Author(s): Martins, Cátia Falcão
Date: 2023
Persistent ID: http://hdl.handle.net/10400.5/29145
Origin: Repositório da Universidade de Lisboa
Subject(s): Piglets; Spirulina; Chlorella vulgaris; Digestibility; Enzymes; Leitões; Espirulina; Chlorella vulgaris; Digestibilidade; Enzimas
ABSTRACT - Worldwide swine production will face challenges in the coming years associated with feeding, mainly due to the high cost and environmental impact of importation of conventional feedstuffs. Therefore, the need for sustainable alternative feedstuffs is clear. Microalgae, due to their production systems, may be a sustainable alternative. However, their recalcitrant cell walls decrease nutrient bioavailability for pigs. To solve the association with feed enzymes, namely Carbohydrates-Active enZymes (CAZymes), has been equated. Arthrospira platensis (Spirulina) and Chlorella vulgaris are the two most studied microalgae, as a supplement, in swine feeding. Thus, in an initial approach, the aim of this Thesis was to evaluate the inclusion of 10% Spirulina in diets of post-weaned piglets, supplemented with two CAZymes (Rovabio® Excel AP or lysozyme) on growth performance, nutrient digestibility, health status, liver metabolism and meat quality traits. Growth performance was negatively affected by this dietary inclusion, with a significant increase in digesta viscosity and a lower protein digestibility. The use of lysozyme, in contrast to Rovabio® Excel AP, proved to be more efficient in the degradation of cell walls; however, the released proteins were not absorbed, as animal growth was impaired. Meat quality traits were not affected by the inclusion of Spirulina, individually or supplemented with feed enzymes, as well as no changes were observed on hepatic metabolism despite the improvement in hepatic antioxidant potential, especially in terms of total carotenoids. On a second approach, a post-weaning piglet trial was performed to determine the nutritional value of diets with 5% Chlorella vulgaris, supplemented with two CAZymes (Rovabio® Excel AP or a mixture of 4-CAZymes previously tested in vitro). Chlorella vulgaris inclusion negatively affected the digestibility of nutrients but without direct effects on growth performance, which can be explained by the compensatory mechanisms observed (greater development of the intestinal mucosa and predominance of beneficial bacteria on intestinal microflora). Meat quality traits were not affected by such dietary inclusion. Systematic antioxidant potential, immune response and hepatic lipid metabolism were improved in the groups fed with Chlorella vulgaris. In conclusion, the results indicate that microalgae have the potential to be exploited as ingredients in swine diets, providing meat nutritional enhancement and improving the health status of the animals. However, reducing the production cost and further knowledge of their nutritional value is necessary
