Standardized Ileal Digestible Lysine Requirements for Finishing PIC Pigs Under Commercial Conditions: A Meta-Analysis

The objective of this meta-analysis was to evaluate the standardized ileal digestible (SID) lysine (Lys) requirement for PIC finishing pigs under commercial conditions. A total of 27 commercial experiments were used in the meta-analysis with a total of 45,102 pigs. Number of pens/treatment and pigs/experiment ranged from 9 to 16 and 12 to 25, respectively. The average pen BW range in these experiments was from 23-135 kg. Dam lines were Camborough 1050 in 18 experiments and Camborough 29 in 9 experiments. Sire lines were PIC 337 in 24 experiments and PIC 327 in 3 experiments. Ingredient loadings values used were based on NRC (2012). Responses were analyzed separately for each experiment using general linear and non-linear heterogeneous variance mixed models (Gonçalves et al, 2016). Each treatment within an experiment was considered as an observation (n=213) and each experiment was used as random effect. Models that differed in their bayesian information criterion values by at least 2 points were considered to have meaningful differences in their data fit (Raftery, 1996). The requirements presented are an average of the requirement for ADG and F/G. Requirements estimates for boars were based on relative differences from barrows published by Bertram et al., (2014) and NRC (2012). There was no interaction between sireline nor damline and treatment (P>0.10). The SID Lys requirement and their SID Lys:calorie ratio equations are presented in tables 1 and 2, respectively. The SID Lys requirements from this meta-analysis are 106, 103, and 132% of NRC (2012) for barrows, gilts, and boars after adjusting for feed intake, respectively. This is probably due to increased rate of growth and improved feed efficiency from modern PIC lines.

Table 1. Standardized Ileal Digestible (SID) Lysine percentage requirement and average daily feed intake of PIC pigs for a diet with 2,475 kcal NE/kg
		Body weight range, kg
	ADFI, kg	25-50		50-75		75-100		100-135
Barrows	2.40	1.11		0.91		0.78		0.70
Gilts	2.22	1.16		0.94		0.80		0.75
Boars	1.88	1.39		1.16		1.00		0.90

Table 2. Standardized Ileal Digestible (SID) Lysine to net energy (NE) ratio equations for PIC pigs
Gilts = 0.000056 × (body weight, kg × 2.2046)2  – 0.02844 × (body weight, kg × 2.2046) + 6.6391
Barrows
= 0.000042 × (body weight, kg × 2.2046)2 – 0.02372 × (body weight, kg × 2.2046) + 6.1452
Boars
= 0.000046 × (body weight, kg × 2.2046)2 – 0.02704 × (body weight, kg × 2.2046) + 7.5417