Heavy Metal Concentration in Neotropical Aquatic Snakes (Helicops Pastazae) and Its Potential as a Bioindicator of Water Pollution

The purpose of the present study was to test the potential role of the aquatic snake Helicops pastazae as indicators of water pollution caused by heavy metals. In particular, we tested whether the total heavy metal concentration is related to (1) the position (upstream vs downstream) of the sampling point and its distance from the point where wastewater is discharged; (2) the taxonomic group studied and its place in the trophic chain: piscivorous snakes vs characid fish that co-occur with them; and (3) the organ or tissue examined: snake liver versus muscle. We quantified cadmium (Cd), chromium (Cr) and lead (Pb) by using atomic absorption spectrophotometry with electrothermal atomization. Significant differences were found between some of the sampling points, particularly high metal concentrations were detected upstream at point 1, but no clear spatial pattern was found. There were no significant differences in the concentration of any of the metals between fish and snake muscle, suggesting potential mechanisms of metal excretion in snakes. With regard to interactions, the snake liver had the highest concentrations of cadmium and the muscle of lead and chromium, which may indicate tissue affinity differences for certain metals. Altogether, our results indicate that H. pastazae accumulates contaminants differentially, depending on the tissue and location, which render them useful bioindicators of water contamination.

Heavy metal concentration in Neotropical Aquatic Snakes (Helicops pastazae) and its potential as a bioindicator of water pollution

The present study aimed at testing the potential role of the aquatic snake Helicops pastazae as indicators of water pollution by heavy metals. In particular, we tested whether the total heavy metal concentration is related to (1) the distance and position (upstream vs downstream) of the sampling point with the discharge of wastewater; (2) the taxonomic group studied and its place in the trophic chain: piscivorous snakes vs characid fish that co-occur with them; and (3) the organ or tissue examined: snake liver versus muscle. We quantified cadmium (Cd), chromium (Cr) and lead (Pb) by using atomic absorption spectrophotometry with electrothermal atomization. Significant differences were found between some of the sampling points, particularly high metal concentrations were detected upstream on point 1, but no clear spatial pattern was found. There were no significant differences in the concentration of any metal between fish and snake muscle, suggesting potential mechanisms of metal excretion in snakes. With regard to interactions, the snake liver had the highest concentrations of cadmium and the muscle of lead and chromium, which may indicate tissue affinity differences for certain metals. Altogether, our results indicate that H. pastazae differentially accumulates contaminants, depending on the tissue and location, which render them useful bioindicators of water contamination.

Rapeseed forage in lactating cow feeding at the 8–9th month of gestation

Кормовые продукты, полученные из маслосемян рапса, всё шире применяются в питании молодняка и кормлении молочных коров. С внедрением в производство и использованием безэруковых, низкоэруковых (двунулевых, нулевых), с низким содержанием глюкозинолатов сортов рапса всё шире используются рапсовые корма в хозяйствах и на предприятиях по производству молока в Калининградской, Липецкой, Ленинградской, Новгородской, Московской областях, на Урале, в Западной и Восточной Сибири, а также в Польше и др. С использованием глубокой заморозки семян рапса с последующей экструзией получены кормовые продукты с высокими антиоксидантными, антитоксичными и сорбционными свойствами для повышения экологической и пищевой ценности молока коров на 89-м месяце стельности. В этот период производственного цикла в организме коров и молоке накапливаются тяжёлые и токсичные металлы, отрицательно влияющие на обмен веществ, здоровье и качество молока при силосно-сенном типе кормления. Целью исследования являлось изучение влияние антиоксидантных, антитоксичных и сорбционных свойств рапсовых кормов в составе рационов коров на 89-м месяце стельности на экологичность молока, обменные процессы и экскрецию тяжёлых и токсичных металлов из организма. Рапсовые корма в составе рационов способствовали повышению переваримости органических веществ. Дозированное их использование при силосно-сенном типе кормления коров в условиях круглогодового способа содержания позволило снизить ретенцию тяжёлых и токсичных металлов в организме животных. Rapeseed forage becomes more and more popular in cow feeding. After the introduction of erucic acid-free rapeseed varieties or those with low content of erucic acid and glucosinolates, dairy factories started using rapeseed feed in the Kaliningrad, Lipetsk, Leningrad, Novgorod, Moscow regions, the Urals, Western and Eastern Siberia as well as Poland. Deep freezing of rapeseed followed by extrusion resulted in fodder having high antioxidant, antitoxic and sorption properties to improve ecological and nutritional values of cow milk at the 89th month of gestation. During this period cow organism and milk tend to accumulate heavy and toxic metals that have negative effect on metabolism, health and milk quality when feeding cows with silage and hay. The aim of the experiment was to test an effect of rapeseed forage with antioxidant, antitoxic and sorption properties on milk value, metabolism and heavy and toxic metal excretion at the 89th month of cow gestation. Rapeseed fodder improved the digestibility of organic substances and reduced the accumulation of heavy and toxic metals in livestock organism.