EFEITOS DA INCLUSÃO DE UREIA EXTRUSADA ASSOCIADA A ÓLEOS ESSENCIAIS NA NUTRIÇÃO DE OVNOS

Abstract

Extruded urea has stood out as an efficient source of non-protein nitrogen as it promotes controlled release of ammonia, synchronizing it with energy availability in the rumen, favoring microbial protein synthesis. Additionally, garlic and cinnamon essential oils emerge as natural alternatives to growth-promoting antibiotics, due to their selective antimicrobial action and ability to modulate ruminal fermentation. However, its use still has limitations due to the difficulty in replicating in vivo the effective doses observed in vitro. The objective was to evaluate the effect of increasing the inclusion of extruded urea associated with encapsulated essential oils of garlic and cinnamon, on the consumption and apparent digestibility of nutrients, water intake, nitrogen balance, blood, physiological and behavioral parameters in the diet of confined sheep. Four sheep with an initial average live weight of 53 ± 5.65 kg were distributed in a 4×4 Latin square design with four replications. The diets were formulated with a roughage:concentrate ratio of 400:600 g/kg based on dry matter, using whole corn silage as a source of roughage. The treatments consisted of increasing levels (0; 7.5; 15.0 and 22.5 g/kg DM per animal/day) of commercial additive (NFeed®) containing extruded urea associated with the components (cinnamaldehyde, diallyl disulfide, trisulfide and tetrasulfide). The average DM intake was 1,808.22 g/day, with no significant linear or quadratic effect (P>0.05). The apparent digestibility coefficients of nutrients were not influenced (P>0.05), as well as water intake (3.934 L/day). There was a progressive reduction in the cost of the diet per kg (R$ 1.57 to R$ 1.46), daily cost (R$ 5.12 to R$ 4.30) and total cost per treatment (R$ 429.81 to R$ 361.26), with treatment with a higher dose of NFeed® being more economical. Ingestive behavior was not changed, with averages of 152.19 min/day for eating, 406.25 ruminations, 781.56 idleness and 104.06 for other activities. There was a tendency for a quadratic effect for the number of rumen boluses/day (P=0.0958) and for the time per bolus (P=0.0810; 0.0570). There was no effect (P>0.05) for the levels of total protein, creatinine, urea and urinary volume (22.90; 144.63; 2916.54 mg/dL and 1.22 L/day). The values of nitrogen ingested, urinary, fecal, retained and nitrogen balance did not differ (P>0.05; 40.28; 0.10; 8.13; 32.05 g/day and 80.02%, respectively). Increasing levels of additive did not alter (P>0.05) blood and physiological parameters. All observed values were within the reference ranges for the species. The inclusion of up to 22.5 g/kg of dry matter of extruded urea associated with essential oils can replace soybean meal in diets for confined sheep, without compromising the consumption and digestibility of nutrients, physiological, biochemical and behavioral parameters, in addition to contributing to reducing the cost of diets.

Keywords: Animal metabolism; Cinnamaldehyde; Cinnamon; Garlic; Non-protein nitrogen; Nutritional additives.