Isolation, Identification and Antimicrobial Susceptibility of AvibacteriumParagallinarum from Backyard Chicken in Retail Markets of Karaj and Tehran Cities, Iran.

Avibacterium (Haemophilus) Paragallinarum (Av. Paragallinarum) is the causative agent of Infectious Coryza (IC) in chickens. Despite the worldwide distribution of IC, no systematic study, to the best of our knowledge, was conducted on isolation and characterization of Av. Paragallinarum in Iran. The present study aimed to isolate and perform antibacterial susceptibility testing (AST) of IC agents from suspected backyard chickens with typical symptoms of IC in avian markets. From 18 collected choanal swab samples, four (22%) isolates of Av. Paragallinarum were detected by culture methods based on satellite growth on blood agar, which was confirmed by the biochemical reaction of Catalase and Oxidase tests and species-specific PCR (HPG-2). The hypervariable region of the hemagglutinin genes of 4 isolates was amplified and obtained sequences were deposited at a gene bank for more characterization. Meanwhile, 12 (66%) positive reactions were detected by observing expected 500 bpb and using PCR (HPG-2) on swab samples. Antibiotic susceptibility testing (AST) of obtained isolates were analyzed using the Kirby-Bauer disk diffusion method on Columbia agar with horse blood. Isolates were found to be resistant to amoxicillin, oxytetracycline, streptomycin, trimethoprim/sulfamethoxazole (up to 75%) and sensitive to cefalexin, ceftriaxone, enrofloxacin, florfenicol, gentamycin, linco-spectin, neomycin, doxycycline (50%), danofloxacin (75%), flumequine (50%), ofloxacin (75%). An intermediate growth inhibitionzone has been observed around antibiotic discs for ampicillin, colistin, erythromycin, penicillin, tiamulin (75%), tylosin (75%). In summary, to the best of our knowledge, this study is the first report of isolation and identification of AvibacteriumParagallinarum from backyard chickens which may be a source of IC for commercial chicken flocks. Moreover, the prevalence of resistance to some antibacterial drugs of IC agents may impose an additional threat to the poultry industry. A more in-depth study is recommended to develop a low-cost autogenous IC vaccine for small-scale flocks of poultry to prevent and manage the disease and establish antimicrobial resistance.

Effect of crude protein and fat content of diet on productive performance and egg quality traits of brown egg-laying hens with different initial body weight.

A trial was conducted to study the influence of CP and fat content of the diet on performance and egg quality traits of brown egg-laying hens from 22 to 50 wk of age. The experiment was conducted as a completely randomized design with 8 treatments arranged factorially with 4 diets and 2 initial BW of the hens (1,592 vs. 1,860 g). Three of these diets differed in the CP content (16.5, 17.5, and 18.5%) and included 1.8% added fat. The fourth diet also had 18.5% CP but was supplemented with 3.6% fat instead of 1.8% fat. Each treatment was replicated 4 times, and the experimental unit consisted of 21 hens allocated into groups of 7 in 3 adjacent cages. All diets were isocaloric (2,750 kcal of AME/kg) and met the recommendations of brown egg-laying hens for digestible Arg, Ile, Lys, Met, Thr, Trp, TSAA, and Val. Productive performance and egg quality were recorded by replicate every 28 d. For the entire experimental period, diet did not affect any of the productive performance traits studied, but the heavier hens had higher ADFI (120.6 vs. 113.9 g; P < 0.001), egg production (92.5 vs. 89.8%; P < 0.01), and egg weight (64.9 vs. 62.4 g; P < 0.001) than the lighter hens. Initial BW did not affect feed conversion per kilogram of eggs or hen mortality, but BW gain was higher (289 vs. 233 g; P < 0.01) and feed conversion ratio per dozen of eggs was better (1.52 vs. 1.57; P < 0.01) for the lighter than for the heavier hens. None of the egg quality variables studied was affected by dietary treatment or initial BW of the hens. It is concluded that brown egg-laying hens, irrespective of their initial BW, do not need more than 16.5% CP to maximize egg production, provided that the diet meets the requirements for key indispensable amino acids. Heavier hens produce more eggs that are larger than lighter hens but feed efficiency per kilogram of eggs is not affected.

Effects of wheat inclusion and xylanase supplementation of the diet on productive performance, nutrient retention, and endogenous intestinal enzyme activity of laying hens.

An experiment was conducted to study the effects of inclusion of a wheat cultivar (high in nonstarch polysaccharides) and xylanase supplementation of the diet on productive performance, pH of the gastrointestinal tract, nutrient retention, and intestinal enzyme activity of Hy-Line W-36 laying hens from 25 to 47 wk of age. The experiment was completely randomized with 8 treatments arranged factorially with 4 levels of wheat (0, 23, 46, and 69%) that corresponded to a dietary arabinoxylan content of 3.0, 3.3, 3.6, and 3.9%, with or without xylanase supplementation. Each treatment was replicated 5 times. For the entire experimental period, egg weight (P < 0.05) and egg mass (P < 0.01) were reduced and the feed conversion ratio was hindered (P < 0.05) with increased levels of wheat in the diet, but ADFI and egg production were not affected. Xylanase supplementation improved egg production (P < 0.05), egg mass (P < 0.01), and the feed conversion ratio (P < 0.01). Diet did not affect egg quality at any age, except for shell thickness at 47 wk that was improved with xylanase supplementation (P < 0.05). Digesta pH of the different organs of the gastrointestinal tract was not affected by wheat inclusion or xylanase supplementation. Ileal viscosity increased (P < 0.001) with wheat inclusion and decreased (P < 0.001) with xylanase supplementation at all ages. Fat digestibility (P < 0.001) decreased with increased levels of wheat but AME(n) content of the diets (P < 0.05) and nitrogen retention were not affected. Wheat inclusion increased (P < 0.001) amylase (33 wk), lipase (33 wk), and aminopeptidase (47 wk) activity in the duodenum as well as lipase activity in the jejunum at 47 wk of age. However, xylanase supplementation did not affect the activity of any of the enzymes studied. It is concluded that most of the negative effects of wheat inclusion in the diet were reduced or even disappeared with xylanase supplementation. Wheat with a high nonstarch polysaccharide content (Pishtaz cultivar) can be used at levels of up to 69% in laying-hen diets without negatively affecting bird performance, provided that feeds are supplemented with xylanase.

Effects of the main cereal and type of fat of the diet on productive performance and egg quality of brown-egg laying hens from 22 to 54 weeks of age.

The influence of the main cereal and type of supplemental fat in the diet on productive performance and egg quality of the eggs was studied in 756 brown-egg laying hens from 22 to 54 wk of age. The experiment was conducted as a completely randomized design with 9 treatments arranged factorially, with 3 cereals (dented corn, soft wheat, and barley) and 3 types of fat (soy oil, acidulated vegetable soapstocks, and lard). Each treatment was replicated 4 times (21 hens/replicate). All diets were formulated to have similar nutrient content, except for linoleic acid, which ranged from 0.8 to 3.4% depending on the combination of cereal and fat source used. This approach allows for the estimation of the minimum level of linoleic acid in the diets that maximizes egg weight. Productive performance and egg-quality traits were recorded every 28 d, and the BW of the hens was measured individually at the beginning and at the end of the experiment. No significant interactions between main factors were detected for any of the variables studied. Egg production, egg weight, and egg mass were not affected by dietary treatment. Body weight gain was higher (P < 0.05) for hens fed corn or wheat than for hens fed barley, and also higher for hens fed lard than for hens fed soy oil or acidulated vegetable soapstocks. Egg quality was not influenced by dietary treatment, except for yolk color, which was greater (P < 0.001) for hens fed corn than for hens fed wheat or barley, and greater for hens fed lard than for hens fed soy oil or acidulated vegetable soapstocks. We concluded that brown-egg laying hens do not need more than 1.0% of linoleic acid in their diet (1.16 g/hen per d) to maximize egg production and egg size. The 3 cereals and the 3 fat sources tested can replace each other in the diet provided that the linoleic acid requirements to maximize egg size are met.

Efficiency-enhanced photon sieve using Gaussian/overlapping distribution of pinholes.

A class of photon sieve is introduced whose structure is based on the overlapping pinholes in the innermost zones. This kind of distribution is produced by, for example, a particular form of Gaussian function. The focusing property of the proposed model was examined theoretically and experimentally. It is shown that under He-Ne laser and white light illumination, the focal spot size of this novel structure has considerably smaller FWHM than a photon sieve with randomly distributed pinholes and a Fresnel zone plate. In addition, secondary maxima have been suppressed effectively.