Nanopartículas de extratos vegetais de plantas nativas do Rio Grande do Sul na dieta de leitões recém desmamados, como alternativa ao uso de antimicrobianos

Abstract

The possibility of cross-resistance with human pathogens led Europe to ban the use of most antibiotics as growth promoters in animal feed from 1999. This ban led researchers and nutritionists to look for new alternatives, including the use of plant extracts. These extracts are usually manufactured by micronisation. The innovation of this project is to design and synthesise silver nanoparticles with plant extracts with proven antimicrobial effects, such as Carqueja (Baccharis trimera), Erva Mate (Ilex paraguariensis) and Losna (Artemisia absinthium L), with the aim of enhancing the bacteriostatic action of these extracts in diets for newly weaned piglets. The objective was to evaluate nanoparticulate plant extracts from plants native to Rio Grande do Sul in diets for newly weaned piglets in the nursery phase, in terms of performance, apparent digestibility of the diets, incidence of diarrhoea and morphometry of digestive organs. A total of 144 newly-weaned piglets were used in a randomised block design, with eight treatments: diet without antimicrobials, feed with commercial antimicrobials, diets containing micronised extracts (40 ppm) from Carqueja plants (Baccharis trimera), Erva Mate (c) and Losna (Artemisia absinthium L) and diets containing micronised extracts (40 ppm) of the plants Carqueja (Baccharis trimera), Erva Mate (Ilex paraguariensis) and Losna (Artemisia absinthium L), and a diet containing nanoparticulate extracts (40 ppm) with the same plants, with six repetitions of three animals each. The piglets' weight, daily feed consumption and feed conversion were measured weekly until the end of the experiments, for five weeks each, with repetitions over time, totalling three experiments. Faeces were monitored daily and consistency scores were assigned. Apparent digestibility was obtained after evaluating the gross energy of the diets. Organ morphometry was obtained at the end of the experiment by evaluating the piglet closest to the average weight of the block, weighing it and measuring the length of the different intestinal segments. There were no significant differences (P>0.05) between the proposed treatments. The addition of plant extracts or nanoparticulate plant extracts did not increase animal performance, but they can be used as a substitute for conventional antimicrobials in the diets of newly weaned piglets.