Interpretive Summary: Determining the impact of increasing SID lysine for primiparous and multiparous sows during lactation
By Anne Zinn
A research team at Kansas State University, in collaboration with Pillen Family Farms, has conducted two experiments to determine the impact of increasing standardized ileal digestible (SID) lysine for primiparous and multiparous sows during lactation. Results of these experiments and the full paper were published in the December 2017 edition of Translational Animal Science.
The objective of these experiments was to determine the effect of increasing SID lysine on the performance of lactating primiparous sows and their litters and the mixed parity sows and their litters under commercial conditions. In lactation, nutrients need to support both sow maintenance and litter growth. With milk production representing about 75% of total nutrient requirements in lactation, it can become challenging to meet the sow’s requirement as litter size increases. This inadequate nutrient intake during lactation can increase sow body protein mobilization, which can decrease subsequent litter size. Early research has evaluated the use of lysine, the first limiting amino acid in corn and soybean meal-based swine diets, but genetic improvements and increased productivity levels indicate that requirements to reduce mobilization of body protein reserves, maximize litter growth, and maintain reproductive function needs to be re-evaluated.
Experiment 1 was conducted at the Kansas State University Teaching & Research Center from January-April 2016. 111 primiparous sows were allotted to 1 of 4 dietary treatments at day 110 of gestation. From day 113 to farrowing, sows received 2.7 kg per day of the dietary treatment; dietary treatments were corn-soybean meal-based and included increasing dietary SID lysine (0.8, 0.95, 1.10, & 1.25%). Sow body weight and back fat depth were measured on day of farrowing, day 10 post-farrowing, and at weaning. Results of experiment 1 showed that, during lactation, there were no differences in average daily feed intake or sow body weight at weaning, resulting in no differences in body weight loss between the four groups. However, back fat loss during lactation decreased as SID lysine increased. There were no differences in litter weaning weight, litter gain from day 2 to weaning, farrowing weight, or subsequent litter characteristics.
Experiment 2 was conducted on a commercial sow farm in central Nebraska from mid-June-mid-August 2016. 710 primiparous and multiparous sows were weighed and, on a subsample of sows, back fat and longissimus muscle depth were collected via ultrasound on day 112 of gestation. They were then allotted to 1 of 4 dietary treatments. From day 113 to farrowing, sows received 2.5 kg per day of the dietary treatment; dietary treatments were corn-soybean meal-based and included increasing SID lysine (0.75, 0.90, 1.05, and 1.20%). At weaning, sow body weight was determined and back fat and longissimus muscle depth were again measured via ultrasound; a post-farrowing weight was calculated for each sow by subtracting the weight of conceptus from each sow’s day 112 body weight. Results showed that the sow body weight at weaning increased and sow body weight loss from post-farrow to weaning decreased as SID lysine increased, and that sow back fat loss increased as SID lysine increased. Additionally, longissimus muscle depth loss decreased as SID lysine increased, and litter weight at day 17 and litter gain from day 2-17 increased up to 1.05% SID lysine; there were no differences in subsequent litter characteristics.
In conclusion, the results of these experiments demonstrate that the sow will mobilize body fat reserves to satisfy litter growth requirements if nutrients are not met by dietary intake. Results also indicate that increasing levels of amino acids can support the reduction of protein loss in lactation. It is apparent that the optimal level of dietary SID lysine required by the sow may vary, but it is clear that reducing protein mobilization is beneficial to reproductive performance.
To read the full article, "Determining the impact of increasing standardized ileal digestible lysine for primiparous and multiparous sows during lactation," please visit Translational Animal Science.