Interpretive Summary: Efficiency of standardized ileal digestible lysine utilization (kSID) in pregnant gilts and sows
By: Anne Kamiya, MS
The efficiency of standardized ileal digestible (SID) amino acid (AA) utilization, or kSID, defines the digestibility of AAs in animal feed. The kSID coefficient helps estimate AA availability from feedstuffs. However, due to extreme biological, hormonal and metabolic changes that occur during pregnancy, kSID may differ depending on gestation stage. In this recent Journal of Animal Science study, researchers determined the kSID for Lysine (kSID Lys) during early-, mid- and late-stage gestation in pregnant gilts and sows. They hypothesized that one kSID coefficient would not be broadly applicable during all stages of gestation, and that kSID would vary based on the stage of pregnancy.
A total of 88 pregnant gilts and sows were assigned to one of four different isocaloric SID Lys diets containing at least 100% of the daily Lys requirement. Supporting the authors’ initial hypothesis, kSID Lys was different based on whether gilts were in early-, mid- or late-gestation. In sows with previous pregnancies (multiparous sows), the results were indeterminate. The authors say their data suggests the issue with multiparous sows was due to excessive Lys intake, suggesting that the current Lys requirement for multiparous sows may be overestimated.
The results of this study support the authors’ hypothesis that a dynamic kSID may be required for pregnant gilts based on gestation stage. Whether this finding also applies to multiparous sows still requires more in-depth studies. Re-evaluation of the minimum Lys requirements for multiparous sows is also a potential area of interest for future studies.
The original article, Efficiency of standardized ileal digestible lysine utilization for whole body protein deposition in pregnant gilts and sows during early-, mid-, and late-gestation, will be available in the Journal of Animal Science.