Effects of dietary betaine supplementation on reproductive performance of Tibetan chickens and serum lipid metabolism-related indexes of its offspring - Nawei Jike; Zhichao Hei; Weimei Ma; Yuxing Chen; Yongliang Zhang; Yucai Sun; Tingting Liu; Weidong Feng; Kaiqing Rao (Tropical Animal Health and Production, 2026)