Chicken egg lysozyme enhanced the growth performance, feed utilization, upregulated immune-related genes, and mitigated the impacts of Aeromonas hydrophila infection in Nile tilapia (Oreochromisniloticus).

Functional supplements, including lysozyme, are highly approved as immunostimulant and antibacterial agents with a high potential for use in aquaculture. In this regard, Nile tilapia was treated with lysozyme at 0, 0.5, 1, 1.5, and 3 g/kg for 60 days, then challenged with Aeromonas hydrophila. Fish were stocked in 15 glass aquaria (70 L each) with an equal initial weight of 10.72 ± 0.71 g per fish and 15 fish per aquarium. The regression analysis revealed that dietary lysozyme supplementation at 1.83-2 g/kg enhanced the growth performance, protein efficiency ratio, and protein productive value while reducing the feed conversion ratio of tilapia. Markedly, tilapia treated with lysozyme had a low mortality rate (30-50 %) compared to the control, which recorded a 70 % mortality rate after 15 days of challenge with A. hydrophila. The regression analysis also revealed that the highest lysozyme activity of tilapia-fed lysozyme for 60 days is achieved by 2.05 g/kg lysozyme. The expression of Nf-κb, IL-1ß, and IL-8 genes is upregulated in tilapia-fed lysozyme at 0.5, 1, 1.5, and 3 g/kg for 60 days before and after A. hydrophila infection. The expression of GPX and CAT genes was higher in tilapia-fed lysozyme at 0.5, 1, 1.5, and 3 g/kg for 60 days before and after A. hydrophila infection. Before infection, the relative transcription of the lysozyme and C3 was upregulated in tilapia-fed lysozyme at 0.5, 1, 1.5, and 3 g/kg. However, lysozyme gene expression in tilapia treated with 0.5 g/kg lysozyme had no significant differences from those fed 0 g/kg lysozyme. After infection, the relative transcription of the lysozyme gene was upregulated in tilapia fed 1 and 1.5 g/kg, while tilapia fed 1 g/kg lysozyme had the highest C3 gene transcription. After infection, the hepatocytes in the livers of fish fed 0 g/kg lysozyme exhibited a noticeable fatty alteration, along with congestion, a light infiltration of inflammatory cells, and the start of necrosed cell regeneration. However, the livers of fish that received lysozyme were normal except for infiltrations of perivascular and interstitial mononuclear cells, depending on the supplementation dose. In conclusion, dietary lysozyme is recommended at 1.83-2.05 g/kg to gain high growth performance, immune response, and high resistance to A. hydrophila in Nile tilapia.

Yucca schidigera Extract Mitigates the Oxidative Damages, Inflammation, and Neurochemical Impairments in the Brains of Quails Exposed to Lead.

The present study explored the neurotoxic impacts of lead (Pb) and the potential alleviating effect of Yucca schidigera extract (YSE) in Japanese quails. About 360 adult Japanese quails (8 weeks old) were used. Quails were randomly distributed to six groups with 4 replicates each: the control group (fed basal diet, BD), the BD + YSE1 and BD + YSE2 groups (BD + 100 and 200 mg/kg diet of YSE, respectively), the Pb group (BD + 100 mg/kg Pb), and the Pb + YSE1 and Pb + YSE2 groups (BD + Pb + 100 and 200 mg/kg YSE, respectively). This feeding trial lasted for 8 weeks. The exposure to Pb in the diet induced oxidative damage stress in the brain of exposed quails reflected by the significant increase in the oxidative markers including malonaldehyde (MDA) and protein carbonyl (PC) and the significant reduction in the activities of antioxidants including catalase (CAT), superoxide dismutase (SOD), and the reduced glutathione (GSH). Brain neurochemistry and enzyme activities were also altered following Pb exposure. Pb significantly reduced serotonin, dopamine, norepinephrine, GABA, Ach, and Na + /K + -ATPase activities. Pb dietary intoxication markedly increased brain inflammatory biomarkers, including tumor necrosis factor (TNF-α), myeloperoxidase, and nitric oxide. Peripherally, Pb toxicity decreased the amino acid neurotransmitters (glutamic acid, glycine, and aspartic acid) in the serum of birds. At the transcriptomic level, Pb exposure upregulated the transcription patterns of CASP3, TNF-α, HSP70, and IL-1ß. The single effect of YSE maintained that all the assessed parameters were not changed compared to the control. Interestingly, the YSE co-supplementation with Pb alleviated the Pb-induced neuro-oxidative damages by lowering the lipid, protein, and DNA damage, and the inflammatory biomarkers.

Extender Supplementation with Glutathione (GSH) and Taurine Improves In Vitro Sperm Quality and Antioxidant Status of New Zealand Rabbits during Chilled Storage for up to 72 hours.

This study assessed the influence of supplementing the rabbit semen extender with various concentrations of glutathione (GSH) and taurine at 24, 48, and 72 h postchilling at 5°C. Semen samples were collected from 20 New Zealand bucks, and ejaculates with standard color, motility (>85%), about 0.5 mL volume, and ∼400 × 106/mL concentration were used and diluted with extenders supplemented with 0.5, 1, and 2 mM of GSH and 1, 5, and 10 mM of taurine and chilled at 5°C. Nonsupplemented samples were used as a control. Sperm's progressive motility, acrosome reaction, and extracellular oxidative stress biomarkers such as MDA contents and GPx, SOD, and CAT concentrations and intracellular transcriptomic levels of SOD and CAT genes were assessed. GSH and taurine supplementation improved the sperm's kinetics by reducing cooling-associated stress, which was ascertained by lowering MDA concentration and increasing SOD, CAT, and GPx concentrations (P < 0.05). Increasing the levels of antioxidant enzymes in the extender was due to the increasing mRNA copies of the SOD and CAT genes (P < 0.05). Furthermore, GSH and taurine maintained the fructose levels in the extender and lowered the GPT levels, which implies sperm membrane stability is maintained through GSH and taurine supplementation. GSH and taurine supplementation to the extender had protective influences on the in vitro rabbit semen quality during chilled storage for up to 72 h, which were remarkable with increasing supplementation dose and cooling time at 5°C.

Detection of two SNPs of the LIPE gene in Holstein-Friesian cows with divergent milk production.

The LIPE gene (lipase E, hormone-sensitive type), also known as hormone-sensitive lipase, acts as a primary regulator of lipid metabolism during lactation in cows. We studied a total of two hundred Holstein-Friesian cows and performed sequencing analysis that revealed two synonymous nucleotide changes within the LIPE gene: a transition change, c.276 T > C in exon 2 (g.50631651 T > C; position 351 of GenBank: ON638900) and a transversion change, c.219C > A in exon 6 (g.50635369C > A; position 1070 of GenBank: ON638901). The observed genotypes were TC and CC for the c.276 T > C SNP and CC and CA for the c.219C > A SNP. Notably, the heterozygous TC genotype of the T351C SNP exhibited a significant association with high milk yield. Furthermore, the T351C SNP displayed significant associations with various milk parameters, including temperature, freezing point, density and the percentages of fat, protein, lactose, solids and solids-not-fat, with the homozygous CC genotype showing higher values. The c.219C > A SNP also demonstrated a significant association with milk composition, with heterozygous genotypes (CA) exhibiting higher percentages of fat, protein, and lactose compared to homozygous genotypes (CC). This effect was consistent among both high and low milk producers for fat and lactose percentages, while high milk producers exhibited a higher protein percentage than low milk producers. These findings highlight the importance of considering the detected SNPs in marker-assisted selection and breeding programs for the identification of high milk-producing Holstein-Friesian cows and potentially other breeds. Moreover, this study strongly supports the fundamental role of the LIPE gene in milk production and composition in lactating animals.

Association of insulin receptor substrate 1 (IRS-1) gene polymorphism with growth and litter-related traits in NMER rabbits.

This study investigated the associations between the c.189G > T polymorphism of the insulin receptor substrate-1 (IRS-1) gene and the growth and litter size-related traits in the Native rabbit in Middle Egypt (NMER). One hundred sixty-two NMER rabbits were genotyped by RFLP-PCR using Sau3AI restriction enzyme and the associations of the reported genotypes with body weights at 5th, 6th, 8th, 10th, and 12th week old, body gain, and daily gain plus, the litter size-related traits were determined. Additionally, the genotypic and allelic frequencies, the effective (Ne) and observed (NA) numbers of alleles, observed (Ho) and expected (He) heterozygosity, Hardy-Weinberg equilibrium (HWE), and the decrease in heterozygosity because of inbreeding (FIS) were calculated. Three genotypes; GG, GT, and TT with 0.65, 0.33, and 0.02 frequencies, respectively which fit HWE were reported. These genotypes displayed a marked low FIS value. Significant associations of the genotypes with the body weights, and gains, except at the 5th week old determined with superiority of the GT genotype compared with the other genotypes. All reported litter size-related traits significantly varied among different genotypes. In summary, the c.189G > T SNP of the IRS-1 gene is an effective genetic marker to improve growth performance and litter size traits of the NMER rabbits.

The comparison of two different plumage-color lines of Japanese quail (Coturnix japonica) disclosed a significant effect in increasing abdominal fat contents with increasing age.

This study aimed to investigate the characteristic differences between the white and brown-feathered Japanese quails, by evaluating the carcass traits and egg fat content, blood parameters, and intestinal histopathological features. A total of 1200 1-day-old Japanese quail chicks of two varieties (brown and white-feathered) were used in this study. Live body weight and feed intake were reordered every week. At the 4th week of age, 80 birds from each variety were slaughtered and carcass quality measurements and histopathological changes were recorded. After 6 weeks of age, eggs were collected, and egg quality was assessed. The results revealed that white-feathered quails had significantly heavier body weights and higher growth rates. At 4 weeks of age, females of the white-feather quail had significantly heavier slaughter, after de-feathering, and carcass weights. Remarkable variations between the studied quail varieties, with significant dominance of females in both varieties, at the level of water holding capacity, pH, and meat tenderness ascertained an obvious superiority of white-feathered quails compared to brown ones and indicated the higher tendency of the white quails for meat production. These results were linked with significant changes in biochemical profiles including lipids biomarkers, total protein, and Ca and phosphorus levels along with variations in the intestinal morphometry. It can be concluded that white-feathered quails had, in general, higher values of productivity compared with the brown-feathered ones during growing and laying periods.

Assessment of variations in productive performance of two different plumage color varieties of Japanese quail and their reciprocal crosses.

This study aimed to detect the phenotypic differences between the brown (BB) and white (WW) feathered quails and their reciprocal crosses (BW and WB) over two successive generations. The WW and cross quails, especially the BW, had the heaviest body weights, throughout the studied period, with significant variations between the two studied generations (P<0.05). Moreover, the WW and BW possessed the largest egg production during the F1, while in the F2, the BB had superiority among the studied quails with a prominent superiority of the F2 over the F1 (P<0.05). However, the F1 had higher egg weights than F2 with superiority of WW quails compared to the others (P<0.05). Also, the WW quails had the lowest lipid contents of the eggs. These phenotypic variations among the studied quails might be preliminarily explained by the results of the analyzed microsatellite markers despite the few markers used. The high variability among the BW and WB quails might be due to the larger number of alleles (NA and Ne) and the lower values of FIS with low heterozygosity levels (HO and He). Moreover, the BW and BB were the closest, while WB and WW were the farthest because of the high and low genetic identities and the high and low genetic distance between them, respectively. So the obtained results might introduce an initial scientific basis for evaluating and employing the genetic properties of BB, WW, BW, and WB quails in further genetic improvement program, and more microsatellite markers are recommended.

Growing and laying performance of two different-plumage color Japanese quail varieties supplemented with corn silk in their diet.

The current study aimed to investigate the dietary supplementation effect of corn silk (CS) on performance and blood chemistry of brown and white-feathered quails during the grower and layer periods. Japanese quails of brown and white-feathered color (180 birds/variety at 2 wks old) were randomly allotted into three groups with 3 replicates each (n = 20 birds/replicate). Corn silk powder (CS) was supplemented to the basal diet at 0, 1, and 2% of the diet for each quail variety for 1-month growing period, then continued for another 6-wk laying period to assess the egg production and egg quality characteristics. CS supplementation at 1% and 2% for brown and white-feathered quails respectively improved their growth performance (body weight and weight gain), carcass yield, and intestinal villi length with increasing feed consumption but without changes in feed conversion ratio. In both quail varieties, CS addition had a hypolipidemic effect, confirmed by lowering serum triglyceride (TG), cholesterol (CHO), and low density lipoprotein (LDL) while increased high density lipoprotein (HDL) concentrations (P < 0.05) with a clear response observed in white quails than the brown ones. Besides, CS supplementation increased (P = 0.002) hen day egg production in brown feathered quails, while reducing it in the white-feathered quails compared with the CS-free diet. The increased egg production was not significantly (P > 0.05) correlated with lower content of TG and CHO, while significantly increased the antioxidant content in both quail varieties (P < 0.05). Moreover, CS dietary supplementation significantly enhanced (P = 0.003) the yolk color, especially in brown-feathered quail. In conclusion, CS can be safely supplemented to the Japanese quail diet (1% and 2% for brown-feathered and white-feathered quails respectively) to improve growth performance, and egg quality characteristics.

The synergetic effect of Bacillus species and Yucca shidigera extract on water quality, histopathology, antioxidant, and innate immunity in response to acute ammonia exposure in Nile tilapia.

Acute ammonia toxicity suppresses the immune function and enhances the inflammatory pathways in Nile tilapia. The aim of this study was to compare the effect of Bacillus strains probiotic mixture (BS) or Yucca shidigera liquid extract (YSE) alone or their combination in water treatment and in reliving toxicity of an acute ammonia exposure in Nile tilapia through the assessment of fish immune response, inflammatory pathway, oxidative stress response with respect to the histopathological changes, gene expression, enzymes levels and phagocytosis. Five groups were used; the 1st and 2nd groups fed the basal diet; the 3rd group fed basal diet with BS in water, 4th group fed basal diet and supplemented with YSE in water and 5th group received a combination of BS and YSE. After two weeks of treatments, the 2nd, 3rd, 4th, and the 5th groups were exposed to acute ammonia challenge for 72 h. Fish exposed to ammonia displayed significant decreases in RBCs, Hb, PCV, WBCs, phagocytic activity (PA) and index (PI), lysozyme activities and serum antioxidant enzymes (glutathione peroxidase (GPX) and catalase (CAT)). Also, a significant increase in Malondialdehyde (MDA), degenerative changes in the gills, hepatopancrease and spleen associated with an elevated un-ionized ammonia level. A significant restoration of the hematological parameters was observed with the use of BS, YSE or their combination. Additionally, they improved the innate immunity, antioxidant responses, and histopathological changes. At transcriptomic level, ammonia toxicity significantly lowered the mRNA transcription levels of Nuclear erythroid 2-related factor 2 (Nrf2), quinone oxidoreductase 1 (NQO-1), Heme oxygenase 1 (HO-1) and Heat shock proteins (HSP70). While nuclear factor kappa ß (NFкß), Tumor necrosis factor α (TNF-α), Interleukin 1ß (IL-1ß), and Interleukin 8 (IL8), transcription levels were increased. Interestingly, BS and YSE and their combination significantly increased the expression of these genes with the highest levels reported with BS and YSE combination. We observed that, the most pronounced restoration of some important inflammatory and immune related genes close to the control level was observed when BS-YSE mix was used. Furthermore, a restored water pH, and a maintained ammonia level to the control level were observed in this group. Otherwise, equal effects for the three treatments were observed on the assessed parameters. We recommend the used of BS-YSE mix for water ammonia treatment and relieving ammonia toxicity in fish.

Moringa oleifera Leaf Powder Dietary Inclusion Differentially Modulates the Antioxidant, Inflammatory, and Histopathological Responses of Normal and Aeromonas hydrophila-Infected Mono-Sex Nile Tilapia (Oreochromis niloticus).

This study aimed to detect the impact of Moringa oleifera leaf powder dietary inclusion on the antioxidant and innate immune responses of mono-sex Nile tilapia fingerlings. A total of 180 fingerlings were allocated in a random method into three groups with triplicate each. One group (1st group) received the control diet (basal diet (BD) free of moringa) and the other groups (2nd and 3rd) fed BD containing M. oleifera leaf powder at 5 and 10% of the diet, respectively. After 6 weeks of feeding, fish were randomly redistributed into four replicates and rested for 24 h. Then, each fish in the first two replicates was injected with 0.2 mL of PBS, while the others were injected with 0.2 mL of A. hydrophila suspension (1.8 × 106 CFU/mL). Healthy fish fed on M. oleifera leaf powder showed enhanced immune response manifested by significant increases in phagocytic and lysozyme activities with a marked H/L ratio (P < 0.05). In addition, significant alterations of the lymphocytic and heterophilic population in circulation with increasing infiltration in tissue such as the spleen were noticed. Also, M. oleifera significantly upregulated the antioxidants, CAT and GPx, proinflammatory cytokines, IL1-ß, IL-8, and IFN-γ relative mRNA levels. On the other hand, following A. hydrophila challenging conditions, M. oleifera caused downregulations of IL1-ß, IL-8, and IFN-γ transcription levels, and also lowered the CAT and GPx mRNA levels. In addition, a marked reduction of leukocytic infiltration plus a significant improvement of the degenerative changes in intestinal architecture has occurred. So, M. oleifera leaf powder can be included in the fish diet to enhance immune response under normal health conditions and lower the infection-associated inflammatory response.

Phytochemical characteristics of Paulownia trees wastes and its use as unconventional feedstuff in animal feed.

Due to the continuous increase in animal feed prices, and the presence of competition between humans and animals on food materials, it is imperative to identify other non-food plant resources to assist the animal feed industry and improve livestock productivity. Plant wastes may cause air, soil, and water pollution. However, if judiciously managed, they would be important resources. Plant wastes are used as feedstuffs and fertilizers. However, their use as animal feed is more useful than fertilizers. Because of the high content of fiber and non-protein N, these wastes are more valuable for feeding ruminants than poultry. The use of the plant wastes as feedstuffs could improve the environmental quality and profits for feed producers. Paulownias are fast-growing trees initially cultivated for wood production. However, due to their good nutritive value, their leaves have been used for ruminants, non-ruminants animals and poultry feeding. Furthermore, they are well-known for its medicinal and antibacterial properties. However, little is still known about its characteristics. This review aimed at providing detailed information about the nature, nutritional value, phytochemicals, and uses of Paulownia as a promising feedstuff in the fields of ruminants, non-ruminants, and poultry nutrition.

Corrigendum: Moringa oleifera leaf powder dietary inclusion differentially modulates the antioxidant, inflammatory, and histopathological responses of normal and Aeromonas hydrophila-infected mono-sex Nile tilapia (Oreochromis niloticus).

[This corrects the article DOI: 10.3389/fvets.2022.918933.].

Stress and immunity in poultry: light management and nanotechnology as effective immune enhancers to fight stress.

The poultry industry plays a significant role in boosting the economy of several countries, particularly developing countries, and acts as a good, cheap, and affordable source of animal protein. A stress-free environment is the main target in poultry production. There are several stressors, such as cold stress, heat stress, high stocking density, and diseases that can affect birds and cause several deleterious changes. Stress reduces feed intake and growth, as well as impairs immune response and function, resulting in high disease susceptibility. These effects are correlated with higher corticosteroid levels that modulate several immune pathways such as cytokine-cytokine receptor interaction and Toll-like receptor signaling along with induction of excessive production of reactive oxygen species (ROS) and thus oxidative stress. Several approaches have been considered to boost bird immunity to overcome stress-associated effects. Of these, dietary supplementation of certain nutrients and management modifications, such as light management, are commonly considered. Dietary supplementations improve bird immunity by improving the development of lymphoid tissues and triggering beneficial immune modulators and responses. Since nano-minerals have higher bioavailability compared to inorganic or organic forms, they are highly recommended to be included in the bird's diet during stress. Additionally, light management is considered a cheap and safe approach to control stress. Changing light from continuous to intermittent and using monochromatic light instead of the normal light improve bird performance and health. Such changes in light management are associated with a reduction of ROS production and increased antioxidant production. In this review, we discuss the impact of stress on the immune system of birds and the transcriptome of oxidative stress and immune-related genes, in addition, how nano-minerals supplementations and light system modulate or mitigate stress-associated effects.

Reducing the Abundance of Harmful Bacteria of Rooftop Tank-Stored Drinking Water Using Silver Nanoparticles and Acetic Acid and Its Impact on Japanese Quail Growth Performances.

This study evaluated the microbial diversity of rooftop tank-stored drinking water consumed by Japanese quail (Coturnix coturnix japonica) using silver nanoparticles (AgNPs) and acetic acid (AC) and their mixture. Japanese quails (2 weeks old) of two different plumage colors, white and brown, were divided into four groups. In group 1 (control), birds received rooftop tank-stored water. In groups 2, 3, and 4, birds received rooftop tank-stored water treated with AC (0.5 mL/L), AgNPs (0.1 mg/L), or both AC and AgNPs. A reduction in the total coliform count was observed for AgNP- and AC-treated water after 2 h, 24 h, 48 h, and 5 days (P < 0.05). Growth rates and feed intake in both white- and brown-feathered quails were also increased using both AC and AgNPs (P < 0.05). A significant decrease in water consumption was observed in the brown-feathered quails, whereas the white-feathered quails drank more water (P < 0.05). Meanwhile, serum parameters remained unchanged in the white-feathered quails using both AC or/and AgNP purifiers (P > 0.05), whereas brown-feathered quails receiving water treated with AC or both AC and AgNPs displayed a significant increase in serum total protein and hemoglobin compared with quails receiving water treated with AgNPs alone or non-treated water (P < 0.05). Cholesterol and triglycerides levels were significantly increased when using both AC or/and AgNP purifiers (P < 0.05). In conclusion, both AgNPs and AC are recommended as efficient purifiers to eliminate pathogenic bacteria and to increase the growth performance and health condition of white- and brown-feathered Japanese quail birds.

Role of gamma-aminobutyric acid in regulating feed intake in commercial broilers reared under normal and heat stress conditions.

This study was conducted to investigate the effects of dietary GABA supplementation on blood biochemical parameters, the overall growth performance, and the relative mRNA expression of some FI- regulating genes in broiler chickens. A total of 192, three-day old chicks of mixed sex from two commercial broiler strains (Ross 308 and Cobb 500) were distributed into 2 groups; a control group and GABA-supplemented group (100 mg/kg diet). When the chicks reached 21 days of age, each group of each strain was randomly subdivided into two subgroups: one was exposed to HS (33 ±â€¯2 °C for 5 h/day for 2 weeks), while the other remained at thermoneutral temperature (24 °C). GABA significantly improved bird growth performance under normal and HS conditions, by increasing body weight (BW), weight gain (WG), and FI and significantly reduced the elevated body temperature of birds under HS. GABA supplementation increased FI by reducing the mRNA expression levels of FI-inhibiting neuropeptides, such as POMC, leptin, Ghrelin, and CCK, during HS and by increasing the expression of FI-stimulating neuropeptides such as AgRP and NPY. Moreover, GABA significantly altered FAS and ACC gene expression, resulting in significant increases in abdominal fat content in birds reared normally. In contrast, GABA lowered fat content in Cobb birds and increased it in Ross birds under HS. Therefore, GABA (100 mg/kg diet) is a strong FI-stimulating neurotransmitter and its regulatory effects depend on broiler strain and housing temperature.

Ameliorative effect of dietary supplementation of copper oxide nanoparticles on inflammatory and immune reponses in commercial broiler under normal and heat-stress housing conditions.

Heat stress (HS) is one of the most serious adverse conditions that affect poultry causing immunosuppression and decreasing production. In a novel approach, we investigated effects of supplementing copper oxide nanoparticles (CuO-NPs) on the immune response in two commercial broiler strains (Ross 308 and Cobb 500). At one day old, birds were divided into 3 groups with 3 replicates for each. The first group received diet supplemented with 100% of their recommended copper requirements as CuO while, in the second and third groups, birds were given diets supplemented with 100% and 50% of the recommended Cu requirements in the form of CuO-NPs, respectively. At age of 21 day, each group was subdivided randomly into normal (24 ±â€¯2 °C) and heat stressed (33 ±â€¯2 °C for 5 h per day for two successive weeks) groups. Under normal housing temperature, CuO-NPs, significantly enhanced the immune response in these birds, compared to CuO shown by the increased levels of phagocytic activity (PA), lysozyme serum activity, and by upregulating immune-modulator genes including NF-κß, PGES, IL-1ß, TGF-1ß, IFN-γ, BAX and CASP8. The responses were different between the two studied strains especially at the level of gene expression. In HS birds, supplementation of CuO-NPs reduced HS induced inflammatory conditions, as shown by lower gene expression levels, lower degenerative changes in the spleen, and altered heterophils/lymphocytes (H/L) ratio. We suggest CuO-NPs supplementation, especially in those chickens that received diet supplemented with 50% of their recommended Cu requirements, could be used under normal housing temperature to enhance the birds' immune response, and during HS to lower heat stress-induced degenerative changes depending on the magnitude of the HS.

Modulatory Effect of Monochromatic Blue Light on Heat Stress Response in Commercial Broilers.

In a novel approach, monochromatic blue light was used to investigate its modulatory effect on heat stress biomarkers in two commercial broiler strains (Ross 308 and Cobb 500). At 21 days old, birds were divided into four groups including one group housed in white light, a second group exposed to blue light, a 3rd group exposed to white light + heat stress, and a 4th group exposed to blue light + heat stress. Heat treatment at 33°C lasted for five h for four successive days. Exposure to blue light during heat stress reduced MDA concentration and enhanced SOD and CAT enzyme activities as well as modulated their gene expression. Blue light also reduced the degenerative changes that occurred in the liver tissue as a result of heat stress. It regulated, though variably, liver HSP70, HSP90, HSF1, and HSF3 gene expression among Ross and Cobb chickens. Moreover, the Cobb strain showed better performance than Ross manifested by a significant reduction of rectal temperature in the case of H + B. Furthermore, a significant linear relationship was found between the lowered rectal temperature and the expression of all HSP genes. Generally, the performance of both strains by most assessed parameters under heat stress is improved when using blue light.

Expression and Regulation of Cholecystokinin Receptor in the Chicken's Immune Organs and Cells.

Cholecystokinin (CCK) is a neuropeptide that affects growth rate in chickens by regulating appetite. CCK peptides exert their function by binding to two identified receptors, CCKAR and CCKBR in the GI tract and the brain, respectively, as well as in other organs. In mammals, CCK/CCKAR interactions affect a number of immunological parameters, including regulation of lymphocytes and functioning of monocytes. Thus, food intake and growth can potentially be altered by infection and the resulting inflammatory immune response. It is uncertain, however, whether chicken express CCKAR in immune organs and cells, and, if so, whether CCKAR expression is regulated by pathogen derived inflammatory stimuli. Herein, we identify expression of CCKAR protein in chicken peripheral blood mononuclear cells (PBMC) including monocytes, and expression of the CCKAR gene in PBMC, thymus, bursa, and spleen, in selected commercial and pure chicken breeds. Further, stimulation with various types of E. coli heat-labile enterotoxins or lipopolysaccharide significantly regulated expression of CCKAR on monocytes in the different breeds. Ligation of CCKAR with antibodies in PBMC induced mobilization of Ca2+, indicating that CCKAR is signal competent. Injection with polyinosinic: polycytidylic acid (poly I:C), a synthetic analogue of double stranded viral RNA that binds Toll-Like Receptor-3 (TLR3), also regulated gene expressions of CCKAR and proinflammatory cytokines, in the different breeds. Interestingly, variations in the expression levels of proinflammatory cytokines in the different breeds were highly correlated with CCKAR expression levels. Taken together, these findings indicate that the physiological function of CCKAR in the chicken is tightly regulated in immune organs and cells by external inflammatory stimuli, which in turn regulate growth. This is the first report CCKAR expression in immune organs and cells, in any species, and the initial observation that CCKAR is regulated by inflammatory stimuli associated with bacterial and viral infection.

Cell clustering and delay/arrest in T-cell division implicate a novel mechanism of immune modulation by E. coli heat-labile enterotoxin B-subunits.

The B-subunits of heat-labile enterotoxins LT-I (LT-IB) and LT-IIa (LT-IIaB) are strong adjuvants that bind to cell-surface receptors, including gangliosides G(M1) and GD1b, respectively. LT-IIaB also binds TLR-2. We demonstrate for the first time that co-incubation with the B-subunits induces significant clustering of B cells after only 4h, and B and T cells in 24h. Clustering was dependent on intact B-subunits, but not on the TLR-2 binding activity of LT-IIaB, indicating it was ganglioside-mediated. Treatment of B cells with LT-IB, a mixture of LT-IB+LT-IIaB, but not LT-IIaB alone, caused a delay in T cell division following ovalbumin endocytosis. B cell receptor-mediated uptake in presence of each treatment caused an arrest, but with increased production of IL-2. Further, treatments differentially increased the proportion of macrophages expressing MHC class-II. These results highlight the outcomes of interplay between signals involving different receptors and implicate a novel mechanism of adjuvanticity.