Rapeseed glucosinolates and iodine in sows affect the milk iodine concentration and the iodine status of piglets

I in the chain sow diet --> blood serum of sow --> sow milk --> piglet seru m was investigated in two experiments with a total of eighty-one sows and t heir piglets. In experiments conducted during the last trimester of gravidi ty and the 28 d of lactation, diets with glucosinolates (1.9 mmol/kg diet v ia 100 g ground rapeseed/kg diet (Expt 1) and 2.1 and 4.2 mmol/kg diet via 75 and 150 g rapeseed press cake/kg diet (Expt 2)) were compared with contr ol groups without rapeseed products. From 0 to 600 mug I/kg was added to so w diets during lactation. Diets without supplementary I decreased the I con centration particularly in milk and piglet serum. The presence of rapeseed and rapeseed press cake were indicated by a thiocyanate concentration incre ase, mainly in sow serum. The diets with glucosinolates decreased the milk and piglet serum I concentration. Spot urine and faeces samples from sows e ating the rapeseed-press cake diets had increased I concentration. The sows ' serum I and thyroxine did not respond to glucosinolates (Expt 1) or these diets caused an increase in concentration (Expt 2). Both these criteria se em unsuitable for the diagnosis of I status of adult animals. Glucosinolate s and their degradation compounds may affect the thyroid and the mammary gl ands resulting in lower I milk transfer and higher renal and intestinal I e xcretion.