Ruminal Degradability and Intestinal Digestibility of Dm and Cp in High-Protein Fraction from Sunflower Meal - A Cheap Source of Dietary Protein for Ruminants

| The objective of this study was to evaluate the ruminal degradability and intestinal digestibility of high protein fraction from sunflower meal (HPSFM). Three non-lactating Jersey cows with an average body weight of 436 ± 18 kg, fitted with a fistula in the dorsal rumen and a T-duodenal cannula were used to estimate rumen degradability and intestinal digestibility of dry matter (DM) and crude protein (CP). The HPSFM was produced by mechanical processing of sunflower meal. Five samples (HPSFM1 to HPSFM5) from different batches produced in interval of 20 days were collected and incubated in the rumen for 0, 2, 4, 8, 16, 24, and 48 h in 6 replications. The values for the rapidly degradable fraction а of DM ranged from 212 to 238 (SD = 9.15) g/kg. The effective degradability of DM of HPSFM at rumen outflow rate of 0.06/h ranged from 635 to 706 (SD = 28.7) g/kg. The fraction a of CP of the high protein sunflower meal samples was within the ranges from 167 to 197 (SD = 12.6) g/kg. Effective degradability of HPSFM CP at rumen outflow rate of 0.06/h was relatively high and varied from 661 to 730 g/kg (SD = 23.6). The intestinal digestibility of the DM measured by mobile bag technique ranged from 489 to 552 (SD = 22.1) g/kg. The intestinal digestibility of CP was relatively high and averaged 945 g/kg, varying from 939 to 954 (SD = 5.23) g/kg. The average value for Protein Digestible in the small Intestine (PDI) according to the Bulgarian protein system (assuming 618 g of rumen fermentable organic matter from a well dehulled sunflower meal), and a rumen outflow rate of 0.06/h was 205 (SD = 13.2) g/kg DM, while the Rumen Protein Balance (RPB) was 187 (SD = 9.52) g/kg DM, respectively. The results of the present study could be used in formulating rations for ruminant animals. HPSFM may effectively replace the expensive soybean meal in cow/calf diets and reduce costs in the feedlot, thus it will greatly improve the profitability of the beef cattle industry. The data shows possibilities for improvement of the protein value of HPSFM by applying stem-heating toasting or other effective technologies for decreasing degradability in the rumen.