Abstract
This study investigated the associations between abundance of rumen ciliate protozoa and the proportion of the main bioactive fatty acids related to rumen biohydrogenation, as 18:0, t10-18:1, t11-18:1, c9,t11-18:2, 18:3n-3 and 18:2 n-6, in rumen and meat of growing lambs, using data derived from 3 production experiments. A global correlation analysis and a linear regression analysis considering the effect of the experiment were performed. Ten of the 86 lambs involved in the experiments did not present ciliate cells in rumen liquor and the remaining lambs presented an average of 1.35 × 106ciliates / ml rumen liquor. From the nine genera of ciliates identified, Entodinium was the most abundant, averaging 1.17 × 106 cells / ml of rumen liquor. A large variation among lambs was observed for both rumen concentration and community structure of ciliates. Rumen t11-18:1 (P < 0.001) and meat deposition of t11-18:1 (P < 0.001) and of c9,t11-18:2 (P < 0.001) increased linearly with total ciliates, whereas the t10/t11 ratio in rumen (P = 0.002) and in meat (P = 0.036) decreased linearly. Entodiniomorphids seems to be strongly related with meat deposition oft11-18:1 and c9,t11-18:2 and with the reduction of the trans-10 shifted pathway. Completeness of RBH decreased linearly with Holotrichs (P = 0.029), Entodiniomorphids (P = 0.029), Isotricha (P = 0.011) and Epidinium (P = 0.027) abundances. Rumen 18:0 also decreased linearly with increasing counts of total ciliates (P = 0.015), Holotrichs (P = 0.020), Entodiniomorphids (P = 0.010) and Isotricha (P = 0.014). Rumen protozoa were positively linked with the deposition of healthy bioactive FA and simultaneously negatively associated with the occurrence of trans-10 shift.