A study of iodine concentration in soils and grasses of pastures of Bryansk and Gomel regions affected by the Chernobyl accident

<p>Bryansk (Russia) and Gomel (Belarus) regions were among the areas most exposed to the so-called "radioiodine impact" (<sup>131</sup>I) that occurred as a result of the Chernobyl accident in 1986. Medical examination of different groups of local population after the accident revealed a pronounced increase in thyroid cancer among children which was associated with not only <sup>131</sup>I fallout but also with a deficiency of natural iodine in these areas [1].</p><p>The aim of the research was to study iodine in vegetation and soils of different grasslands adjacent to rural settlements in the Bryansk and Gomel regions and used by local residents for grazing. The basic original data was iodine concentration in soil and plant samples collected in the affected areas of Russia and Belarus in 44 test sites.</p><p>Soil samples were collected from upper layers 0-5, 5-10 and 10-20 cm deep with the help of the soil auger, averaged vegetation samples were taken from the plots 25x25 or 50x50 cm depending upon the vegetation density. Iodine determination was performed with the help of kinetic rhodanide-nitrite technique.</p><p>The results showed insignificant difference of iodine concentration in soil samples taken from various depth and considerable variation in the content of iodine in the upper soil layer (0-5 cm) both in the Bryansk region (0.24-1.36 mg/kg, n=29) and in the Gomel region (0.23 - 5.27 mg/kg, n=15), depending upon soil type and texture.</p><p>In the Bryansk region, the highest average iodine content was observed in gray soils characteristic for its central part (mean value 0.85±0.12 mg/kg in the top 5-cm layer). In the Gomel region, the highest iodine content was observed in meliorated peat-bog soils (5.27 mg/kg, mean value equaled to 1.02±0.42 mg/kg in the top 5-cm layer).</p><p>The iodine content in the pasture vegetation ranged from 23 µg/kg to 271 µg/kg dw. Both median and mean value of iodine concentration in vegetation of upland meadows (autonomous landscapes) were significantly lower than those in lowland meadows (57 and 113 µg/kg; 67±10 and 125±16 µg/kg correspondingly).</p><p>Accounting of considerable soil ingestion by cows we hypothesize that grazing in lowland pastures with the highest stable iodine content in soils and domination of hydrophyte plant species causes higher <sup>127</sup>I consumption by cattle and transfer to milk. In case of contamination of the area by <sup>131</sup>I this can lead to a relatively lower <sup>131</sup>I transfer to milk, other conditions being equal.</p><p>The study was carried out with partial financial support by RFBR grant No. 16-55-00205 and RFBR and BRFBR, project No. 20-55-00012.</p><p>References</p><p>1. Cardis et al. 2005. Risk of thyroid cancer after exposure to 131I in childhood //Journal of National Cancer Institute, vol. 97, No 10, Pp. 724 – 732.</p><p> </p>

Kinetics of trans-10, cis-12-conjugated linoleic acid transfer to plasma and milk following an abomasal bolus in lactating dairy cows

Trans-10, cis-12-conjugated linoleic acid (CLA) is a potent bioactive fatty acids (FA) that causes milk fat depression in lactating animals. FA are transferred to milk directly through chylomicrons and indirectly by recycling through other tissues. The objective of this study was to characterise the kinetics of trans-10, cis-12 CLA transfer to plasma and milk after a single bolus infusion. Five multiparous mid-lactation cows received a single abomasal bolus infusion of an enriched CLA mixture providing 15 g of trans-10, cis-12 CLA and 15 g of cis-9, trans-11 CLA over a 30-min period. Plasma concentration of trans-10, cis-12 and cis-9, trans-11 CLA peaked 2 h post-bolus, reaching 0·29 and 0·38 % of total plasma FA, respectively, and returned to pre-bolus values at 72 h post-infusion. Milk trans-10, cis-12 CLA yield and concentration peaked 14 h post-bolus (0·25 g/h) and was not detectable in milk after 86 h. Total apparent transfer of trans-10, cis-12 CLA to milk was 41 %, with 73 % transferred to milk through the direct pool (chylomicrons) and the remaining 27 % transferred through the indirect pool (tissue recycling). Compartmental modelling revealed the existence of a transient unavailable pool of trans-10, cis-12 CLA in extravascular tissues represented primarily by the mammary gland, which slowly exchanges with an available pool for secretion in milk fat and transfer to milk. In conclusion, trans-10, cis-12 CLA is predominantly transferred to milk through the direct pathway; however, how this CLA isomer is processed within the mammary gland requires further investigation.

Probiotics in human milk and probiotic supplementation in infant nutrition: a workshop report

Probiotics in human milk are a very recent field of research, as the existence of the human milk microbiome was discovered only about a decade ago. Current research is focusing on bacterial diversity and the influence of the maternal environment as well as the mode of delivery on human milk microbiota, the pathways of bacterial transfer to milk ducts, possible benefits of specific bacterial strains for the treatment of mastitis in mothers, and disease prevention in children. Recent advances in the assessment of early host–microbe interactions suggest that early colonisation may have an impact on later health. This review article summarises a scientific workshop on probiotics in human milk and their implications for infant health as well as future perspectives for infant feeding.