Impacts of hempseed and multicarbohydrase on growth performance, digestibility, intestinal morphology and microbial population of broilers.

This study evaluated the effects of hempseed (H) inclusion and multicarbohydrase (MC; xylanase and β-glucanase) supplementation on growth performance, apparent ileal digestibility (AID), intestinal morphology, and selected ileal bacterial populations in broilers. A total of 768 one-day-old male Ross 308 chicks received a common starter diet to d 7 and, from d 8 (mean initial BW 164 g, P > 0.05 among treatments) to d 28, were assigned to a 4 × 2 factorial arrangement of four hempseed levels (0, 8, 16, and 24%) and two MC levels (0 or 0.104 g/kg). No hempseed × MC interaction was observed for growth performance (P > 0.05). Hempseed increased body wight (BW; P < 0.001) and BW gain (P = 0.006) and reduced feed conversion ratio (FCR; P = 0.036), while MC improved BW gain (P = 0.041) and FCR (P = 0.011). Hempseed increased AID of crude protein (CP), ether extract (EE), and gross energy (GE) and decreased AID of dry matter, neutral detergent fiber (NDF), and acid detergent fiber (ADF; P < 0.001). MC increased AID of dry matter, organic matter, CP, NDF, and GE (P ≤ 0.004). Significant interactions were found for AID of EE, CP, ADF, and GE (P ≤ 0.03): MC increased AID of CP only in the control diet and AID of GE at 0 and 8% hempseed, but reduced AID of EE at 24% hempseed. Hempseed increased villus height (VH) and villus height to crypt depth (VH:CD) ratio in all segments (P < 0.001), and MC reduced crypt depth (CD) in the duodenum and jejunum (P ≤ 0.01). Interactions for duodenal VH (P = 0.043) and VH:CD ratio (P = 0.033) and jejunal VH:CD ratio (P = 0.029) indicated that MC increased the duodenal VH and VH:CD at 0 and 8% hempseed but not at 16 and 24%. Hempseed and MC modestly increased ileal Lactobacillus counts (P < 0.001) and reduced total aerobic (P < 0.001) and coliform counts (P ≤ 0.032), with interactions for total aerobic bacteria (P < 0.001) and Lactobacillus (P = 0.009). In conclusion, up to 24% hempseed supported growth performance and was associated with higher AID of CP, EE, and GE and improved villus morphology. The response to MC depended on hempseed level, with its effects on digestibility and duodenal morphology most evident at 0 and 8% hempseed. These findings are limited by the short experimental period (28 d) and by culture-based enumeration of only three bacterial groups.