Broiler meat quality: Proteins and lipids of muscle tissue

Proteins and lipids of muscle tissue are important meat quality parameters. They contribute substantially to the nutritional characteristics of meat. A number of studies has been conducted on the effect of different factors on the protein and lipid content of broiler meat. Given the above, the subjectmatter of the present paper was to provide a review of latest research results on the said quality traits as affected by the most commonly tested factors. The results were grouped and presented in terms of the effect of nutrition, genotype, sex, age and rearing system. The objective of the paper was to review major previous studies on the subject in an attempt to define a future research pathway and facilitate the promotion of scientific findings towards wider practical implementation.Keywords: Broilers, meat quality, proteins, lipid

PHYTASE IN DIET FOR FATTENING CHICKENS, INFLUENCE ON BONE’S QUALITY**

Abstract: The influence of phytase added in diet for fattening chickens on the meat quality, was examined during the feed experiment. The experimental examinations were done on the chickens of Arbor Acres strain. There were 440 chickens in the experiment, divided into the 4 experimental groups considering the levels of mineral sources of phosphorus and phytase added into the diet. Control group K (110 chickens) dicalcium phosphate 2%, O-I group (110 chickens) monocalcium phosphate 1,4%; O-II group (110 chickens) dicalcium phosphate 1 % + 0,1 % phytase; O-III group (110 chickens) monocalcium phosphate 0,7 % + 0,1 % phytase. The feeding experiment lasted for 42 days. The chemical analyzes of white and red meat of experimental chickens that the meat of the chickens that gained phytase by diet with lower level of mineral source of phosphorus have more proteins and less fat phytase by diet (P<0,05). Key words: chickens, phytase, sources of phosphorus, meat, quality

THE AGE AND HOUSING SYSTEM EFFECTS ON THE GROWTH OF BROILERS**

**Original scientific paper Abstract: Bearing in mind certain established European Union regulations on the conventional extensive broiler rearing system as well as poultry breeding specificities of our country, experimental investigations were organised with the aim of making a comparison between broiler growth in two different non-industrial rearing systems. The systems included extensive fattening in a poultry house and free-range rearing. The fattening period in both rearing systems lasted up to the 63 rd day of broiler age. During the fattening period chicken growth was controlled by individual chicken weighing on a weekly basis. Based on the research results it was determined that the growth of broilers in both rearing systems was similar up to the 49 th day of age. The differences established were small and statistically insignificant (P>0.05). The controls at 56 and 63 days of age showed somewhat higher differences in mean body weights of chicks. The difference determined on the 63rd day was statistically significant (P<0.05). From the results mentioned it could be concluded that the differences in broiler growth between the rearing systems examined increased with the prolongation of the fattening period. Key words: chickens, rearing systems, age, body weight

Carcass characteristics of two strains of native broilers (White Naked Neck and Black Svrljig) fattened under a semi-intensive system

This study involves the analysis of two breeds [Naked Neck (NN) and Svrljig chickens (Sv)], that is, strains [White Naked Neck (WNN) and Black Svrljig strain (BSv)] of chickens (birds) of both sexes reared under a semi-intensive system until day 84 of age. At 28 days of age, the test birds were kept in a litter housing system (about 8 birds/m 2), following which they were provided a free-range paddock at 4 m 2/bird. The following parameters were evaluated in the two strains and sexes of broilers (totalling 56 chickens) aged 84 days: body weight at slaughter, carcass weight, yields of breasts, thighs, drumsticks, wings, pelvis, back, head, neck, feet, abdominal fat and giblets. At the end of the fattening period, the test broilers of both sexes of the WNN strain had higher values (P0.05); however, a similar yield was obtained for ready to grill carcass (61.73 to 61.99%) when compared with the black Svrljig strain. The differences obtained were not statistically significant (P>0.05). In addition to the genotype (breed, strain), broiler sex had a statistically significant effect (P<0.001; P<0.01; P<0.05) on body weight, carcass yield, yields of drumsticks and thighs, wings, head, feet, giblets and abdominal fat. Specifically, male broilers were found to have higher live body weight (1669.29 to 1480.07 g), carcass weight (1342.86 to 1198.28 g), yields of head (5.13 to 4.39%), drumsticks and thighs (34.26 to 33.96%), feet (5.39 to 5.06%) and giblets (6.46 to 6.31%), whereas the relative yields of carcass (conventional processing (CP): 80.96 to 80.44%; ready to roast (RR): 73.02 to 72.19%; ready to grill (RG): 62.30 to 61.45%), wings (14.06 to 13.76%) and abdominal fat (1.13 to 1.07%) were higher in female broilers. © 2011 Academic Journals

Production performance and egg quality of laying hens as influenced by genotype and rearing system

The aim of this study was to evaluate the effect of rearing systems and genotypes on production performance and egg quality. Isa Brown and New Hampshire genotypes were used in this study. These two genotypes were housed in floor and organic rearing systems. During the experimental period, which lasted one year (52 weeks), the following production performance parameters were recorded: egg production, daily egg mass, feed consumption, feed conversion efficiency, and mortality. Fifteen eggs per group were collected for analysis at 64 weeks of hen age. These samples were evaluated for external parameters (egg weight and egg shape index), internal parameters (albumen height, Haugh unit, and the proportions of albumen, yolk and shell), eggshell quality parameters (shell thickness, shell deformation and shell breaking strength), and eggs’ chemical composition (dry matter, minerals, protein and lipids). Generally, Isa Brown hens had better production performance than New Hampshire hens. At the same time, organic New Hampshire layers performed better than floor-reared ones. Genotype had a significant effect on all ten egg quality parameters (external, internal and eggshell quality), rearing system independently affected only egg weight, and the interaction of the observed factors significantly influenced seven parameters. Genotype had a significant effect on three of the four chemical composition parameters, while no significant effect of the rearing system was established on the chemical composition of eggs. The rearing system x genotype interaction significantly affected the eggs’ protein content

The effect of using rosemary (Rosmarinus officinalis) in broiler nutrition on production parameters, slaughter characteristics, and gut microbiological population

© TÜBİTAK. The aim of this study was to investigate the effects of the supplementation of different concentrations of rosemary in broiler diets from day 1 to 42 on growth performance, carcass quality, and cecal microbiological composition of chickens. The research was carried out with 1200 Ross 308 chickens, divided into 4 groups with 6 repetitions per group. The treatment groups were: control group (C) without rosemary, 0.2% rosemary group (0.2R), 0.4% rosemary group (0.4R), and 0.6% rosemary group (0.6R). Production parameters and the European Production Efficiency Factor (EPEF) were determined. At the end of the trial 12 chicks per group were selected and euthanised in order to determine the slaughtering properties and for the microbiological analysis of the cecum contents. The obtained results showed that the use of rosemary in diets leads to increase in average daily gain, feed conversion, and EPEF value. The share of abdominal fat in carcasses was lower (P < 0.05) in the 0.4R and 0.6R groups. Lactobacilli count was found higher in the 0.4R and 0.6R groups (P < 0.001) compared to the C group. These results demonstrate that addition of 0.4% rosemary powder to broiler feed could have positive effects on the gain, feed conversion, fat deposition, and cecal microbiological composition. Further increase in the amount of added rosemary had no additive effect in this research