N. Milosevic

The effect of stocking density on certain broiler welfare parameters.

In broiler production, stocking density, i.e. floor surface per chicken, is very important welfare factor which directly and indirectly influences and determines the level of growth of chicken body weight, but it is also related to other welfare indicators. Objective of the paper was to define the broiler welfare in different stocking densities by evaluation of their walking ability (gait score), feathering, incidence and degree of hock burns, foot pad lesions, and by determination of the biochemical blood parameters (glucose concentration, total cholesterol concentration), as indicators of condition of stress. One day old chickens of Hubbard genotype were housed in boxes in floor rearing system, in 3 stocking densities and 5 repetitions of each treatment. Treatment A scored stocking density of 10 birds/m 2 ; treatment B, 13 birds/m 2 and treatment C, 16 birds/m 2 . Results of the trial indicate absence of significance of differences between trial groups of broilers in regard to their walking ability, condition of skin and legs, and stress indicators. In general, broiler welfare in all trial groups was satisfactory. However, determined tendencies of worsening of the condition of litter, increase of the frequency of lower scores for walking ability (gait score), hock burns and foot pad lesions which occur with increase of stocking density, indicate the importance of this rearing factor and need to define limiting stocking densities from the aspect of broiler welfare but also economical efficiency of production.

Improving the poultry sector in Serbia: major economic constraints and opportunities

Poultry production is an important livestock sector in Serbia. It accounts for about 12% of the total value of countrys livestock production. Providing relatively cheap food of high quality it is nowadays of particular importance due to economic transition problems and the consequent economic crisis that the country has faced since the beginning of the 1990s. However, despite the sectors importance, poultry production has actually had no institutional support for many years, and the poultry population, as well as broiler meat and table eggs production, has significantly declined over the last two decades. The sector is characterized by insufficient level of concentration, specialization, vertical integration and efficiency. It is estimated that small-scale farms and backyard poultry production in Serbia account for more than half of poultry meat production and two thirds of egg production, with a significant seasonal impact on local markets. The following paper gives an overview of both commercial and small-scale poultry production in Serbia and examine the major economic constrains to and opportunities for poultry sector improvement needed in view of Serbias prospective EU integration.

The effect of genotype of broiler chickens on carcass quality in extensive rearing system

Research was carried out on chickens of four genotypes: two slow-growing genotypes, Master Gris (MG) and Farm Q (FQ), one fastgrowing, Hubbard Classic (HC) and one medium-growing Red Bro (RB). To the age of 3 weeks, chickens were reared according to all technological norms for intensive production. After that period, chickens were moved and fattening in extensive conditions resumed, using unlimited free range. The significance of genotype on body mass was established. The greatest final body mass was established in chickens of the Master Gris genotype (1983 g) and the lowest in Farm Q (1371 g). Fast-growing chickens of genotype Hubbard Classic at the age of 84 days had body mass at the level of medium-growing Red Bro genotype at the age of 91 days (1730 g, and 1759 g, respectively). In accordance to the established body mass, slaughter yields of Farm Q broilers were significantly the lowest. Also, chickens of this genotype also had significantly (p<0.05) lower share of abdominal fat compared to other genotypes. Chickens of Master Gris and Red Bro genotypes had significantly greater shank length (22.57 and 21.01 g/mm, respectively), whereas in fast-growing genotype Hubbard Classic a significantly greater breast angle (90.15 degrees) was determined. Accordingly, share of breast (15.90 %), as well as share of breast meat (10.11 %) was significantly greater in carcasses of Hubbard Classic chickens.

Use extruded rapeseed meal in the feed of broiler chickens

The aim of the study was to investigate the effects of extruded rapeseed meal in the diet on broiler performance. Chickens of Ross 398 hybrid were used in the trial. The trial lasted 42 days. Rape seed meal was extruded prior to use and included in the diet at the level of 4% (group 2) and 8% (group 3), and control group of chickens (group 1) fed the standard mixture based on corn, soybean meal and soybean grits. Chickens of the control group scored the highest ranking and realized the final body mass of 2212 g, whereas the chickens of group 2 had the final body mass of 2191 g, and chickens of group 3 with final body mass of 2148 g were the worst. Falling behind of the trial groups in relation to the control group in regard to the body mass at the end of the trial was by 0,91% group 2 and by 2,89% for group 3. Feed conversion ratio was the best in group 2, followed by control group, and the worst was the group 3 (1,882; 1,866; 1,894, respectively). The lowest mortality rate was realized by chickens of the control group, followed by group 2 and group 3 (4,00%; 4,33%; 5,33%, respectively). The control group of chickens had the best production index value, followed by group 2 and the lowest value of the production index was established for chickens of group 3 (270,95; 265,18; 255,63, respectively). It can be observed that the depression in trial groups was within the limits of toleration, which indicates that extruded rapeseed meal can be included in the diets for fattening chickens in ratio up to 10%.

The nutritive value of extruded corn in nutrition of broiler chickens.

In poultry farming is increasing effort to increasing profitability and decreasing of feed cost. Behind the components that are part of the mixture, the most of cost makes processing of nutrients. Extrusion is process which is increasingly used in order to enhance the quality of different feed for poultry. The aim of this research was comparative testing of nutritional value of extruded and nonextruded corn in nutrition of broiler chicken. The experiment was conducted under experimental growing conditions, in duration of 42 days. The following parameters were measured: growth, feed intake and vitality of broilers. The experiment was divided into two groups of chickens hybrid Ross-308, which were grown separately by sex with 8 replication. The first group was fed standard pelleted mixtures for growing chickens, in which the entire amount of corn in the mixture was extruded, and the second, control group was fed the same food in which corn was not extruded. In the second week of rearing the body weight was 437 g in both groups. In 4th week of age the average body weight was 1439g in group I, and 1419 in group II. For the first group conversion was 1,69 and for the second it was 1,71. The final body weight amounted 2595g for the first group and 2609 for the control group. In the first group conversion was 1,91, mortality 4,39% and the production index had a value of 309, and in the second 1,92; 4,56% and 306. In this study excellent production effects were achieved, so it was not expected that extrusion could achieve better production effects. These results showed that extrusion process does not always give the expected effects.

Effect of different litter treatments on production performance of broiler chickens.

In modern poultry production, foot pad dermatitis (FPD) represents one of the main problems on broiler chicken legs with significant affect on animal welfare and performance. This problem is not solved by the using of straw as litter. Different treatments of straw are needed to eliminate the adverse effects of this material as litter. The most widely used method to improve the quality of litter is chopping straw and application of microbial products on that. These procedures can decrease the moisture in the litter and reduce the population of microorganisms whose activity produces ammonia, and hence improving environmental conditions in facilities. The experiment involved four treatments with four replications with a total of 300 broilers per treatment. The treatment I was unchopped straw, treatment II was chopped straw, treatment III unchopped straw with the addition of microbial products, and treatment IV was chopped straw with the addition of microbial preparation. Duration of trial was 42 days. During the experiment, the following production parameters were measured: body weight per week of the experiment, feed conversion ratio, mortality and FPD. Results of the trial point out that the best production results were in treatment IV with an average final body weight of 2.456g and feed conversion ratio of 1.71. [Projekat Ministarstva nauke Republike Srbije, br. TR 31033]

EFFECTS OF DIETARY SOYBEAN, FLAXSEED AND RAPESEED OIL ADDITION ON BROILERS MEAT QUALITY

The aim of this paper is was to investigate the effects of soybean oil, flax and rapeseed oil on the body weight, fatty acid composition of lipids and sensory characteristics of chicken breast meat. At the beginning, six groups with 40 one day old chicks Cobb 500 hybrid line, with five replications was formed. Chickens were fed with three mixtures of 21, 20 and 18% protein, respectively. The experiment lasted 42 days. The use of different types of oils in the diet did not exhibited statistically significant (P>0.05) differences in body weight of chickens. The control group achieved final body weight of 2704 g and 2695 g, and the experimental groups in a row 2735, 2645, 2735 and 2670g. The use of flax oil and rapeseed oil changes the fatty acid composition of lipids. Replacing rapeseed with soybean oil reduces the percentage of palmitic, stearic and linoleic acids, and increases the share of oleic and linolenic acids in the abdominal fat pad. The inclusion of flax oil in the diet of chickens in an amounts of 4% and 8% increase the amount of linoleic acid to 63% and 203%, which was statistically highly significant (P<0.01) difference compare to the control groups I and II, whereas the amount of linoleic acid is reduced by 14% and 33%. Dietary addition of vegetable oils in this experiment did not show any improvement of chicken breast meat sensory quality, but lipids of meat was improved with the higher levels of PUFAs which contributes to a higher quality of gained chicken meat.

Determining Some Exterior and Interior Quality Traits of Japanese Quail Eggs (Coturnix japonica)

The aim of this research was to determine some exterior and interior quality traits of Japanese quail eggs. A total of 60 Japanese quail eggs were collected from two different farms near Novi Sad, and the eggs quality traits were tested in the laboratory of poultry science at the Department of Animal Science of the Faculty of Agriculture in Novi Sad. The egg weight, albumen weight, yolk weight, shell weight, shell breaking force, shell thickness, albumen height and egg yolk colour were determined. The external and internal egg quality traits of quail eggs from two farms in Serbia do not differ from the results of quality traits from other countries.

Chelating forms of microelements in poultry nutrition

The aim of this review was to analyse the available literature on the effects of the use of microelements and their chelated forms on performance parameters of poultry as well as the cholesterol content in the tissues of broiler chickens. Published research has indicated that the significantly lower levels of organic minerals had a positive influence on the production performance of meat poultry and improved the production performance of laying hens and their heavy line hybrid parents. This has major impacts not only in terms of more efficient utilisation of chelated minerals in poultry diets, but also for less excretion of unused inorganic minerals into the environment, which is a major problem in many countries.

Effect of vegetable oils on productive performances and lipid fatty acid composition of chicken abdominal fat

This paper investigates the effect of soybean, flax and rapeseed oil on productive performance and lipid fatty acid composition of broiler chickens. Six groups of 40 one day-old chicks hybrid line Cobb 500, with five replications were formed. Three mixtures with 21, 20 and 18% protein were used. The first 14 days groups were fed with the starter mixture. The control group was based on the 4% and 8% soybean oil while in the experimental groups were included the same concentration of flax and rapeseed oil. The experiment lasted 42 days. At the end of the experiment 10 chickens from each group were sacrificed for examination of fatty acid composition of lipids. The control group achieved weight of 2704g and 2695g, and the experimental group in 2735, 2645, 2735 and 2670g, respectively. Feed conversion was improved with increasing the amount of oil in the diet. The usage of flax and rapeseed oil changed the fatty acid composition of lipids. Substituting soybean oil with rapeseed oil reduces the percentage of palmitic, stearic, and linoleic acids, and increases participation of oleic and linoleic acids in abdominal fat. The inclusion of flaxseed oil in the diet of chickens in the amount of 4% and 8%, increases the amount of linoleic acid by 63% and 203%, which is a statistically high and significant difference for the control group I and II, while the amount of linoleic acid is reduced by 14% and 33 %, which presents a statistically significant difference compared to group II.