Resumen:
The objective of this study was to evaluate the effects of different levels of energy and encapsulated pepper (ENP) supplementation on nutrient intake and digestibility, ruminal modification, nitrogen and energy balance, and physiological parameters of steers grazing on pasture. Six Nellore steers weighing 313 ± 31 kg (mean ± SD) (with silicone cannulas in the rumen, Kehl®) were distributed in a 3 × 3 double Latin square design, in a 3 × 2 factorial arrangement (three levels of energy supplementation × two levels of ENP with periods of 21 days each, with the first 14 days for adaptation and the remaining days for current data collection, on Pangola grass (Digitaria decumbens) pasture, in a continuous pasture. The animals were randomly assigned to the following treatments maintaining the same amount of protein and varying the energy concentration: 0.15, 0.30 and 0.45% of body weight (BW) of protein/energy supplementation without encapsulated pepper and 0.15, 0.30 and 0.45% BW of supplementation with the same amount of protein and encapsulated pepper (450 mg/animal/day of CAPCIN®, NutriQuest, Campinas, Brazil).
The inclusion of PEN did not affect the intake of dry matter and nutrients, however, with increasing supplementation levels, there was an increase in the intake of non-fiber carbohydrates (NFC) (P < 0.001) and in the digestibility of NFC (P = 0.008). There was an increase in propionate concentration (P<0.001), a reduction in the C2:C3 ratio (P=0.044) and a reduction in the methane (CH4) estimate (P=0.018), without changing the pH and a reduction in ruminal concentrations of ammonia toxicity (N-NH₃) with increasing supplementation levels, regardless of the addition of PEN (P = 0.001). Among the blood metabolites, a trend towards an increase in serum glucose (P=0.083) and creatinine (P=0.075) levels was observed, in addition to a trend towards a reduction in gamma-glutamyltransferase (GGT) (P=0.067). Heart rate increased in animals receiving PEN (P=0.012). The levels of 0.30% and 0.45% with PEN promote greater total chewing time and shorter idle time. It is concluded that PEN supplementation, especially at levels of 0.30% and 0.45% of BW, is a promising strategy for cattle raised on pasture, generating benefits in rumen modification, physiological safety, hematological parameters, and ingestive behavior in thermal systems.
