Determination of the optimum dietary lysine concentration for growing pigs housed in pairs and in groups

Abstract

Three 28-day trials were carried out to determine the optimum dietary lysine concentration for growing pigs between 20 and 68 kg. There were 96 pairs of pigs in experiment 1 (20 to 41 kg), 72 pairs in experiment 2 (40 to 68 kg) and 42 groups (14 per group) in exp. 3 (40 to 62 kg). All experiments were arranged as randomized complete block designs, blocked on the basis of sex and start weight. Treatments consisted of isoenergetic (13·8 MJ digestible energy per kg) diets with increasing lysine concentrations. Dietary lysine concentrations were 9·7, 10·7, 11·6, 12·5, 13·5 and 14·4 g/kg (experiment 1) and 9·0, 9·9, 11·0, 12·1, 13·1 and 14·1 g/kg (experiments 2 and 3). Response curves were fitted to the data to determine the optimum dietary lysine concentration for maximum average daily gain (ADG) and minimum food conversion ratio (FCR). In experiment 1, ADG and FCR responded quadratically to dietary lysine content ( P < 0·01 and P < 0·05). Male pigs had better FCR and lysine conversion ratio (LCR) than female pigs ( P < 0·05). In experiment 2, there was a quadratic effect of increasing dietary lysine concentration on FCR ( P < 0·05). Male pigs had lower daily food intake (DFI, P < 0·01) and daily lysine intake (DLYIN, P < 0·01) and had better FCR ( P < 0·01) and LCR ( P < 0·01) than female pigs. In experiment 3, there was a quadratic effect of increasing lysine concentration on FCR ( P < 0·05). Male pigs had better FCR and LCR ( P < 0·05) than female pigs. In all experiments, increasing dietary lysine concentration resulted in an increase in DLYIN and a deterioration in LCR (all linear, P < 0·001). Regression analysis predicted optimum dietary lysine concentrations for maximum ADG at 13·1 and 12·7 g lysine per kg in experiments 1 and 2, and minimum FCR at lysine concentrations of 14·6, 12·2 and 12·7 g/kg for experiments 1, 2 and 3 respectively. In conclusion, the optimum dietary lysine concentration for maximum ADG and minimum FCR could be predicted using quadratic models and although males had better FCR than females, optimum dietary lysine concentrations were similar for both sexes.

The effect of immunization against GnRF on nutrient requirements of male pigs: a review

“…King et al (2000) found that there was no difference in the lysine requirement to maximize protein deposition and minimize FCR in heavy (80 to 120 kg BW) finisher entire males and gilts. O'Connell et al (2005) found that, in three studies in grower entire males and gilts (20 to 68 kg BW), there were no differences in the lysine requirements (g/kg) to maximize growth and minimize FCR. In heavier pigs (60 to 100 kg BW), these authors found the lysine requirement (g/kg) was slightly higher in entire males than in gilts in one study but not in two others (O'Connell et al, 2006).…”

“…However, studies from the early 2000s suggested that, although the daily protein deposition and growth potential of entire males was greater than that of gilts, there was little difference in the lysine (g/kg feed) requirement of grower and finisher entire males and gilts O'Connell et al, 2005 and. King et al (2000) found that there was no difference in the lysine requirement to maximize protein deposition and minimize FCR in heavy (80 to 120 kg BW) finisher entire males and gilts.…”

“…per MJ digestible energy (DE)). The studies used in these analyses included those reported by Batterham et al (1985), Giles et al (1986and 1987, Hansen and Lewis (1993), King et al (2000), O'Connell et al (2005 and, Moore et al (2012) and Rikard-Bell et al (2012) with some publications containing more than one study. The meta-analysis indicated that entire males have a higher dietary lysine requirement than gilts (0.600 v. 0.549 g SID lysine/MJ DE, P 5 0.009) over the finisher stage.…”

Systematic comparison of the empirical and factorial methods used to estimate the nutrient requirements of growing pigs

“…This shows that the Lys requirement for FCR can be higher than for ADG. Previous studies also suggest that the Lys requirement may be higher for maximal feed efficiency than for maximal weight gain (O'Connell et al, 2005;Main et al, 2008). In this study, however, the effect was different because the InraPorc model does not represent the effect of Lys deficiency on feed intake.…”

“…In linear-plateau models, the slope of the response between Lys deposition and Lys intake represents the marginal efficiency of dietary Lys retention, whereas the intercept between the linear and plateau sections can be interpreted as the Lys requirements. In quadratic-plateau models, the first derivative of the ascending part of the response function, which is curvilinear, represents the instant marginal Lys efficiency and the intercept with the plateau section In weight ranges similar to those simulated during the first feeding phase, studies using a quadratic function estimated optimal Lys : NE ratios for maximum ADG responses to be 1.07 g/MJ (Warnants et al, 2003) A decrease in the marginal efficiency of nutrients given to a population at decreasing limiting levels is frequently observed in animal studies (Bikker et al, 1994;O'Connell et al, 2005) or in simulation studies (Pomar et al, 2003;Brossard et al, 2009). Variability among the animals of a given population may contribute significantly to the decrease in nutrient efficiency over varying nutrient levels (Curnow, 1973), independently of animal variation arising from genetic (Pomar et al, 2003), environmental or animalmanagement sources (Wellock et al, 2004).…”