Líquido da casca da castanha de Caju(Anacadium occidentale L.) e Óleo de Mamona(Ricinus communis L.) na fermentação ruminal in vitro de dietas com diferentes relações volumoso:concentrado

Abstract

The aim of this study was to evaluate the potential of Cashew Nut Shell Liquid (CFCL) and castor oil in diets with different volume:concentrate ratios as a modulator of rumen fermentation, with a focus on clarifying the ability to mitigate methane emissions from the in vitro fermentation of the substrate by the rumen microbiota of cattle. Three experiments were carried out. In experiment I, the treatments consisted of four diets with different volume:concentrate ratios (100:00, 67:33, 33:67 and 00:100) and the addition of three levels of LCCC (0%, 1% and 2%). In experiment II, the diet from experiment I was used, with the addition of three levels of castor oil (0%, 1% and 2%), and in experiment III, a commercial mixture (Essential®) of LCCC-Omamona (50:50) was used, with the addition of three levels (0%, 1% and 2%), using the diet from experiment I. Using the semi-automatic in vitro gas production technique, the accumulated gas production, degradability, the proportion of the main short-chain fatty acids (SCFA) produced during rumen fermentation and methane production were evaluated. The results were analyzed separately. The trials were conducted in a randomized block design in which the treatments, twelve in total, consisted of a 4x3 factorial scheme with four diets and the addition of three levels of oil. The results were submitted to analysis of variance and the means of the factors were compared using the Tukey test at 5% probability of type I error. The statistical analysis was carried out using the SAS 9.3 program. In experiment I, it was found that the inclusion of LCCC had a significant effect on the variables dry matter degradability (DMD), methane and propionate ratio and a non- significant effect on organic matter degradability (OMD), acetate and butyrate ratios and acetate:propionate ratio. In experiment II, it was found that the inclusion of castor oil had a significant effect on the variables dry matter degradability (DMD) and methane and a non- significant effect on organic matter degradability (OMD) and the proportions of short-chain fatty acids (SCFA). In experiment III, the inclusion of the commercial blend (Essential®) only had a significant effect on DMS and methane and there was no significant effect on the proportions of short-chain fatty acids (SCFA). The data showed that higher proportions of concentrate in the diet of the three experiments improved the degradability of the feed, contributing to a reduction in the proportion of acetate, an increase in the proportion of propionate and a lower acetate:propionate ratio. On the other hand, the inclusion of any functional oil, despite reducing degradability, did not alter the profile of short-chain fatty acids (SCFA), but it was found that the inclusion of 1% in a diet with higher proportions of concentrate resulted in lower methane production.