Effect of protein and lysine supply on performance, nitrogen balance, and body composition changes of sows during lactation.

Abstract

Using 73 Large White gilts, we studied the lysine requirement during lactation. Sow and pig performance and nitrogen balance of sows were measured during the total 21-d lactation period. Variation in body composition of sows between farrowing and weaning was determined by the comparative slaughter technique. Two levels of crude protein (15.5 and 17.1%) were combined with two levels of L-lysine HCl supplementation (0 and .16%), resulting in four diets termed P1L1, P1L2, P2L2, and P2L3, containing .66, .77, .77, and .87% crude lysine, and 15.5, 15.5, 17.1, and 17.1% crude protein, respectively. Sows' feed intake, litter growth rate, and milk energy and protein output were not affected by the diet. Nitrogen balance over the total lactation increased (P < .001) with an increase in lysine and(or) protein (-11.7, -7.0, -3.4, and .4 g N/d for P1L1, P1L2, P2L2, and P2L3 diets, respectively). The losses of body weight and muscle weight were higher in P1L1 gilts (P < .01 and .05, respectively) than in gilts on other treatments, whereas the loss of adipose tissue and backfat was similar for the four groups. Multiple linear relationships between lysine intake and milk nitrogen output as predictors and nitrogen balance (N balance = -15.8 + 1.22 lysine - .63 N milk, R2 = .89) or variation of muscle weight (Vm = -477 + 30.1 lysine - 14.7 N milk, R2 = .70) as predicted values were calculated to estimate lysine requirement according to production performance of sows. Calculations show that for achieving a zero protein balance, 45 to 55 g/d of crude lysine are required for normal to high-yielding sows, respectively.

Determination of protein and amino acid requirements of lactating sows using a population-based factorial approach

“…Test of accuracy of the model The k lys was set to 0.80 after comparing the model prediction of SID lysine requirement and six studies (King et al, 1993;Coma et al, 1996;Dourmad et al, 1998a;Sauber et al, 1998;Yang et al, 2000;Huang et al, 2013; Figure 2). The k lys at 0.80 was consistent with what was derived from the InraPorc model (Dourmad et al, 2008), but was higher than the efficiency reported by NRC (2012), possibly due to the method used to obtain milk yield data.…”

“…A literature survey on body and mobilized body tissue composition in lactating sows (Dourmad et al, 1998a;Sauber et al, 1998;Jones and Stahly, 1999;McNamara and Pettigrew, 2002;Gill, 2006) showed that the sow mobilizes both fat and protein, although the protein requirement has been met by the diet. The calculated dietary protein requirement should cover the AA requirement for maintenance and milk production, as excessive mobilization from muscle protein is not desired because of the effects on subsequent reproductive performance (e.g.…”

“…This assumption may be a simplification and it is hard to quantify to what extent mobilized body protein is used for milk protein (Kim et al, 2001). During the first week postpartum, the uterus is degenerated and protein could be available for milk production (Dourmad et al, 1998a), but the quantity of released AA from the uterus is hard to determine and the model does not account for this.…”

“…The ratio between body fat (kg) and protein (kg) loss is an average of the total loss from farrowing to weaning and was found by reviewing the literature (Sauber et al, 1998;Dourmad et al, 1998a;Jones and Stahly, 1999;McNamara and Pettigrew, 2002;Gill, 2006; also see Hansen et al, 2014).…”

“…Results from the literature on lysine requirements (King et al, 1993;Coma et al, 1996;Dourmad et al, 1998a;Sauber et al, 1998;Yang et al, 2000;Huang et al, 2013) were used to test the accuracy of the model using inputs from the studies (BW, BF, LG, LS and dietary ME content). From each study, numbers from the group with lowest body protein loss or N balance closest to zero were chosen.…”