Increasing Dietary Lysine Impacts Differently Growth Performance of Growing Pigs Sorted by Body Weight

Abstract

An experiment was conducted analyzing whether growing pigs classified in different initial body weight categories (BWCAT) have a different response to increasing standardized ileal digestible lysine to net energy ratio (SID Lys:NE), to assess whether light pigs might benefit from being differentially fed. A total of 1170 pigs in pens of 13 were individually weighed, classified in 3 BWCAT (Lp: 32.1 ± 2.8 kg, Mp: 27.5 ± 2.3 kg, and Sp: 23.4 ± 2.9 kg), and afterwards pens were randomly allocated to 5 dietary SID Lys:NE treatments (3.25 to 4.88 g/Mcal) fed over 47 days. Results reported a greater linear improvement of growth and feed efficiency of Sp compared to Lp when increasing SID Lys:NE. Modelling the response to SID Lys:NE using quadratic polynomial models showed that the levels to reach 98% of maximum growth from day 0–47 were 3.67, 3.88, 4.06 g SID Lys/Mcal NE for Lp, Mp, and Sp, respectively. However, due to the overlapping SID Lys:NE confidence intervals at maximum performance, it was not possible to determine if requirements were different between BWCAT. Summarizing, the results suggested that feeding small pigs greater SID Lys:NE than large pigs can improve their performance and increase the efficiency of the overall production system.

Limiting Dietary Lysine Increases Body Weight Variability by Restricting Growth Potential of the Lightest Growing Pigs

“…The hypothesis of the present study was that the greater effect of SID Lys:NE on BW gain of small pigs when grouped in BWCAT’s shown previously in Aymerich et al [ 12 ] could be observed in body weight variability. Therefore, this study compared the response to SID Lys:NE between BWCAT’s in terms of body weight variability and individual BW gain.…”

“…Numerous strategies such as prolonging lactation [ 10 ], using complex diets at weaning [ 11 ], increasing amino acid density [ 12 , 13 ], energy density [ 14 ], or sorting by BW [ 15 ] have already been proved as useful in some conditions to increase BW of the lightest pigs. Nevertheless, the impact of some of those strategies, especially the nutritional ones, on BW variability still remains unclear.…”

Interrelationships between sex and dietary lysine on growth performance and carcass composition of finishing boars and gilts1

“…Most authors just report the effect of dietary lysine on each sex. As recently shown by Aymerich et al (2020) , comparing the linear or quadratic response in a single model gives an indication of how certain we can be that the effect of SID Lys:NE differs between categories of a factor. However, being linear or quadratic should be considered carefully as this could be strongly influenced by the range of SID Lys:NE in which the experiment evaluated the effects on pig performance.…”

The Implications of Nutritional Strategies that Modify Dietary Energy and Lysine for Growth Performance in Two Different Swine Production Systems

“…The SID Lys levels used in the experiments were chosen based on previous trials [ 18 ] and on published nutrient requirements [ 35 ]. As Pietrain sire line was expected to have a lower ADFI than a Duroc sire line, the differences in dietary SID Lys were greater in Exp.…”

“…When it is necessary to minimize the cost of feed, it is possible to reduce energy density without negatively impacting average daily gain (ADG), because pigs increase their average daily feed intake (ADFI) to reach a similar energy intake [ 12 , 13 ]. However, in some conditions, pigs cannot completely compensate for the reduced energy density, especially younger animals [ 14 , 15 , 16 ] or low-weight pigs [ 17 ] with a limited ADFI [ 18 ]. Under these circumstances, the lower energy intake may impair ADG by limiting protein [ 19 , 20 ] or fat deposition [ 21 , 22 , 23 ], depending on whether pigs are in the energy or amino acid-dependent phase [ 24 ].…”