Milk enzyme activities and subclinical mastitis among women in Guinea-Bissau.
BACKGROUND
Subclinical mastititis (SCM) is a condition with raised milk concentration of sodium and milk immune factors. The milk enzymes N-acetyl-beta-D-glucosaminidase (NAGase), lactate dehydrogenase (LDH), acid phosphatase (AcP), and alkaline phosphatase (AP) have attracted attention in dairy research as indicators of SCM, udder health, and milk quality.


METHODS
To investigate if milk enzyme activities and the inflammatory interleukin 8 (IL-8) level are increased in women with SCM, we measured sodium, potassium, NAGase, LDH, AcP, AP, and IL-8 in breastmilk samples collected at 2 months postpartum from 797 women in Guinea-Bissau, West Africa.


RESULTS
SCM, as indicated by a molar milk sodium/potassium ratio (Na/K ratio) greater than 0.6, was present in 26% of the women, and 9% had Na/K ratios larger than 1. The Na/K ratio was positively associated with NAGase, LDH, AcP, AP, and IL-8 in univariate linear regression (p < 0.001 for linear trend for all milk enzymes and IL-8).


CONCLUSIONS
A positive association between the Na/K ratio and the breastmilk enzymes NAGase, LDH, AcP, and AP was found. Breastmilk enzymes have not previously been investigated in relation to SCM in women, and further research is warranted to highlight their specific role in the etiology of SCM.
Rasmussen
Lill-Brith Wium
LB
Department of Human Nutrition, Faculty of Life Sciences, University of Copenhagen, Frederiksberg, Denmark. lill@dsr.ku.life.dk
Hansen
Ditte Hartvig
DH
Kaestel
Pernille
P
Michaelsen
Kim Fleischer
KF
Friis
Henrik
H
Larsen
Torben
T
D000118:Acetylglucosaminidase / Q000032:analysis / Q000378:metabolism; D000328:Adult; D000469:Alkaline Phosphatase / Q000032:analysis / Q000378:metabolism; D005260:Female; D006169:Guinea-Bissau; D006801:Humans; D016209:Interleukin-8 / Q000032:analysis / Q000096:biosynthesis; D007770:L-Lactate Dehydrogenase / Q000032:analysis / Q000378:metabolism; D008413:Mastitis / Q000175:diagnosis* / Q000276:immunology / Q000378:metabolism*; D008895:Milk, Human / Q000737:chemistry / Q000201:enzymology* / Q000276:immunology; D011188:Potassium / Q000032:analysis / Q000378:metabolism; D012964:Sodium / Q000032:analysis / Q000378:metabolism; D055815:Young Adult
D016209:Interleukin-8; D012964:Sodium; D007770:L-Lactate Dehydrogenase; D000469:Alkaline Phosphatase; D000118:Acetylglucosaminidase; D011188:Potassium