Potential and Metabolic Impacts of Double Enrichments of Docosahexaenoic Acid and 25-Hydroxy Vitamin D3 in Tissues of Broiler Chickens.

BACKGROUND: Chicken may be enriched with 25-hydroxy D3 [25(OH)D3] and docosahexaenoic acid (DHA) to enhance the dietary intake of the public. OBJECTIVES: Two experiments (Expt.) were conducted to determine the potential and metabolic impacts of enriching both DHA and 25(OH)D3 in the tissues of broiler chickens. METHODS: In Expt. 1, 144 chicks (6 cages/treatment and 6 birds/cage) were fed a corn-soybean meal basal diet (BD), BD + 10,000 IU 25(OH)D3/kg [BD + 25(OH)D3], BD + 1% DHA-rich Aurantiochytrium (1.2 g DHA/kg; BD + DHA), or BD + 25(OH)D3+DHA for 6 wk. In Expt. 2, 180 chicks were fed the BD, BD + DHA-rich microalgal oil (1.5-3.0 g DHA/kg, BD + DHA), BD + DHA + eicosapentaenoic acid (EPA)-rich microalgae (0.3-0.6 g EPA/kg, BD + DHA + EPA), BD + DHA + 25(OH)D3 [6000 to 12,000 IU/kg diet; BD + DHA + 25(OH)D3], and BD + DHA + EPA + 25(OH)D3 for 6 wk. RESULTS: Supranutrition of these 2 nutrients resulted in 57-62 mg DHA and 1.9-3.3 µg of 25(OH)D3/100 g of breast or thigh muscles. The DHA enrichment was independent of dietary EPA or 25(OH)D3, but that of 25(OH)D3 in the liver was decreased (68%, P < 0.05) by dietary DHA in Expt. 1. Compared with BD, BD + 25(OH)D3 enhanced (P < 0.05) gene expression related to D3 absorption (scavenger receptor class B type 1 and Niemann-pick c1 like 1) in the liver and D3 degradation (cytochrome P450 24A1) in the breast, and decreased mRNA or protein concentrations of vitamin D binding protein in the adipose tissue or thigh muscle. Supranutrition of DHA decreased mRNA concentrations of lipid metabolism-related genes (fatty acid desaturase 1,2, ELOVL fatty acid elongase 5, fatty acid desaturase 2, fatty acid synthase, and sterol regulatory element-binding protein 1). CONCLUSIONS: Both DHA and 25(OH)D3 were enriched in the muscles up to meeting 50%-100% of the suggested intakes of these nutrients by consuming 2 servings of 100 g of fortified chicken. The enrichments altered gene expression related to lipid biosynthesis and vitamin D transport or storage.

Dissemination of mcr-1 and ß-lactamase genes among Pseudomonas aeruginosa: molecular characterization of MDR strains in broiler chicks and dead-in-shell chicks infections.

OBJECTIVES: Pseudomonas aeruginosa (P. aeruginosa) is one of the most serious pathogens implicated in antimicrobial resistance, and it has been identified as an ESKAPE along with other extremely significant multidrug resistance pathogens. The present study was carried out to explore prevalence, antibiotic susceptibility phenotypes, virulence-associated genes, integron (int1), colistin (mcr-1), and ß-lactamase resistance' genes (ESBls), as well as biofilm profiling of P. aeruginosa isolated from broiler chicks and dead in-shell chicks. DESIGN: A total of 300 samples from broiler chicks (n = 200) and dead in-shell chicks (n = 100) collected from different farms and hatcheries located at Mansoura, Dakahlia Governorate, Egypt were included in this study. Bacteriological examination was performed by cultivation of the samples on the surface of both Cetrimide and MacConkey's agar. Presumptive colonies were then subjected to biochemical tests and Polymerase Chain Reaction (PCR) targeting 16S rRNA. The recovered isolates were tested for the presence of three selected virulence-associated genes (lasB, toxA, and exoS). Furthermore, the retrieved isolates were subjected to phenotypic antimicrobial susceptibility testing by Kirby-Bauer disc diffusion method as well as phenotypic detection of ESBLs by both Double Disc Synergy Test (DDST) and the Phenotypic Confirmatory Disc Diffusion Test (PCDDT). P. aeruginosa isolates were then tested for the presence of antibiotic resistance genes (ARGs): int1, mcr-1, and ESBL genes (OXA-10, OXA-2, VEB-1, SHV, TEM, and CTX-M). Additionally, biofilm production was examined by the Tube Adherent method (TA) and Microtiter Plate assay (MTP). RESULTS: Fifty -five isolates were confirmed to be P. aeruginosa, including 35 isolates from broiler chicks and 20 isolates from dead in-shell chicks. The three tested virulence genes (lasB, toxA, and exoS) were detected in all isolates. Antibiogram results showed complete resistance against penicillin, amoxicillin, ceftriaxone, ceftazidime, streptomycin, erythromycin, spectinomycin, and doxycycline, while a higher sensitivity was observed against meropenem, imipenem, colistin sulfate, ciprofloxacin, and gentamicin. ESBL production was confirmed in 12 (21.8%) and 15 (27.3%) isolates by DDST and PCDDT, respectively. Antibiotic resistance genes (ARGs): int1, mcr-1, and ESBL genes (OXA-10, SHV, TEM, and CTX-M), were detected in 87.3%, 18.2%, 16.4%, 69.1%, 72.7%, and 54.5% of the examined isolates respectively, whereas no isolate harbored the OXA-2 or VEB-1 genes. Based on the results of both methods used for detection of biofilm formation, Kappa statistics [kappa 0.324] revealed a poor agreement between both methods. CONCLUSIONS: the emergence of mcr-1 and its coexistence with other resistance genes such as ß-lactamase genes, particularly blaOXA-10, for the first time in P. aeruginosa from young broiler chicks and dead in-shell chicks in Egypt pose a risk not only to the poultry industry but also to public health.

Influence of hot red pepper oil in broiler diets on blood, antioxidant, immunological parameters and intestinal bacteria counts.

The present study aimed to examine the impacts of supplementing hot red pepper oil (HRPO) to broiler diets. One hundred and twenty Arbor Acres chicks were divided randomly into four experimental groups as three supplementation levels of HRPO (0.25, 0.5 and 1.0 mL/kg diet) and the control group. Results showed that HRPO supplementation exhibited significantly (p < 0.001) higher red blood cells (RBCs) count, hemoglobin (Hb) and packed cells volume (PCV) percentage, while insignificant effects were shown for white blood cells (WBCs) count or its differentiation. Diets supplemented with different levels of HRPO influenced significantly (p < 0.001) the total protein (TP), albumin (Alb) and glucose (Glo) values of the studied birds. Results also indicated that different levels of HRPO supplementations significantly (p < 0.01) decreased total lipid, triglycerides (Trig), cholesterol (Cho) and low-density lipoprotein (LDL), but did not affect high density lipoprotein (HDL) values. Data revealed that supplementing broiler diets with different levels of HRPO enhanced their liver function. The bactericidal activity index was significantly increased (p < 0.02) compared with control. HRPO supplemented groups had beneficial effects (p < 0.02) on cecal microbiota count. It could be concluded that dietary HRPO supplementation could improve the general internal health status of Arbor Acres broiler chicks.

Effect of rosemary essential oil as nitrite substitute on quality of sausage produced using chicken fed by thymus essential oil and rapeseed oil.

The objective was to determine the effect of rosemary essential oil (REO) as nitrite substitute on the physicochemical, microbiological and sensory quality of sausage from broilers fed different levels of thymus essential oil (TEO) and rapeseed oil (RO). Broiler chicks fed TEO (0, 300 and 500 ppm) and RO (1, 3 and 5%) in a 3 × 3 factorial design. Sausages were made from meat of chicken fed TEO (0 and 500 ppm) treated with REO (120 ppm), REO:nitrite (60:60 ppm), nitrite (120 ppm) or without REO and nitrite in a 2 × 4 factorial design. Results showed that TEO increased water holding capacity and pH value and decreased malondialdehyde concentration. RO (1 and 3%) × TEO (500 ppm) group had higher unsaturated to saturated fatty acids ratio in the meat. Results showed that treatments of REO (120 ppm) decreased lipid oxidation and increased pH value of meat. Sausage produced by nitrite (120 ppm) or REO:nitrite (60:60 ppm) had lower total microbial count, lightness but higher redness and yellowness. Based on the results, TEO in chicken feed decreased lipid oxidation of sausages. Furthermore, substitution at least 60 ppm nitrite with REO had more preserving effect on quality of produced sausages.

The immunotoxicity of decabromodiphenyl ether (BDE-209) on broiler chicks by transcriptome profiling analysis.

Decabromodiphenyl ether (BDE-209) has drawn significant attention due to its suppression of immune functions in animals and even humans. In order to explore the mechanism through which BDE-209 affects the immune system, broiler chicks were fed a diet containing various concentrations of BDE-209 (0, 0.004, 0.04, 0.4, and 4 g/kg) for 42 days. Histopathological observations of immune organs found damaged and necrotic lymphocytes in the spleen and bursa, and losses of lymphoid cells in thymic gland. The activities of catalase, glutathione, glutathione peroxidase, and superoxide dismutase in both the spleen and serum were affected by BDE-209. Obvious bioaccumulation effect was found in spleen tissues (high to 1339 ± 181.9 µg/kg). Furthermore, transcriptome sequencing analyses of the spleen identified 424 upregulated and 301 downregulated DEGs, and the cytokine-cytokine receptor interaction signal pathway was most significantly enriched based on the Kyoto Encyclopedia of Genes and Genomes database. Quantitative real-time PCR affirmed the decreased expressions of interleukin IL18, IL18R1, IL18RAP, IL21, as well as interferon gamma IFNG and tumor necrosis factor superfamily members TNFSF8, indicating significant interference to immunomodulation function and possible disease progression in inflammatory effects resulting from BDE-209 exposure. The immunotoxicity of BDE-209 may cause the suppression of immune and physiological functions of spleen cells, leading to inflammation and apoptosis and ultimately spleen atrophy.

The influence of thyroid state on hypothalamic AMP-activated protein kinase pathways in broilers.

To investigate whether there are important interactions in play in broilers between thyroid hormones and the central regulation of energy homeostasis through AMP-activated protein kinase (AMPK), we induced a functional hyperthyroid and hypothyroid state in broiler chicks, and quantified systemic and hypothalamic AMPK related gene expression and related protein. Thyroid state was manipulated through dietary supplementation of triiodothyronine (T3) or methimazole (MMI) for 7 days. A hypothalamic AMPK suppressor, 0.1% α-lipoic acid (α-LA) was used to assess the effects of the T3 and MMI feed formulations on the AMPK pathways. Feed intake and body weight were reduced in both hypothyroid and hyperthyroid conditions. In hyperthyroid conditions (T3 supplementation) expression of the AMPKα1 subunit increased, while in hypothyroid conditions (MMI supplementation) active phosphorylated AMPK levels in the hypothalamus dropped, but gene expression of the AMPKα1 and α2 subunit increased. For FAS and ACC (involved in fatty acid metabolism), and CRH, TRH and CNR1 (anorexigenic neuropeptides stimulating energy expenditure) there were indications that their regulation in response to thyroid state might be modulated through AMPK pathways. Our results indicate that the expression of hypothalamic AMPK as well as that of several other genes from AMPK pathways are involved in thyroid-hormone-induced changes in appetite, albeit differently according to thyroid state.

Toxic effects of Decabromodiphenyl ether (BDE-209) on thyroid of broiler chicks by transcriptome profile analysis.

The wide usage of decabromodiphenyl ether (BDE-209) results in its increasing occurrence in the environment and increasing attention in regard to human and animal health. BDE-209 is an endocrine disruptor for hypothyroidism, but the toxicity mechanism is unclear. Here, the histopathology and transcriptome sequencing of thyroid tissue from broiler chicks were investigated by supplemental feeding with different concentrations of BDE-209 for 42 days (0-4 g/kg in basal diet), followed by determining the levels of thyroid hormones in serum. The results showed ruptured and even hyperplastic follicular epithelial cells in the thyroid, and a total of 501 differentially expressed genes were screened out: 222 upregulated and 279 downregulated. Based on the Kyoto Encyclopedia of Genes and Genomes database, neuroactive ligand-receptor interaction pathway was significantly enriched, and α1D-adrenergic receptor, follicle-stimulating hormone receptor, thyroid stimulating hormone receptor, and somatostatin receptor type 2 were shown to be candidate biomarkers. Thyroxine was a possible biomarker due to clear reduction in serum and significant correlation with exposure concentrations. These results suggested that oral intake of BDE-209 can cause structural injuries and even hyperplasia, and affect gene transcription involved in the neuroactive ligand-receptor interaction pathway of thyroid, as well as thyroid hormones in serum.

Effects of partial dietary substitution of groundnut meal by defatted, Aspergillus niger-fermented and heated Jatropha curcas kernel meal on feed intake and growth performance of broiler chicks.

This study was conducted to determine intake and growth performance of broiler chicks fed with Jatropha curcas kernel meal physico-chemically and biologically processed. The feed experiment lasted for 7 days with 20-day-old Ross 308 strain unsexed broiler chicks. Two dietary treatments were given each to ten animals, according to a complete randomized design. Kernels, manually obtained from J. curcas seed, were defatted, heated, and fermented with a strain of Aspergillus niger and oven-dried, in order to obtain the treated jatropha kernel meal. This latter was used to replace one third of a groundnut meal premix which was then incorporated in a commercial diet to warrant iso-nitrogenous and iso-caloric characteristics of the diets. Data collected were analyzed according to ANOVA procedure. The results revealed that the animals that received the diet incorporating jatropha kernel meal had numerically higher live weight (156.1 vs. 152.7 g/animal) (P > 0.05) and average daily weight gain (12.3 vs. 11.7 g/day/animal) (P > 0.05) than the control ones, at the end of experiment. The average daily feed intake was the same for the two groups of animals (23.2 g/day/animal) (P > 0.05) with a similar feed conversion ratio (2.0 vs. 2.1 respectively for the jatropha group and the control group). The survival rate, at the end of the experiment, was 100% for the two groups of animals. Physico-chemically and biologically processed Jatropha curcas kernel could be an interesting by-product for poultry feeding.

Pathological effects of concurrent administration of aflatoxin B1 and fowl adenovirus-4 in broiler chicks.

The current study was designed to investigate pathological effects of fowl adenovirus in broilers exposed to aflatoxin B1. Fowl Adenovirus-4 (FAdV-4) infection is remerging in all types of poultry birds in Pakistan. Poultry feed contamination with mycotoxin (aflatoxin) is another important global issue. A total of 125-day old broiler birds were divided into six equal groups. Group A served as control. B and C groups were administered with aflatoxin B1 (AFB1) 100 and 200 µg/kg feed. Group D was infected with FAdV-4, while groups E and F administered with both AFB1 (100 & 200 µg/kg) along with FAdV-4. These birds were monitored for clinical signs and mortality. Feed intake, body weight (BW), relative organ weights and gross & histopathological lesions were recorded. The highest mortality was observed in group F (FAdV-4 + AFB1 200 µg/kg feed) and the lowest mortality was observed in group B (AFB1 100 µg/kg feed). Body weights of all the groups were significantly (p < 0.05) lower as compared with control group. Relative weight of liver and kidneys in groups E and F were significantly higher as compared with control. Grossly, liver was swollen, anemic with round margins in groups D, E and F. Kidneys were also swollen with whitish areas indicating dead tissue. Microscopically intranuclear inclusion bodies were observed in group D-F. The hepatic parenchyma was also indicating necrotic changes along with vacuolar degeneration. In renal parenchyma, acute tubular necrosis was observed in groups C, E and F. It was concluded that AFB1 intoxication lead to dose dependent changes in liver and kidneys. Severity of the changes was increased in interactive groups of AFB1 with FAdV-4. Therefore, feed should be regularly monitored for AFB1 levels and day old chicks for vertically transmitted FAdV-4 to prevent losses.

Heat stress as a predisposing factor for necrotic enteritis in broiler chicks.

Heat stress is a physical environmental stressor, which can affect performance, health and welfare of poultry. The present study investigates the effect of cyclic acute heat stress as a predisposing factor for necrotic enteritis in broiler chicks in an experimental challenge model. Two hundred and forty broiler chicks were randomly allocated to four treatment groups, as follows: group A served as negative control (25°C), group B birds were subjected to cyclic acute heat stress (35°C), group C birds were challenged and group D birds were both subjected to heat stress and challenged. From each bird, the intestine, gizzard and liver were collected and scored for gross lesions. The intestinal digesta was collected for pH and viscosity determination. One caecum from each bird was taken for microbiological analysis. The statistical analysis and evaluation of data revealed that the heat stress in challenged birds showed a relative trend to increase the severity and the incidence of necrotic enteritis lesions, although it was not considered as statistically significant (Ρ = 0.077). Additionally, the heat stress induced necrotic enteritis outbreak in unchallenged birds; the challenge of birds as well as its combination with the heat stress affected significantly (Ρ ≤ 0.05) the pH and viscosity of intestinal digesta and the caecal Clostridium perfringens counts. The study provides evidence that cyclic acute heat stress is an environmental stressor, which can significantly affect necrotic enteritis and gut health, and thus should be taken into account in warmer areas of the world where poultry farming becomes a major industry.

[Meat quality in broilers reared in different housing systems].

Meat quality was assessed in Cobb-500 cage vs. floor-housed broilers slaughtered at 38 vs 49 days of age. Broilers (105 birds per housing system) were reared since 1 day of age in conditions of vivarium of Center for Selection and Genetics «Zagorskoye EPH¼. Fat content in breast meat was significantly higher (p<0.05) at both slaughter ages in cage-housed broilers (2.0 and 2.7% at slaughter age 38 and 49 days, respectively) compared to floor-housed (1.6 and 2.2%). Protein content in breast meat was higher in floor-caged broilers. Total collagen content in thigh meat of floor housed broilers (789.88 mg/100 g) was 1.5 fold higher compared to cage-housed (515.80 mg/100 g, p<0.05). Fatty acid profiles of meat were mostly affected by the type of meat (red vs white) and to a lesser extent by housing system and slaughter age. Water-holding capacity in red meat significantly differed between slaughter ages and between housing systems at slaughter age 38 days (р<0.05): at slaughter age 38 days water-holding capacity in red meat was 67.3 in cage-housed broilers vs. 70.1% in floor-housed; at slaughter age 49 days 74.9 vs. 76.0%, respectively. The five-point scores of sensory taste evaluation for the meat of floor-housed broilers (4.55 and 4.91 for breast meat at slaughter ages 38 and 49 days; 4.40 and 4.90 for thigh meat) were better compared to cage-housed (4.47 and 4.83 for breast meat at slaughter ages 38 and 49 days; 4.37 and 4.70 for thigh meat). The conclusion was made that meat quality estimated by a set of the relevant parameters was marginally better in floor housed broilers in compare to cage-housed.

Infectious bronchitis vaccine virus detection and part-S1 genetic variation following single or dual inoculation in broiler chicks.

An investigation was undertaken of the extent of genetic variation occurring within infectious bronchitis virus (IBV) vaccine strains following vaccination of day-old broiler chicks. Chicks were divided into seven groups, with two groups receiving single Massachusetts (Mass) vaccinations while the other four were inoculated with combinations of different IBV serotypes; Mass, 793B, D274 and Arkansas (Ark). The remaining group was maintained as an unvaccinated control. Following vaccination, swabs and tissues collected at intervals were pooled and RNA was extracted for detection of IBV by reverse transcription polymerase chain reaction. Positive amplicons were sequenced for the part-S1 gene and compared to the original vaccine strain sequences. Single nucleotide polymorphisms, amino acid variations and hydrophobicity changes were identified and recorded for each sampling point. A total of 106 single nucleotide polymorphisms were detected within 28 isolates. The average single nucleotide polymorphism counts of swab isolates were greater than those found in tissue samples. This translated into 64 amino acid changes; however only six resulted in a change to the hydrophobicity properties. All hydrophobic alterations occurred within swab isolates and the majority were recovered at 3 days post vaccination suggesting such changes to be detrimental to early virus survival. Nucleotide deletions were seen only in the group given the combination of Mass and Ark. Of the 16 sequenced samples in this group, 13 contained the same AAT deletion at position 1033 1035 in the Ark strains. Findings presented in this study demonstrate alteration in the S1 nucleotide sequence following co-administration of live IBV vaccines.

Alpha-lipoic acid impairs body weight gain of young broiler chicks via modulating peripheral AMPK.

In mammals, the AMP-activated protein kinase (AMPK) pathways in the central and peripheral tissues coordinately integrate inputs from multiple sources to regulate energy balance. The present study was aimed to explore the potential role of hepatic AMPK in the energy homeostasis of broiler chickens. Diets with 0, 0.05% or 0.1% alpha-lipoic acid (α-LA), a known AMPK inhibitor were provided to broiler chicks for 7days. As a result, α-LA supplementation decreased the relative growth rate of broiler chicks. Hepatic AMPKα2 mRNA levels were significantly upregulated by dietary α-LA, in concert with the increased phosphorylated AMPKα protein levels. In addition, hepatic FAS mRNA levels together with the malonyl-CoA to total CoA ester ratio were reduced by α-LA supplementation. Moreover, the hepatic phosphorylated glycogen synthase levels were increased resulting in a markedly decreased hepatic glycogen content. In conclusion, dietary α-LA supplementation decreased the in vivo hepatic glycogenesis and lipogenesis via stimulating hepatic AMPKα mRNA levels and the phosphorylated gene product. The stimulatory effect of α-LA on hepatic AMPK mRNA and pAMPKα protein levels together with our previous observations regarding its inhibitory effect on hypothalamic AMPK may have altered the energy balance and hence impaired body weight gain of broiler chicks.

Effects of dietary inclusion of silymarin on performance, intestinal morphology and ileal bacterial count in aflatoxin-challenged broiler chicks.

This study was conducted to investigate the effect of dietary supplementation of silymarin on performance, jejunal morphology and ileal bacterial population in broiler chicks intoxicated with a mix of aflatoxins. A total of three hundred thirty six 7-day-old Ross broiler chicks were randomly distributed between seven experimental groups with four replicates of 12 birds each. Experimental treatments consisted of a control group (unchallenged), and a 2 × 3 factorial arrangement, including two aflatoxin levels (0.5 and 2 ppm) and three levels of silymarin (0, 500 and 1000 ppm). Birds were challenged with a mix of aflatoxins from 7 to 28 days of age. Results showed that increasing aflatoxin level resulted in decreased average daily feed intake (ADFI) and weight gain (ADWG), consequently impaired feed conversion ratio (FCR) throughout the trial period. Dietary supplementation of silymarin resulted in the marked increases in ADFI and ADWG, and improved FCR values in aflatoxin-challenged chicks. Ileal bacterial populations at days 28 and 42 of age were increased by incremental levels of aflatoxins. On the other hand, dietary silymarin supplementation suppressed ileal populations of Escherichia coli, Salmonella, Klebsiella and total negative bacteria in aflatoxicated birds. Increase in dietary aflatoxin level resulted in the decreased villi height, villi height-to-crypt depth ratio (VH:CD), villi surface area and apparent villi absorptive area, while it increased crypt depth, goblet cell count and lymphoid follicular diameter. Feeding silymarin at the level of 1000 ppm increased villi height and VH:CD in aflatoxicated birds. Present results indicate that dietary inclusion of silymarin could improve performance by suppressing ileal bacteria and enhancing absorptive surface area in aflatoxin-challenged broiler chicks.

Heterologous live infectious bronchitis virus vaccination in day-old commercial broiler chicks: clinical signs, ciliary health, immune responses and protection against variant infectious bronchitis viruses.

Groups of one-day-old broiler chicks were vaccinated via the oculo-nasal route with different live infectious bronchitis virus (IBV) vaccines: Massachusetts (Mass), 793B, D274 or Arkansas (Ark). Clinical signs and gross lesions were evaluated. Five chicks from each group were humanely killed at intervals and their tracheas collected for ciliary activity assessment and for the detection of CD4+, CD8+ and IgA-bearing B cells by immunohistochemistry (IHC). Blood samples were collected at intervals for the detection of anti-IBV antibodies. At 21 days post-vaccination (dpv), protection conferred by different vaccination regimes against virulent M41, QX and 793B was assessed. All vaccination programmes were able to induce high levels of CD4+, CD8+ and IgA-bearing B cells in the trachea. Significantly higher levels of CD4+ and CD8+ expression were observed in the Mass2 + 793B2-vaccinated group compared to the other groups (subscripts indicate different manufacturers). Protection studies showed that the group of chicks vaccinated with Mass2 + 793B2 produced 92% ciliary protection against QX challenge; compared to 53%, 68% and 73% ciliary protection against the same challenge virus by Mass1 + D274, Mass1 + 793B1 and Mass3 + Ark, respectively. All vaccination programmes produced more than 85% ciliary protection against M41 and 793B challenges. It appears that the variable levels of protection provided by different heterologous live IBV vaccinations are dependent on the levels of local tracheal immunity induced by the respective vaccine combination. The Mass2 + 793B2 group showed the worst clinical signs, higher mortality and severe lesions following vaccination, but had the highest tracheal immune responses and demonstrated the best protection against all three challenge viruses.

AMPK is involved in the differential neonatal performance of chicks hatching at different time.

We have recently reported that the hatching time may be in relation to the distinct neonatal performance of female chicks. The present study was aimed to investigate the potential involvement of AMPK, an energy sensor which plays a pivotal role in energy homeostasis, in the distinct performance of the spread of hatching time model. As a result, hypothalamic AMPKα1 isoform gene expression was significantly higher in the late hatcher as compared to that of their early counterparts, whereas the total and phosphorylated levels of AMPKα subunit did not differ between the three hatchers. The hypothalamic orexigenic NPY and AgRP mRNA levels were higher in the late hatchers as compared to the early, and that of the middle hatchers was at an intermediate level. However, the anorexigenic POMC and CRH was also higher expressed in the late hatchers as compared to the early hatchers. In the liver, AMPKα2 mRNA level and the phosphorylation ratio of AMPKα was significantly lower in the late hatchers, as compared to their early counterparts. The hepatic phosphorylated GS levels of the late and middle hatchers were lower than that of their early counterparts. The expression of hepatic FTO gene of the late hatchers was significantly higher than that of their early and middle counterparts. Taken together, AMPK may play a significant role in the different neonatal performance of the spread of hatching time model. The central and peripheral AMPK in late hatchers exhibited a pattern of higher energy intake and lower energy expenditure, which resulted in a faster post-hatch growth.

Effect of cyclical cold stress during embryonic development on aspects of physiological responses and HSP70 gene expression of chicks.

The objective of the present study was to evaluate the effects of cyclical lower incubation temperature at different embryonic ages on the hatchability, body and organs weights, thyroid hormones, and liver HSP70 gene expression of newly hatched chicks. In a completely randomized design, fertile eggs of a broiler breeder (34 weeks of age) were assigned to three treatment groups with six replicates and 145 eggs per each. The treatment groups were as: control group (C) that eggs were incubated at 37.6°C during the whole incubation period; incubation temperature was decreased to 36°C for 3h per day at embryonic age from 12 to 14 (T1); and incubation temperature was decreased to 36°C for 3h per day at embryonic age from 15 to 17 (T2). No significant difference was found among treatments for hatchability (P>0.05). There were no differences (P>0.05) among treatments for body weight and liver weight, while heart weight of chicks in T1 and T2 groups were significantly higher than the control group (P<0.05). There were no differences (P>0.05) among treatments for the levels of thyroid hormones, however, the levels of both hormones tended to increase in chicks exposed to cold stress (T1 and T2). Chicks in T2 group had higher liver HSP70 gene expression compared with those in T1 and the control group (P<0.05). Cold stress in both incubation periods had no significant effect on the plasma levels of aspartate aminotransferase and alanine aminotransferase. Treatments had no effect on the plasma levels of glucose, cholesterol and triglyceride. The results of this study suggest that cyclical lower incubation temperatures (36°C) at the embryonic age from day 15-17 could induce the liver HSP70 gene expression, without negative effects on the hatchability and body weight of hatched chicks.

Physiological adaptive indicators in fasted neonate broiler chicks in response to calcium gluconate injection.

Four hundred and eighty mixed-sex broiler chicks aged 3 h after hatching were allotted according to a completely random design in a 6 × 2 × 2 factorial schedule into two groups of 12 replications of 20 chicks each. The main experimental factors were fasting for 0, 6, 12, 24, 36 and 48 h after chick placement and calcium gluconate (Ca-glu) injection (0 and 0.6 ml). Live body weight (BW) of chicks decreased linearly (Y = 43.36-0.109BW0 h , r(2)  = 0.876) as neonatal fasting extended. Injection of 0.6 ml Ca-glu at 3 h post-hatching did not affect weight loss of chicks. Yolk residuals (YR) utilized linearly (Y = 5.75-0.062YR, r(2)  = 0.956) by 0.062 g/h in neonate fasted chicks up to 48 h, showing no effect of Ca-glu injection. Neonatal fasting periods longer than 12 h increased liver weight (p < 0.05). The mean absolute and proportional (% of BW0 h ) breast and leg weight were reduced linearly as neonatal fasting extended (p < 0.05). Serum glucose concentration increased up to 6 h and then reduced linearly to 150 mg/dl after 48-h fasting. The Ca-glu treatment influenced serum glucose level for a short period up to 6 h of fasting. Serum Ca concentration sharply increased up to threefolds in the birds received Ca-glu injection resulting in acute hypercalcemia, then decreased to the initial level after 24-h feed withdrawal (p < 0.05). The mean serum level for creatinine, uric acid, cholesterol, HDL, albumins and total proteins significantly increased during the fasting periods of 6 to 48 h and significantly elevated in the birds receiving 0.6-ml Ca-glu injection compared with the non-treated chicks (p < 0.05). It was concluded that subcutaneous administration of 0.6 ml Ca-glu in the chick's neck did not suitably support the increased metabolic demands for glucose and calcium in feed-deprived neonate chicks.

Effects of different sulphur amino acids and dietary electrolyte balance levels on performance, jejunal morphology, and immunocompetence of broiler chicks.

As alterations of dietary electrolyte balance (DEB) can influence amino acid metabolism via changes the ions incur in their configurations, performance and immunological responses of broiler chicks might be affected. So, the current study was carried out to investigate the effects of different levels of sulphur amino acids (SAA) and DEB on performance, jejunal morphology and immunocompetence of broiler chicks. A total of 360 1-day-old male Ross 308 broiler chicks were randomly assigned to nine experimental treatments with four replicates of 10 birds each. Experimental treatments consisted of three levels of SAA (100, 110, and 120% of NRC recommendation, provided by methionine supplementation in diets with the same cysteine level) and three levels of DEB (150, 250, and 350 mEq/kg) that were fed during the entire of trial in a 3 × 3 factorial arrangement. Results showed that the relative weights of intestine and abdominal fat were decreased markedly (p < 0.001) with increasing levels of SAA and DEB respectively. Antibody titre against sheep red blood cell was neither individually nor in combination influenced by supplementation of SAA or DEB. Nevertheless, a decrease in DEB level led to a suppression in heterophile (p < 0.05) and an increase in lymphocyte counts (p = 0.06); consequently, heterophile to lymphocyte ratio was significantly decreased (p < 0.05) by decremental levels of DEB. Albumin to globulin ratio was increased after inclusion of at least 10% SAA (p < 0.001) and 150 mEq DEB/kg in the diet (p = 0.11). Although feeding high-DEB level led to a remarkable decrease in villus height (p < 0.01) and goblet cell numbers (p < 0.001), supplementing the highest level of SAA improved the height of jejunal villus. During the entire trial period, average daily feed intake (ADFI) was increased by incremental SAA levels (p < 0.05). However, inclusion of 150 mEq/kg led to not only a remarkable increase (p < 0.0001) in both ADFI and average daily weight gain (ADWG) but also to improved (p < 0.001) feed conversion ratio (FCR) both during the growing and over the entire trial periods. The present findings indicated that inclusion of low DEB decreased the heterophile to lymphocyte ratio and improved both the albumin to globulin ratio and intestinal health indices. The best growth performance was obtained with 150 mEq DEB/kg in the diet for each level of SAA.

Rapamycin, a specific inhibitor of the target of rapamycin complex 1, disrupts intestinal barrier integrity in broiler chicks.

To uncover the molecular mechanisms underlying the intestinal barrier integrity, this study determined whether the rapamycin (RAPA)-sensitive target of rapamycin complex 1 (TORC1) pathway was involved in this process. Three groups of 4-day-old male chicks were randomly subjected to one of the following treatments for 6 days: high-dose RAPA [a specific inhibitor of TORC1; an intraperitoneal injection of 1.0 mg/kg body weight (BW), once daily at 09:00 hours], low-dose RAPA (0.4 mg/kg BW) and RAPA vehicle (control). Results showed that the RAPA treatment increased mortality, while decreasing villus height (p < 0.01), claudin 1 expression, content of immunoglobulin A (IgA), extent of TORC1 phosphorylation (p < 0.05), ratio of villus height to crypt depth (p < 0.01), and population of IgA-positive B cells in intestinal mucosa, particularly for the jejunum. Some aspects of these responses were dose dependent and appeared to result from weight loss. Together, RAPA exerts the expected inhibition of small intestinal development and IgA production in birds, suggesting the important role of TORC1 in gut barrier integrity.