44 research outputs found
Effect of the supplementation of vitamins and organic minerals on the performance of broilers under heat stress
The objective of this experiment was to evaluate the effect of diet supplementation with vitamins C and E and organic minerals Zn and Se on the performance of 1 to 35 day-old broilers from, kept under cyclic heat stress (25 to 32ÂşC). Four levels of vitamin-mineral supplementation were used (T1-control diet (60/30 IU of vit E for starter and growing diet, respectively, zero vit. C, 80 ppm of inorganic Zn, 0.3 ppm of inorganic Se); T2-control diet + 100 UI vit E and 300 ppm vit C/kg; T3-control diet + 40 ppm Zn and 0,3 ppm Se/kg; T4-control diet + T2 and T3 levels) and two environments - thermoneutral and cyclic heat stress (TN and HS) from 14 to 35 days of age. In the period when part of the birds was submitted to HS, from 14 to 35 days, it was observed lower feed intake (FI) and better feed conversion (FC) for HS birds receiving supplementation compared to the group without supplementation. Evaluating the total period, all the types of supplementation provided lower FI and better FC than the control treatment, but not affected weight gain (WG). The supplementation of vitamins C and E and/or organic minerals Zn and Se improved the performance of birds due to a lower FI resulting in better FC, independently on the environment
Quantitative Hydrogeology of Volcanic Lakes: Examples from the Central Italy Volcanic Lake District
Volcanic lakes are surface expressions of the hydrogeology of volcanic
complexes. Hydrogeological analysis of volcanic complexes is important
both in terms of management of the water resource and from the point of
view of associated geothermal and volcanic processes. In particular
volcanic lakes are the site of possible mixing between superficial fluids
(water) and endogenous fluids (gas and/or magma). The Tyrrhenian
volcanic domain hosts several volcanic lakes, which, depending on their
origin, can be classed as crater lakes or caldera lakes. The presence of
large cities (like Rome), and intense industrial and agricultural activities
have significantly modified the “natural” equilibrium and groundwater
resources have been significantly depleted during the last 20–30 years. In
many areas the situation has turned “critical”, involving both the lowering
of groundwater and lake levels. In this chapter, we present the results of
quantitative hydrogeological analysis of two volcanic lakes in the
surroundings of the densely urbanized hinterland of Roma capital city
(Italy): the Bracciano caldera lake basin (Sabatini volcanic complex) and
the Albano crater lake basin (Colli Albani volcano). The groundwater flow
systems have been analyzed and the hydrogeological water balances
defined. A focus has been put on the areas with larger aquifer depletion.
The methodologies applied to the lake water balances include GIS
analyses supported by geostatistics