Significance of Intestinal Helminth Infection and Animal Sex for Mercury Concentrations in Two Rodent Species.

We compared the effects of animal gender, species, and intestinal helminth burden on mercury concentrations in rodents. Total mercury concentrations were determined in the liver and kidney tissues of 80 small rodents (44 yellow-necked mice, Apodemus flavicollis, and 36 bank voles, Myodes glareolus) captured in the Ore Mountains (northwest Bohemia, Czech Republic). Overall, 25/80 (32%) of animals were infected by intestinal helminths. The differences in mercury concentration between rodents infected and not infected with intestinal helminths were not statistically significant. Statistically significant differences in mercury concentrations were found only between voles and mice (that were not infected with intestinal helminths). This suggests the differences may be associated with host genetics. Apodemus flavicollis body tissues had significantly lower (P=0.01) mean Hg concentrations (0.032 mg/kg) than Myodes glareolus (0.279 mg/kg), provided that animals were not infected by intestinal helminths; if the animals were infected by intestinal helminths, the difference between both groups was insignificant. The effect of gender in this study was significant only for voles (without helminth infection); for mice (either with or without helminth infection) the differences between genders were not significant. Myodes glareolus males had significantly lower (P=0.03) Hg concentrations in liver and kidney tissues (0.050 mg/kg) than Myodes glareolus females (0.122 mg/kg). These results reveal the importance of considering species and gender when evaluating mercury concentrations.

Effect of Milk Intake, Its Composition, and Fatty Acid Profile Distribution on Live Weight of Suckling Wallachian Lambs until Their Weaning.

This study determined effects of milk production, milk components, or fatty acids (FA) profile on live weight of suckling lambs till their weaning. Live weight (LW, kg) of 42 purebred Wallachian lambs (from 33 ewes) was recorded during four control days with approximately 30-day intervals during rearing. At the same time, their mothers were examined for milk production (kg), milk fat (g), proteins (g), lactose (g), and fatty acids (%) contents. Results investigated using linear regression analysis showed 5.93 kg (p < 0.05) increase of lambs LW corresponded with 1 kg of ewe's daily milk production increase during the observed period. Similarly, significant 0.13 kg or 0.11 kg increases of lambs live weight corresponded with 1 g increase of milk protein or milk lactose at this time. Milk with higher prevalence of trans-palmitoleic acid, trans-vaccenic acid, cis-vaccenic acid, linolelaidic acid, linoleic acid, or conjugated linolenic acid (CLA) significantly improved lambs LW. Moreover, significantly positive Pearson partial correlation between LW and trans-vaccenic acid (r = 0.305) or CLA (r = 0.347) indicated on genetic correlation between these traits. Therefore, milk (natural or artificially supplied) with higher distribution of these specified FAs could improve lambs' LW.

Analysis of fatty acid profile in milk fat of Wallachian sheep during lactation.

In this Research Communication we evaluate the fatty acid (FA) profile of Wallachian sheep milk. The study was performed on 38 ewes in Beskydy Mountains. Samples were collected 4 times during the lactation, at monthly intervals. FA profile as well as groups of saturated, monounsaturated (MUFA), and polyunsaturated (PUFA) FAs were investigated. Considerable increase over the lactation was detected for lauric, myristic, myristoleic and palmitic acids, while stearic acid showed the opposed tendency. Variability, supported by significant differences among particular days of milk collection, was demonstrated for oleic acid; its highest distribution occurred at the beginning and at the end of the trial. The highest distribution of CLA was at the second sample day. Milk of Wallachian sheep naturally grazed at permanent pasture areas showed higher content of PUFA and MUFA in contrast with intensive or semi-intensive sheep breeds reported in the literature.