›› 2018, Vol. 45 ›› Issue (8): 2227-2235.doi: 10.16431/j.cnki.1671-7236.2018.08.023

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Effects of Dietary Energy and Crude Protein Levels on Growth Performance, Serum Biochemical Indexes and Slaughter Performance of Graylag

YUAN Yingliang1, TANG Dan1, LU Ying1, RAN Guixia2   

  1. 1. Baicheng Research Academy of Animal Science, Baicheng 137000, China;
    2. Baicheng Taobei District Quality and Safety Center for Livestock and Poultry Products, Baicheng 137000, China
  • Received:2018-01-15 Online:2018-08-20 Published:2018-08-15

Abstract:

This experiment was conducted to study the effects of dietary energy and crude protein levels on growth performance,serum biochemical indexes and slaughter performance of graylag to provide theoretical foundation for scientific feeding.A double factors experimental design was used with metabolic energy (ME) levels of 11.0,12.0,13.0 MJ/kg and crude protein (CP) levels of 14.0%,15.0%,16.0%,respectively.Four hundred and fifty 28-day-old graylags were randomly assigned into 9 groups with 5 replicates per group and 10 graylags per replicate.Graylags in each group were fed one kind of diet.The experiment lasted for 92 days including 12-day pretest period and 80-day formal test period.The results showed as follows:①The average daily gain of graylag with metabolic energy level of 12.0 MJ/kg was significantly higher than those with metabolic energy level of 11.0 and 13.0 MJ/kg (P<0.05);The average daily gain with crude protein level of 14.0% was significantly lower than those with crude protein level of 15.0% (P<0.05).②As the metabolic energy level reached 13.0 MJ/kg,the serum triglyceride of graylag was significantly lower than those with metabolic energy level of 11.0 MJ/kg (P<0.05);The uric nitrogen of graylag with crude protein level of 16.0% was significantly higher than those with crude protein level of 14.0% (P<0.05).③As the metabolic energy level reached 11.0 MJ/kg,the semi-eviscerated percentage, eviscerated percentage,breast muscle percentage and leg muscle percentage of graylag were lower than those with metabolic energy level of 12.0 and 13.0 MJ/kg;As the metabolic energy level reached 13.0 MJ/kg,the abdomen fat percentage was significantly higher than those with metabolic energy level of 11.0 and 12.0 MJ/kg (P<0.05);As the crude protein level was 14.0%,the breast muscle percentage and leg muscle percentage was lower than those with crude protein level of 15.0% and 16.0%.In conclusion, the dietary metabolic energy level had significant effects on final weight,abdominal fat percentage,triglyceride of graylags,and excessive metabolic energy level could increase abdominal fat percentage,which resulted in higher feed cost.The crude protein level had significant effects on final weight and uric nitrogen of graylag.It was suggested that the optimal metabolic energy should be 12.0 MJ/kg and crude protein should be 15.0% for 5 to 16-week-old graylags.

Key words: graylag; metabolic energy; crude protein; growth performance; slaughter performance; serum biochemical parameter

CLC Number: