Effects of Improved Amino Acid Balance Diet on Lysine Mammary Utilization, Whole Body Protein Turnover and Muscle Protein Breakdown on Lactating Sows

Authors

Sai Zhang
Juan C Marini
Vengai Mavangira
Andrew Claude
Julie Moore
Mahmoud A Mohammad
Nathalie L Trottier

Publication Date

5-7-2024

Journal

Journal of Animal Science and Biotechnology

DOI

10.1186/s40104-024-01020-9

PMID

38711075

PMCID

PMC11574995

PubMedCentral® Posted Date

5-7-2024

PubMedCentral® Full Text Version

Post-print

Published Open-Access

yes

Keywords

Amino acid, Efficiency, Lactating sows, Protein breakdown, Protein turnover, Reduced protein diet

Abstract

Background: The study objective was to test the hypothesis that low crude protein (CP) diet with crystalline amino acids (CAA) supplementation improves Lys utilization efficiency for milk production and reduces protein turnover and muscle protein breakdown. Eighteen lactating multiparous Yorkshire sows were allotted to 1 of 2 isocaloric diets (10.80 MJ/kg net energy): control (CON; 19.24% CP) and reduced CP with "optimal" AA profile (OPT; 14.00% CP). Sow body weight and backfat were recorded on d 1 and 21 of lactation and piglets were weighed on d 1, 14, 18, and 21 of lactation. Between d 14 and 18, a subset of 9 sows (CON = 4, OPT = 5) was infused with a mixed solution of 3-[methyl-2H3]histidine (bolus injection) and [13C]bicarbonate (priming dose) first, then a constant 2-h [13C]bicarbonate infusion followed by a 6-h primed constant [1-13C]lysine infusion. Serial blood and milk sampling were performed to determine plasma and milk Lys enrichment, Lys oxidation rate, whole body protein turnover, and muscle protein breakdown.

Results: Over the 21-d lactation period, compared to CON, sows fed OPT had greater litter growth rate (P < 0.05). Compared to CON, sows fed OPT had greater efficiency of Lys (P < 0.05), Lys mammary flux (P < 0.01) and whole-body protein turnover efficiency (P < 0.05). Compared to CON, sows fed OPT tended to have lower whole body protein breakdown rate (P = 0.069). Muscle protein breakdown rate did not differ between OPT and CON (P = 0.197).

Conclusion: Feeding an improved AA balance diet increased efficiency of Lys and reduced whole-body protein turnover and protein breakdown. These results imply that the lower maternal N retention observed in lactating sows fed improved AA balance diets in previous studies may be a result of greater partitioning of AA towards milk rather than greater body protein breakdown.