Slobodan Stojanovic

THE INFLUENCE OF LONG TERM SOUND STRESS ON HISTOLOGICAL STRUCTURE OF BROILER'S ADRENAL GLANDS

The aim of this paper is to examine the effect of different sound stress duration on adrenal gland of broiler chickens of different age. The experiments were conducted on 90 HYBRO broiler chickens, divided into nine groups (each group consisting of 10 birds) by different age and lenght of sound stress duration. The chickens were exposed to sound stress in sound attenuated building using a fire alarm bell (95 dB) for stress sessions lasted 120 min every day. The histological structure of adrenal gland was analyzed by light microscopy. The results indicate that adrenal gland is sensitive on this kind of stress and sound as stressor could introduce organism in stress reaction. Adrenal glands of broilers exposed to sound stress characterized by marked hyperemia, hypertrophy of interrenal cells, smaller affinity for staining of chromaffin cells compared with control groups. According to our results, degree of histological changes of adrenal gland under the influence of sound stress depends on the length of exposure and age of chickens.

Morphodynamics of embryonic development of skeletal musculature of broiler and layer chickens.

Eggs of broiler (Ross 308) and layer (Hy-Line Brown) chicken hybrids were incubated and tissue samples from the leg muscle (m. biceps femoris) and breast muscle (m. pectoralis profundus) were taken on embryonic days 9, 12, 15, 18 and 20, as well as on the first day post hatching. Histological preparations were made from the samples and the diameter of muscle cells, the volume density of connective tissue of muscles, and the nucleocytoplasmic ratio of muscle cells were recorded. Comparison of the diameter of muscle cells of leg muscle and the breast muscle between broiler and layer chicken during the period of late incubation and day 1 post hatching showed the diameter of the examined muscle cells was greater in layers, while the nucleocytoplasmic ratio of muscle cells was higher in broilers. No differences were established between these two strains in the volume density of connective tissue in both muscles examined. Such results are explained by the prolonged proliferation of myoblasts and delayed differentiation of muscle cells in broilers, which leads to a greater development of the skeletal musculature during the postnatal period. These processes in the embryonic period of development are the cause of differences in the morphodynamics of embryonic development of the skeletal musculature between broilers and layers presented in this paper.

Skeletal muscle characteristics of broiler chickens under modified incubation factors

Four groups of broiler chicken hybrid (Ross 308) eggs were incubated under different temperature and light conditions to assess the effects of both variables on musculature development. During the incubation, the first group was the control and the eggs were incubated at a temperature of 37.8 °C without light, the second group was exposed to increased temperature, while the third group was exposed to monochromatic green light. The fourth group of eggs was incubated under simultaneously changed temperature (according to the regime of the second group) and light (according to the regime of the third group) conditions. Tissue samples from the breast muscle (M. pectoralis superficialis) were taken on embryonic days 9, 12, 15, 19 and 20, as well as on days 1, 3, 7, 14, 21 and 42 after hatching. Histological preparations were used to assess muscle cell diameter, connective tissue volume density, and the nucleocytoplasmic ratio of muscle cells. Our findings indicate that thermal and light manipulations during incubation increase diameter and decrease nucleocytoplasmic ratio in postnatal skeletal muscle cells. No differences were found among groups with regard to connective tissue volume density. These results can be explained by the influence of thermal and light manipulations during incubation on prolonged myoblast proliferation, as well as on the greater postnatal development of skeletal muscle cells.

İlave Koenzim Q10 ile Beslenerek Derin Pektoral Myopati Oluşturulan Etlik Piliçlerde Miyopatinin Devrelerinin Belirlenmesi

The aim of this study was to examine the structural characteristics and incidence of different stages of deep pectoral myopathy (DPM) that was induced in broilers fed a coenzyme Q10 (CoQ10) supplemented diet. A total of 288 1-day-old chicks (Cobb 500) were equally divided among 8 pens (pens 1 to 8). The diet was the same for all chicks until day 35 post-hatching. Subsequently, broilers in pens 5 to 8 were fed the 20 mg of CoQ10/kg finisher diet until the end of the experiment (day 42 post-hatching). To induce DPM, 5 male birds from each of the pens 1 to 8 were subjected to encouraged wing flapping (EWF) at the end of their 37th day. At the end of the trial, the incidence of DPM stages in broilers was determined and an analysis of the histological parameters of deep pectoral muscles was performed. Results showed that, in the groups subjected to EWF, broilers with the CoQ10 supplement had a lower average DPM stage and volume density of necrotic muscle cells, as well as a higher volume density of non-necrotic muscle cells. These results can be related to the antioxidant properties of CoQ10, which, in chickens subjected to EWF, reduced the effects of DPM on cell necrosis and muscle tissue damage.

Effect of Litter on Development and Severity of Foot-Pad Dermatitis and Behavior of Broiler Chickens

ABSTRACT This study was conducted to evaluate the impact of litter type and litter treatment with enzymatic-bacterial production incidence and severity of footpad dermatitis and consequently on behavior of broiler chickens. A total of 1,200 one day-old Ross 308 broilers were randomly allocated to 4 treatments with 4 replicates in 2 x 2 factorial design. The first factor was the physical form of the straw (chopped on approximately 2 cm or un-chopped) and the second factor was addition of enzymatic-bacterial product applied directly on the straw. Each replicate consisted of 75 as-hatched birds per pen. Occurrence and severity of the footpad dermatitis and histological evaluation of the scores was done at the end of the trial (42 days of age). During the trial, at 3 and 6 weeks of age, broiler behavior was observed by Scan Sampling Method. The results showed that chopped straw significantly lowered the incidence of footpad dermatitis. Chopped straw in combination with enzymatic-bacterial product showed the lowest footpad dermatitis score in broilers. Histological procedures confirmed the macroscopic evaluation of the footpad dermatitis severity. The chopped straw had a significant effect on some behavioral patterns of broiler chickens. Differences were observed for dust bathing and scratching. Correlation between footpad dermatitis and birds locomotor activity was not confirmed.

Histological and Morphometric Examination of the Testes of Boars and Male Pigs Immunocastrated with Improvac

Background: Surgical castration of male piglets is frequently performed to prevent development of an unpleasant taste and flavor in meat of mature males, called boar taint. Disadvantages of this method are primarily related to the lower feed efficiency of surgically castrated male pigs, production of less lean meat and more fat on the carcasses than boars, as well as ethical issues associated with the procedure itself. Immunocastration is a method of immunization against gonadotropinreleasing hormone (GnRH) and represents an alternative to avoid boar taint. This study aimed to examine the influence of immunocastration on histological and morphometric parameters of male pig testes. Materials, Methods & Results: A total of 60 crossbred male pigs selected from 30 litters were assigned to two experimental groups: boars (n = 30) and immunocastrated males (n = 30). Two doses (2 mL per dose) of the Improvac® vaccine were given to pigs scheduled for immunocastration. The first injection was given at 10 weeks of age, and the second injection at 20 weeks of age. All pigs were fed the same commercial diet ad libitum, group-housed (15 pigs/pen) and slaughtered at 25 weeks of age. After slaughter, testicle weights were measured and samples of testicular tissue were taken for histological examination. Immunocastrated males had lower testicle weights than boars (P < 0.01). Furthermore, structural damage to the germinal epithelium was visible in the seminiferous tubules of vaccinated pigs. In the testicular interstitium of these animals, the number of Leydig cells were reduced; almost all of these cells exhibited different degrees of abnormality. Moreover, the diameter of the seminiferous tubules and thickness of the germinal epithelium were greater (P < 0.01), and the percentage of germinal epithelium in the seminiferous tubules as well as percentage of blood vessels in the interstitium were higher in boars as compared to immunocastrated males (P < 0.01). Seminiferous tubule lumen diameter was greater (P < 0.01), and percentage of lumen in the seminiferous tubules as well as percentage of non-blood vessel tissue in the interstitium were higher in immunocastrated males than boars (P < 0.01). Discussion: Vaccination against GnRH, as used in this study, reduced the synthesis of follicle-stimulating hormone (FSH) and luteinizing hormone (LH), which led to decreased spermatogenesis and androgen production. The smaller diameter of the seminiferous tubules as well as germinal epithelium thickness, and lower percentage of germinal epithelium in the seminiferous tubules in immunocastrated males could be explained by reduced FSH synthesis, and subsequent reduced spermatogenesis. The described testicular malformations in immunocastrated animals caused their lower weight, and greater diameter of the lumen as well as a higher lumen percentage of the seminiferous tubules. The vaccine reduced LH synthesis, so the Leydig cells of immunocastrated animals had lower activity than the same cells in boars. The percentage of blood vessels in the interstitium of boar testes was higher, which was related to the blood supply required for normal function of Leydig cells. It was concluded that differences existed in the structure of the seminiferous tubules and interstitium between boars and immunocastrated males , which were reflected in values of the examined histological and morphometric parameters. The development of these differences was related to the inhibition of GnRH synthesis and secretion.

Influence of modified incubation factors on carcass characteristics of broiler chickens.

Incubation factors have a great influence on embryonic and postnatal development of broiler chickens. The aim of changing of incubation factors is to obtain the best possible production characteristics of broilers. In previous studies, it was determined that the application of monochromatic green light and thermal conditioning during incubation give the most satisfactory results on the postnatal development of chickens. This paper examines the effects of green monochromatic light and thermal conditioning during incubation on the carcass characteristics of broilers. In this paper four experimental groups were set. The first group was incubated under the standard conditions (37.8 ° C, no light). In the second group incubation temperature were increased, while in the third group incubation was carried out under green monochromatic light. In the fourth group temperature and light conditions of incubation were changed simultaneously. In all groups, changes of incubation factors were made at precisely defined time intervals. After hatching, chickens were grown up to day 42, when they were sacrificed and their carcass characteristics examined. Analysis of results showed that all treated groups have significant higher body weight, weight of drumsticks, thighs and toes. The fourth group have significant higher weight of breasts and wings compared to control group. These results are explained by the influence of the temperature and light changes during incubation on the increased proliferation of myoblasts, the growth of skeletal muscle cells, and the activity of satellite cells, which are reflected in changes of carcass characteristics.