NATURAL EXTRACTS IN ANIMAL NUTRITION: ANIMAL WELL¿BEING AND PRODUCTS QUALITY

The main objective of this thesis was to have a deeper knowledge about the influence of feeding strategies with several natural plants extracts on pig performance and meat quality in different phases of pig production. To achieve this objective, a set of 4 studies were performed (chapter 2-6). The first study evaluated the effect of dietary supplementation with a mixture of algae plus polyphenols (AM) in lactating sow on maternal and piglets performance and sows reproductive data until the subsequent farrowing. This study showed that integration of AM in sow diet decreased the fat mobilization during lactation. Moreover, dietary AM inclusion in lactating sows positively affected body weight and average daily gain in piglets at 21 days. Moreover, sows that received AM had more total number of piglets born at the subsequent farrowing. Regarding the effects of plant extracts on meat and product quality, two different studies were performed. In the second study of the thesis, the impact of dietary integration with vitamin E and verbascoside (AOX) in pigs, on carcass characteristics, meat quality, shelf life of pork under modified atmosphere packaging (MAP) was evaluated. This study demonstrated the positive effects of plant extracts as antioxidant. Particularly, highlighted that dietary AOX positively affected carcass dressing percentage and pork oxidative and colour stability. Moreover, sensory analysis revealed that, at 15 days under MAP, meat from AOX was comparable with fresh meat in appearance and aroma. In the same way, the third study showed that vitamin E and verbascoside (AOX) also affected the quality of derived product like smoked cured ham. Results relieved infact that the AOX dietary inclusion affected the seasoning losses and influenced the consumers' preference of smoked cured ham, without affecting other quality parameters. Finally, the fourth experimental trial examined the impact of 3 % hydrolysable tannins (HT) from chestnut extract and two levels of polyunsaturated fatty acid (PUFA) in the diets on growth performance, carcass traits, meat quality and boar taint compounds in entire males. Results showed that dietary HT reduced the feed efficiency but not feed intake and the pigs final weight. These results show that performance, carcass composition and meat quality traits are not affected by dietary 3% chestnut extract supplementation in entire male. The boar taints compounds like androstenone, skatole and indole tended to be lower in HT group. The cytochrome mRNA expression in the liver and colon mucosa was not affected by the diet. No evident relationship between dietary PUFA level and boar taint compound levels was observed. Overall, these results contribute to improve the knowledge regarding beneficial effects of plant extracts. The inclusion of bioactive components contained in natural extracts can be considered an innovative approach to improve pig wellbeing and pork quality without negative effects on animal production.