Kun GuoHuabin CaoYuanjun ZhuTiancheng WangGuoliang HuBunlue KornmatitsukJunrong LuoMahidol UniversityJiangxi Agricultural University2019-08-232019-08-232018-09-01Animal Science Journal. Vol.89, No.9 (2018), 1280-128617400929134439412-s2.0-85052698193https://repository.li.mahidol.ac.th/handle/20.500.14594/44678© 2018 Japanese Society of Animal Science This study was aimed to investigate the effects of rumen-protected γ-aminobutyric acid (RP-GABA) on apparent nutrient digestibility, growth performance and health status in heat stressed beef cattle. Fifty Jinjiang Yellow cattle were randomly assigned to 5 treatments (10 animals/treatment). Treatments 1 to 5 were basal diets affixed with 0 (control), 8, 16, 24 and 32 mg of RP-GABA/kg of body weight (BW) respectively. The trial lasted 45 days. Apparent digestibility of crude protein (CP), crude fiber (CF) and calcium (Ca) quadratically increased with increasing RP-GABA (p <.01), while apparent digestibility of phosphorus (P) tended to quadratically increase (p =.09). Dietary supplementation with increasing RP-GABA linearly increased DM digestibility and average daily gain (ADG) (p <.01), whereas the feed to gain (F:G) ratio linearly decreased with increasing RP-GABA (p <.01). The average daily feed intake (ADFI) value tended to linearly increase with RP-GABA supplementation (p =.08). Total protein (TP), blood urea nitrogen (BUN) and malondialdehyde (MDA) levels quadratically decreased (p <.01) with increasing RP-GABA, however albumin (ALB), glucose (GLU), superoxide dismutase (SOD), triiodothyronine (T3) and thyroxine (T4) levels quadratically increased (p ≤.01). In conclusion, the present results indicated that dietary supplementation with RP-GABA led to improved nutrient digestibility, growth performance and antioxidant status in heat stressed beef cattle.Mahidol UniversityAgricultural and Biological SciencesArticleSCOPUS10.1111/asj.13053