Reticular outflow, ruminal dynamics and ingestive behavior of steers in grazing supplemented with Capsicum oleoresin

This study aims to evaluate the effects of capsaicin supplementation on rumen kinetics and ingestive behavior of steers on grazing. Eight Holstein/Zebu crossbred cattle, with 313 ± 31 kg [body weight; BW ± SD] (4 animals with 4” silicone rumen cannulas), in a double 4 × 4 Latin square, kept on pangola grass (Digitaria decumbens) grazing and supplemented with 0.5% of BW, distributed in the following treatments: Control (CON), with basic supplementation of 0.5% of BW without the addition of the additive containing capsaicin (CAP)(CAPCIN,® NutriQuest, Campinas, Brazil); CAP150, basic supplementation and addition of 150 mg animal day of CAPCIN®-1;CAP300, basic supplementation and addition of 300 mg animal day of CAPCIN®-1 and CAP450, basic supplementation and addition of 450 mg animal day of CAPCIN®-1. There was no effect of encapsulated pepper supplementation on dry matter intake (DMI) (Kg day-1), DMI (%BW), and forage intake (% BW) (P > 0.05). CAP supplementation, regardless of dose, decreased rumination time in minutes and % episode-1 (P = 0.035), and there was a decreasing linear effect for rumination time in minutes and % episode-1 with increasing CAP doses (P = 0.022). Encapsulated pepper supplementation showed a decrease (P = 0.015) in the relative rumen digestibility of NDF compared to the CON diet, and there was (P = 0.015) a linear reduction in the effect of rumen digestibility of NDF with the inclusion of encapsulated pepper. The inclusion of encapsulated pepper alters rumen dynamics, reducing NDF digestibility and increasing the passage rate and DM turnover, probably due to the stimulatory effects of capsaicin on salivation, water intake, and gastric emptying.