ISSUE FOCUS 24 FEED & ADDITIVE MAGAZINE April 2023 massive catabolism of fat takes place to support lactation. The sows often suffer from obstipation leading to higher permeability of the intestinal wall, with bacteria, respectively endotoxins being transferred into the bloodstream. Another “source” of endotoxins can be the udder, as the prevalence of gram-negative bacteria in the mammary glands is remarkable (Morkoc et al., 1983). The endotoxins can lead to an endocrine dysfunction: ↑ Cortisol, ↓ PGF2α, ↓Prolactin, ↓ Oxytocin. MMA stands for: – Mastitis, a bacterial infection of the udder: Mastitis can be provoked from two sides: on the one hand, endotoxemia leads to an elevation of cytokines (IL1, 6, TNFα). Lower Ca- and K-levels cause teat sphincter to be less functional, facilitating the entry of environmental pathogens into the udder and resulting in mastitis. On the other hand, due to farrowing stress, Cortisol concentrations get higher. The resulting immunosuppression enables E. coli to proliferate in the udder. – Metritis, an infection of the uterus with vulvar discharges: It leads to reduced contractions and, therefore, to prolonged and/or complicated farrowing or dead piglets. Metritis can be promoted by stress causing a decrease in oxytocin and prostaglandin F2α secretion. Morkoc and co-workers (1983) didn’t find a relation between metritis and endotoxins. – Agalactia, a reduction or total loss of milk production: In many cases, agalactia is not detected until the nursing litter shows signs of hunger and/or weight loss. At worst, the mortality rate in piglets increases. Probably, milk deficiency is caused by lower levels of the hormones involved in lactation. Prolactin levels e.g., may be dramatically reduced by small volumes of endotoxin (Smith and Wagner, 1984). The levels of oxytocin are often half those in normal sows (Pig Progress, 2020). Endotoxin shock A septic shock can be the response to the release of a high amount of endotoxins. In the case of an infection with gram-negative bacteria, the animals are treated with (often bactericidal) antibiotics. Also, the immune system is eliminating the bacteria. Due to bacterial death, endotoxins are massively released. When not bound, they activate the immune system including mac-
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