Effects of sugar beet pulp and roasted canola seed, on performance, rumen and small intestine digesta volatile fatty acid concentrations, and small intestine morphology of Arabian lambs

Abstract

The effects of partial replacement of barley (B) with sugar beet pulp (SBP) with and without roasted canola seed (RCS) on performance, rumen fluids and small intestine digesta volatile fatty acids (VFA) concentrations, digesta viscosity, and small intestine morphology were investigated. Twenty-four Arabian male lambs (118 ± 10 d, 23.7 ± 2.5 kg BW) were fed with diets containing 1) 68% barley (B-RCS); 2) 68% B plus 7% RCS (B + RCS); 3) 36% SBP (SBP-RCS); 4) 36% SBP plus 7% RCS (SBP + RCS). Feeding (fattening) was undertaken for 99 days including 14 day adaptation period. Rumen fluid was collected on d 27, 54, and 81 of fattening period. At slaughter, small intestine tissue samples and digesta were collected. Results showed that lamb performance was not affected (P > 0.05) by carbohydrate source, however it was improved by inclusion of RCS. Lambs fed with SBP had higher (P < 0.05) total VFA and molar proportions of acetate, isobutyrate, and acetate to propionate ratio compared to those lambs fed without SBP diet. Inclusion of RCS increased (P < 0.05) propionate and decreased acetate and isobutyrate in the rumen fluid but there was no interaction of SBP × RCS treatments observed for any of the time points measured. In duodenum and jejunum digesta, lambs fed SBP had higher (P < 0.05) acetate, total VFA molar concentrations, and acetate to propionate ratio than lambs fed without SBP diet. Inclusion of RCS increased (P < 0.05) acetate, total VFA concentration in duodenum and jejunum. Both pH and viscosity of the small intestine digesta in duodenum and jejunum were higher (P < 0.05) in lambs fed SBP than those fed without SBP diet. Partial replacement of barley with SBP increased crypt depth throughout small intestine and also increased thickness of tunica muscularis and villus height in jejunum and ilium. Feeding lambs with diets containing SBP + RCS increased (P < 0.05) number of Brunner's glands, number of villi, and epithelium thickness. In conclusion, partial replacement of barley by SBP along with RCS altered molar proportion of VFA in the rumen, intestine and improved small intestinal morphology of fattening Arabian lambs.