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The camel economy is of considerable importance for arid countries. In the last decade, studies about camel immune system and immune responses have recorded increasing interest. However, drawing a comprehensive picture of the camel immune system remains far from reached. A major part of this review is to cover the studies of the primary and secondary immune organs and the markers of the camel immune cells and certain lymphoid tissues. At the same time, immune responses to different diseases and the nature of effective immunity were included, with an emphasis on the most important zoonotic diseases in camels such as MERS CoV; brucellosis. New findings on the diversity mechanisms of camel immunoglobulin genes were addressed. However, detail of the mechanism of MHC-restricted cellular immunity and the mechanism of B lymphocyte activation in camels await further attention. Interestingly, the gross and the histological structure of the lymphoid tissues of the camel’s thymus, tonsils, and peyer’s patches have indicated significant differences from other animals in terms of structure and function. The most peculiar CD expression, such as LPAM-I, MAdCAM-1 and CX3CR1, in certain camel cells and tissues refers to possible extraordinary mechanisms of immune hemostasis in camel in comparison to other ruminants. The widely applied immunodiagnostic techniques to control camel diseases and to assist in improving the camel resistance were considered. Extensive studies of the camel immune system were greatly hampered by lack of specific reagents to camel markers and low funds in the field of camel immunology.

Mycobacteriumavium subsp. paratuberculosis (MAP) infection in camel requires extensive research, particularly the immune responses in the intestine. This study aimed to investigate the nature of the cellular populations that are driven by the immunopathological responses in the camel intestine infected with MAP at different ages. Immunohistochemical staining was carried out on tissues obtained from naturally infected young (5–10 years old) and older (12–15 years old) camels. The staining of the tissues, ileum, mesenteric lymph node, jejunum, and supramammary lymph nodes, with anti-CD3+, CD4+, CD8+, CD25+, CD11c+, CD14+, WC1+, CX3CR1, and Madcam-1 monoclonal antibodies revealed high expression of the molecules CD8+, CD25+, CD11c+, CD14+, WC1+, CX3CR1, and Madcam-1 in the ileum and mesenteric lymph node of the infected older camels. The results indicated the recruitment of CD8+lymphocytes, CD14+ macrophages, and CD11c+ dendritic cells to the ileal lamina propria. High expression of CX3CR1 could indicate a vital role for this special macrophage phenotype in the ileal lamina propria in maintaining intestinal homeostasis. Madcam-1 expression could have an essential role in defining the nature of the recruited cells to the site of the infection. Expression of CX3CR1 and Madcam-1 is a novel finding that merits further attention and pursuit to reveal their significance in the immune responses to MAP in the camel’s intestine.

SUMMARY: Genetic improvement of muscle and meat quantity and quality of broiler chicken over the last 50 yr played a key role in broiler meat production. Thermal manipulation technique has been suggested to promote muscle growth and development. The combination of incubating temperature and timing or duration is very critical to determine the optimum protocol of thermal manipulation which underlines muscle growth improvement. Therefore, this study was to elucidate the optimum timing of thermal manipulation (TM) during embryogenesis on broiler pectoral and thigh muscle growth by assessing muscle growth parameter. This was achieved by analyzing the molecular expression levels of muscle insulin-like growth factor-1 (IGF-1), growth hormone (GH) and atrogin-1 during embryogenesis and d 35 post-hatch in addition to the measurement of sarcomeres length at d 35 post-hatch. One thousand, four hundred forty fertile eggs were randomly divided and equally into 5 groups. A control (no TM) and 4 thermal manipulated groups TM1, TM2, TM3, and TM4 that thermally subjected to 39°C for 18 h with 65% relative humidity daily during embryonic days (ED) ED7-11, ED 11-15, ED 15-18, and ED 7-18, respectively. IGF-1 and GH expression from early thermal manipulated chicks (ED7-11) were significantly higher in both pectoral and thigh muscles when compared to the control (P < 0.05). This improvement was in parallel with significant improvement in sarcomeres length of the same TM group on post-hatch d 35 (P < 0.05). On the other hand, Atrogin-1 expression was significantly lower in all treatment groups during post-hatch d 35 compared to the control (P < 0.05) (P < 0.05). It can be concluded that TM1 during ED 7-11 leads to improved pectoral and thigh muscles development without adversely affecting their performance. In addition, molecular and ultrastructure investigation of broiler chicken muscles can be used to predict meat quality and may be beneficial for commercial breeders to enhance broiler chicken growth and productivity.

Effects of thermal manipulation during broiler chicken embryonic days 12-18 on body temperature (T(b)) and mRNA expressions of Hsp108, Hsp70, Hsp47 and Hsf-3 in muscle, heart and brain tissues during subsequent thermal challenge (TC) were investigated. Fertile chicken eggs were divided randomly into four groups (n=375): eggs in the control group were maintained at 37.8°C and 56% (RH). Eggs in TM1 group were subjected to TM at 39°C for 9h during ED 12-18. Eggs in the TM2 and TM3 groups were subjected to the same protocol of TM1 except for increasing the period of exposure to 12h and 18h, respectively. During TC (43°C for 6h) at days 10 and 28, T(b) of TM chicks was significantly lower compared to controls. Furthermore, significant changes in mRNA expressions of Hsp108, Hsp70 and Hsp47 in muscle, heart and brain tissues were observed.

The conjunctiva is important adnexa of the eye that maintains the stability of the tear film. The objective of current study is to describe the histological features of palpebral conjunctiva of the dromedary, emphasizing the distribution of Muc1 using indirect tissue immunofluorescence technique. Conjunctival samples of ten adult, apparently healthy dromedary camels of both sexes were collected, fixed, embedded in paraffin and stained with H&E for general histological structure, Masson´s trichrome for fibrous tissue, Periodic acid–Schiff (PAS) for goblet cells and immunofluorescence for the distribution of Muc1. The palpebral conjunctiva of the dromedary camel is lined with stratified squamous to stratified columnar epithelium. Large numbers of goblet cells were identified associated with conjunctival epithelial cells. The lamina propria consisted of loose superficial cell layer and a deeper tarsal plate. Within the lamina propria, there were lymphoid follicles, numerous tarsal glands and palpebral seromucoid glands. The palpebral conjunctiva and associated palpebral glands were stained positive for PAS and Muc1. In conclusions, the eye of the dromedary camel is protected with a palpebral conjunctival tissue that is richly populated with PAS positive cells and numerous Muc1-producing cells.

The objective of the study was to characterize the macro- and microscopic features of the third eyelid, also called the nictitating mem- brane, and associated structures in the one-humped camel. The texture, length, thickness, and width of the normal third eyelid were studied in adult camels of both sexes. The results showed that the third eyelid of the camel was formed of a relatively large semilunar fold of conjunctiva that extended up to 3 cm from the medial canthus of the eye, over the anterior surface of the globe. Histological examination revealed that the third eyelid of the camel was formed of glandular and lymphoid tissues that were enveloped by fibrous connective tissue and supported by a cartilaginous plate. Both the bulbar and palpebral surfaces of the third eyelid were covered with stratified squamous nonkeratinized epithelium. Many goblet cells were interspersed among the epithelial cells that covered the bulbar surface, especially near the base of the third eyelid. The stroma underneath the epithelium was composed of fibrous connective tissue that was infiltrated with different types of leukocytes and that surrounded glandular tissue and lymphoid nodules. The cartilage that supported the third eyelid was of the elastic type and formed of two parts. A T- shaped segment of cartilage existed within the membrane of the third eyelid and a root-shaped appendix was embedded within the gland of the third eyelid. The gland of the third eyelid was also examined and it was found to be a tubuloalveolar mucous gland.

Background The aim of the current study was to evaluate the effect of different thermal manipulation (TM) protocols during embryogenesis on thermotolerance acquisition parameters during subsequent thermal challenge (TC) at posthatch day 28. A total of 1500 fertile chicken eggs were divided randomly into five treatments (300 eggs each): control was maintained at 37.8 °C and 56 % relative humidity (RH) whereas, TM1, TM2, TM3 and TM4 were subjected to 38.5, 39, 39.5 and 40 °C for 18 h and 65 % RH daily during embryonic days ED 12–18. Hatched chicks from each treatment group allocated randomly into two sub-treatment groups (thermo-neutral, naïve (TN) and thermal challenge (TC). At day 28 of age, chicks subjected to TC by adjusting room temperature to 42 °C for 6 h while naïve chicks kept under regular conditions (22 ± 1 °C and 50–60 % RH). Chick’s response to TC evaluated by determination of plasma T3, T4, corticosterone, total proteins, albumin, selected enzymes and some electrolytes at the beginning (0 h) and after 1, 3 and 5 h of TC in TM and TN chicks. Furthermore, pectoral and thigh muscles mRNA expression of Atrogin-1, CK, avUCP, DIO3, DIO2 were evaluated in TC and TN sub-treatment groups. Results TM induced a significant reduction in free T3 and elevation in total proteins and albumin in plasma with significant down-regulation of Atrogin-1 and DIO2 and significant up-regulation of DIO3 mRNA expression in muscle of TM chicks compare to control. During TC at day 28, decrease in the concentrations of plasma free T3, total proteins and albumin with increase in T4 have been detected in control and TM chicks. TC induced up-regulation of Atrogin-1 and DIO3 with down-regulation of DIO2 gene expression in muscles of all TC chicks. Conclusion The present study indicated that, TM improved thermotolerance acquisition by decreasing basal metabolic rate and muscle injury during thermal stress. Basal metabolic rate decreased via reduction of plasma T3 concentration with up and down regulation of expression of DIO3 and DIO2, respectively in muscles. Muscle injury protected by stimulation of protein biosynthesis and down-regulation of Atrogin-1 expression.