Plant secondary compounds in ruminant feeding: implication and effect on meat fatty acid.

Abstract

According to FAO, about 9 billion of people will ask for food by 2050. The agriculture challenge is to increase food production by preserving food quality and natural resources. According to WHO, red meat can favor the onset of cardiovascular disease and colon-rectal cancer; however, they are also an important source of vitamin, protein and functional fatty acids (CLA, EPA, DHA). Future animal breeding techniques aims will be improving food nutritional profile and reducing environmental impact at the same time. Rumen lipolysis and bio-hydrogenation allow the synthesis of a pool of fatty acids; this process is affected by animal diet. Pasture feeding increase omega-3 and CLA content in food; however, the problems related to pasture availability ask for innovative techniques that promote their synthesis even if green herbage is not present. The use of plants, or plant-extracts, containing bioactive compounds represents an achievable prospect. The aim of this PhD was to deepen how different plants bioactive compounds affect fatty acid composition in lamb meat. In the first experiment, the use of Trifolium pratensis (containing polyphenol oxidase enzyme, PPO) and Onobrychis viciifolia (containing condensed tannins, CT) silages were tested. The effect of PPO and CT on rumen lipid profile was comparable and even additive when silages were supplied as a mixture. In this case, meat fatty acid profile was similar to pasture-fed animals. In the second experiment, three plants extract were added to lambs diet: hydrolizable tannins from chestnut (Castanea sativa), CT from mimosa (Acacia dealbata) and from gambier (Uncaria gambir). The effect of the different source of tannins on meat fatty acid composition was not very strong; however, multivariate analysis allowed discriminating the different groups.