Different energy and protein levels for growth performance, serum biochemistry and intestinal development of squabs ( <i>Columba livia</i> ) under artificial feeding conditions

1. The purpose of this study was to investigate the effects of different metabolisable energy (ME) and crude protein (CP) levels on the growth performance, serum biochemical indices, and intestinal development of pigeon squabs.2. A total of 324, 12 d old squabs were used and fed one of three ME (13, 12.5 and 12 MJ/kg) and three CP levels (18, 17 and 16%) to give nine experimental diets with six replicates each containing six birds (<i>n</i> = 6).3. Body weight of squabs at 28 d of age were the highest in group 3 (13 MJ/kg ME, 16% CP). Increasing ME or CP levels significantly elevated the relative weight of abdominal fat of squabs.4. A higher ME level in the diet induces higher serum content of total cholesterol and low-density lipoprotein, and greater levels of aspartate aminotransferase activity in 28 d old squabs. Compared with lower CP (16%) treatment, 18% dietary CP significantly increased the contents of serum urea nitrogen and uric acid. Duodenal villus length and pancreatic trypsin activity were the greatest in diet 3.5. The optimal dietary energy and protein levels of artificial crop milk for pigeon squabs in the late stage of growth were 13 MJ/kg ME and 16% CP from days 12-28 of age.