This study was performed to determine the effects of a natural yeast-based feed ingredient (natural carbohydrate fraction (NCF) isolated from a specific strain of yeast) on broiler chickens, and to examine its mode of action. The trial was set up as a complete randomized design with three treatments and eight replicates (38 Ross 308 chickens per pen). Two levels of NCF, 0.2 g/kg and 0.4 g/kg, were compared to a negative control. The NCF addition increased body weight during the initial period, but this benefit was lost towards the end of the trial. Feed conversion ratio was improved significantly with 0.4 g NCF/kg (1.79 compared with 1.83 in control group). Mortality was numerically lower in the groups receiving NCF. Significant effects on caecal bacterial population were not found. Intestine length and weight were not affected by treatments, while some changes in intestine histology were found. The area described as the 'cup' of mucus-producing cells, representing the quantity of stored mucins, was significantly larger in chickens receiving NCF. Relative weights of the spleen and bursa of Fabricius did not change significantly compared with the control. The NCF can improve performance and affects mucus-producing cells. Full elucidation of the mechanisms of action requires further research.

In this 3х2 factorial design trial with three different levels of metabolizable energy (13.4, 13.00, 12.6 MJ/kg), with and without exogenous enzymes (nutrition density was reduced by introducing sunflower meal in different percentage to diet (0, 8 и 16%)), the goal was to investigate the effects of exogenous enzymes Roxazyme G2G (cellulase (endo-1,4-(β-glucanase), βglucanase (endo-1,3(4)-β-glucanase) and xylanase (endo-1,4-β xylanase)) on digestibility and energy utilization. Effects of enzymes were most visible in diet with 13.00 MJ/kg and 12.6 MJ/kg while this effect was unnoticed in the group with 13.4 MJ/kg. Reducing of ME caused the decrease in digestibility and metabolizability (ME/GE). The results suggest that exogenous enzymes, used in this trial, increase digestibility of crude proteins, NDF, hemicelluloses and ash (р<0.05), but the effects were most evident in diets with the reduced level of metabolizable energy.

The aim of this research was to determine the influence of lactation number and parity on milk yield of Saanen goat’s breed. It has been concluded that milk yield was higher for goats that had given birth to twins and three kids than for goats that had given birth to a single kid (P<0.05). The longevity has a great positive impact on production, given that goats in the fifth lactation produced more milk than goats in first or second lactation (P<0.05), while goats in the sixth lactation still produced more milk than goats in first lactation (P<0.05). During the period from 2014- 2019, the research was conducted on a farm of multiparous Saanen goats in Vojvodina (northern part of Serbia). In the observed period, the farm had between 350 and 400 goats per milking, and the research included a total of 1,628 concluded lactations, within which the first lactations were the most 484, then the second 381. According to the number of lactations, goats were grouped into classes from one to seven and from one to three for parity. By comparing each individual lactation, it was determined that in first lactation goats produced significantly lower milk than goats in the rest lactations(P<0.05), except the seventh. Research has shown that lactation number has a significant influence on milk yield (P=0.00). Increasing the fertility of goats significantly affects the production capacity of dairy goats, since does with a larger number of kids in the litter had a significantly higher milk production (P<0.05). Due to the larger number of kids in the litter, milk production also increases. Likewise, it is assumed that the increase in milk yield of goats with two and three kids is a consequence of a larger placenta, i.e. stronger lactogenic activity during pregnancy.

Nutrition of dairy cattle is based on two components, concentrates and forages. The main forages in Vojvodina, north province of Serbia is silage made from the whole plant of corn. After the outbreak of aflatoxin B1 in corn in 2012, the occurrence of aflatoxin B1 in corn as a source of contamination of aflatoxin M1 in milk was very broadly investigated. There is no data regarding the occurrence of aflatoxin B1 in silage and how much silage can contribute to the overall intake of aflatoxin B1 in this region. This work is an attempt to estimate how much silage, in condition and practice used in Vojvodina, contributes to the intake of aflatoxin B1, and consequently aflatoxin M1 in milk. In total, 82 samples of corn grain and 72 samples of corn silage were analyzed on the occurrence of aflatoxin B1 during 2017-2018 period. Aflatoxin B1 was found in 13.41% of corn samples in the range from 6.82 to 187.5 ppb (average 63.5 ppb). All positive samples were from 2017, while no positive samples were found during 2018. Incidence of aflatoxin B1 in silage was 54.17% in the range of 3.5-58.0 ppb (12% moisture content) or 0.95-16.1 ppb in the fresh matter. Results suggest that silage can be a significant factor to overall intake of aflatoxin B1 and that further research is needed.

&lt;p&gt;Osnovni pravac razvoja sistema otkopavanja leži&amp;scaron;ta uglja podzemnim sistemom usmeren je ka uvođenju i unapređenju metoda &amp;scaron;irokih čela sa kompleksnom mehanizacijom. Međutim, u pojedinim leži&amp;scaron;tima prirodno-geolo&amp;scaron;ki uslovi eksploatacije ne omogućavaju primenu ove metode, te se iznalaze druga specifična re&amp;scaron;enja otkopavanja. Jedna od fleksibilnih i prilagodivih složenim uslovima eksploatacije je i metoda kratkih mehanizovanih otkopa. Na osnovu svestrane analize u ovom radu je matematičkim modeliranjem izvr&amp;scaron;eno određivanje optimalnih tehničkih parametara ove metode otkopavanja ugljenih slojeva.&lt;/p&gt;