The nutritive value of poultry diets containing sunflower meal supplemented by enzymes

The international limitations imposed on the utilization of meat and bone meals in animal diets, together with the increasing demand for soybean meal, create a necessity to search for other protein sources to economically balance compound feeds. In this regard it is important to note that sunflower is the best adapted high-protein crop available in some European regions and that is useful to use it in poultry farming as the replacement of other protein sources. Protein and many other nutrients are “imprisoned” to variable degrees, inside sunflower meal fibrous structures, and remain less available for digestion by the poultry’s own proteases and other endogenous enzymes. Added exogenous enzymes (phytase, hemicellulase, cellulase, carbohydrase, protease, etc.) offer a number of creative possibilities for breakdown and “liberation” of these nutrients, their easier digestion and absorption, and thus development of new nutritional standards and new diets formulation. Supplementation of poultry diets containing sunflower meal by different enzymes increasingly contribute to sustainable poultry farming by enhancing production efficiency, increasing the effectiveness of nutrient utilization and upgrading in environmental protection. [Projekat Ministarstva nauke Republike Srbije, br. III46012

The analysis of impact of intensity of contact load and angular shaft speed on the heat generation within radial ball bearing

This paper considers the factors that influence the heat generation within ball bearing. Various lubrication regimes are taken into consideration and a mathematical model for determination of the coefficient of heat generation is set up. Due to the complexity of mathematical tools, and in order to perform better and easier analysis of the considered phenomenon, the application that integrates the mathematical models of load distribution and heat generation was developed. The impact of the contact load and angular shaft speed on the level of heat generated in radial ball bearing was analyzed

Rosemary essential oils as a promising source of bioactive compounds: Chemical composition, thermal properties, biological activity, and gastronomical perspectives

Rosemary (Rosmarinus officinalis L.) is a plant worldwide cultivated mainly for essential oils, extracts, and as a spice. Up-to-date results showed diversity in composition of the essential oils, which may influence their quality, biological activity, and thermal properties. Therefore, the aim of this study was to investigate the chemical composition, antimicrobial activity, and thermal properties of the rosemary essential oils originating from Serbia and Russia. Additionally, oils were added to the sunflower oils in order to investigate possible antioxidant activity during the frying. Investigation of the chemical profile marked α-pinene, eucalyptol, and camphor as the most abundant compounds in both oils. However, overall composition influenced in such manner that Russian oil showed significantly higher antimicrobial activity, while Serbian oil proved to be better antioxidant agent in case of frying of sunflower oil. This would significantly influence possible application of the oils, which could be used as an antioxidant agent for extension of the food shelf life, or antimicrobial agent for protection against different microbial strains

The possibility of in vitro multi-enzymatic method application for the assessment of the influence of thermal treatments on organic matter digestibility of feed for ruminants

In vitro multi-enzymatic method is a two-step procedure that uses exogenous enzymes for incubation of feed that aim to imitate digestive processes in the animal. It is used for determination of organic matter digestibility (OMD) of various feedstuffs and complete mixtures used in ruminant nutrition. The aim of the present work was to determine whether this in vitro multi-enzymatic method can be applied for the assessment of the influence of thermal treatments on OMD of feed for ruminants. Samples of corn and complete mixture for cows (based on corn) were subjected to pelleting, steam flaking, micronization and extrusion. Statistical analysis of the results did not show significant increase of corn and complete mixture OMD after various thermal treatments compared to untreated samples, which can be explained by high digestibility of corn itself (exceeds 90%). Based on obtained results it can be concluded that applied in vitro method is not suitable for the assessment of the influence of thermal treatments on OMD of corn and corn based mixture, while future research should be broadened to analysis of samples with lower OMD, such as sorghum, oats and barley

The analysis of impact of intensity of contact load and angular shaft speed on the heat generation within radial ball bearing

This paper considers the factors that influence the heat generation within ball bearing. Various lubrication regimes are taken into consideration and a mathematical model for determination of the coefficient of heat generation is set up. Due to the complexity of mathematical tools, and in order to perform better and easier analysis of the considered phenomenon, the application that integrates the mathematical models of load distribution and heat generation was developed. The impact of the contact load and angular shaft speed on the level of heat generated in radial ball bearing was analyzed

EFFECTS OF CYTOPLASMIC MALE STERILITY ON MAIZE HYBRIDS YIELD

The principal aim of breeding and seed production in Serbia is to provide sufficient amounts of all seed categories of the most productive hybrids for national needs and export. Climate conditions in Serbia are favourable for maize seed production (soil quality, effective precipitation sum, long freeze-free periods, etc.). The introduction of sterile forms of parental lines in the development of seed material of maize hybrids has resulted in the improvement of maize growing practices and provided easier control of seed crops. Therefore, the objective of the present study was to observe the optimum ratio of sterile to fertile hybrid variants for the commercial maize production and their effects on yields. The trial was set up according to the randomise complete block design with three replications. The elementary plot size amounted to 5.18m². The used material consisted of seed mixtures of 0, 5, 10,… to 100% fertile plants mixed with the sterile variant of the observed hybrid. Upon processing of obtained results, the highest yield of 17.341 t ha-1 was recorded in the fertile to sterile variant ratio of 80%: 20%. The coefficient of correlation points out to a low correlation of yields on fertility percentage (rxy=0.164). Furthermore, based on the coefficient of determination, a low percentage of dependence of yields on fertile plants percentage was established (R²=0.027)