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This study aimed to assess the effects of different dietary levels of the protease enzyme and sex on skin, bone and muscle yields and percentages of breast, drumsticks and thighs as the most valuable carcass parts of broilers. A total of 300 one-day-old, mixed-sex broiler chickens (Cobb 500) were randomly divided into 3 dietary treatments with different levels of protease supplementation (group C: a standard diet without Ronozyme ProAct; group E-I: a diet with 200 mg/kg Ronozyme ProAct and a 4% crude protein reduction compared to the standard diet; and group E-II: a diet with 300mg/kg Ronozyme ProAct and a 6% crude protein reduction compared to the standard diet). All diets were maize- and soybean meal-based. Feed and water were provided ad libitum throughout the 49-day feeding trial. The results obtained indicate that the dietary treatments had no significant effect on skin, bone and muscle yields and percentages of the drumsticks, thighs and breast (P > 0.05), except for the breast muscle weight in the female chickens (especially between the E-I and E-II groups), and the drumstick bone percentage in the males between the C and E-2 groups (P < 0.05). In all three groups, the male chickens exhibited higher weights of skin, muscle and bone in breast, drumsticks and thighs than the female chickens, and the differences were not significant only in the skin weight of drumsticks and thighs (P > 0.05). The females had a higher yield of muscle tissue in breast and drumsticks, a higher percentage of skin in drumsticks and thighs, and a lower percentage of bone in drumsticks and thighs than the males (P < 0.05). Major differences resulted from the effect of broiler sex, whereas the dietary treatments containing 3 levels of protease supplementation had a very small effect on the yields and percentages of skin, bone and muscle in breast, drumsticks and thighs.

The first few weeks after broilers hatch are the period of most intense bone growth and development, and the time when they are most susceptible to the influence of various external and internal factors. Research in the recent decades has focused on the involvement of melatonin in bone development during early life in chickens. Melatonin release from the pineal gland has a circadian rhythm, with the highest levels circulating during the night and decreasing during the light phase of the day. Various types of lighting are used in intensive broiler production. In this study, the effects of melatonin on the tibial structure and growth of broilers were investigated. During the first two weeks of life, two groups of chickens were kept under continuous light and fed the same diet, with the experimental group receiving melatonin in the amount of 0.03 g/kg of feed. The results obtained showed that the addition of melatonin in the diet had positive effects on the development and growth of the tibia, which was expressed in a significantly greater thickness of the diaphysis and cortical bone of the diaphysis, higher breaking force and higher values of alkaline phosphatase activity. The cortical bone mineral density of the tibia did not differ significantly between the groups of chicken.

The aim of the study was to examine the influence of the rearing system and age on the phenotypic correlation of the physical properties of the eggs of the Banat naked neck layers. In both examined systems (extensive and semi-intensive system) there were 50 Banat naked neck layers each. The egg properties were examined at three evenly distributed time intervals (40, 45 and 50 weeks of age) in the period from May to July. In order to determine the external properties of egg quality, three basic measures were observed: egg weight, egg length and egg width. Based on the measured length and width of the eggs, the egg shape index was calculated, and subsequently the volume and surface area of the eggs were determined. For each examined factor, the correlation between the mentioned characteristics was determined. The obtained results showed a significant effect of the rearing system on all examined egg properties (R < 0.05), while the influence of age as well as the interaction of the two examined factors had no significant effect. The highest correlation among all investigated factors was found between surface area and egg volume.

Milk fat content stands out as a crucial production trait in cows, and this study delves into its variability based on various factors. The research investigated how the housing method (large farm or individual producers), origin (domestic-rearing or imported cows), and calving season collectively impact this trait. Cows reared on the farm exhibited a higher milk fat content compared to those raised by individual producers. Additionally, primiparous cows from domestic rearing displayed lower milk fat content than their counterparts of imported origin. Among primiparous cows on the farm, those calving in the summer and autumn produced the highest milk fat content. Conversely, primiparous cows calving in the spring season and raised by individual producers recorded the lowest milk fat content. The statistical analysis revealed a highly significant influence of calving season, with a noteworthy interaction among housing method and origin on the observed trait. The significance ranged from statistically highly significant (P ≤ 0.01) to statistically very highly significant (P ≤ 0.001).

The aim of this research was to examine the influence of the year (production cycle) and laying age on the quality of eggs for consumption. Examination of certain properties of egg and shell quality was carried out over a period of three years continuously and in four evenly spaced time intervals (24, 35, 46, and 57 weeks of age). Determining the external quality of eggs included determining the weight and shape index. Examination of the internal quality of eggs included the determination of albumen height and Haugh units. At the same time, the quality of the eggshell involved the determination of the following properties: (weight, thickness, deformation, breaking force, and color of the shell). The obtained results showed that during three production cycles, the genetic progress of this hybrid was confirmed, which is primarily reflected in a statistically significantly higher (p

Gene expression at the phenotypic level varies due to a number of influences from the environment in which the animals are reared. Ignoring this reality or due to insufficient knowledge, farmers are often disappointed when choosing a population of sheep when they do not get the production results that the breed achieves where they bought it. The investigation of the reproductive and production characteristics of parent herds of Sjenica sheep was conducted on four farms. In the research, it included a total of 921 lambs and 474 sheep. The influence of sheep body weight on the weight of lambs at birth within a farm was analyzed. Based on the research conducted on the sheep population and after the obtained and processed data, we can state the following: certain differences were found in the fertility of sheep depending on the farm and body weight. We also perceived that certain differences in the body weight of the lambs are evident depending on the weight group of the sheep and the farm where the sheep were raised. All of the above leads us to the general conclusion that management is extremely important in sheep farming. If the selection of the breeding population is carried out correctly and adequate measures of keeping, nutrition and reproduction are applied, success is guaranteed.

Consumer demand for healthier foods has led the industry to look for alternatives to reduce high-fat levels. Dietary fibers such as inulin have emerged as promising substitutes for fat, increasing nutritional value and reducing fat absorption. The aim of this research was to formulate chicken cooked sausages in which the fat was replaced by inulin suspension at different levels. Four groups of sausages participated in the experiment: group K without fat replacement and groups 50%IN, 75%IN, and 100%IN with 50%, 75%, and 100% fat replacement, respectively. The results show a significantly higher process and cooking loss in the experimental groups compared to group K (p

SUMMARY: Functional foods are foods that offer health benefits over and above their nutritional value. As eggs are a food of global importance, many authors believe that they are an ideal candidate for functional foods of the future, as it is possible to influence their chemical composition through production technology. Vitamins are one of the most important groups of micronutrients essential for human health, and eggs are recognised as an important source of vitamins in the diet, especially fat-soluble vitamins. The egg yolk contains large amounts of vitamins A, D, E and K. Eating two eggs a day covers 10% to 30% of a person's vitamin requirements. This paper reviews the results of a large number of researchers on the influence of various aspects of production technology on the content of fat-soluble vitamins in eggs. Most attention has been paid to the influence of vitamin supplements in feed for laying hens, but also to the influence of the rearing system and the genotype as well as the interaction between the vitamins. [ABSTRACT FROM AUTHOR]

The egg production sector is in a transitional period with regard to the permitted housing systems, i.e. rearing in conventional cages under certain conditions to the complete ban of any form of cage system. The changes were caused by concern for the layer wellfare but with the expected effects on productivity as well. The aim of the research was to determine the effects of the floor space allowance in cage and non-cage housing systems on the feather score and egg production of laying hens of three ages, from the aspect of the regulated minimum and optimal space in the cage system (C) and the space provided in the extensive rearing system with hens in smaller groups in the facility (extensive indoor -EI). In order to determine the feather score, the body weight of the laying hens and the weight of the eggs, three groups of laying hens were formed: C4 (564 cm2 per hen, cage system), C3 (751 cm2 per hen, cage system) and EI ( 3000 cm2 per hen, extensive indoor). The feather score and body weight of laying hens were determined in three ages of hens (30, 40, 50 weeks), by individual assessment and measurement of all hens in the experiment. The hen-day egg production and egg weight were determined in the same weeks of laying age. In addition to the expected decrease in feather score with the age of hens, results indicated a significant interaction between age and space allowance per hen. Observed by individual body parts, as well as based on the overall feather score, the space allowance per hen exhibited a full, cumulative effect at 50 weeks of age. Based on the space allowance, it was possible to rank the overall feather score, with the laying hens with the most space having the best feather score. The effect of the space allowance on the body weight of the laying hens was manifested through the space available on the feeder, which resulted in the lowest (p

In order to evaluate the effect of raw meat's freezing/thawing process on meat products produced from them, frankfurter's quality was monitored. Fresh beef meat was grounded and separated into two lots - the first lot was immediately used in the preparation of frankfurters (G1F), and the other lot was frozen and stored at -18°C for 4 weeks, when it was used in the preparation of the second group of frankfurters (G2F). Physicochemical and technological properties were investigated on fresh (CG-FM) and thawed meat (G-F/TM) samples and the frankfurters made from these samples. Frozen storage significantly affected (p

Calcium and phosphorus represent very important nutrients when it comes to poultry diet formulations. In this paper, we will briefly discuss the relevance and nutritional requirements of these minerals in poultry feedstuffs as well as the average amounts in poultry feed commercially sold in the Serbian market. A total of 1,058 samples of standard complete feed mixtures for broilers and laying hens were collected from the Serbian market, produced by the four major Serbian manufacturers (I-IV) of animal feed over a period of five years (2017-2021). The samples were classified into five groups: broiler starter feed (n = 198) - SF, grower feed (n = 239) - GF, and finisher feed (n = 204) - FF; layers feed 1 (n = 204) - LF1, and layers feed 2 (n = 213) - LF2. This research suggests that the mineral composition of poultry feed is highly variable among manufacturers, but also among the batches of the same manufacturers. All manufacturers for the analyte in focus had values for certain batches that were outside the limits set by the Rulebook. In general, the results of our research indicate that the average content of total phosphorus in feed for broilers and laying hens in Serbia was mostly close to the minimum-to-mid value of the defined (and declared) range of permitted concentrations by the Rulebook, while the calcium content was predominantly close to the maximum-to-middle value. Based on the results of this study, it is recommended that feed manufacturers more frequently conduct an external analysis of samples of feed components and poultry feed products for the composition of these nutrients. Quality control of animal feed could be advised for poultry farms as well in order to make sure that the feed is actually within the parameters given by the manufacturers' declaration.

In less intensive production systems, native poultry breeds can be used in order to diversify the products and achieve self-sustainability of these breeds through production. Given the missing data on the sustainability of quality of eggs obtained from indigenous, native hens, during storage, the aim of the study was to determine the most important parameters of egg quality of indigenous breed of Banat Naked Neck hens during a four-week period in different storage conditions. The design of the experiment was two-factorial with 4 levels of storage time factors (fresh eggs - 0, 1, 2, 3 and 4 weeks of storage) and 2 levels of temperature storage condition factors (room temperature and refrigerator). The room temperature was on average 21.3°C and the refrigerator temperature 8°C. Quality analysis was performed on a total of 200 eggs, and it included following parameters: egg weight, egg weight loss, weight and proportion of structural components: shell, yolk and albumen, albumen height, yolk colour, Haugh Units and albumen pH. The storage time had a significant effect on all properties of egg quality, except for the yolk colour, which was under the impact of the interaction of storage time and temperature. Storage temperature influenced egg weight loss (

The study objective was to examine the effect of the addition of different concentrations of a mixture of three plants (garlic, mint and rosemary) in the diet of broiler chickens on production and slaughter results. The mixture was formed by grinding plants after drying and mixing them in a ratio of 1: 1: 1. The experiment was performed on 600 chickens divided into 4 groups with 3 replicates per group. The chickens were fed at will and the composition of the diet differed only in the amount of added mixture. No mixture was added in control group (C). Group MIX-I chickens consumed a diet supplemented with 0.25% of the mixture, group MIX-II diet contained 0.5% of the mixture supplement, while group MIX-III broilers received 0.75% of the mixture in their diet. At the end of the experimental period, at the age of 42 days, the body weight of the chickens was measured. Mortality, feed conversion and EPEF were determined. At the end of the experiment, 12 chickens (6 males and 6 females) were sacrificed by random sampling from each group in order to determine slaughter results. The obtained results showed that the use of the mixture of three plants had a positive effect on the production parameters. MIX-II group chickens had significantly higher (p

A comparative study of production traits was performed between COBB 500 broilers from a 52-week-old breeder flock and a ROSS 308 from two breeder flocks of different ages (52 weeks and molted flock 79-week-old) in equal, relatively suboptimal ambiental (temperature oscillations) and nutritional conditions (market feed of average quality). The experiment was performed on a total of 720 day-old chicks of both sexes in 4 experimental groups (Cobb; Ross 52; Ross 79; Ross mix - a mixture of Ross broilers from two breeder ages), with 6 replications per group and 30 chickens in each replication. Mortality, body weight (days 0, 7, 21 and 42), weight gain, feed conversion and production index (EPEF) were monitored in 42 days of fattening. It was determined that heavier day-old chickens (p

The comparison of physical quality properties of table eggs of commercial hybrid Tetra SL and two native indigenous breeds of hens, Banat Naked Neck and Svrljig hen, was performed in conditions of alternative production in the pasture system in portable cages without the floor. The experiment was conducted during the vegetation period, at the age of hens of 53-57 weeks. In order to produce good quality eggs, the diet was designed with a complete mixture based on maize and soybean. In addition, constant availability of pastures was ensured. Egg sampling was performed in the morning and the initial egg quality was examined based on egg weight, shape index, egg white, egg yolk and shell quality parameters. Layer hens of the commercial hybrid Tetra SL had significantly higher egg weight and better internal egg quality (p

The aim of the experiment was to investigate the effect of adding flax seed to the cattle diet in the final stage of fattening. A total of 30 male Simmental cattle of uniform initial weight were selected for the trial, which were divided into 2 groups (KON (control) and LS (experimental)). Animals in the control group did not consume flax seed as a dietary supplement, and animals in the experimental group consumed flax seeds in the amount of 3.75% of the concentrated portion of the meal in the last 90 days of fattening, i.e 300 g per day. After slaughtering and cooling, the left carcass side was cut into basic parts according to the Regulation. The study included examination of the tissue fraction of parts of the carcass of the young, determined by dissection. The results of the study showed that the addition of flax seed in the diet had no statistically significant effect on the composition of the carcass parts of the young bulls at the end of the experiment.

Pulmonary hypertension syndrome or ascites is a complex problem in poultry production. This disease has multiple causes, including genetic factors (genotype, sex) and non-genetic factors (altitude, improper egg incubation, ambient conditions in the poultry house, diet, etc.). Results from numerous studies have shown that improper diet and its interaction with other factors are among major reasons for the incidence of ascites symptoms. The objective of this study was to highlight major nutritional aspects related to pulmonary hypertension syndrome in broiler chickens. Therefore, particular attention should be paid to the dietary levels of antioxidant compounds, some minerals, energy and protein, feed forms, type of diet, and feed supplementation with ingredients which reduce the incidence of ascites.

The aim of this study was to compare the effect of two alternative rearing systems (floor and organic) on egg quality traits of New Hampshire laying hens in three different phases of the productive cycle (32, 48 and 72 weeks of age). Egg samples (15 eggs per group) were analysed for quality (egg weight, egg shape index, albumen height, Haugh unit, yolk colour) and chemical composition (dry matter, minerals, proteins and lipids). Egg weight, dry matter and protein content increased, while albumen height, Haugh unit and lipid content decreased with hen age (p≤0.05). Eggs from the floor rearing system had a higher shape index and lipid content compared to organic eggs (p≤0.05). Both factors and their interactions had a significant effect on yolk colour (p≤0.05).

The possibility for use of high light intensity in broiler production management to improve the health of broilers' legs was examined in a study aiming to determine the effect of two levels of light intensity in different stocking densities of broiler chickens. The study was carried out on 1200 Ross 308 broilers according to a random block system with 6 treatments (2 x 3 factorial design) and 4 replicates per treatment. The examined light intensity levels of 150 lx (high light intensity-HLI) and 20 lx (low light intensity-LLI) were applied to 3 stocking densities of broilers: 10, 13 and 15 birds/m2 . Scoring of foot pad (FP) and hock burns (HB) was carried out on the 42nd day, on a sample of 240 broilers. Osteometric and biomechanical measurements on tibia were performed after slaughtering and primary processing, on a sample of 72 broilers. The high level intensity of light exerted no significant effect on the development and firmness of the tibia of broilers grown in the densities of 10, 13 and 15 birds/m2 . There are indications that in the highest studied stocking density the increased light intensity can improve the individual properties of tibia. The differences in the average assessment of hock burns were concluded to be the result of the stocking density that was observed only in conditions of the increased intensity of light. The average score of foot pad lesions was under the significant main effect of both investigated factors. The differences in the average FP estimation between the light intensity treatments were confirmed in the stocking density of 13 birds/m2 .

The trial was designed in order to examine the impact of flax seed in the nutrition of young cattle/bulls, in the final stage of the fattening. In the trial, 30 bulls of Simmental breed of uniform initial weight were selected, divided into 2 groups (control and experimental). The control animal group did not consume flax seed as a food supplement. Cattle of the experimental group consumed flax seed in an amount of 3.75% (300 g per day) of concentrated meal in the last 90 days of fattening, i.e. 300 g per day. The study included the examination of the fattening performance, slaughter traits and the composition of the bovine carcass. After slaughtering, warm carcass sides, with and without kidneys, were measured individually. Subsequent to period of cooling, the left carcass side it was cut into the main carcass parts according to the Rulebook. The results of the study showed that the addition of flax seed in the diet did not have a statistically significant effect on the body weight of bulls at the end of the trial. It was found that the addition of flax seed in the feed during the final stage of fattening did not have an impact on the differences in the average overall gain of bulls and the feed conversion ratio. Based on the data obtained by cutting of carcass sides to main parts, it was established that feeding with flax seeds had no significant effect on the share of carcass parts.

The aim of this study was to evaluate the effect of rearing system and hen's age on quality and chemical composition of eggs. The tested rearing systems were: cage, floor and organic (30 birds Isa Brown hybrid per group). Fifteen eggs per group were collected for analyses in each of three phases of the productive cycle (32, 48 and 72 weeks hen's age). In these samples were investigated external (egg weight and egg shape index), internal (albumen height, Haugh unit and yolk colour) and chemical composition of eggs (dry matter, minerals, protein and lipids content). The general conclusion is that the egg weight and Roche values were increased, while egg shape index, albumen height and Haugh unit were decreased with hen's age. Organic eggs had higher albumen height and more Haugh units in the 48 and 64 weeks compared to the floor and cage eggs. Yolk colour of the floor and cage hens most dependent on the hen's age, on the other hand-yolk colour of organic hens most dependent on the grass availability at the outlet. Eggs from the organic rearing system had a lower dry matter, proteins and lipid content as compared to the cage system.

In order to determine the effect of intensity of light and stocking density, as well as the interaction of light intensity x stocking density on body weight and individual carcass traits, an experiment was performed on 1200 broilers of the Ross 308 genotype. The investigated factors were the intensity of light (LI): 20 lx (K) ; 150 lx (O) and stocking density (SD): 10 broilers/m2 (A); 13 broilers/m2 (B); 15 broilers/m2 (C), in 4 repetitions. The light source was incandescent bulbs of adequate intensity and a light program 16L: 4D: 2L: 2D was applied. Broiler body weight was controlled on 11th, 21st, 35th and 42nd day, by individual measurement of all chickens in the trial. The average sample containing 12 chickens per treatment with equal gender representation (total of 72 broilers) was used to study the slaughter quality of carcasses based on the parameters of absolute and relative yield of more valuable carcass parts (breast, thighs and drumsticks) and meat in the more valuable parts of the carcass. The effect of light with different intensity on the body weight differed depending on the broiler rearing phase. The interaction effect of the intensity of light and stocking density on the body weight of broilers was confirmed in all stages of growing up to the age of 42 days. A higher intensity of light (150 lx) showed the potential to alleviate the negative effects of higher stocking density (15 broilers/m2 ) on the final body weight of the broiler. The carcass traits were not significantly affected by the intensity of the light, while the stocking density, as well as the intensity of the light x stocking density did influence the yield of whole breast and the yield of breast meat.

This study was conducted to evaluate the effect of different feed formulations, fattening period and sex of broiler chickens on absolute carcass conformation measurements (metatarsus length, keel length, breast depth, breast angle and thigh girth) and conformation indices of medium-growing Master Gris chickens. The results showed that, as induced by intensive fattening, body weights were greater and carcass quality, expressed through conformation measurements, was better than the values characteristic of this hybrid (as the hybrid is designed for extensive farming). Regardless of the time of slaughter (at 49 or 63 days of the fattening trial), male chickens had better carcass conformation values (P

The aim of this study was to evaluate the effect of rearing system, genotype and hens age on egg weight and eggs components share. The tested rearing systems were the floor and organic, and tested genotypes were Isa Brown hybrid and New Hampshire breed. Eggs were collected for analyses three times in production cycle (32 weeks hens age, 48 weeks hens age, and 72 weeks hens age). In these samples (fifteen eggs per group, eggs were one day old) were investigated: egg weight, albumen share, yolk share and shell share. Egg weight was increased with hens age. Also, the interaction between the genotype and hens age was found, so the New Hampshire eggs in 32 weeks had less weight then Isa Brown eggs (p≤0.05), while in the 48 and 72 weeks this difference was lost (p≥0.05). The share of egg albumen and yolk was significantly affected by the rearing system, genotype and hens age (p≤0.05). Floor produced eggs had a lower proportion of albumen and a higher proportion of yolk compared to organic eggs. New Hampshire eggs had a higher content of yolk and the smaller content of albumen compared to Isa Brown eggs (p≤0.05). With hens age, the share of yolk was increased and albumen share was decreased. Interaction of all three studied factors - rearing system x genotype x hens age had the most important effect on the shell share.

Rainfall is one of the most important environmental factors influencing crop production under dry land farming conditions. In the Republic of Serbia, the soybean is produced under rainfed conditions, and therefore online monitoring of the rainfall use efficiency (RUE) is essential for efficient management of production. The research aim was to estimate the effects of amount rainfall during the growing season (RGS) and average monthly rainfall on soybean grain yield (GY) in the Vojvodina during the sixteen year period (2000-2015). Distributions of RGS were not satisfactory and negatively influenced the expression genetic yield potential of cultivars. Rainfall deficits during the growing season limited the soybean plant reproductive growth stages leading to GY loss. The coefficient of variation indicated that RGS and monthly rainfall changed moderately from year to year. Regression equations showed that GY tended to increase with the amount of rainfall. GY had strong positive relationship with RGS and rainfall in May, July and August. Since the amount and distribution of rainfall during growing season are critical determinants of GY, soybean cultivars of shorter vegetation periods should be developed and cultivated so that maximum utilization of rainfall is ensured.

This study analyses the effect of different protein levels in broiler feeds (supplemented with protease) and different lengths of fattening period on some parameters related to dressed carcass quality. Medium-growing Master Gris broiler chickens were used in a fattening trial lasting 63 days. At slaughter, dressing percentages and abdominal fat percentages were determined based on traditionally dressed carcass weights and abdominal fat weights of broilers at 49 and 63 days, and conformation indices were calculated based on absolute conformation measurements. Results showed that dietary treatment had an effect only on one relative conformation measurement - body weight/shank length in chickens at 49 days, as control broilers had higher values of this index compared to chickens receiving feeds containing reduced levels of crude protein and protease supplementation (0.2% or 0.3%). Length of fattening period affected almost all studied parameters, except breast angle, dressing percentage of traditionally dressed carcass and abdominal fat percentage.

The paper presents the results of a comparative examination of the beef quality obtained from females of two genotype groups: domestic Simmental breed (A) and its crosses with Charolais breed. The sample included a total of 20 heads, 10 in each group. Cattle were slaughtered at the same age with uniform body weights. After slaughtering, warm carcass sides were individually weighed, with and without kidney fat. After cooling, the left carcass sides were cut into the basic parts according to the Rulebook and the three-rib cut was cut off from the back part (9-10-11 rib). The content of tissues in the three-rib cut was statistically different among the groups, the content of muscle tissue was significantly higher (p

This paper presents research results on the effect of protease on the dressing percentage of conventionally dressed carcass and body conformation in broiler chickens. Broiler diet was supplemented with 0.2% protease (group E-I) and 0.3% protease (group E-II), and protein content in the feed was reduced by 4% (E-I) and 6% (E-II) through a decrease in soybean meal content. Fast-growing Cobb 500 broilers were used for a 63-day fattening trial. Body conformation measurement included absolute carcass conformation measures (metatarsus length, keel length, breast depth, breast angle, thigh girth) and relative body conformation measures - conformation indices (body weight/metatarsus length, body weight/keel length, body weight/breast depth, body weight/thigh girth). Results showed a significant effect of sex on the dressing percentage of conventionally dressed carcass and all body conformation measures, whereas diet had a significant effect on the dressing percentage of conventionally dressed carcass and breast angle values.

This study evaluates the effect of different crude protein levels in broiler diets supplemented with 0.2% and 0.3% protease enzyme (Ronozyme Pro Act) on dressed carcass weight and dressing percentage during two fattening periods (49 and 63 days). The fast-growing strain Cobb 500 was used. At the end of the fattening trial i.e. at 49 and 63 days, 10 male and 10 female birds were randomly sacrificed from each experimental group to determine body weights and conventionally dressed, ready-to-roast and ready-to-grill carcass weights. The data obtained were used to calculate the dressing percentages of the differently dressed carcasses. Results indicated that carcass weights and dressing percentages were not affected by diet (P>0.05), but also showed that the increase in the length of the fattening period by two weeks (from 7 to 9 weeks) led to increased carcass weights, while dressing percentages decreased (P

The aim of this paper was to estimate the effect of rearing systems (floor and organic) on the chemical composition of meat of laying hens. The tested genotypes were Isa Brown hybrid and dual purpose breed New Hampshire. Based on the results of this research can be concluded that the rearing system, generally, did not caused statistically significant differences in any of the parameters examined chemical composition of meat. On the other hand, the breast meat - white meat and thigh and drumstick - dark meat of New Hampshire genotype had significantly higher fat content compared to the Isa Brown hybrid. It must be noted that in the breast meat reported significant interaction genotype x rearing system. The other parameters of the chemical composition of meat were not significantly different between reared genotypes.

The experiment of the supstitution of soybean meal with raw soybean in the final diet was carried out on Hubbard F15 chickens at the age of 35-42 days. The effect of different levels and varieties of raw soybeans in diets on carcass conformation and share of major carcass parts was determined in a two factorial experiment 2 x 5 (2 soybean varieties x 5 levels of raw grains in the mixture), ie a total of 10 dietery treatments. At the end of the trial, by a random sample method, 12 chickens (6 males and 6 females) from each group were sacrificed and examined. The results showed that the index of drumstick girth and share of drumstick were under significant (p

The objective of the present trial was to evaluate the effects of nettle leaves (Urtica dioica) supplementation, broiler gender and muscle portion on meat fatty acid and mineral profiles. Prior to the trial, a total of 600 one-day-old Cobb 500 broiler chickens of both genders, equally, were randomly divided into three groups: a basal diet (control group) and a basal diet supplemented in the last two weeks of fattening with fresh nettle leaves (30 g/kg diet) or with oven dry nettle leaves (5 g/kg diet). After reaching 42 days of age, twenty birds per diet group were randomly selected (four birds per box, both genders equally) and slaughtered, and breasts and drumsticks were collected for analysis. The dry nettle supplementation increased the MUFA and lowered the PUFA, n-6 and n-6/n-3 ratio, mainly in female broilers (p < 0.05). Drumsticks had higher MUFA and PUFA and lower SFA and n-6/n-3 ratio compared to breast meat (p < 0.05). The addition of nettle to broiler diet increased Fe, Zn and Se and decreased Ca levels, mainly in drumsticks (p < 0.05). Furthermore, drumstick meat had more elements with proven health benefits, such as Fe, Zn, Ca and Mn, than breast meat. This study suggests that feeding Cobb 500 broilers with the addition of nettle leaves can significantly change meat fatty acid and mineral composition, but this effect differed between gender and portion. [ABSTRACT FROM AUTHOR]

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Intensive broiler chicken production involves different lighting regimes, which affects a natural cycle of secretion of melatonin, a hormone included in multiple physiological processes in a bird's body. This research aimed to determine the effects of dietary melatonin supplementation during the first two weeks of broiler chickens' life, bred under constant 24 h lighting, on their health and some hematological, biochemical, and production parameters. The study lasted 6 weeks. Three hundred and twenty 1-day chickens were divided into two groups (control - C and experimental - M), with four replications and 40 chickens in each replica. In the first two weeks (the first phase of the study), a continuous lighting mode 24L: 0D was applied. Group M was receiving a diet supplemented with 30 mg/kg synthetic melatonin only during the first phase. Group C had a diet without melatonin supplementation throughout the whole study. Melatonin addition had a statistically significant effect (P<0.01) on the mean values of body weight and daily weight gain at the end of the 1st, 2nd, 3rd, 4th, 5th, and 6th week. The chickens of the experimental group have had a significantly higher value of the European Production Efficiency Factor (EPEF) (P<0.05). The results presented in this paper indicate a direct benefit in stress relief in broilers and a value of the organism's antioxidant system promotion, manifested by improved production performance and fattening efficiency. [ABSTRACT FROM AUTHOR]

Key questions for a local broiler farm are: which broiler hybrid to rear and which industrial feed to use? To show how farmers can manage them, a combination of biological tests and feed characterizations of the most commonly used hybrids and broiler feeds in the local (Serbian) market was designed and performed. The hybrids Cobb 500 and Ross 308 were used, as well as feed of the same quality category from three established domestic producers (A, B, and C) available in the market. A factorial trial (2 × 3) was performed on a total of 1800 unsexed day-old chicks divided into six experimental treatments, with six repetitions per treatment and 50 chickens in each repetition. Prior to and after the biological trial, the feed was characterized. The results confirm the equally high production potential of the two tested fast-growing hybrids, the different quality of the three industrial feeds, and that for the expression of genetic potential, each feeding and fattening period was equally valuable. A complete picture of the tested feeds was obtained within a suitable post-test feed characterization with a farm economy included in the analysis, and the results differed in different production and market scenarios, which allows for finding the optimal feed for the local farm. [ABSTRACT FROM AUTHOR]