Effect of Source and Level of Dietary Supplementary Copper on In Vitro Rumen Fermentation in Growing Yaks
Xinsheng Zhao,
Lizhuang Hao,
Yanfeng Xue,
Allan Degen,
Shujie Liu
Affiliations
Xinsheng Zhao
Key Laboratory of Plateau Grazing Animal Nutrition and Feed Science of Qinghai Province, Qinghai Plateau Yak Research Center, Qinghai Academy of Science and Veterinary Medicine of Qinghai University, Xining 810016, China
Lizhuang Hao
Key Laboratory of Plateau Grazing Animal Nutrition and Feed Science of Qinghai Province, Qinghai Plateau Yak Research Center, Qinghai Academy of Science and Veterinary Medicine of Qinghai University, Xining 810016, China
Yanfeng Xue
Key Laboratory of Plateau Grazing Animal Nutrition and Feed Science of Qinghai Province, Qinghai Plateau Yak Research Center, Qinghai Academy of Science and Veterinary Medicine of Qinghai University, Xining 810016, China
Allan Degen
Desert Animal Adaptations and Husbandry, Wyler Department of Dryland Agriculture, Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Beer Sheva 8410500, Israel
Shujie Liu
Key Laboratory of Plateau Grazing Animal Nutrition and Feed Science of Qinghai Province, Qinghai Plateau Yak Research Center, Qinghai Academy of Science and Veterinary Medicine of Qinghai University, Xining 810016, China
Copper (Cu) is essential for the health of livestock, however, the optimal source and level of dietary Cu for yaks are uncertain. To fill this important gap, we designed an in vitro study to examine the effects of three Cu sources, namely Cu methionine (Met-Cu), Cu chloride (CuCl2) and tribasic Cu chloride (TBCC), at five levels, namely 5, 10, 15, 20 and 25 mg/kg DM (includes Cu in substrate), on rumen fermentation in yaks. In vitro dry matter degradability (IVDMD) and amylase activity were greater (p 3-N), microbial protein (MCP) and propionate contents were greater with Met-Cu and CuCl2 than with TBCC. Total gas production and lipase activity were greater with Met-Cu and TBCC than CuCl2 (p 4 production did not differ (p = 0.92) among Cu sources. IVDMD and lipase activity were greatest (p < 0.05) at 15 mg Cu/kg DM in the substrate and MCP, isobutyrate, butyrate and isovalerate contents, and amylase and trypsin activities were greatest or second greatest at 10 and 15 mg Cu/kg DM. It was concluded that Met-Cu was the best source of Cu and 10 to 15 mg Cu/kg DM was the optimal level for yaks, at least under in vitro conditions.
