Effects of dietary supplementation with rosemary oil on methanogenic bacteria density, blood and rumen parameters and meat quality of fattening lambs

Abstract

This study aimed to determine the effect of rosemary (Rosmarinus officinalis) essential oil (REO) in lamb fattening diets on blood, rumen parameters, fattening performance and meat quality. Thirty Norduz male lambs weaned at 4 months of age with average body weight 22.0 ± 4.41 kg were used. Lambs were divided into three groups: no rosemary oil (control, R0), with 250 mg/kg DM (R250) and with 500 mg/kg DM (R500) rosemary oil added to the basal ration, and fed for 70 d. The daily feed intake of the R500 lambs (1.63 kg) was lower than other groups (1.70 kg) (p ¼ .01). Rosemary oil did not change the density of methane-producing bacteria in the rumen fluid. Rumen pH was 6.31 in R250 lambs, while it was 6.16 in control (p < .04). The proportion of propionic acid (PA) increased in R250 (26.5 molar%) and R500 (26.0 molar%) lambs compared to control lambs (22.7 molar%) (p < .001). Serum glucose levels increased with REO dose (p < .01) and serum IGF-1 levels were significantly higher in R250 lambs (p < .001). The dose rates of REO used in fattening lambs had limited effect on fattening performance, carcase and meat quality. The results showed that although it does not affect the final live weight, the negative effect of REO on feed intake at 500 mg/kg was considered as a limiting factor and 250 mg/kg dose of REO may have positive effects on ruminal fermentation. Hence, it may be beneficial to try doses lower than 500 mg in further studies. HIGHLIGHTSRosemary oil may improve rumen pH and the propionic acid (PA) concentration at 250 mg of REO/kg DM of the diet. Serum IGF-1 levels were significantly increased with 250 mg/kg dose of REO. Feed intake and feed conversion ratio were negatively affected by REO at 500 mg/kg DM. Lambs supplemented with 500 mg REO/kg DM in the diet had the lowest CLA. The effect of rosemary oil on slaughter-carcase characteristics and meat quality was limited.

Essential Oils as a Dietary Additive for Small Ruminants: A Meta-Analysis on Performance, Rumen Parameters, Serum Metabolites, and Product Quality

“…This could improve the health status of the animals and consequently increase their productive performance. In addition, previous studies [56,58] have shown that in lambs the dietary inclusion of low doses (50, 80, and 250 mg/kg DM) of EOs increases serum levels of IGF-1 (insulin-like growth factor 1), which is positively correlated with ADG in sheep [59]. For this reason, similar effects of EO consumption in the present study would partially explain the observed improvements in ADG and FCR [59].…”

Effects of Oregano Essential Oil (Origanum onites L.) Supplementation on Growth and Biochemical Metabolites in Merino Lambs

“…So, IGF-1 is an important metabolite to evaluate the nutrient balance. In a study, serum IGF-1 level increased significantly with the supplementation of 250 mg/kg rosemary oil low dose group in lambs (Guney et al, 2021). Besides, in our study IGF-1 levels improved at ORG 500mg/kg group.…”

“…However, in our study total protein and triglyceride concentrations were higher in ORG 500 group than control and other treatment group at 45 th day. Guney et al, (2021) found that glucose and total protein concentrations increased significantly in the dietary supplementation with rosemary oil group. Ran et al, (2018) claimed that plasma glucose, NEFA and BHBA concentrations can be used indicator of energy balance in ruminants.…”

Preliminary Investigation of the Effects of Rosemary Extract Supplementation on Milk Production and Rumen Fermentation in High-Producing Dairy Cows

“…Furthermore, the increasing propionate concentrate points toward the potential of RE supplementation to lower the production of hydrogen, the electron donor in methanogenesis. However, few studies have been conducted on the methane emissions after RE supplementation in dairy cows and different forms of rosemary had different impacts on rumen methanogens in sheep and goats [ 55 , 56 ]. Thus, further studies are needed to investigate the role of RE in methane emissions.…”