Variability in rumen degradability and intestinal digestibility of sunflower meals protein.

The aim of this study was to evaluate variability in the nutritional value of sunflower meal (SFM) protein by determining both its ruminal degradability and intestinal digestibility. Three non-lactating Jersey cows fi tted with a rumen and T-type duodenal cannulas were used to estimate rumen degradability and intestinal digestibility of SFM dry matter (DM) and crude protein (CP). Samples of SFM were collected from seven sunflower processing plants (SFM1 to SFM7). The SFM were incubated in the rumen of the cows for 0, 2, 4, 8, 16, 24 and 48 h in 6 replications. The soluble or rapidly degradable fraction a of SFM DM ranged from 208 to 264 (SD = 21.2) g/kg. The effective degradability of DM at assumed rumen outflow rate of 0.06/h ranged from 533 to 585 (SD= 22.1) g/kg. Fraction a of CP ranged from 208 to 279 (SD = 26.8) g/kg. Effective degradability of SFM CP at rumen outflow rate of 0.06/h was relatively high and ranged from 639 to 723 g/kg (SD = 29.4). Intestinal digestibility of SFM DM and CP measured by mobile bag technique varied from 387 to 473 g/kg (SD = 25.9) and from 863 to 930 (SD = 22.5), respectively. Estimated Protein Digestible in the small Intestine (PDI) was 159 to 201 (SD = 14.1) g/kg DM, and Protein Balance in the Rumen (PBR) varied from 105 to 146 (SD = 14.9) g/kg DM. This study showed that protein degradability and digestibility of commercial SFM samples varied considerably, suggesting that nutritive value of SFM protein will fl uctuate depending on agronomic conditions, sunflower variety, and processing technology. This variability should be considered when formulating rations with SFM for ruminant animals. [ABSTRACT FROM AUTHOR]