The chemical composition of selected dried fruit pomaces and their effects on the growth performance and post-slaughter parameters of young turkeys

Abstract

The objective of this study was to verify the hypothesis that add- ing dried fruit pomaces differing in their polyphenol contents to diets for young turkeys does not compromise bird performance. Young turkeys aged up to 15 weeks were fed diets containing a cellulose preparation (C) or 5% dried apple pomace (AP), blackcurrant pomace (BCP), strawberry pomace (SP), or seed- less strawberry pomace (SSP). The crude protein content of AP was 6.64% and exceeded 15% in the remaining pomaces. In comparison with soyabean meal protein, the value of the essential amino acid index was lowest in AP (78.6%), higher in SP and SSP (approximately 85%) and highest in BCP (93.4%). The crude fat content ranged from 2.63% in AP to 13.8% in BCP, whereas the di- etary fibre content was found to be in the range of 56.5% in AP to 62.9% in SP. AP, BCP, SP and SSP were characterized by different polyphenol con- centrations: 5.75, 12.43, 11.51 and 32.81 g · kg -1 of gallic acid, respectively. Dietary inclusion of 5% of dried fruit pomaces that increased the polyphenol content of the experimental diets by a maximum of 0.3 g · kg -1 relative to the control diet did not affect feed intake at the beginning or at the end of the feeding trial. In comparison with the cellulose-supplemented diet, the inclusion of fruit pomaces that increased the dietary polyphenol content did not impair the growth performance of turkeys or feed conversion. Production parameters, including slaughter results, were not affected by the higher polyphenol content or the higher antioxidant potential of blackcurrant and strawberry pomaces, compared with apple pomace.