Ovo Treatment Research Articles

Early-life immunomodulation by carvacrol delivered in ovo in broiler chickens

In the first 2 wk after hatching, broiler chickens are vulnerable to enteric pathogens due to underdeveloped gastrointestinal and immune systems. Carvacrol has been reported to improve digestive and immune functions. This study aimed to optimize immune development of broiler chickens by delivering carvacrol in ovo. Effects of 2 in ovo treatments delivered at embryonic day (E)17.5 (saline or carvacrol) were evaluated at 3 stages (E19.5, hatch, and d 14 posthatch). Hatchability, performance parameters, lymphoid organ and yolk sac weights were determined. Histomorphology assessment was performed for jejunal samples at hatch and bursa of Fabricius samples at hatch and d 14. Gene expression of immune-relevant genes was determined for jejunal, bursal, and yolk sac samples over time. At hatch, BW was 0.85% lower (P = 0.02) after in ovo carvacrol delivery compared to the controls. Interactions between in ovo treatment and age were found for gene expression. At hatch, carvacrol treatment resulted in lower expression of proinflammatory cytokines IL-8 and IFN-γ in the yolk sac compared to the controls (P = 0.05 and < .001, respectively) suggesting a potential role for carvacrol-mediated immune modulation. At d 14, carvacrol treatment led to lower expression of proinflammatory cytokine IL-6 in the bursa compared to the controls (P = 0.002). In ovo carvacrol delivery led to bursal histomorphometric changes, including a larger cortex in the bursal follicles (P = 0.03), and a higher cortex/medulla ratio (P = 0.04) compared to the controls, indicating increased B-cell stimulation and maturation. Main effects were found for carvacrol treatment in the jejunum, with overall higher expression of proinflammatory mediators IL-1β and NF-κB, and anti-inflammatory IL-10 compared to the controls (P = 0.04, 0.02, and 0.02 respectively) from E19.5 to d 14. Age-related main effects showed various alterations in expression dynamics of immune-related genes across all tissues over time. Our findings suggest changes in immune parameters occur as the chicken develops, but these mostly do not interact with in ovo carvacrol treatment. In ovo carvacrol treatment alters immune activity of broiler chickens independent of age.

Enhancements in the expressions of genes associated with the immunity, muscle growth, and antioxidant activity of 14 d broilers in response to the in ovo injection of the Marek's disease vaccine alone or in conjunction with in ovo and dietary supplemental administration of 25-hydroxycholecalciferol

Influences the Marek's disease vaccine (MDV) alone or combined with the in ovo and dietary administration of 25-hydroxycholecalciferol (25OHD3) on the expression of genes associated with the breast muscle deposition, adaptive and innate immunity, and antioxidant and vitamin D activities of 14 d-old broilers were investigated. Four in ovo treatments were: non-injected; commercial MDV-alone-injected (50 μl); or 50 μl of MDV containing 1.2 (MDV+25OHD3-1.2) or 2.4 (MDV+25OHD3-2.4) μg of 25OHD3. Two dietary treatments were a commercial diet containing 25OHD3 (250 IU)/kg of feed (control) or the same diet supplemented with additional 25OHD3 (2,760 IU)/kg of feed (Hy-D diet). One bird per pen (48 total) was sampled at 14 d for determination of the expression of genes involved with the muscle deposition (MyoD1, MyoG, Pax3, and Mrf4), immunity (INF-γ, IL-10, IL-8, IL-1β, and TGF-β4), antioxidant capacity (SOD1, SOD2, GSH-P1, GSH-P7, and CAT), and vitamin D activity (VDR, 1α-hydroxylase, and 24-hydroxylase) in the spleen and pectoralis major (P.major) muscle. The treatment differences were considered significant at P ≤ 0.05. In the P. major, Mrf4 and MyoG were up-regulated in Hy-D-fed birds. Also, the in ovo and dietary 25OHD3 sources individually increased SOD2 gene expression in the P. major. In the spleen, the expressions of IL-1β and IL-8 were down-regulated and IL-10 and TGF-β4 gene expressions were up-regulated in Hy-D-fed birds than those commercial-fed broiler. In ovo and dietary 25OHD3 sources enhanced vitamin D gene (1α-hydroxylase and 24-hydroxylase) activities in the breast and spleen. In ovo x dietary treatment interactions were significant for the MyoD1, IL-8, Pax3, TGF-β4 genes of the P. major, in which the combined MDV with 1.2 μg of 25OHD3 enhanced their expressions in birds fed the Hy-D diet. In conclusion, both 25OHD3 sources promoted the expression of genes associated with immunity and P. major growth. It is recommended that both 25OHD3 sources can be used to promote the gene expression of 14-d-old broilers in the spleen and breast muscle when MDV administered in ovo.

Ross 708 broiler small intestine morphology and immunity improvements in response to in ovo Marek's Disease vaccine administration alone or in conjunction with in ovo and dietary supplemental calcifediol

Investigations were performed to determine the systemic immune and small intestine (SI) morphological responses of Ross 708 broilers to the Marek's Disease vaccine (MDV) administered alone or in conjunction with the in ovo and dietary administration of calcifediol (25OHD3). Live embryonated hatching eggs were assigned at random to 3 in ovo treatments at 18 d of incubation. Pre-specified in ovo treatments were: commercial MDV-alone-injected (50 µL) or commercial MDV containing 1.2 (MDV+25OHD3-1.2) or 2.4 (MDV+25OHD3-2.4) μg of 25OHD3. A non-injected control treatment was also included. For the growing phase, broilers received a commercial diet containing 250 IU of vitamin D3 /kg (control) or a commercial diet supplemented with 2,760 IU of 25OHD3 /kg (Hy-D diet). For determination of serum IgG, nitric oxide, and α-1-acid glycoprotein (AGP) at 14 and 40 d of age (doa), blood was collected from 1 bird per pen (48 total). In the duodenum, jejunum, and ileum of the same bird, villus length (VL), crypt depth (CD), VL to CD ratio (VCR), and villus surface area were also determined. There were no significant dietary x in ovo treatment interactions for any of the variables examined. However, birds fed Hy-D diets had lower serum AGP levels at 14 doa when compared to those fed un-supplemented commercial diets. Additionally, at 40 doa, birds in the MDV+25OHD3-1.2 and MDV+25OHD3-2.4 treatments experienced a decrease in serum AGP in comparison to those belonging to the non-injected and MDV-alone treatment groups. A higher jejunal VCR was observed at 14 and 40 doa in birds that belonged to the MDV+25OHD3-1.2 treatment when compared to those in the non-injected and MDV-alone treatment groups, and dietary Hy-D increased the VL of the duodenum and jejunum in birds at 14 and 40 doa when compared to those fed the commercial diet. In conclusion, both dietary or in ovo administration of 25OHD3 lowered inflammatory reactions and improved the SI morphology of broilers that were in ovo-injected with the MDV.

Effects of nicotinamide riboside in ovo feeding on high-yield broiler performance, meat quality, and myopathy incidence.

Introduction: The objective of this study was to examine the effects of in ovo nicotinamide riboside (NR) feeding on high-yield broiler growth and meat quality. Methods: Fertilized Cobb 700 by-product eggs (N = 3,240) were randomly assigned to one of four in ovo treatments and injected with 0 (0NR), 250 (250NR), 500 (500NR), or 1,000 (1,000NR) mM NR at incubation-day 10. Chicks were hatched, vent sexed, and randomly placed 18 per pen in one of 32 floor pens. On day 48, birds were processed and deboned. Results: There were dose effects for all part weights (p < 0.05). Pectoralis major weight of 250, 500, and 1,000NR carcasses were heavier than 0NR (p < 0.03) but did not differ from remaining NR doses (p > 0.26). Pectoralis minor weight of 250NR carcasses was greater (p < 0.01) than 0NR and did not differ from other NR tenders (p > 0.21). Pectoralis minor weight of 500 and 1,000NR carcasses was greater than 0NR (p < 0.09), but did not differ (P = 0.82) from each other. There were no dose effects for all Pectoralis major and minor myopathy scores and incidence except incidence of tenders scoring "0" and "1" for woody-like tender. Percentage of NR1,000 tenders scoring 0 and 1 for woody-like tender were less than and greater than all other treatments, respectively (p < 0.05). There were no differences among remaining NR doses and NR0 tenders (p > 0.10). There were dose effects for muscle fiber number (P = 0.03). There tended to be more muscle fibers within 250 and 1,000NR muscles compared to 0NR (p < 0.09). Pectoralis major muscle from 500NR did not differ in muscle fiber number compared to 250 and 1,000NR (p > 0.18), but had more (p < 0.01) fibers than 0NR muscle. There tended to be more fibers in 250 and 1,000NR muscles compared to 0NR muscle (p < 0.09). Discussion: Nicotinamide riboside in ovo feeding caused birds to produce heavier parts; however, myopathy scores and incidence were minimally affected which may have been due greater muscle fiber number.

Effects of in ovo feeding of xylobiose and xylotriose on growth performance, carcass traits, ileal histomorphometry, and immune-related gene expression in broiler chickens

Xylooligosaccharides (XOS) are known as prebiotics which promote beneficial gut microbes, improve gut health and the performance of broilers. Xylobiose (XOS2) and xylotriose (XOS3) are two compounds in the XOS group. In ovo feeding could deliver these prebiotics to the embryo, and this is considered as an effective method for studying the effects of the prebiotics during embryonic development and the post-hatch period. This study investigated the effects of in ovo feeding of XOS2 and XOS3 on growth performance, carcass traits, ileal histomorphometry, and immune-related gene expression in broilers. A total of 144 fertilized eggs of Cobb 500 broilers were divided into three groups: (a) non-injected control (CON), (b) XOS2, and (c) XOS3. The eggs from XOS2 and XOS3 groups were injected with 0.5 ml of 0.85% normal saline solution containing 3 mg of XOS2 and 3 mg of XOS3, respectively, into their amniotic sac on the 17th embryonic day. A total of 131 hatched chicks were raised in 18 replicate pens (5 or more chicks per pen) following standard management practices and fed a corn-soybean meal-based diet for 21 days. The feed intake and body weight (BW) data were recorded weekly. The chickens were euthanized on day 7, day 14, and day 21 to collect ileum sections, and the carcass traits were recorded on only day 21. Total RNA was extracted from ileum tissues, and qPCR was performed to measure the gene expression. All the statistical analyses considered the significance level at a P value <0.05. The result showed that in ovo treatments did not affect the hatchability of the eggs. The XOS2 group showed a trend to increase the BW on day 0, compared to CON (P=0.052), and the XOS3 group showed better FCR improvement than the XOS2 group in the first week. There was no difference (P>0.05) among the groups for the weight of the breast muscle, drumsticks, gizzard, proventriculus, and carcass weight at the age of 21 days. The histomorphometry of the ileum on day 7 revealed a significant reduction (P<0.05) of villi height (VH), villi width (VW), and crypt depth (CD) in XOS2, compared to the CON group. On day 7, a lower CD and a higher VH to CD ratio were recorded in XOS3, compared to CON. On day 14, XOS3 showed an increase in VW and villi surface area (VSA) compared to XOS2 birds. On day 7, the expression of IL10 in XOS2 was higher compared to CON and XOS3, and CD56 was significantly higher (P<0.05) in the XOS2 compared to CON group. On day 21, the XOS2 and XOS3 significantly lower the expression of IFNγ. Overall, XOS2 and XOS3 significantly increased immunity until day 21. In conclusion, in ovo XOS feeding demonstrated the potential to modulate gut morphology and immunity of the chickens during the post-hatch days.

The potential of in ovo-fed amino acids to alleviate the effects of heat stress on broiler chickens: effect on performance, body temperature, and oxidative status during the finisher phase

The aim of the current study was to investigate the potential of in ovo-fed amino acids (AA) to reduce the effects of heat stress on finishing broiler chickens. To achieve this, a total of 1,400 fertile hatching eggs were randomly distributed into 5 groups (n = 280/group) and injected with one of the following in ovo treatments on embryonic day 18: 52 µL of sterile diluent/egg (CTRL), CTRL + 1.0 mg of L-Leucine (T1), CTRL + 0.45 mg of leucine + 1.15 mg of methionine (T2), CTRL + 3.0 mg of methionine + 2.0 mg of cysteine (T3), and CTRL + 0.40 mg of leucine + 1.60 mg of methionine + 1.60 mg of cysteine (T4). After hatch, chicks were allocated according to a complete randomized block design comprising 2 thermal conditions: thermoneutral (24°C, 45% RH) and heat stress (34°C, 55-60% RH) with 5 pens/group/condition. The cyclical heat stress regimen (10 h/d) was then applied from d 29 to d 34. Compared to the CTRL group, T3 and T4 exhibited a higher BW during the starter phase (P < 0.001). T4 also had a lower feed conversion ratio (FCR) than CTRL during this same phase (P = 0.03). During the grower phase, males of all treatment groups consistently exhibited higher BW compared to the CTRL group, which was not observed among female birds (PSex × TRT = 0.005). During the finisher phase, the in ovo treatment effect on performance was not significant. However, heat-stressed birds from treatment group T3 and T4 exhibited lower facial temperatures (Pday × TRT < 0.001) as well as lower plasma (Pcondition x TRT = 0.039) and liver (Pcondition x TRT < 0.001) malonaldehyde concentrations compared to the CTRL group. In conclusion, in ovo-fed AA have the potential to modulate the effects of heat stress on finishing broiler chickens by limiting its detrimental consequences, including increased body temperature and oxidative damage.

Adapted tissue assay for the assessment of ileal granulocyte degranulation following in ovo inoculation with select bacteria or coccidial challenge in chickens.

A previously described heterophil degranulation assay was adapted for use with ileal mucosal tissue via quantification of β-D-glucuronidase and assay end product 4-methylumbelliferone (4-MU). Three initial experiments evaluated the effect of in ovo inoculations of Citrobacter freundii (CF) or mixed lactic acid bacteria (LAB) on ileal granulocyte degranulation. Inoculations were administered on embryonic d18, body weights (BW) were recorded on day of hatch (DOH) and d10 to calculate body weight gain (BWG), and ileal mucosal scrapings were collected on DOH or d10 for the 4-MU assay. In all experiments, treatments were statistically analyzed relative to control groups. Treatments minimally affected BWG in all in ovo experiments (p > 0.05) relative to respective control groups. Similarly, ileal degranulation in in ovo treatments did not statistically differ (p > 0.05). Based on BWG, in ovo treatments may have induced low-level inflammation unable to elicit detectable changes via the 4-MU assay. Four subsequent experiments were conducted to evaluate effects of Eimeria maxima (EM) on ileal degranulation. Treatments included non-inoculated controls and low, medium, or high EM infection. Across all four experiments, final BW or BWG over the inoculation period were suppressed (p < 0.05) in EM groups relative to respective controls with the exception of EM-low (p = 0.094) and EM-medium (p = 0.096) in one trial. Ileal mucosal scrapings for the 4-MU assay were collected on day of peak lesions. Resulting values were reduced (p < 0.05) for EM treated birds in three experiments with the exception of EM-medium (p = 0.247). No differences were observed in one experiment (p = 0.351), which may have been attributed to a variation in strain of infecting Eimeria. Although refinement for low level inflammation is warranted, results indicate successful adaptation of the 4-MU assay for use with intestinal tissue during significant gastrointestinal inflammation.

Effects of the In ovo Administration of L-Ascorbic Acid on Tissue L-Ascorbic Acid Concentrations, Systemic Inflammation, and Tracheal Histomorphology of Ross 708 Broilers Subjected to Elevated Levels of Atmospheric Ammonia

The effects of in ovo injection of L-ascorbic acid (L-AA) on tissue L-AA concentrations, systemic inflammation, plasma mineral concentrations, and tracheal histomorphology of Ross 708 broilers subjected to elevated atmospheric ammonia (NH3) levels after hatch were investigated. The four in ovo treatments included non-injected (control), saline-injected (control), or saline containing 12 or 25 mg of L-AA. The in ovo treatments were applied at 17 days of incubation by injecting a 100 μL volume of each pre-specified treatment into the amnion. At hatch, 12 male chicks were randomly allocated to each of the 12 replicate battery cages belonging to each treatment group. The cages were arranged in a randomized complete block design within a common room. All birds were exposed to 50 ppm of NH3 at 35 days of posthatch age (doa), and the concentration of NH3 in the room was recorded every 20 s. At 0, 7, 14, 21, and 28 doa, one bird from each cage was arbitrarily selected and euthanized for determinations of liver and eye L-AA concentrations at 0, 7, 14, 21, 28 doa; plasma nitric oxide concentrations at 0, 14, 21, and 28 doa; and plasma calcium and trace mineral concentrations at 0 and 21 doa. Tracheal histomorphology evaluations were performed at 0, 21, and 28 doa. There were no significant treatment differences for plasma nitric oxide and mineral concentrations, and for liver and eye L-AA concentrations at each sampling timepoint. In ovo injection of either 12 or 25 mg of L-AA decreased tracheal attenuation incidence at 0 doa compared to the non-injected or saline-injected control groups. Furthermore, the percentage of mild tracheal inflammation scores was lower at 28 doa in response to the in ovo injection of 12 mg of L-AA compared to the non-injected or saline-injected control groups. These results indicate that in ovo injection of 12 mg of L-AA reduces tracheal inflammation in broilers subjected to elevated atmospheric NH3.

An investigation of the effect of folic acid and its delivery routes on broiler chickens' hatch and growth performance, blood biochemistry, anti-oxidant status, and intestinal morphology.

This study investigated the effect of folic acid (FA) and its delivery routes (in-feed or in ovo) on broiler chicken's hatch and growth performance, blood biochemistry, anti-oxidant status, and intestinal morphology. A total of 1,860 Cobb 500 hatching eggs were incubated for 21 d. On day 12 of incubation, viable eggs were randomly allotted to four groups: the noninjected group, in ovo saline (injected with 0.1 mL/egg of saline solution), in ovo FA 1 (injected with 0.1 ml FA containing 0.1 mg/egg; FA1), and in ovo FA 2 (injected with 0.1 ml FA containing 0.15 mg/egg). All in ovo treatments were delivered via the amnion. At hatch, chicks were re-allotted to five new treatment groups: FA1, FA2, in-feed FA (FA 3; 5mg/kg in feed), in-feed bacitracin methylene disalicylate (BMD; 55 mg/kg in feed), and negative control (NC; corn-wheat-soybean diet) in 6 replicate pens (22 birds/pen) and raised in starter (days 0 to14), grower (days 15 to 24), and finisher (days 25 to 35) phases. Hatch parameters were assessed on day 0, and body weight and feed intake (FI) were determined weekly. On day 25, 1 bird/cage was euthanized, immune organs weighed, and intestinal tissues harvested. Blood samples were collected for biochemistry and anti-oxidant (Superoxide dismutase-SOD and Malondialdehyde-MDA) analysis. Data were analyzed in a randomized complete block design. While FA1 and FA2 decreased (P < 0.001) hatchability in a dose-dependent manner, FA2 caused a 2% increase (P < 0.05) in average chick weight compared to the noninjected group. Compared to the BMD treatment, FA3 decreased (P < 0.05) average FI across all feeding phases. At the end of the trial on day 35, FA2 had similar feed conversion ratio as the BMD treatment while recording less (P < 0.001) FI. FA1 and FA2 recorded a tendency (P < 0.1) to increase MDA levels and SOD activity by 50% and 19%, respectively, compared to the NC treatment. Compared to NC treatment, FA2 increased (P < 0.01) villus height, width, and villus height to crypt depth ratio in the duodenum, and villus width in the jejunum. Besides its negative effect on hatchability, FA2 may help improve embryonic development and anti-oxidant status in broiler chickens.

Effect of In Ovo Vitamin C Injection against Mobile Phone Radiation on Post-Hatch Performance of Broiler Chicks.

This study aimed to investigate the effect of in ovo injection of vitamin C to reduce the harmful effects of electromagnetic waves (EMWs) emitted from mobile phones on chicken embryos. In this study, a total of 750 fertilized eggs of Ross 308 were exposed to EMWs for 1050 min during the incubation period. On the 17th day of incubation, the eggs were divided into three groups and solutions were injected into the amnion sac of embryos. The chicks were housed separately in accordance with in ovo treatments for 5 wk after hatching. An in ovo vitamin C injection resulted in a lower hatching weight. The post-hatch mortality or production efficiency factor of birds in the in ovo vitamin C injection group and the intact egg group were comparable, and were better than that of the other negative control group. In ovo vitamin C injection in eggs subjected to EMWs significantly increased their body weight gain, carcass weight, abdominal fat weight, and AST levels, but reduced spleen weight and PON-1 levels. In conclusion, an in ovo vitamin C injection in eggs subject to mobile phone EMWs improved the post-hatch performance of chicks, but low PON and high AST activities indicate an increase in oxidative damage among broiler chicks.

The effects of In Ovo Injection of Garlic (Allium sativum L.) Extract on Hatchability, Liver Enzymes and Antioxidant status of Broiler Chickens

The objective of this study was to investigate the effect of in ovo injection of alcoholic garlic extract on hatching traits, liver enzymes, and antioxidant status of broiler chickens post-hatch. In total, 625 broiler breeder eggs (ROSS 308 strain with an average weight of 58.5 g) were divided into 5 treatments (each treatment had three replicates). At 0 embryonic day, the eggs were injected as follows: the first treatment without in ovo injection (negative control), eggs of second treatment were injected with 100 μL.egg-1 distilled water (sham control). The third, fourth, and fifth treatments were injected with 50, 100, and 150 μL.egg-1 of an alcoholic garlic extract respectively. The chicks were reared for 4 weeks after hatching according to in ovo treatments. Hatchability, embryonic mortality, chicks' weight, serum AST, ALT, GPx, SOD activities, and MDA concentration were all measured. The results showed that the hatchability of the fifth treatment was higher (P≤0.05) than those of the other treatments. On the other hand, the embryonic mortality of the fifth treatment was recorded less (P≤0.05) than those of the other treatments. The results of serum AST, ALT, GPx, SOD activities, and MDA concentration were non different significance (P&gt;0.05) among treatments. It is concluded that a garlic extract injection with 150 μL.egg-1 improved hatchability and reduced embryonic mortality. Moreover, it did not affect the chick's weight, serum liver enzymes, and antioxidant status post-hatch.

Pre-hatching and post-hatching environmental factors related to epigenetic mechanisms in poultry.

Epigenetic modifications are phenotypic changes unrelated to the modification of the DNA sequence. These modifications are essential for regulating cellular differentiation and organism development. In this case, epigenetics controls how the animal's genetic potential is used. The main epigenetic mechanisms are microRNA activity, DNA methylation, and histone modification. The literature has repeatedly shown that environmental modulation has a significant influence on the regulation of epigenetic mechanisms in poultry. The aim of this review is to give an overview of the current state of the knowledge in poultry epigenetics in terms of issues relevant to overall poultry production and the improvement of the health status in chickens and other poultry species. One of the main differences between birds and mammals is the stage of embryonic development. The bird's embryo develops outside its mother, so an optimal environment of egg incubation before hatching is crucial for development. It is also the moment when many factors influence the activation of epigenetic mechanisms, i.e., incubation temperature, humidity, light, as well as in ovo treatments. Epigenome of the adult birds might be modulated by nutrition, supplementation, and treatment, as well as modification of the intestinal microbiota. In addition, the activation of epigenetic mechanisms is influenced by pathogens (i.e., pathogenic bacteria, toxins, viruses, and fungi) as well as the maintenance conditions. Farm animal epigenetics is still a big challenge for scientists. This is a research area with many open questions. Modern methods of epigenetic analysis can serve both in the analysis of biological mechanisms and in the research and applied to production system, poultry health, and welfare.

Parental methyl-enhanced diet and in ovo corticosterone affect first generation Japanese quail (Coturnix japonica) development, behaviour and stress response

The role of maternal investment in avian offspring has considerable life history implications on production traits and therefore potential for the poultry industry. A first generation (G1) of Japanese quail (Coturnix japonica) were bred from a 2 × 2 factorial design. Parents were fed either a control or methyl-enhanced (HiBET) diet, and their eggs were treated with a vehicle or corticosterone injection during day 5 of incubation. A subset of G1 birds were subjected to an open field trial (OFT) and capture-restraint stress protocol. Significant effects of HiBET diet were found on parental egg and liver weights, G1 hatch, liver and female reproductive tract weights, egg productivity, latency to leave the OFT central zone, male baseline 11-dehydrocorticosterone, and female androstenedione plasma concentrations. In ovo treatment significantly affected latency to return to the OFT, male baseline testosterone and androstenedione, and change in androstenedione plasma concentration. Diet by treatment interactions were significant for G1 liver weight and male baseline plasma concentrations of corticosterone. These novel findings suggest significant positive effects on reproduction, growth, precociousness, and hypothalamic–pituitary–adrenal axis function from enhanced methyl diets, and are important in understanding how in ovo stressors (representing maternal stress), affect the first offspring generation.

EFFECTS OF IN OVO SYNBIOTIC INJECTION ON GROWTH PERFORMANCE, INTESTINAL BACTERIAL LOAD AND ANTIBODY TITRES IN BROILER CHICKENS VACCINATED AGAINST INFECTIOUS BURSAL DISEASE

The present study investigated the efficacy of a synbiotic (Lactobacillus delbrueckii subsp. bulgar-icus, Streptococcus salivarius subsp. thermophilus, and mannan oligosaccharide) along with an infectious bursal disease (IBD) vaccine in Cobb 500 broilers. A total of 1200 embryonated chicken eggs were randomly allocated in 10 groups with eight replicates. The first group did not receive any treatment. The second group was vaccinated post-hatch (PV), the third group was vaccinated in ovo (IV), the fourth group received dietary synbiotic and in ovo vaccination (DS+IV), the fifth group was treated in ovo with synbiotic (IS), the sixth group received in ovo and dietary synbiotic (IS+DS), the seventh group received in ovo synbiotic plus post-hatch vaccination (IS+PV) and the eighth group  in ovo and dietary synbiotic and post-hatch vaccination (IS+DS+PV). In the ninth group, the synbiotic and the vaccine were administered in ovo (IS+IV) while the tenth group re-ceived in ovo and dietary synbiotic, plus in ovo vaccine (IS+DS+IV). The in ovo treatment with the synbiotic in combination with DS, IV or PV had a positive effect on weekly weight gain. The sixth group provided a better feed conversion ratio at the end of fourth week. The synbiotic appli-cation, individually in sixth group or along with PV or IV treatment in eighth and tenth groups, elevated feed intake in fifth and sixth weeks respectively.The antibody titre of IBD was higher for groups which received IV along with IS. It is concluded that the application of synbiotic along to IBD vaccine improved growth performance and had positive effects on IBD antibody titres.

Effects of in ovo probiotic administration on the incidence of avian pathogenic Escherichia coli in broilers and an evaluation on its virulence and antimicrobial resistance properties

Avian pathogenic Escherichia coli (APEC) causes colibacillosis in poultry, which has been traditionally controlled by the prophylactic in-feed supplementation of antibiotics. However, antibiotics are being removed from poultry diets owing to the emergence of multidrug-resistant (MDR) bacteria. Therefore, alternatives to control APEC are required. This study aimed to evaluate the effects of in ovo inoculation of probiotics on the incidence of APEC in broilers and evaluate the virulence and antimicrobial resistance properties of the APEC isolates. On embryonic day 18, 4 in ovo treatments (T) were applied: T1 (Marek's vaccine [MV]), T2 (MV and Lactobacillus animalis), T3 (MV and Lactobacillus reuteri), and T4 (MV and Lactobacillus rhamnosus). A total of 180 male broilers per treatment were randomly placed in 10 pens. The heart, liver, spleen, and yolk sac were collected on day 0, 14, 28, and 42. Presumptive E. coli isolates were confirmed by real-time PCR. The positive isolates were screened for the APEC-related genes (iroN, ompT, hlyF, iss, and iutA), and E. coli isolates containing one or more of these genes were identified as APEC-like strains. A total of 144 APEC-like isolates were isolated from 548 organ samples. No differences (P > 0.05) among treatments were observed for the incidence of APEC-like strains in all organs when averaged over sampling days. However, when averaged over treatments, the incidence in the heart, liver, and yolk sac was different among sampling days; a significant increase was observed in these organs on day 14 compared with day 0. Twenty-five antimicrobial resistance genes were evaluated for all APEC-like isolates, and 92.4% of the isolates carried at least one antimicrobial resistance gene. Thirty-seven isolates were then selected for antimicrobial susceptibility testing; MDR strains accounted for 37.8% of the isolates. In conclusion, the in ovo inoculation of a single probiotic strain did not confer protection against APEC strains in broilers. The high prevalence of MDR isolates indicates that further research on antibiotic alternatives is required to prevent APEC infections in broilers.

In ovo injection of black cumin (Nigella sativa) extract on hatching and post hatch performance of thermally challenged broiler chickens during incubation

The objective of this study was to investigate the effects in ovo injection of black cumin (BC) extract on chick's quality and response of thermally challenged broiler chickens. A total of 700 hatching eggs of broiler chickens (Marshall) were assigned to 7 treatments of 100 eggs each and incubated using the conventional protocol (37.8°C) for the first 10 d and then exposed to a high temperature (39.6°C) for 6 h daily from day 10 until day 18 of the incubation. At embryonic day 17.5, the eggs were randomly allotted to 7 treatment groups, viz.: eggs without in ovo injection (WA), eggs injected with 0.9% saline solution (SA), 3 mg ascorbic acid (AA), 2 mg BC (TB), 4 mg BC (FB), 6 mg BC (SB), and 8 mg BC (EB) extracts. Experiment was laid out in a Completely Randomized Design. After hatching, the chicks were reared separately according to in ovo treatments for 8 wk. Data were collected on hatchability, chick quality, internal organs, growth performance, plasma superoxide dismutase, malondialdehyde, and triiodothyronine (T3). The results showed that the hatchability of the eggs in the AA group was similar to that of SB eggs and higher than that of the other treatment groups. The intestinal weights of SB and EB birds were significantly higher (P < 0.05) than those of TB, SA, and WA. The final weights of the birds of SB and AA were higher (P < 0.05) than those of other treatments. The feed conversion ratio of the birds of TB and FB was comparable to that of EB and WA but higher than that of SB and AA. At hatch, the creatinine of the birds in SA and WA was similar to that of EB, FB, and TB but higher (P < 0.05) than that of AA and SB. Also, the plasma malondialdehyde, T3, and superoxide dismutase of SB and AA birds were better (P < 0.05) than those of the control groups. Overall, it was concluded that 6 mg of BC extract improved the antioxidant status and posthatch performance of thermally challenged broiler chickens.

In ovo corticosterone administration alters body composition irrespective of arginine supplementation in 35-day-old female chicken meat birds

Context Exposure to maternal hormones can permanently alter an embryo’s developmental trajectory. Maternal mediated effects have significant potential in the chicken meat industry, as breeder hens are feed restricted in a bid to improve performance. Evidence suggests breeder hens are chronically stressed, resulting from periods of prolonged hunger. However, evidence linking embryonic exposure to early-life stress and altered offspring phenotype in meat chickens is lacking. Additionally, methods to alleviate the phenotypic consequences of early-life stress have not been comprehensively explored. Nutritional supplementation with amino acids, such as arginine (Arg), may provide one such option, as Arg reportedly enhances performance characteristics in chicken meat birds. Aims An in ovo study was conducted to investigate whether exposure to in ovo stress altered offspring performance in meat chickens. Additionally, Arg was supplemented post-hatch to alleviate reductions in performance, hypothesised to occur as a result of exposure to corticosterone. Method A total of 400 eggs were divided into two groups and administered a corticosterone (CORT) or control (CON) solution at embryonic Day 11. At hatch, birds were separated into four groups based on in ovo and dietary treatments: CORT-Control, CORT-Arg, CON-Arg and CON-Control. Birds fed supplementary Arg diets received an Arg:lysine inclusion of 125%. Bodyweight (bwt) and feed conversion were recorded weekly. Birds were euthanised at embryonic Day 15, Day 0, 7, 21 (n = 40 birds/time point), 28 and 35 (n = 48 birds/time point) for organ collection. A total of 12 additional female birds were euthanised and subjected to a dual-energy X-ray absorptiometry scan for body composition at Day 35. Results Neither in ovo nor diet treatments influenced bwt, bwt gain, feed conversion or plasma corticosterone at any time point, nor did any in ovo by diet interaction exist. Female birds exposed to CORT exhibited significantly greater fat mass (%bwt; P = 0.007) and reduced lean mass (%bwt; P = 0.026) compared with CON females at Day 35. Supplementary Arg did not influence bird body composition. Conclusions These findings suggest in ovo exposure to CORT may negatively influence body composition of female birds. Implications Understanding the effects of the maternal/in ovo environment may provide a novel approach to further improve carcass quality and flock uniformity.

Effect of in ovo application of hydroxyapatite nanoparticles on chicken embryo development, oxidative status and bone characteristics

ABSTRACT Intensive selection in modern lines of fast-growing chickens has caused several skeletal disorders. Therefore, current research is focused on methods to improve the bones of birds. A new potential solution is in ovo technology using nanoparticles with a high specificity for the bone tissue. Thus, the objective of the present study was to evaluate the effect of in ovo application of hydroxyapatite nanoparticles (HA-NP) in different concentrations (50, 100 and 500 μg/ml colloids) on chicken embryo development, with a particular focus on the oxidative status and bone characteristics of the embryo. The results showed that in ovo treatment with HA-NP did not negatively affect hatchability and body weight. However, bone weight was reduced in 500 μg/ml group. The concentrations of calcium, phosphorus and crude ash were not affected. The modulatory effect of HA-NP was observed on the basis of antioxidative markers – superoxide dismutase, total antioxidant status, malondialdehyde in serum and selected tissues. Glutathione concentration in serum suggested higher metabolic stress. Among bone turnover markers, the concentration of osteocalcin was found to be significantly affected by HA-NP injection. Thus, the in ovo application of HA-NP could modify the molecular responses at the stage of embryogenesis but these changes were not reflected in embryo growth and even slowed down bone development. Nevertheless, the question for the follow-up research is whether in ovo administration of HA-NP would affect the antioxidative status and bone turnover resulting in improved bone conditions and body gain in post hatch chickens.

Effect of galactooligosaccharides delivered in ovo on meat quality traits of broiler chickens exposed to heat stress

A study was carried out to evaluate meat quality traits in fast-growing chickens stimulated in ovo with trans-galactoolighosaccarides (GOS) and exposed to heat stress. On day 12 of egg incubation, 3,000 fertilized eggs (Ross 308) were divided into prebiotic group (GOS) injected with 3.5 mg GOS/egg, saline group (S) injected with physiological saline, and control group (C) uninjected. After hatching, 900 male chicks (300 chicks/treatment) were reared in floor pens in either thermoneutral (TN; 6 pens/group, 25 birds/pen) or heat stress conditions (HS, 30°C from 32 to 42 D; 6 pens/group, 25 birds/pen). At 42 D of age, 15 randomly chosen birds/treatment/temperature were slaughtered and the pectoral muscle (PM) was removed for analyses. Data were analyzed by GLM in a 3 × 2 factorial design. In ovo treatment had no effect on PM weight, pH, water-holding capacity, and shear force. GOS and S birds had lighter (L*, P < 0.01) PM than C group, whereas the latter showed a higher (P < 0.05) yellowness index (b*) compared to S group. Proximate composition, cholesterol, and intramuscular collagen properties were not affected by treatment. As for fatty acid composition, only total polyunsaturated fatty acids (PUFA) content and n-6 PUFA were slightly lower in GOS group compared to S. Heat stress had a detrimental effect on PM weight (P < 0.01) and increased meat pH (P < 0.01). PM from HS chickens was darker with a higher b* index (P < 0.05) and had a higher (P < 0.01) lipid content and a lower (P < 0.05) total collagen amount. Total saturated fatty acids (SFA), monounsaturated fatty acids (MUFA), and PUFA were similar among groups. Significant interactions between factors were found for fatty acid composition: GOS decreased (P < 0.01) SFA and increased (P < 0.05) MUFA contents in HS birds. In conclusion, in ovo injection of GOS could mitigate the detrimental effect of heat stress on some meat quality traits.

In ovo Injection of a Galacto-Oligosaccharide Prebiotic in Broiler Chickens Submitted to Heat-Stress: Impact on Transcriptomic Profile and Plasma Immune Parameters.

Simple SummaryGalactooligosaccharides (GOS) delivered in ovo stimulate development of indigenous microflora in the chicken embryo. Such stimulation may create a eubiotic environment in the guts which positively influences intestinal function and health. This study aimed to evaluate the impact of GOS delivered in ovo on the modulation of the transcriptomic responses in the intestinal tissues of broiler chickens challenged (or not challenged) with heat in the last growing phase. GOS stimulated several groups of genes in jejunum and in cecum independently of the heat stress provision. A general favourable effect of GOS was recognized due to the enrichment of energetic metabolism-related gene sets, mainly in jejunum. The enrichment of lipid metabolism-related gene sets in the GOS group might have contributed to gut function and barrier maintenance, which might also be linked to a reduced immune system activation, mainly at cecum level. The heat stress impaired gut functions in terms of energy and immunity, in agreement with previous studies. Under heat stress condition, the in ovo injection of GOS did not provide additional benefits to the intestinal transcriptomic response.This study investigated the effects of a galactooligosaccharide (GOS) prebiotic in ovo injected on intestinal transcriptome and plasma immune parameters of broiler chickens kept under thermoneutral (TN) or heat stress (HS) conditions. Fertilized Ross 308 eggs were injected in ovo with 0.2 mL physiological saline without (control, CON) or with 3.5 mg of GOS (GOS). Three-hundred male chicks/injection treatment (25 birds/pen) were kept in TN or HS (30 °C) conditions during the last growing phase, in a 2 × 2 factorial design. At slaughter, from 20 birds/injection group (half from TN and half from HS), jejunum and cecum were collected for transcriptome analysis, and plasma was collected. No differences in plasma parameters (IgA and IgG, serum amyloid) and no interaction between injection treatment and environment condition were found. GOS-enriched gene sets related to energetic metabolism in jejunum, and to lipid metabolism in cecum, were involved in gut barrier maintenance. A homogeneous reaction to heat stress was determined along the gut, which showed downregulation of the genes related to energy and immunity, irrespective of in ovo treatment. GOS efficacy in counteracting heat stress was scarce after ten days of environmental treatment, but the in ovo supplementation modulates group of genes in jejunum and cecum of broiler chickens.