Avaliação in vitro da quitosana como aditivo em dietas para ruminantes

Abstract

There are mechanisms to enhance the performance of ruminant through manipulation of ruminal fermentation patterns, so that changes in the ruminal ecosystem leverage the synthesis products from digestion of food, making it more effective and less costly in terms of energy. Chitosan is a naturally occurring polysaccharide that has shown great versatility and promising properties for safe use in a wide variety of products and applications, chemical flexibility is one of the advantages that allows the optimization of their biological profile. As an alternative to replace antibiotics additives, this study aimed to evaluate the effect of including chitosan levels on diets with different forage: concentrate. Three experiments were conducted in which:Experiment 1 evaluated the effect of chitosan levels in vitro digestibility of organic matter (IVOMD), dry matter (DM), neutral detergent fiber (IVNDFD) and protein (IVCPD) in different forage: concentrate in vitro digestibility MS and nutrients;Experiment 2 evaluated the ruminal fermentation in rumen fluid in vitro with different forage: concentrate combined with chitosan levels; and Experiment 3 evaluated the effect of chitosan levels in kinetic parameters of degradation made in vitro in gas production system with different forage: concentrate. As rumen fluid donors used two from Jersey cows fitted with rumen cannula, with approximate average weight of 360 kg, kept in paddocks consist of grass Marandu, receiving only mineral supplementation. For determining the in vitro digestibility of nutrients and in vitro fermentation parameters were used: four levels of chitosan (0, 1625, 3500 and 7500 mg / kg DM) and five ratio forage to concentrate (100: 0, 65:35, 50:50, 35:65, 20:80); and the test for fermentation kinetics for gas production technique were evaluated five levels of chitosan (0, 400, 800, 1200 and 1600 mg / kg DM) and six ratio forage concentrate (100: 0; 80:20; 65 : 35; 50:50; 35:65; 20:80). In Experiment 1 was no effect of the main factors and the interaction between the chitosan levels and ratio V:C in IVDMD and IVCPD. effect was observed only major factor in IVDMD and IVNDFD. The results showed that chitosan negatively affects the digestibility of dry matter with increasing doses irrespective of the diets. In Experiment 2 was observed significant effect in relation V C and the time for the pH, which maintained their mean minimum limit of 6.2 for the occurrence of the maximum activity of microorganisms, as well as microbial growth, ruminal fermentation and degradation of NDF; time interaction effect with the relations V:C for concentrations of ruminal ammonia. Corroborating the digestibility data, which showed a decrease in IVCPD indicating a reduction in deamination of diets with decreasing quadratic effect. In Experiment 3 was a significant effect of chitosan on the parameters A (fast fraction), C (time - lag time), D (slow fraction), and A + D (cumulative gas production of fast and slow fractions); significant effect relations of V C for parameters A, C, D, E (production rate of the slow fraction per hour), and A + D; significant interaction of the main factors for the parameters A, C, D, E and A + D. With the increasing addition of chitosan increases gas production and reduces the time of fermentation with high concentrate diets, featuring greater efficiency in the diet degradability confirming its potential use more energy for ruminant diets. Chitosan changes the parameters evaluated more efficiently at the lowest dose of 1722 mg / kg DM for all diets.