Effect of omega fatty acids sources alone or combined with essential oils on feed intake, apparent d

Author links open overlay panelMohadesah Karimian, Ahmad Riasi, Ebrahim Ghasemi, Saeid Ansari Mahyari

https://doi.org/10.1016/j.smallrumres.2024.107201Get rights and content

Abstract

The objective of this study was to determine some effects of omega-6/omega-3 ratio by adding low level of calcium soap of fish oil (CSFO), calcium soap of soybean oil (CSSO) with or without a mixture of pennyroyal and rosemary essential oils (EO) on feed intake and apparent total-tract digestibility of nutrients, rumen fermentation characteristics, rumen bacteria community, back fat thickness changes, feeding behavior and blood metabolites in peripartum ewes. For this purpose, 40 pregnant Shall ewes in a completely random design were used from 21 d before to 80 d after lambing. Four experimental groups were: (1) diet containing CSSO – EO; (2) diet containing CSSO + EO; (3) diet containing CSFO – EO; and (4) diet containing CSFO + EO. The fat sources and a mixture of EO were added to rations based on 1.3% of DM and 0.6 g/kg of DM, respectively. Results showed that the interaction of fat sources and EO (Fat×EO) affected (P0.05) some characteristics such as feed intake, nutrient digestibility, butyrate and NH3-N production in rumen, rumen bacteria population; and blood urea, total protein and globulin. Moreover, supplementation the mixture of EO increased (P0.05) feed intake, total apparent tract digestibility, ruminating and chewing behavior and the plasma glucose level. Also, EO caused an increase (P0.05) in population of some rumen bacteria such as R. Flavefaciens, R. albus and B. fibrisolvens, total VFA, acetate and butyrate production in rumen and pH of ruminal fluid. On the other hand, proportion of propionate and NH3-N concentration in the rumen fluid, triglyceride level of plasma were decreased (P0.05) by EO. Adding fish oil to the diets enhanced (P 0.05) feed intake before and after lambing and it caused a reduction (P 0.05) of F. succinogenes and P. ruminicola bacteria and a higher (P 0.05) proportion of butyrate in the rumen. The changes of back fat thickness were not affected by fat sources and EO supplementation. It was concluded that essential oil and low level of fish oil had synergetic effect on feed consumption and apparent total tract digestibility in Shall ewes. Also, the interaction of fat sources and essential oil changed and improved rumen fermentation, without having adverse effects on blood metabolites.