ACTA VETERINARIA ET ZOOTECHNICA SINICA ›› 2017, Vol. 48 ›› Issue (4): 678-689.doi: 10.11843/j.issn.0366-6964.2017.04.011

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Effects of Lysine, Methionine, Threonine and Tryptophan in Starter on Growth Performance, Nitrogen Utilization and Serum Parameters in Weaned Lambs

LI Xue-ling1,2, ZHANG Nai-feng1, MA Tao1, TAO Da-yong2, CHAI Jian-min1, WANG Yu-rong1, ZHANG Fan1, DIAO Qi-yu1,2*   

  1. 1. Key Laboratory of Feed Biotechnology of Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China;
    2. College of Animal Science, Tarim University, Alar 843300, China
  • Received:2016-10-25 Online:2017-04-23 Published:2017-04-23

Abstract:

This experiment aimed to investigate the effects of Lys, Met, Thr and Trp in starters on growth performance, nitrogen utilization and serum indices of weaned lambs, and to determine limiting sequence and proportion of amino acids by partial deduction method. One hundred healthy male Hu lambs at 50 days old with an average weight of 11.00 kg were randomly divided into 5 groups and each group had 4 replicates with 5 lambs per replicate according to single factor design. The control group was fed starter with balanced amino acid (PC) with Lys (1.16%), Met (0.38%), Thr (0.58%) and Trp (0.16%), respectively. The 4 experimental groups were fed the starter deducting Lys, Met, Thr and Trp at 30%, respectively compared with control group (PD-Lys, PD-Met, PD-Thr and PD-Trp group). The experiment lasted for 70 days; During 80-90 and 110-120 days old, nitrogen balance of lambs was determined. The results showed as follows: 1) The BW, ADG and F/G in PD-Met group were significantly lower than that in PC, PD-Thr and PD-Trp groups (P<0.05) on 120 days old. 2) Urinary nitrogen emission in PD-Lys and PD-Met groups was significantly higher than that in PC (P<0.05) during 80-90 days old. Nitrogen deposition, nitrogen retention ratio and nitrogen apparent biological value in PD-Met group were significantly lower than that in PC group (P<0.05) during 80-90 days old, and nitrogen deposition, nitrogen retention ratio, nitrogen apparent digestibility and nitrogen apparent biological value in PD-Met group were significantly lower than that in PC group(P<0.05) during 110-120 days old. 3) The limiting sequence of 4 amino acids were Met > Lys > Thr > Trp and Met > Lys > Trp > Thr from 80 to 90 days old and from 110 to 120 days old, respectively, the proper ratio of Lys, Met, Thr and Trp was 100:37:45:12 and 100:41:39:12 when obtaining the maximum NR. 4) Glucose concentration in PD-Met group was significantly higher than that in PC (P<0.05) on 90 days old. Serum total protein, globulin and cholesterol in PD-Met group was significantly lower than that in PC (P<0.05) on 120 days old. In conclusion, the proper ratios of Lys, Met, Thr and Trp in starter of weaned lambs during 60-120 days old was 100:(37-41):(39-45):12. The limiting sequence were Met > Lys > Thr > Trp(80-90 days old) and Met > Lys > Trp > Thr(110-120 days old), respectively.

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