BACKGROUND: Stocking density is one of the most important problems in the poultry industry, which impair their production and welfare.OBJECTIVES: This experiment was done to evaluate the effect of organic selenium supplementation on the growth performance, blood metabolites, and the meat quality of broiler chickens in different stocking densities.METHODS: 216 one-day-old male broiler chickens (Ross 308) were used in 2×2 factorial arrangements by 2 stocking densities (7 and 15 birds/m2) and 2 levels of selenomethionine (0 and 0.4 mg/kg) in a completely randomized design with 4 treatments and 4 replicates.RESULTS: The feed intake (FI), and body weight gain (BWG) were significantly affected by the stocking density and selenomethionine (SE-MET) supplementation in the overall experiment (P<0.05). FI and BWG decreased and feed conversion ratio decreased in 15 bird’s density, while SE-MET inclusion improved these traits (P<0.05). Increasing stocking density increased the plasma glucose (P<0.05). Blood glutathione peroxidase and lymphocyte levels reduced at 15 bird’s density, while increased by 0.4 mg SE-MET supplementation (P<0.05). Increasing stocking density increased blood heterophil, while SE-MET inclusion decreased it (P<0.05). Meat pH and cooking loss were not affected by stocking density. Dripping loss (DL) increased, and water holding capacity (WHC) decreased at 15 bird’s density, but 0.4 mg SE-MET decreased DL and significantly increased WHC (P<0.05).CONCLUSIONS: It was concluded that increasing stocking density had the negative effects on the growth performance and meat quality of broiler chickens; however, the supplementation of 0.4 mg of SE-MET to diet can improve the growth performance, blood metabolites and meat quality of broiler chickens.

BACKGROUND: Lead (Pb) induced oxidative stress is known to suppress growth performance in broiler chickens. The current study was carried out in an attempt to describe the specific underlying mechanisms of such phenomenon. OBJECTIVES: The objective of this study was to investigate the effect of Pb-induced oxidative stress on performance, antioxidant status and behavioral responses of broiler chicken. METHODS: Eighty day-old broiler chicks were randomly assigned to 2 dietary treatment groups of 4 pen replicates, namely i) basal diet containing no lead supplement (control) and ii) basal diet containing 200 mg Pb/kg of diet. RESULTS: The results showed that addition of lead decreased body weight gain (p<0.01) and feed conversion ratio (p<0.01). Also, consumption of contaminated diet significantly increased MDA and H/L Ratio and significantly decreased SOD and GPx activity (p<0.01). Moreover, addition of 200 mg/kg diet significantly increased sitting pasture and aggression behavior and decreased feeding behavior (p<0.01).               CONCLUSIONS: Our data conclude that Pb-induced oxidative stress adversely suppressed feed conversion ratio and growth performance. The proposed underlying mechanism for such phenomenon is Pb-induced oxidative stress by impaired antioxidant status and feeding behavior decreased the growth performance.

BACKGROUND: Heat stress is very important in poultry production. OBJECTIVES: To evaluate the effect of oral elatoninsupplementation and increasing of dark period on biochemical profile of broiler chickens under Heat Stress (HS). ETHODS: A total of 200 day- old broiler (Arian) chicks were randomly allocated in to 4 groups (dark ,melatonin, negative and ositive controls). Melatonin group  received 40 mg melatonin/kg  diet from 30-40 days of age and chickens of dark group were xposed to  a  special lighting schedule from 10-40 days of age. All groups (except negative control) were daily exposed to HS (39± 1 c) for 6 hours per day from 35-40 days of age. At the end of 6 weeks, body weight was measured. At 30, 35, and 40 days, serum uric acid, glucose, total protein, albumin, globulin, activity of AST  and creatinine were measured.  atawas analyzed by ANOVA and Tukey test in SPSS software. RESULTS: In 30 days, there was no significant difference etween groups. In the day 35, only serum uric acid of melatonin group was significantly increased in comparison with egative control. Also, serum uric acid of melatonin group  increased significantly in 40 days in comparison with other roups, as melatonin plays an important role in the antioxidant defense system and uric acid is an important antioxidant inchickens. Serum glucose of positive control compared to other groups significantly increased in 40 days. Other biochemical parameters were not significant. In this study,the mean body weight of dark group was significantly decreased. The  percentage of mortality rate in negative control, dark, melatonin and positive control  treatments was zero, 4 ,5  and 10% respectively. CONCLUSIONS: These results demonstrate that  dark period and oral melatonin supplementation  candecrease HS.

BACKGROUND: The insoluble fiber content of poultry feeds is often considered as an unfavorable factor which reduces the nutritive value of diet. OBJECTIVES: The effects of barley hulls on performance traits of broiler chickens were evaluated. METHODS: The experiment was carried out using 200 Ross 308 broiler chickens in a completely randomized design with 5 treatments and 4 replicates. The experimental diets  consisted of a control hulls-free diet and four diets containing 0.75 or 1.5 percent barley hulls with particle sizes of less than 1 mm or between 1-2 mm. RESULTS: The dietary type did not affect feed intake of the experimental groups. In the whole the experimental period, the weight gain and feed conversion ratio in the broiler chickens feed, the diet that contained 1.5% barley hulls with 1-2 mm particle size improved compared to the control group (p<0.05). In the jejunum, fiber feeding resulted in an increased goblet cell number as compared to the control group (p<0.05). Unexpectedly, barley hulls feeding reduced the villi height compared to the control group (p<0.05). In jejunum the crypt depth in control birds was more than the treatment fed 1.5% barley hulls with less than 1 mm particle size (p<0.05). The ratio of crypt depth to villus height in control group was more than the birds fed the diet that contained 1.5% barley hulls with less than 1 mm particle size (p< 0.05). In ileum the chickens fed the control diet had more lactobacillus and less Escherichia coli than the majority of the treatment fed barley hulls. CONCLUSIONS: Inclusion of 1.5% barley hulls with particle size of 1-2 mm in diet improved performance traits of broiler chickens. On the other hand, using 1.5% barley hulls as a lignocelluloses source increased lactobacillus growth and reduced Escherichia coli population. This alteration in intestinal micro flora suggests a prebiotic effect for barley hulls in the gastrointestinal tract of broiler chickens.

This study was carried out on serum samples collected from broiler breeder chicken flocks vaccinated with avian influenza (AI) H5N1 inactivated vaccine. These flocks included 23 flocks aged 13 to 47 weeks reared in close houses in 7 sites; two vaccinated breeder flocks for HI antibody monitoring by 5 weeks interval samples and 8 flocks aged 41 weeks reared in different sites with identified females and males samples. The vaccine was used in a dose of 0.2 ml at 1 day in hatchery and revaccinated with 0.5 ml at age of 18 days, 19- 20 weeks and 40 weeks. Hemagglutination inhibition (HI) test was carried out against homologous antigen. The study pointed out that AI H5N1 inactivated vaccine under field application induced irregular and low HI titres following the 1st two doses ranged from log 2 0.0 to 4.15 with great variation between flocks, where samples with titre 0-2 ranged from 20 to 100%. The 3rd dose at 19-20 weeks was essential to elevate HI titres 3.25 to 7.44 with more homogenizes flock immunity and lower percentage of titres 0-2 ( 0-20 %) and as measured by HI test. Revaccination of layer flocks at 40 weeks (fourth dose) improves flock immunity facing stress of egg production as evaluated by HI (5.52 - 6.33) and lower negative percentage (5.5-11.7%). Monitoring of breeder flock every 5 weeks is essential to detect proper time of revaccination as each flock has its HI antibody curve. There was a difference in HI tit re rang log 2 0.33 to 1.2 between male and female chicks reared in the same house, but this variation not affecting flock mean. Birds at aged 41 weeks having titres < log2 3 (Seronegative) were protected when exposed to contact with infected flock as showed no clinical signs or change in HI titres after 12 days. In conclusion the usage of homologous inactivated H5N1 vaccine in 4 doses in layer flocks was of value in improving chicken immunity to AI H5N1 wild strain circulate in our field

This study was carried out to evaluate the efficacy of water soluble formulation of diclazuril (1%) in the prevention and control of mixed Eimeria infection in two experimental (semifield) trials and testing efficacy of this medicament in controlling of natural field case of mixed Eimeria infection. The experimental (semifield) trials carried out each on 150-day-old broiler chicks, as they were divided into 3 equal separate subgroups. Infected groups were orally received 1ml of an inoculum containing 50.000 sporulated oocysts of Eimeria tenella, E. acervulina and E. necatrix/ chick at 14 days of age. Diclazuril (1%) liquid at dose of 1 ml / 4 liter of drinking water for 2 successive days just after appearance of bloody dropping (at the 5th day post infection). Birds were given prophylactic diclazuril dose (1 ml / 8 liter) at the 7th day before the experimental inoculation. In both trials were oocyst count (shedding) in the dropping, dropping score, lesion score, body weight gain % and mortality rate were evaluated. Groups treated with diclazuril either in the prophylactic and curative studies gave significant and satisfactory improvement in the assessment criteria when compared with infected non medicated groups. A field trial was conducted 2 commercial broiler chicken farm consisted of 2 flocks aged 33 days; 6000 birds each. Flock (1) was kept as control positive infected non medicated group, whereas flock (2) was medicated with diclazuril (1%) at dose of 1 ml / 4 liter of the drinking water for 2 successive days. The results revealed more reduction in total oocyst count, lesion score and the mortality rate in the medicated than the infected non-treated group. The results proved that diclazuril (1%) liquid is effective in prevention and control of both experimental and field infection field circulating Eimeria species still sensitive to the drug.

This study was carried out to determine the immunomodulating effect of β-glucans and mannan oligosaccharide (MOS) on the immune response of chickens to Newcastle disease vaccine. The results showed that birds received β-glucans and MOS having higher average body weights values and significantly higher ND HI antibody titer than the other non medicated groups. Thymus, spleen and bursal indices of control negative showed significantly lower values than vaccinated medicated and non-medicated groups. Both total and differential leukocytic and lymphocytic counts showed significantly higher in medicated group than other groups. Liver function test showed lower AST and ALT in medicated group than other groups. Results of challenge test with NDV confirmed that MOS and B glucans immunostimulant improved protection rate by 15% in medicated than non- medicated ones. In conclusion MOS and B glucans can be given to chicken to improve both body weight and protection against VV NDV challenge that predominated in Egypt.

In 9 weeks field study, a total of 14100 (Ross broiler breeders) 51 weeks-old chickens fed on the same ration, placed in 2 houses (6600 female + 450 male / house). Birds of house 1 were treated with antimycotoxin adsorbent aluminum silicate (G-V-tox®) 5 kgm/ ton, while those of house 2 were kept as non treated controls. Productivity and reproductivety parameters were calculated for comparison. Treated flock showed improved average egg production (Average 62.2%/week) compared with non treated (Average 61.7%/week), but all still lower than farm stander (Average 76.4%/week). Marked improvement was in the 1st 3 weeks (51-53) of treatment only. Total 9 weeks production declined was 5.5% and 8.4% in control and silicate treated flock; with weekly average of 0.61, and 0.93; respectively. Control flock was slower in decline of production (0.61%/week) than treated flock (0.93%/week). Average weekly egg production and hatching eggs/ hen in treated flock was lower than standard and higher than non treated. Hatchery parameters of treated were improved in treated at the first 3 weeks post treatment. The fertility was higher in aluminum silicate treated group (77.2%), than the untreated one (72.19%). The hatchability was in silicate treated (63.66%) versus (62.25%) in the untreated control. Culls % in hatched chicks was 1.91% in treated flock and lower than in non treated (2.85%). Difference percentage between fertility and hatchability of G.V. tox treated chickens was (10.84%) higher than untreated control (16%). The number of marketable chicks l100 was also improved in treated than non treated. In conclusion, our field study cleared that administration of Silicate in ration for treatment of broiler breeders resulted in an improved production and hatchery performance as compared with non medicated control. However; it did not restore it to the farm stander. Consequently the results indicated that we still in need for more effective products to be used to control mycotoxins in breeder chicken.

In this study, 50 vaccinated broiler and one layer flock from Beni-Suef, Fayoum and Minia governorates were investigated. Necropsy lesions were suggestive of LPAI-H9N2 or NDV. Samples of tracheal swabs and organs were subjected for viral isolation and molecular characterization. Specific RT-PCR for the NDV F-gene and the HA gene of the LPAI-H9N2 viruses was used. Virus isolation and primary identification using HI test revealed 37.5 and 43.3-46.2% prevalence for LPAI-H9N2 and NDV viruses, respectively. Phylogenetic analysis of partial sequences of the F gene showed that NDV viruses belong to genotype II and VII-1.1. as indicated by the F0 protein proteolytic cleavage site motifs (aa112-117) of the NDV strains F-gene. The vNDV isolates were 98.7-99.3% and 96.6-98.9% identical to each other based on nucleotide and amino acid identities, respectively. Compared to their counterpart isolates; the lentogenic strains shared 98-99.2% and 96.3-98.1% nucleotide and amino acid identities to the LaSota reference strain. The LPAI-H9N2 phylogeny of the HA gene showed that the 2 isolates obtained in this study are related to each other and related to recent 2016-2018 Egyptian H9N2 strains. Notably, the 2 strains showed higher identity (≥99%) to recent Israeli 2018 isolates with several amino acid changes. The current study revealed wide spread of both NDV and LPAI-H9N2 viruses. The vaccine failure and the mismatch between the vaccine and circulating NDV viruses is the most probable cause of current outbreaks. The LPAI-H9N2 viruses are divergent form their ancestral viruses in Egypt indicating continuous circulation and vaccine pressure induced mutations

This study was conducted to investigate the efficacy of the Newcastle disease (ND) live vaccines from different commercial sources used in different programs for vaccination of chicks having maternal antibodies against Mycoplasma infection. The immune response was estimated using HI and challenge tests. The effect on the chicken performance was estimated by the detection of the body weight gain. The role of vaccines in stimulating respiratory bacterial stress was pointed out by the lesion scores. Birds vaccinated with live vaccines from source (2) showed higher HI titers than those vaccinated with vaccine from source (1) and birds received the 2nd vaccination from heterologous source showed lower titers than those received from homologous source. Results of the challenge test indicated that birds vaccinated with live ND vaccines from one source and those vaccinated with Hitchner B1 at 33-days of age instead of La Sota showed 100% protection rate as compared with 95 % followed by vaccination with heterologous La Sota. Birds received Hitchner B1 of vaccine source (1) showed only 85% protection rate. All vaccinated chicken groups showed feed conversion rates lower than the non-vaccinated control one. Groups received Hitchner B1 as a 3rd dose of the vaccine showed higher rates than those vaccinated with La Sota. Results of the lesion score for chronic respiratory disease (CRD) in vaccinated groups with different regimes revealed that birds received ND vaccinal strains from source (1) having higher scores than those received ND vaccines from the 2nd source. Administration of Hitchner B1 vaccine at 33-days of age showed lower scores. Hitchner B1 can be recommended in vaccination of chickens derived from Mycoplasma infected hens.