Current experiments with farm animals showed that it is possible to use grape by-products as a source of nutrients in animal nutrition. In the present experiment, we hypothesize that one reason for the variation among feeding trials, besides production steps affecting byproduct quality in winery, the variation among cultivars may have substantial contribution. The main aim of this study was to analyse grape pomace and stems from the area of Slovak Republic and Austria to evaluate their nutritional value for animals. In total, 54 samples of 3 grape varieties from 6 different locations were analysed. In each variety basic nutrients, antioxidant activity, total phenols, condensed tannins and proteins participation was determined according to standard analytical methods. The results show that the grape pomace had the highest ratio of crude proteins, crude fat and crude fibre with the solid concentrations of sugars, except of variety from red grape. Then, the grape stem is characterised with balanced content of crude protein, crude fibre and nitrogen free extracts with residual sugars and the highest antioxidant activity. By-products from the winery production have average nutritional value because of higher content of lignin that could be limiting factor for the digestibility. Neverthelles, there are interactions between the fibre fractions, condensed tannins, total polyphenols and antioxidant activity. Analysed data shows, that grape by-products have a potential in animal nutrition as a source of bioactive compounds, however there exists differences between the locations and varieties.

The objective of the present study was to determine the fatty acid profile of grape pomace, grape stem and grape bunch of three different cultivars of Vitis vinifera sp. (Green Veltliner, Pinot Blanc and Zweigelt) from two countries as a possible sources for animal nutrition. Fatty acid profile analysis was performed using the Agilent 6890 A GC machine. Significant differences (P <0.05) in fatty acid content of analyzed samples were detected between the countries, as well as between the cultivars within countries. Grape pomaces and grape bunches were rich in polyunsaturated fatty acids (70.91-71.86%), represented mainly by linoleic acid (69.79-70.32%), and low in saturated fatty acids (12.42-12.96%). Grape stems were characterized by a high saturated fatty acids content (24.46-30.85%), but on the other hand, these samples had the highest α-linolec acid concentration (9.98-14.52%). Oleic acid (12.24-15.17%) was the most abundant from monounsaturated fatty acids (12.69-15.33%) in all the analyzed samples. These results indicate a strong impact of the grape variety and location on the fatty acid profile of grape by-products and their potential to be evaluated as feed additives with high polyunsaturated fatty acids concentration in animal nutrition.

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The present study investigated the effect of hydrothermic maize processing and supplementation of amino acids (AA) in two experiments. In total, 60 barrows and 384 broilers were fed four diets including either unprocessed (T1), or hydrothermically processed maize, that is short- (T2), or long-term conditioned (LC) (T3), and subsequently expanded maize of the same batch. Assuming a higher metabolizable energy (ME) content after processing, the fourth diet (T4) contains maize processed as treatment T3, but AA were supplemented to maintain the ideal protein value. Performance, digestibility and product quality in both species were assessed. Results show that in pigs receiving T4 the average daily feed intake was lower compared with the other treatments, whereas no difference was observed in broilers. The T3 improved the feed conversion rate compared with T1 (P<0.10) for both species. In contrast, average daily gain (ADG) (1277 g/day for T2 and 1267 g/day for T3 v. 971 g/day for T1) was only altered in pigs. The hydrothermic maize processing increased the apparent total tract digestibility (ATTD) of dry matter, starch and ether extract after acid hydrolysis. This may be a consequence of higher ATTD of gross energy in the finishing phase for both animal species, suggesting a higher ME content in diets with processed maize. The higher ME content of diets with processed maize is supported also by measurements of product quality. Supplementation of AA in T4 enhanced the loin depth in pigs as well as the amount of breast meat in broilers. Further effects of processing maize on meat quality were the reduced yellowness and antioxidative capacity (P<0.10) for broilers, likely due to the heat damage of xanthophylls and tocopherols. Processing also increased springiness and chewiness (P<0.10) of the broilers breast meat, whereas the loin meat of pigs showed a decreased lightness and yellowness (P<0.10) in meat when hydrothermic processed maize was used (for T2, T3 and T4). LC processed maize (T3) showed the lowest springiness in pork, however the supplementation of AA in T4 did not show differences between the treatments. Shown results demonstrated positive effects of hydrothermic processing of maize on animal performance and digestibility in both species. However, effects on carcass characteristics and product quality differed. The negative effects on product quality could be partly compensated with the AA supplementation, whereas a change in meat colour and reduced antioxidative capacity was observed in all groups fed hydrothermic maize processing.

This study investigated the effects of sorghum ensiled as whole grains with different dry matter concentrations on the apparent total tract digestibility (ATTD) of energy, crude nutrients and minerals in growing pigs. Whole grain sorghum batches with varying dry matter (DM) concentrations of 701 (S1), 738 (S2) and 809 g kg−1 (S3) due to different dates of harvest from the same arable plot, were stored in air-tight kegs (6 L) for 6 months to ensure complete fermentation. Subsequently, 9 crossbred barrows (34.6 ± 1.8 kg; (Duroc x Landrace) × Piétrain)) were used in a 3 × 3 Latin square feeding experiment. Diets were based on the respective sorghum grain silage and were supplemented with additional amino acids, minerals and vitamins to meet or exceed published feeding recommendations for growing pigs. The ATTD of gross energy, dry matter, organic matter, nitrogen-free extracts, and crude ash were higher in S1 compared to S3 treatments (p ≤ 0.05), while S2 was intermediate. Pigs fed S1 showed significantly higher ATTD of phosphorus (P) compared to all other groups while ATTD of calcium was unaffected irrespective of the feeding regime. In conclusion, growing pigs used whole grain sorghum fermented with a DM concentration of 701 g kg−1 (S1) most efficiently. In particular, the addition of inorganic P could have been reduced by 0.39 g kg−1 DM when using this silage compared to the variant with the highest DM value (809 g kg−1).