Efficiency of standardized ileal digestible lysine utilization for whole body protein deposition in pregnant gilts and sows during early-, mid-, and late-gestation

Abstract

The efficiency of SID Lys utilization (kSID Lys) in gilts and sows during early (d 48-52), mid (d 75-79) and late gestation (d 103-107) was investigated using 88 pregnant females (PIC 1050; 27 gilts, 27 parity 1 sows, 34 parity 2+ sows; 192.96 ± 22.84 kg at d 42 ±1 of gestation) and whole body nitrogen (N) retention balance studies. Females were assigned to one of 4 SID Lys levels ranging from 40 to 70% of the daily SID Lys requirements above maintenance for a parity 1 sow according to the NRC (2012) gestating sow model in each gestation period. Experimental diets were isocaloric (3,335 kcal ME/kg) and isoproteic (11.75 % CP) and dietary indispensable AA were set to meet or exceed 100% of AA:Lys ratios. The slope of the linear response to graded SID Lys intake was defined as kSID Lys. With the aim of increasing the accuracy of kSID Lys estimates, gilt data from the current study was combined with gilt data from a previous study conducted at the same facility using 4 SID Lys levels ranging from 60 to 90% of the daily SID Lys requirements above maintenance for gilts according to the NRC (2012) gestating sow model. Whole body Lys retention of the combined gilt data set was assessed with different broken-line and nonlinear models. The kSID Lys was 0.65, 0.38 and 0.52 for early, mid, and late gestation, respectively in gilts. A linear response to graded SID Lys intake was found in late gestation only in parity 1 and 2+ sows; kSID Lys was determined as 0.44 and 0.52 in late gestation for parity 1 and parity 2+ sows , respectively. There were no differences in kSID Lys in late gestation between parities. For the combined gilt data, the model of best performance (reduced error and greater goodness of fit) was the Hoerl model. Maximum kSID Lys (i.e. g SID Lys retention/g SID Lys intake) in gilts was 0.67, 0.54, and 0.53 in early, mid and late gestation predicted at 7.2, 9.1 and 13.5 g of SID Lys intake/d, respectively based on the Hoerl model. Maximum SID Lys retention in gilts was similarly predicted at 8.5, 10.5 and 20.9 g of SID Lys intake/d in early, mid and late gestation and resultant kSID Lys of 0.61, 0.51 and 0.44, respectively. The findings of this study demonstrate that kSID Lys varies by stage of gestation and SID Lys intake level and that, at least in gilts, a dynamic kSID adjusted for daily intake more adequately reflects biological response and hence allows more precise feeding of pregnant females.

Feeding the modern sow to sustain high productivity

“…The Lys requirement increases as gestation progresses because more Lys is steadily needed for reproductive purposes (Sola-Oriol & Gasa, 2017). A recent study (Ramirez-Camba et al, 2020) reported that maximal Lys utilization efficiency was achieved in pregnant gilts at 7.2, 9.1, and 13.5 g SID lysine/day in early-, mid-, and late-gestation, respectively. They also found that maximal retention of Lys was achieved with a higher Lys supply, namely at 8.5, 10.5, and 20.9 g SID lysine/day in early-, mid-, and late-gestation, respectively.…”

The Linear-Logistic Model: A Novel Paradigm for Estimating Dietary Amino Acid Requirements

“…The increase in milk production occurred without a decrease in milk quality [53]; consequently, Holstein cows increased their daily production of milk fat and protein. Moreover, a reinterpretation of Ramirez-Camba et al [54], which includes data on the effects of lysine intake on nitrogen retention and reproductive performance of 69 pregnant primiparous sows, revealed that dietary SID lysine levels associated with Rmin were related to increased litter size (Figure 7). which includes data on the effects of lysine intake on nitrogen retention and reproductive performance of 69 pregnant primiparous sows, revealed that dietary SID lysine levels associated with Rmin were related to increased litter size (Figure 7).…”

“…The increase in milk production occurred without a decrease in milk quality [53]; consequently, Holstein cows increased their daily production of milk fat and protein. Moreover, a reinterpretation of Ramirez-Camba et al [54], The studies considered for investigating the physiological responses captured by the linear-logistic model are listed in Table 1 and detailed below. When data on the effects of rumen-protected methionine supplementation in Holstein cows [53] were fitted with a linear-logistic model, milk production was maximized at AA doses corresponding to the inflection point where weight gain was reduced, or Rmin (Figure 6).…”

“…Figure 7. A reinterpretation of Ramirez-Camba et al (2020)[54] shows a reduction in nitrogen retention at an SID lysine intake associated with an increase in the total number of pigs born in pregnant sows fed experimental diets at d 50 of gestation.…”

Optimal protein concentration in diets for sows during the transition period

“…Assuming this AA composition resembles the sow’s actual requirement, dietary treatment effects were attributable to the overall supply of protein and not to any single essential AA. However, it should be kept in mind that of the nine essential AA, Lys has been studied most extensively in gestating sows ( Samuel et al, 2012 ; Ramirez-Camba et al, 2020 ; Thomas et al, 2021 ; Farmer et al, 2022 , 2023 ), while only a few studies have been conducted on the other essential AA [methionine; Bin et al (2018) ; Xia et al (2019) , threonine; Dourmad and Étienne (2002) ; Levesque et al (2011) , tryptophan; Franco et al (2014) and isoleucine; Franco et al (2013) ]. According to Liebig’s law of minimum, the essential AA fed with the most deficit is the limiting factor for AA utilization.…”