Effect of Dietary-Liquid Resveratrol on Growth Performance, Meat Quality Traits, and Ileum Morphology of Broiler Chickens under Moderate Heat Stress

A total of 144 one-day-old male broilers (ROSS ${\times}$ Ross 308) ($42{\pm}0.1g$) were used in a completely randomized design and allotted to one of three dietary treatments to give 6 replicates per treatment (8 birds per cage). The three watery dietary treatments were 1) a corn-soybean meal-based relation [Negative control (NC); no antimicrobial compounds added] with tab water, 2) 8 ppm liquid-alpha-lipoic acid [Positive control (PC)] or 3) 100 ppm liquid-resveratrol. All dietary treatments were continuously provided as a liquid form. Birds were housed in a battery cage (n=48), and were offered liquid dietary treatments at all times. The ambient temperature was maintained at $32{\pm}1^{\circ}C$ for the first 3 weeks and decreased gradually to $28{\pm}1^{\circ}C$ by the end of the experiment (d 35) to induce moderate heat stress. One bird per pen (n=6) was euthanized via cervical dislocation at day 21 to obtain terminal ileum to measure villous height and crypt depth, while another bird per pen (n=6) was similarly euthanized at day 35 and used to harvest breast meat and drumsticks to evaluate meat quality traits. Birds fed liquid-resveratrol did not improve (P>0.05) body weight and average daily gain compared with those fed other dietary treatments from day 1 to day 35. Birds fed liquid-resveratrol had no effect (P>0.05) on villous height compared with birds were in other dietary treatments at day 21. Liquid-resveratrol had no effect (P>0.05) on thiobarbituric acid reactive substance (TBARS) in drumsticks compared with other dietary treatments at day 35. Furthermore, birds fed liquid-resveratrol had no effect (P>0.05) on DPPH radical scavenging activity both in breast meat and drumsticks compared with those fed other dietary treatments at day 35. Morphological changes of ileum were not observed by immunofluorescence, and the level of occludin protein from ileum extracts also did not differ among groups. Our results suggested that liquid form of antioxidant compounds used in the current study such as alpha-lipoic acid (8 ppm) or resveratrol (100 ppm) did not improve growth performance, meat quality traits and histology of terminal ileum compared with those fed negative control in broiler chickens under moderate heat stress for 35 days.

고온 환경 조건에서 액상 라스베라트롤의 급여가 육계의 생산성, 육질 및 회장 형태에 미치는 영향