LAUSR

The objective of this study was to evaluate the effect of inclusion of increasing levels of hempseed meal (HSM) on the morphology of the rumen papillae and volatile fatty acids production in the rumen of intact male goats. Boer x Spanish intact male goats (n = 36), 0 to1 months of age and bodyweight of 44.1 ± 3.8 kg, were randomly assigned to one of the four experimental diets (n = 9 goats/diet): 0% (control), 0%, 20%, and 30% HSM included on an as-fed basis and fed ad-libitum for 60 days. Experimental diets were formulated as total mixed ration (TMR), and the nutrient content of each diet was formulated to be iso-nitrogenous (18% crude protein) and to meet or exceed the nutrient requirement of breeding male goats. At the end of the trial, experimental goats were humanely processed as per USDA standards. Rumen fluid and necropsy samples of rumen tissue from the ventral sac of the rumen were collected, and rumen tissue was processed for histological examination. Morphometric variables of rumen papillae; height and width of rumen papillae, and density (number of papillae/cm2) were recorded, and total absorptive surface area was calculated. The thickness of the stratum corneum (SC) and the thickness of stratum granulosum (SG) was measured from the histological slides of rumen tissue. The rumen fluid was analyzed for the volatile fatty acids (acetate, propionate, and butyrate) concentration. Data were analyzed using one-way ANOVA and orthogonal contrast test for equally spaced treatments using R version 4.2.1. There was no significant difference (P > 0.05) in height of papillae, the width of papillae, papillae density, total absorptive surface area, SC thickness, and SG thickness among the goats feeding different experimental diets. The concentration of propionic acid decreased linearly (P > 0.01) with increasing inclusion of HSM (12.90, 9.51, 8.12 and 7.34 mmol/L for 0 %,0 %, 20 % and 30 % HSM, respectively), whereas the concentration of acetic acid and butyric acid were similar among the experimental groups (P > 0.05). These observed results indicate that the inclusion of HSM at least up to 30 % in the diet does not affect the rumen papillae morphology, and acetate and butyrate concentration in the rumen in intact male goats.