Modelling nitrogen-corrected apparent metabolisable energy requirement for egg production of 3 BW types of Yellow Broiler breeder hens during the egg-laying period

Accurate prediction of energy requirement is important in formulating diets, but an energy model for Yellow Broiler breeder hens is publicly unavailable. The objective of this study was to establish energy prediction models for the nitrogen-corrected apparent metabolisable energy (AMEn) requirement of different categories of Yellow Broiler breeder hens during the egg-laying period. Data for modelling were collected from research papers, public databases and production data from companies. Breeder hens were generally categorised into three BW types: heavy, medium and light (HBWT, MBWT and LBWT). Published articles were cited for providing coefficients of AMEn maintenance requirement (AMEnm, 101 kcal/kg BW^0.75, 423 KJ/kg BW^0.75) and growth requirement (AMEng, 5.33 kcal/g, 22.3 KJ/g), respectively. Models of AMEn for egg production (AMEnp) were established from the known daily intake of AMEn (AMEni) and those of maintenance and growth by the factorial approach: AMEnp = AMEni ? AMEnm ? AMEng. For the three types of hens, AMEnp HBWT (kcal, KJ) = 2.55 kcal (10.7 KJ) × egg mass (EM, g); AMEnp MBWT (kcal, KJ) = 2.70 kcal (11.3 KJ) × EM (g), and AMEnp LBWT (kcal, KJ) = 2.94 kcal (12.3 KJ) × EM (g) were determined. The total AMEni requirements, depending on Gompertz models, were HBWT: BW (g) = 3 144 × e^{?EXP(?0.162×(week of age (wk)?15.6))}; MBWT: BW (g) = 2 526 × e^{?EXP(?0.333×(wk?19.1))}; LBWT: BW (g) = 1 612 × e^{?EXP(?0.242×(wk?16.5))}. Models of egg production, HBWT: egg production (%) = 124 × e^?0.017×wk/(1 + e^{?0.870×(wk?26.2)}); MBWT: egg production (%) = 144 × e^?0.020×wk/(1 + e^{?0.751×(wk?24.9)}); LBWT: egg production (%) = 163 × e^?0.024×wk/(1 + e^{?0.476×(wk?26.5)})) and egg weight for each wk of the three types of hens during the egg-laying period were all established. These models showed good applicability in simulating and predicting the literature or production data.