Effects of Chromium Methionine Supplementation on Growth Performance, Serum Metabolites, Endocrine Parameters, Antioxidant Status, and Immune Traits in Growing Pigs Yao-Yao Tian & Li-Ying Zhang & Bing Dong & Jun Cao & Jian-Xiang Xue & Li-Min Gong Received: 26 September 2014 /Accepted: 2 October 2014 /Published online: 17 October 2014 # Springer Science+Business Media New York 2014 Abstract The effects of dietary chromium methionine (CrMet) on growth performance, serum metabolites, endocrine parame- ters, antioxidant status, and immune traits in growing pigs were investigated. A total of 180 crossbred pigs (30.18±0.28 kg initial body mass) were randomly divided into five groups, each group with six pens, six pigs per pen. Pigs were fed on the same basal diet supplemented with 0 (control), 100, 200, 400, and 800 μg/ kg Cr from CrMet for 35 days. The results showed that supple- mental CrMet did not affect growth performance. Cr at 200– 800 μg/kg significantly decreased serum glucose levels (P<0.05), while other serum metabolites were unaffected by Cr supplementation. Serum growth hormone (GH) levels were significantly decreased by Cr addition (P<0.05). Furthermore, serum insulin-like growth factor I (IGF-I) levels were linearly decreased with increased Cr dose, and a significant reduction was observed in pigs fed 800 μg/kg Cr diets (P<0.05). Serum immunoglobulin A, G, and M concentrations were increased linearly with increased Cr dosage, and pigs fed 400 μg/kg Cr had greater serum immunoglobulin M contents (P <0.05). Cr at 400 μg/kg significantly increased serum superoxide dismutase and total antioxidant capacity activities (T-AOC) (P <0.05). However, Cr at 800 μg/kg increased serum catalase activities, while decreasing serum T-AOC contents (P <0.05). Additional- ly, there was a significant increase in serum malondialdehyde levels for pigs fed 800 μg/kg Cr diets (P<0.05). These results indicated that dietary supplementation CrMet decreased serum glucose, GH, and IGF-I levels. Besides, supplemental 400 μg/kg Cr as CrMet improved serum antioxidant status and immune responses, but additional 800 μg/kg Cr resulted in lipid peroxi- dation in growing pigs. Keywords Chromium methionine . Serum metabolites . Immune traits . Endocrine parameters . Antioxidant status . Growing pigs Introduction Chromium (Cr) has been classified as an essential trace element for human and animals for 50 years [1], trivalent of which is a component of chromodulin involved in the signal autoamplification mechanism of insulin [2]. In recent years, however, its status is questioned due to no experimental evi- dence of Cr deficiency and improvement in symptoms from chromium supplementation, which does not fit the definition about essentiality of a trace element [3]. Moreover, it was confirmed that chromium could no longer be considered an essential element, but had a pharmacological effect increasing insulin sensitivity through an experiment that male Zucker lean rats housed in specially designed metal-free cages were fed a purified diet with little chromium or diets supplemented a vari- ety of chromium concentrations [4]. Nevertheless, additional Cr has been reported to have numerous healthy, nutritional, and economic benefits for animals, such as improving carcass char- acteristics [5–7] and reproductive performance [ 8, 9], alleviating stress by reducing cortisol [10, 11], and strengthening immunity [12, 13]. At present, the best classification of Cr(III) may be that of a nutritionally or pharmacologically beneficial element [ 14]. It is well accepted that chemical forms of chromium affect their bioavailability and consequently, will influence both potential biological responses and economics of mineral sup- ply, which has been supported by Lindermann et al. who determined the relative bioavailability among four organic Cr sources [15]. Although the study in rats using Cr-51- labeled compounds has shown that the apparent absorption of Cr of five forms is generally low with slightly higher values for Cr chloride [16], Cr in organic forms has been proved to Y.<Y. Tian : L.<Y. Zhang : B. Dong : J. Cao : J.<X. Xue : L.<M. Gong (*) State Key Laboratory of Animal Nutrition, Ministry of Agriculture Feed Industry Centre, China Agricultural University, Beijing 100193, China e-mail: gonglimin2004@126.com Biol Trace Elem Res (2014) 162:134–141 DOI 10.1007/s12011-014-0147-9