Antibiotic resistance pattern and pathological features of avian pathogenic Escherichia coli O78:K80 in chickens.

Avian pathogenic Escherichia coli (APEC) induces colibacillosis, an acute and systemic disease, resulting in substantial economic losses in the poultry sector. This study aimed to investigate the antibiotic resistance pattern associated with frequent virulence gene distribution in APEC O78:K80 that may cause pathological alterations in chickens. The antibiogram profile showed high resistance to erythromycin, chloramphenicol, tetracycline, ampicillin, and co-trimoxazole, followed by intermediate resistance to ciprofloxacin, levofloxacin, enrofloxacin, norfloxacin, nitrofurantoin, and doxycycline hydrochloride, and sensitive to amikacin, streptomycin, gentamicin, and colistin. Virulence gene distribution identifies eight (irp-2, iutA, ompT, iss, iucD, astA, hlyF, iroN) genes through a conventional polymerase chain reaction. APEC O78:K80 caused significantly high liver enzyme concentrations, serum interleukin-6 and tumor necrosis factor-alpha levels in experimental birds. Also, infected birds have hypoproteinemia, hypoalbuminemia, and hyperglobulinemia. Necropsy examination revealed fibrinous perihepatitis and pericarditis, congested lungs, intestinal ecchymotic hemorrhages and necrotizing granulomatosis of the spleen. Histopathological examination depicted hepatocellular degeneration, myocardial necrosis, interstitial nephritis, intestinal hemorrhages and lymphopenia in the spleen. This study is the first evidence to assess the antibiotic resistance profile linked with virulence genes and clinicopathological potential of APEC O78:K80 in chickens in Pakistan, which could be a useful and rapid approach to prevent and control the disease by developing the control strategies.

Alternanthera yellow vein virus (AYVV); a betasatellite independent begomovirus infecting Sonchus palustris in Pakistan.

Satellites associated begomoviruses are the most diverse group of plant viruses in tropical and subtropical regions. In Pakistan, during field surveys in 2019-2020, Sonchus palustris (a weed plant) was observed showing begomovirus symptoms i.e., vein yellowing and mosaic patterns on leaves. Rolling circle amplification from total isolated DNA of symptomatic leaves was performed to amplify circular viral genomes. Subsequent cloning and sequencing showed that a new strain of Alternanthera yellow vein virus (AlYVV) is associated with vein yellowing disease of S. palustris. The identity percentage analysis through BLAST search and SDT analysis showed that the new strain is 94-98% identical to AlYVV isolates reported from Pakistan, India and China. In phylogenetic tree, it clustered with AlYVV-[PK:E prostrata:15-KX710155], AlYVV-[PK:E prostrata:13]-KX906697] and AlYVV-[PK:E prostrata:11]-KX906694] previously reported from Pakistan. There was no detectable level of betasatellite or any other satellite molecule in the samples studied here. Phylogenetic analysis of Rep and CP genes of AlYVV with corresponding genes of closely related viruses circulating in Southeast Asia showed intra-specific recombination involving both complementary and virion sense region of virus. Relaxed clock and Bayesian Skyline Plot analysis based on CP gene sequences indicated slight higher substitution rates (4.75 x 10-3 substitutions/nucleotide/year). In the Indian subcontinent satellite-associated monopartite begomoviruses predominately infect crops and non-crop plants. But AlYVV is found infecting mostly non-crop plants independent of satellite molecules. We hypothesize here that AlYVV evolved as a true monopartite begomovirus in the Indian sub-continent and could be a great threat to introduced crops under suitable conditions. Such studies are crucial to understand probable future epidemics of begomoviruses in the region.

Assessing growth performance, morphometric traits, meat chemical composition and cholesterol content in four phenotypes of naked neck chicken.

The present study was conducted to assess the growth performance, morphometric traits, muscle chemical composition and cholesterol content in four phenotypes of naked neck chicken (black, white-black, light brown and dark brown). A total of 320-day-old chicks, 80 from each phenotype, were randomly stratified into 20 replicates (16/replicate), according to a completely randomized design. The results showed higher final body weight, weight gain, and better FCR in both light brown and dark brown phenotypes whereas time of gains was found to be greater in dark brown phenotype. Keel length and shank circumference were greater in dark brown whereas wing spread was found to be higher in light brown phenotype. Drumstick circumference and body length did not show any significant differences (P > 0.05) across the phenotypes. Dry matter was found to be higher in white black, crude protein in black, white black and dark brown, moisture in light brown, and cholesterol content in black whereas ether extract and ash content were found to be greater in black and white black phenotypes. In conclusion, both light brown and dark brown phenotypes showed superior growth performance and morphometric traits. Similarly, from a health point of view, the dark brown and light brown phenotypes seem superior because their cholesterol content was low. Thus, it is strongly recommended that there should be a conscious effort to improve economically important traits of the light and dark brown birds to be used as dual-purpose slow growing chicken, especially in developing countries.

Assessing behavior in Aseel pullets under free-range, part-time free-range, and cage system during growing phase.

The objective of this study was to explore the effects of free-range (FR), part-time free-range (PTFR), and cage system (CS) on behavioral repertoire in Lakha (LK), Mushki (MS), Peshawari (PW), and Sindhi (SN) varieties of Aseel chicken during the growing phase (9 to 18 wk of age). In total, 144 Aseel pullets were allotted to 12 treatment groups in a 3 × 4 (rearing system × Aseel variety) factorial arrangement, according to a randomized complete block design (RCBD). Each treatment group was replicated 3 times with 4 birds in each replicate (12 birds per treatment group). The pullets were randomly marked weekly for identification, and their behavior was observed through the focal animal sampling method. Time spent on different behavioral activities was recorded and converted to a percentage. The data were analyzed using 2-way ANOVA under a factorial arrangement using SAS 9.1, and the behavioral parameters were evaluated. The results indicated greater (P < 0.05) sitting, standing, drinking, preening, and aggressiveness in CS; walking, running, and jumping in PTFR; and foraging and dustbathing in both FR and PTFR, whereas feather pecking was found to be reduced in FR compared with PTFR and CS. Among varieties, PW showed the least feeding/foraging and feather pecking behavior, and greater standing, running, and jumping behavior (P < 0.05). However, SN spent less time in walking and preening, and more time in sitting, drinking, and aggressiveness. Dustbathing was found to be similar in all Aseel varieties (P = 0.135). In conclusion, the PTFR system could be suggested as a substitute for conventional housing systems because it better accommodates normal behavior in Aseel pullets.

Blood biochemistry and immune response in Aseel chicken under free range, semi-intensive, and confinement rearing systems.

A study was conducted to investigate the effects of 3 different rearing systems [free range ( FR: ), semi-intensive ( SI: ), and confinement ( CF: )] on blood biochemical profile and immune response in 4 varieties of Aseel chicken [Lakha ( LK: ), Mushki ( MS: ), Peshawari ( PW: ) and Sindhi ( SN: )] for 10 wk duration (7 to 16 wk). At the age of 6 wk, in total, 180 cockerels were assigned to 12 treatment groups, 3 (rearing system) × 4 (Aseel chicken variety) factorial arrangement in 7 randomized complete blocks, replicated 3 times with 5 birds in each replicate (45 birds of each variety; 60 birds in each rearing system; 36 total replicates). Blood samples were collected through brachial vein at the end of wk 16. After laboratory analysis, the recorded data for blood biochemical profile and immune response were analyzed by using 2-way ANOVA under factorial arrangement. The results showed higher (P < 0.05) plasma glucose and total protein in birds under CF. Titer against Newcastle disease virus ( NDV: ) and infectious bronchitis virus ( IBV: ) was found to be greater (P < 0.05) in SI and FR, respectively. Peshawari birds indicated higher (P < 0.05) concentration of glucose, total protein, albumin, uric acid, creatinine, and titers to NDV and IBV. Birds of LK and SN varieties also indicated maximum antibody titer against NDV and IBV, respectively. Cholesterol level was found to be greater (P < 0.05) in birds of LK and SN. Interaction of SN with FR revealed maximum (P < 0.05) cholesterol whereas interaction of PW with SI indicated maximum antibody titer against NDV. The results highlight that CF rearing system expediently affects glucose and total protein levels in birds; SI and FR confer maximum antibody titers to NDV and IBV. Birds of PW variety indicated higher glucose, total protein, albumin, uric acid, and creatinine, the lowest cholesterol under FR and the enhanced antibody titer against NDV and IBV.