Infectious bronchitis virus (IBV) is a very dynamic and evolving virus, causing major economic losses to the global poultry industry. In early 2011, respiratory disease outbreaks were investigated in Iraq, Jordan, and Saudi Arabia. Five IBV isolates (JOA2, JOA4, Saudi-1, Saudi-2, and Iraqi IBV) were detected by diagnostic-nested nucleocapsid RT-PCR. Strain identification was characterised by sequencing and phylogenetic analysis of the amplified hypervariable region of the spike 1 (S1) gene. These five IBV isolates were found to be of the IBV strain CK/CH/LDL/97I. Nucleotide identity between these five IBV isolates ranged from 96.9% to 99.7%, and between these isolates and the CK/CH/LDL/97I strain in the range of 96.6–99.1%. The sequenced fragment of the S1 gene of the CK/CH/LDL/97I strain had less than 80% nucleotide identity to the IBV vaccine strains commonly used in the Middle East (M41 and H120). The presence of these CK/CH/LDL/97I-like strains may account for vaccination failure against IBV, since all IBV isolates were from vaccinated chickens. In this paper, we documented for the first time the presence of IBV strain CK/CH/LDL/97I in the Middle East. This strain is known to have originated in China and Taiwan.

Effects of embryonic thermal manipulation (TM) on mRNA expressional levels and total antioxidant capacity of genes associated with heat-induced oxidative stress (NOX4, GpX2, SOD2, catalase, and AvUCP) in 2 breeds of broiler chicken were investigated. Fertile Cobb and Hubbard eggs (n = 1,200) were divided into 4 treatment groups: Cobb control, Cobb TM, Hubbard control, and Hubbard TM. Control groups were maintained under standard conditions (37.8°C; 56% relative humidity), whereas TM groups were incubated at 39°C and 65% relative humidity for 18 h a day from embryonic days (ED) 10 to 18. On post-hatch day 28, the broilers were subject to acute heat stress (AHS) at 40°C for 7 h. At certain intervals (0, 1, 3, 5, and 7 h), 12 chickens from each of the 4 groups were humanely euthanized, and liver samples were immediately isolated. During AHS, in both breeds, the mRNA expression levels of NOX4, GPx2, SOD2, and catalase in TM chickens were significantly lower than in controls, but AvUCP mRNA expression in the TM group was higher. The total antioxidant capacity and activity of superoxidase dismutase and catalase were significantly lower in the TM than in the control group in both breeds. The results of this study suggest that TM has a long-lasting effect on the acquisition of thermotolerance in 2 broiler chicken breeds as indicated by the reduction of system genes associated with heat-induced oxidative stress.

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Background In broilers chickens, the molecular bases for promoting muscle development and growth requires further investigation. Therefore, the current study aimed to investigate the effects of daily thermal manipulation (TM) during embryonic days (ED) 12 to 18 on body, carcass and internal organ weights as well as on the expression of muscle growth markers genes during late embryogenesis and post-hatch days. 1500 fertile Cobb eggs were divided into five groups. The first group was a control group and incubated at 37.8°C. The other four groups were thermally manipulated (TM) and exposed to 38.5°C (TM 1 ), 39°C (TM 2 ), 39.5°C (TM 3 ) and 40°C (TM 4 ) daily for 18 h, respectively, with a relative humidity of 56%. Body weights (BW) from ED 12 to 18 and on post-hatch days 1, 2, 3, 4, 5, 6, 7, 14, 21, 28 and 35 were recorded. mRNA expression levels of muscle growth factor genes (IGF-1 and GH) and muscle marker genes (Myogenic Differentiation Antigen; MyoD), Myogenin, Pax7, and PCNA) during ED 12 to 18 and on post-hatch days 1, 3, 5, 7, 14 were analyzed. On post-hatch day 35, the carcass and internal organ weights have been also evaluated. Results TM during certain days of embryogenesis (ED 12 to 18) did not affect the BW of broilers during their embryonic lives. However, TM, particularly TM 1 and TM 2 , significantly increased BW, carcass and internal weights of hatched chicks near to the marketing age (post-hatch days 28 and 35). Most of TM protocols induced up-regulation of muscle growth factor genes (IGF-1 and GH) and muscle marker genes (MyoD, Myogenin, Pax7, and PCNA) during embryonic life (ED 12 to 18) and on post-hatch days. Conclusion Among the various TM conditions, it seems that,TM 1 and TM 2 induced a significant increase in BW, carcass and internal weights of hatched chicks near to the marketing age. This increase in BW induced presumably via up-regulation of muscle growth factor genes and muscle growth markers genes during embryonic life (ED 12 to 18) and on post-hatch days. Both protocols (TM 1 and TM2) can be used in real-world applications of poultry industry for maximum benefit.