Extrato da própolis vermelha na dieta de ovinos confinados: alterações morfométricas do sistema digestório

Abstract

Red propolis stands out as a natural food additive, as it presents a potential source of bioactive compounds of great interest. The objective of this study was to evaluate the effect of the use of increasing levels of red propolis extract (RPE) in the diet of sheep confined on the morphometric parameters of rumen and intestine and histopathological parameters of liver and kidney. For this, 35 Santa Inês crossbreed lambs, non-castrated males, with a mean age of 6 months and initial body weight of 17.08 ± 2.36 kg, distributed in a completely randomized design, with five treatments (0, 7, 14, 21 and 28 mL of RPE/animal/day) and seven replicates, submitted to an experimental period of 68 days. The animal feed was the same for all treatments, and the concentrated bulky ratio of 60:40 was adopted, respectively, consisting of ground corn, soybean meal, mineral supplement and Tifton-85 hay. The feed was supplied twice a day, in the form of a complete mixture. The RPE doses were offered to the animals orally after feeding, with an interval of one hour, using a 10 mL continuous flow dosing gun. After 68 days of confinement, the animals were slaughtered and samples of rumen, small intestine, liver and kidney were collected for histological analysis. The data were submitted to analysis of variance and regression at the level of 5% probability. The variables dry matter intake (DMI), total weight gain (TWG) epithelium thickness (ET), keratinized portion of epithelium (KP), non keratinized portion of epithelium (NKP), papilla height (PH), papilla width (PW), mucosa thickness (MT) and submucosa thickness (ST) exhibited quadratic curve behavior (P<0.05), except for the thickness of the muscle layer, duodenais goblet cell index and hepatic glycogen. The TWG showed an increase of 20.24% when compared to the animals of the 28 mL day-1 RPE treatment with the control group. It was verified that the use of RPE in the diet of sheep confined to the variables ET, NKP, PW, MT and ST had as maximum point estimated at levels 17 (174.38 μm), 14 (153.06 μm), 16 (429.36 μm), 33 (548.85 μm) and 9 (1382.52 μm) mL day 1RPE, respectively, and obtained an estimated minimum point at levels 13 (0.65 kg of DM day 1), 11 (4.81 kg), 9 (19.99 μm) and 12 (1374.25 μm) mL day-1 RPE for the variables DMI, TWG, KP and PH, respectively. Based on the results obtained in the present study, it is recommended the level of 28 mL day-1 RPE in the diet of confined sheep, in order to provide greater absorptive areas in the digestive system, increase in total weight gain and does not cause histopathological changes in liver and kidneys.