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Acta Prataculturae Sinica ›› 2023, Vol. 32 ›› Issue (2): 148-159.DOI: 10.11686/cyxb2022053

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Effects of dietary rumen-protected cysteine on growth performance, nutrient apparent digestibility and serum biochemical indexes of sika deer during weight gain

Qian-long YANG1(), Qian-qian WEI1, De-hui ZHAO1,2, Xiao-lan GUO1, Tie-tao ZHANG1, Xiao-xu WANG1, Kun BAO1, Kai-ying WANG1()   

  1. 1.Institute of Special Animal and Plant Sciences,Chinese Academy of Agricultural Sciences,Changchun 130112,China
    2.College of Animal Science and Technology,Hebei Normal University of Science and Technology,Qinhuangdao 066004,China
  • Received:2022-01-29 Revised:2022-04-28 Online:2023-02-20 Published:2022-12-01
  • Contact: Kai-ying WANG

Abstract:

This experiment was conducted to study the effects of dietary rumen-protected cysteine (RPCys) on growth performance, nutrient apparent digestibility and serum indexes of sika deer during weight gain. A single factor experimental design was adopted. Twelve 7-month-old healthy sika deer were divided into 4 groups with 3 replicates per group and 1 deer per replicate. There was no significant difference in body weight between groups (33.63±0.73 kg) at the start of the experiment. The control group (Group Ⅰ) was fed a basal diet, and the experimental groups were the fed basal diet supplemented with RPCys (active ingredient 51.70%) at 1.25 (Group Ⅱ), 2.50 (Group Ⅲ) and 5.00 g·kg-1 (Group Ⅳ). Following a pre-trial period of 15 days, the trial period lasted for 112 days. It was found that, compared to Group Ⅰ: 1) Dietary RPCys significantly increased total weight gain and average daily gain of Group Ⅲ (P<0.05) and significantly increased the feed conversion efficiency in this group (P<0.05). 2) Dietary RPCys significantly increased the apparent digestibility of crude protein, calcium and phosphorus of all groups (P<0.05), and significantly increased the apparent digestibility of dry matter and organic matter of Group Ⅲ (P<0.05). 3) Dietary RPCys significantly increased the apparent digestibility of glycine in Group Ⅱ and Group Ⅲ (P<0.05), and significantly increased the apparent digestibility of cysteine, methionine, serine, lysine, threonine, valine, isoleucine, leucine, arginine, phenylalanine, histidine, aspartic acid, tyrosine, glutamate, alanine and proline of all groups (P<0.05). 4) Dietary RPCys significantly increased the total protein content in Group Ⅲ (P<0.05). 5) Dietary RPCys significantly increased the catalase activity in Group Ⅲ (P<0.05), and significantly reduced the malondialdehyde content of all groups (P<0.05). 6) Dietary RPCys significantly reduced serum cysteine concentration of Group Ⅲ (P<0.05), and significantly increased concentration of taurine, serine, aspartic acid and glutamic acid of Group Ⅲ (P<0.05). In summary, dietary RPCys significantly increased the total gain, average daily gain and feed conversion efficiency of sika deer during weight gain, significantly increased the apparent digestibility of crude protein, crude ether extract, calcium, phosphorus, organic matter, dry matter and amino acid, significantly increased serum total protein content and antioxidant function of the body, significantly increased concentration of serum taurine, serine, aspartic acid and glutamic acid, and significantly reduced serum cysteine concentration. Under the conditions of this experiment, the appropriate dietary supplementation level of RPCys was 2.50 g·kg-1, or 1.29 g kg-1 active ingredient.

Key words: rumen-protected cysteine, sika deer, growth performance, nutrient apparent digestibility, serum biochemical indexes