Dietary metabolizable energy and crude protein levels affect the performance, egg quality and biochemical parameters of a dual-purpose chicken

Abstract

Effects of dietary metabolizable energy (ME) and crude protein (CP) level on performance, egg quality and biochemical parameters were studied in a dual-purpose chicken-Beijing You Chicken (BYC) at peak laying period. A 3 × 3 factorial experiment was arranged, including 3 levels of dietary ME (11.31, 11.51, 11.71 MJ/kg) and 3 levels of dietary CP (14%, 15%, 16%). The results showed that dietary CP level alone and the interaction of ME by CP affected the total feed intake (TFI) during 27–30 wks, dietary ME level affected the mortality rate of 27–34 wks of age (p = 0.018), with the highest mortality rate found in 11.31 MJ/kg group (3.10%). The albumen height (AH), Haugh unit (HU) and egg grade (EG) of 16% group was higher than those in 14% and 15% groups (p < 0.05). Serum immunoglobulin G content in 11.31 MJ/kg group was lower than in 11.51 MJ/kg and 11.71 MJ/kg groups (p = 0.037). The present study suggested that dietary levels of 11.51 MJ/kg ME and 16.0% CP are enough to maintain the performance and egg quality of BYC at peak laying period. 11.31 MJ/kg ME increased the mortality of the chicken, which may be related to the decrease of the humoral immune function and antioxidative capability.

Keywords:

• Energy
• protein
• performance
• egg quality
• biochemical parameters

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The data sets are available upon request from the corresponding author.

Additional information

Funding

The authors wish to thank BAAFS Academy Capacity Building Project [KJCX20200421], National Natural Science Funds [grant number 31372353], China Agriculture Research System of MOF and MARA [grant number CARS-41] for providing financial supports, and the staff from Lvdudu Farm for feeding and management of the experimental birds.