Effect of feeding three lysine to energy diets on growth, body composition and age at puberty in replacement gilts

Abstract

This study evaluated the effect of diets differing in standard ileal digestible (SID) lysine on lysine intake, growth rate, body composition and age at puberty on maternal line gilts. Crossbred Large White×Landrace gilts (n=641) were fed corn-soybean diets differing in SID lysine concentration (%, g SID lysine:Mcal ME); diets were not isocaloric. Gilts received three grower, finisher diet combinations: low (0.68% lysine grower, 0.52% lysine finisher), medium (0.79% lysine grower, 0.60% lysine finisher) or high (0.90% lysine grower, 0.68% lysine finisher). Grower diets were fed from 100 until 142days of age, and finisher diets were fed until they reached 220days of age. Body weight (BW), backfat thickness (BF), and loin depth (LD) were recorded every 28days. From 160-220days of age, gilts were exposed daily to vasectomized boars and observed for behavioral estrus. Gilts fed the low lysine diet had lower average daily gain and BW (P<0.05), but not fat depth:LD ratio. The percentage of gilts that displayed natural estrus by 220days of age was low but not different among dietary treatments (low 27.7%, medium 31.0% and high 37.7%, respectively; P=0.1201). Gilts fed the high and medium diets reached puberty 10 and 6days earlier, however, than gilts fed the low lysine diet (P<0.05). The rate of puberty attainment may have been less because all gilts contracted porcine epidemic diarrhea (PEDv) just as boar exposure was to begin for the first group of gilts. Results from the present study indicate that growth rate and age at puberty can be altered by ad libitum fed diets that differ in SID lysine concentration.

Dietary lysine-to-energy ratios for managing growth and pubertal development in replacement gilts

“…Although these dietary treatments were implemented in a previous study (Calderón Díaz et al, 2017), only about 30% of gilts in that study exhibited a spontaneous natural estrus. In the current study, approximately 55% of gilts with an estrus experienced a spontaneous natural first estrus (Table 5).…”

“…A single boar entered up to 4 pens per day with up to 24 gilts per pen and was rotated daily among pens so that gilts were stimulated by different boars on consecutive days. Each gilt was assigned a daily estrus score (0 to 3) as described previously (Calderón Díaz et al, 2015b;Calderón Díaz et al, 2017). Scores were based on daily vulva changes and gilt behavior in the presence of the boar.…”

“…Serum was collected by centrifugation (1,500 × g; 20 min; 4°C), and concentrations of progesterone were quantified by RIA to determine whether gilts were prepubertal or behaviorally anestrus. Procedures for the assay (ImmuChem Coated Tube RIA kit, MP Biomedicals, Santa Ana, CA) were validated previously (Calderón Díaz et al, 2017). Pools of porcine serum measuring 23.4 and 2.0 ng/mL progesterone were included in each assay.…”

“…Previous studies using varied concentrations of either ME or SID lysine fed to gilts during development indicated that growth rate, body composition, and reproductive development of gilts were unaffected (Calderón Díaz et al, 2015a,b). Using the SID lysine-to-energy content (g of SID lysine: Mcal of ME ratio) to formulate diets fed to replacement gilts showed these traits could be marginally improved (Calderón Díaz et al, 2017). The present study was conducted within a large commercial production system with the objective to evaluate growth and pubertal development in replacement gilts fed diets with varying SID lysine-to-ME ratios during the growing-finishing phase of development.…”

Review: kisspeptin and reproduction in the pig

“…In general, higher growth rates and backfat are positively associated with earlier cyclicity. Limiting dietary energy and amino acids, or feed restriction, even if supplying metabolizable energy above maintenance requirements, delays sexual maturity in gilts (Beltranena et al, 1991;Miller et al, 2011;Calderón Díaz et al, 2017) and decreases LH pulsatility (Prunier et al, 1993;Booth et al, 1996). Gilts of modern genotypes typically exhibit more than adequate growth rates (Amaral Filha et al, 2009), but these are less fat and are leaner than in previous generations.…”