increased carotenoid and dry matter content in new varieties of pumpkin (Cucurbita maxima D.) make it a valuable fresh feed and a good material for ensiling. The study used the ambar variety of pumpkin (C. maxima D.), which was ensiled with dried sugar beet pulp at a 80:20 ratio of fresh matter. Silages were prepared with or without a commercial bacterial-enzyme inoculant. Silages were made in 20-L mini-silos, 10 for each treatment. The effect of ensiling and the addition of inoculants on fatty acid composition, carotenoids content (β-carotene, α-carotene, violaxanthin, zeaxanthin), α-tocopherol content, total polyphenol content and antioxidant potential of the silages (TAS, FRAP) was studied.Compared to fresh material, silages had a significantly higher proportion of SFA and a significantly lower proportion of PUFA. Inoculant-treated silages were characterized by higher proportions of SFA and a lower proportion of MUFA compared to untreated silages. As a result of ensiling, the content of carotenoids (β-carotene, α-carotene, violaxanthin, zeaxanthin) and α-tocopherol decreased significantly in silages in comparison with fresh material. Comparison of the silages showed that untreated silage had a significantly lower content of β-carotene, α-carotene and α-tocopherol. In comparison with the pre-ensiled material, silages had a higher content of total polyphenols (TPC). The antioxidant potential of the silages (TAS, FRAP) was similar to that of the fresh material and there were no significant differences between silage treatments.