A dose-response of cinnamaldehyde supplementation on intake, ruminal fermentation, blood metabolites, growth performance, and carcass characteristics of growing lambs

The objective of this study was to determine the effect of different doses of cinnamaldehyde on feed intake, gain, feed efficiency, ruminal fermentation parameters, blood metabolites, carcass yield, and meat quality of lambs fed barley-based diets. Forty-eight ewe lambs were stratified by live weight (LW) and randomized among treatments (n = 4) at weaning (LW = 20.4 ± 1.12 kg). Animals had ad libitum access to pelleted diets (140 g CP/kg of DM; 309 g NDF/kg of DM) and water over 18-week period. There were four treatments with 12 animals each: 1) Control (no cinnamaldehyde); 2) cinnamaldehyde at 100 mg/kg of dry matter (DM); 3) cinnamaldehyde at 200 mg/kg of DM; 4) cinnamaldehyde at 400 mg/kg of DM. Dry matter intake (DMI), average daily gain (ADG) and feed conversion (DMI/ADG) were not affected by cinnamaldehyde supplementation. Ruminal pH, total VFA concentrations, molar proportions of individual VFA (acetate, propionate and valerate) and ammonia concentration were similar between lambs fed cinnamaldehyde and those fed the control diet. For blood metabolites, except urea nitrogen concentration which was higher (P = 0.05) in lambs fed cinnamaldehyde at 200 mg/kg compared to those fed the control diet, no changes were observed for non-esterified fatty acids (NEFA), cholesterol and triglycerides concentrations. The addition of cinnamaldehyde to the diet had no effect on carcass characteristics [liver and rumen weights, hot carcass weight, dressing percent, back fat thickness (grade), quality grade, saleable meat yield (as primal cuts)] and fatty acid (FA) composition of back fat and liver. Overall, sensory attributes of sirloins were not altered although off-flavor intensity was higher (P < 0.01) for sirloins from lambs fed cinnamaldehyde at 100 and 400 mg/kg of DM compared to the control. Results from this study suggest that cinnamaldehyde may have limited potential to improve feed efficiency and growth in lambs fed concentrate-based diets.