Bibliographical Mapping of Research into the Relationship between In Ovo Injection Practice and Hatchability in Poultry

Recent advances in poultry practice have produced new tools enabling the poultry industry to increase productivity. Aiming at increasing production quality, varying protocols of in ovo injection facilitate the introduction of exogenous substances into the egg to complement the nutrients that support embryonic development up to hatching, which are already available in the internal and external compartments. Due to embryonic sensitivity, adding any substance into the egg can be either advantageous or disadvantageous for embryonic survival and can influence hatch rates. Thus, understanding the relationship between poultry practices and production rates is the first step towards successful commercial application. This review aims to assess the influence on hatch rates of injecting different substances in ovo, including effects on embryo and chick health parameters where these are reported. Bibliographic mappings of co-authorship of citations, co-occurrence of keywords, and bibliographic coupling based on the in ovo injection technique and hatchability parameters were also performed. Using the Scopus database, 242 papers were retrieved, reviewed, and submitted for bibliographic mapping using the VOSviewer^® software. This review provides a broad overview of just over 38 years' research on the subject, revealing that studies have significantly increased and peaked in 2020, being produced primarily by US researchers and published primarily in the journal Poultry Science. It also reveals that despite negative reports relating to some substances in the embryo, in ovo delivery of substances may possibly change the poultry industry for the better in terms of production rates (hatchability) and/or poultry health.

Effect of Muscle Extract and Graphene Oxide on Muscle Structure of Chicken Embryos

Simple Summary

Genetic selection of broilers increased muscle growth; however, very fast growth can lead to pathological conditions caused by the deficiency of nutrients. The number of muscle cells is mainly formed during the embryonic period, and consequently, in ovo supplementation of proteins to embryos may impact future muscle structure. We hypothesized that proteins from chicken embryo muscle extract (CEME) caused by the unique, natural composition and biocompatibility can supply additional proteins. However, supplemented proteins are actively metabolized, which may reduce their utilization for improved muscle synthesis. Nevertheless, CEME can be transported and protected by graphene oxide (GO). The objective of the present work was to investigate the effects of in ovo-injected CEME and the complex of GO-CEME on embryonic cell cultures and the growth of chicken embryo hind limb muscle. Toxicity and cell proliferation were measured in vitro with cell cultures and mortality, morphology, histology, and blood biochemistry in vivo with embryos. CEME increased the number of cells and nuclei in muscle, but the complex GO-CEME did not further improve the muscle structure. The results indicate a vital role of CEME as in ovo enhancer of muscle development in broilers.

Abstract

The effects of CEME and it complex with GO injected in ovo on the growth and development of chicken embryo hindlimb muscle were investigated. First, the preliminary in vitro study on primary muscle precursor cell culture obtained from a nine-day-old chicken embryo was performed to assess toxicity (MTT assay) of CEME, GO (100 ppm) and it complex with different concentrations (1, 2, 5, and 10 wt.%). The effect on cell proliferation was investigated by BrdU assay. CEME at concentrations 1–5% increased cell proliferation, but not the complex with GO. In vitro cytotoxicity was highest in 10% and GO groups. Next, the main experiment with chicken embryos was performed with CEME, GO and it complex injected in ovo on day one of embryogenesis. On day 20 of embryogenesis survival, morphological development, histological structure of the muscle, and biochemical parameters of blood serum of the embryos were measured. No negative effect on mortality, body weight, or biochemistry of blood after use of CEME or GO-CEME complexes was observed. Interestingly, the slight toxicity of GO, observed in in vitro studies, was not observed in vivo. The use of CEME at the levels of 2% and 5% improved the structure of the lower limb muscle by increasing the number of cells, and the administration of 2% CEME increased the number of nuclei visible in the stained cross-section of the muscle. The complex GO-CEME did not further improve the muscle structure. The results indicate that CEME can be applied as an in ovo enhancer of muscle development in broilers.

Influence of in ovo threonine on growth performance, immunocompetence and carcass characteristics in broiler chickens

The experiment was conducted to investigate the effect of in ovo threonine (Thr) injection on 18th embryonation day at the broad end of the egg using 24G needle on growth performance, organs development, immunocompetence and carcass yield in broiler chickens. Fertile eggs (n=500) were randomly distributed to 5 groups, viz. (i) uninjected control, sham control (0.5 mL sterile water), Thr @15 mg/egg, Thr @30 mg/egg, and Thr @45 mg/egg. Hatchability was better in chicks treated with 45 mg Thr/egg compared to other Thr-injected groups. In ovo Thr injection had quadratic effect on weight gain (WG) and production index at the 2nd and 3rd weeks. Chicks fed 45 mg Thr/egg had better feed conversion ratio (FCR) at 2nd week compared to other groups while feed intake (FI) was not affected. Thr injected chicks had higher thymus weight (d0), bursa weight (d3), spleen weight (d3 and d7) whereas quadratic effect were observed on weights of bursa, thymus and spleen at d21. In ovo Thr administration improved (group-wise, linear or quadratic) the relative weights of gizzard, intestine, and liver at hatch, proventriculus at d7, as well as intestine and liver at d21. No significant difference was recorded for humoral and cell mediated immune response following in ovo Thr injection. Carcass traits of broiler chickens were not influenced by in ovo Thr administration, except breast meat which slightly differs, among the treatment groups. The results of this study suggested that in ovo Thr can improve growth performance, digestive and immune organs development at the early age.

Effects of in ovo feeding of L-lysine on hatchability, hatching time, and early post-hatch development in domestic pigeons (Columba livia)1

This study was conducted to evaluate the effects of in ovo feeding (IOF) of L-lysine (Lys) on hatchability and development in pigeon neonates. At day 13 of incubation, fertile eggs were injected with 200 μL of sterilized saline (0.75%, SC group), 1% Conc. Lys solution (Lys group, 2.11 mg Lys dissolved in 200 μL of sterilized saline), with controls not injected (NC group). The results showed that IOF of Lys decreased the hatchability (P < 0.05) compared with other groups, whereas the hatching time was not affected among groups. On day 14 of post-hatch (D14), the body weight (BW) of squabs received Lys IOF was increased relative to the NC group (P < 0.05). Squabs in Lys group exhibited higher (P < 0.05) body weight gain (BWG) than other groups from D14 to day of hatch (DOH). Meanwhile, IOF of Lys increased the brain relative weight on DOH (P < 0.05), and organ index of heart, legs, and gizzard on day 7 of post-hatch (D7) compared with other groups. In addition, the length index of duodenum, jejunum, or ileum had no difference between groups, as well as the weight index except the weight index of duodenum in Lys group was higher than that of SC group on DOH. However, squabs received Lys IOF showed lower villus height, crypt depth, and villus surface area of jejunum than NC group (P < 0.05) on DOH, and lower crypt depth than NC and SC groups on D7. The situation was improved by D14, although there was no significant difference in morphometric trait of jejunum between Lys group and NC group, squabs received Lys IOF showed higher villus height, crypt depth, and villus surface area of jejunum than NC group. In conclusion, the present study demonstrates that IOF of Lys has negative effects on hatchability and development of early post-hatch squabs, but the situation will be improved with the growth of age.

Effect of In Ovo Injection of L-Arginine in Different Chicken Embryonic Development Stages on Post-Hatchability, Immune Response, and Myo-D and Myogenin Proteins

Simple Summary

In the current study, we hypothesized that the in ovo injection of L-arginine (L-Arg) at different stages of embryonic development, which would have positive effects on the survival rate, hatching rate, immunoglobulin M (IgM) levels, heat shock proteins (HSPs) such as HSP-47, HSP-60, and HSP-70, and muscle development markers as well: Mainly, myoblast determination protein (myoD) and myogenin in pectoral muscles. As indicated, the in ovo injection of L-Arg resulted in an increased hatch rate and weight, survival rate, higher levels of IgM, and myogenin and MyoD expression in the muscles. At the same time, a decrease in the level of HSP-47, HSP-60, and HSP-70 expressions in the tissues was observed on the 14th day of injection compared to the eighth and 18th day of the injection period. In addition, the in ovo injection of L-Arg decreased the serum glutamate oxaloacetate transaminase (SGOT) and serum glutamate pyruvate transaminase (SGPT) concentration in serum as well micronuclei and nuclear abnormality in the blood on the 14th day of the incubation period. Hence, the 14th day would be a suitable day for the injection of L-Arg to promote the hatching rate and muscle growth of broiler chickens.

Abstract

The aim of this study was to evaluate the effect of in ovo injection with different ratios of L-arginine (L-Arg) into Ross broiler eggs at three different embryonic developmental stages (eighth day (d), 14th day, and 18th day) on the survival, hatchability, and body weight (BW) of one-day-old hatched chicks. Additionally, we have analyzed the levels of serum glutamate oxaloacetate transaminase (SGOT) and serum glutamate pyruvate transaminase (SGPT), the protein expression of heat shock proteins (HSPs), and we have also determined micronuclei (MN) and nuclear abnormality (NA). In addition, the genotoxic effect was observed in peripheral blood cells such as the presence of micronuclei and nuclear abnormalities in the experimental groups. The results showed that survival and hatching rates as well as body weight were increased on the 14th day of incubation compared to the eighth and 18th day of incubation at lower concentrations of L-Arg. Moreover, the levels of SGOT and SGPT were also significantly (p < 0.05) increased on the 14th day of incubation at the same concentration (100 μg/μL/egg) of injection. In addition, immunoglobulin (IgM) levels were increased on the 14th day of incubation compared to other days. The protein expressions of HSP-47, HSP-60, and HSP-70 in the liver were significantly down-regulated, whereas the expression of myogenin and myoblast determination protein (MyoD) were significantly up-regulated on the 14th day after incubation when treated with all different doses such as 100 μg, 1000 μg, and 2500 μg/μL/egg, namely 3T1, 3T2, and 3T3, respectively. However, the treatment with low doses of L-Arg down-regulated the expression levels of those proteins on the 14th day of incubation. Histopathology of the liver by hematoxylin and eosin (H&E) staining showed that the majority of liver damage, specifically intracytoplasmic vacuoles, were observed in the 3T1, 3T2, and 3T3 groups. The minimum dose of 100 μg/mL/egg on the 14th day of incubation significantly prevented intracytoplasmic vacuole damages. These results demonstrate that in ovo administration of L-Arg at (100 μg/μL/egg) may be an effective method to increase chick BW, hatch rate, muscle growth-related proteins, and promote the immune response through increasing IgM on the 14th day of the incubation period.

In ovo injection of branched-chain amino acids: Embryonic development, hatchability and hatching quality of turkey poults

In this study, the influence of a branched-chain amino acid blend (BCAA composed of 3 l-leucine:1 l-valine:2 l-isoleucine) injected into the amniotic fluid was evaluated for embryonic growth, yolk-sac (YS) utilization and development of gastrointestinal tract (GIT) and skeletal muscles of turkey embryos from day 24 of incubation (24E) to hatching, together with hatchability, poult quality and liver L* (lightness), a* (redness) and b* (yellowness) values at hatch. At day 22 of incubation, embryonated eggs (n = 240) were assigned to three treatments, that is, eggs were not injected (control, NC) or injected with 1.5 ml sterile solution with 0.9% salt (SA) or 0.2% BCAA blend (BCAAb). These solutions were injected manually into the amniotic fluid of the embryonated eggs. To determine weights and lengths (where appropriate) of the studied organs and tissues, four embryonated eggs and poults per treatment were selected at 24E and at hatch. While the BCAAb decreased the YS and embryo weight, hatchability and the liver L* value, it increased the weight and quality of poults and the weights of breast and thigh muscles at hatch. In conclusion, the in ovo feeding of the BCAA blend negatively affected hatchability but positively affected hatching weight and poult quality by improving development of skeletal muscles and by regulating energy metabolism.

Effects of In Ovo Methionine-Cysteine Injection on Embryonic Development, Antioxidant Status, IGF-I and TLR4 Gene Expression, and Jejunum Histomorphometry in Newly Hatched Broiler Chicks Exposed to Heat Stress during Incubation

Sulfur amino acids are typically the first-limiting amino acids (AA) used in protein metabolism in poultry. Therefore, we hypothesized that their utilization in the pre-hatch period would affect embryonic development, IGF-I and TLR4 gene expression, antioxidant status, serum biochemical profile, and jejunum histomorphometry of newly hatched Ross broiler chicks incubated under heat stress conditions. A total of 150 fertile broiler eggs were subjected to heat stress (39.6 °C for 6 h/d) from d10 until d18 and injected at d 17.5 of incubation with methionine and cysteine (Met-Cys) at a dose of 5.90 mg l-methionine plus 3.40 mg l-cysteine. The effects of Met-Cys administration were examined and compared with the control (Non-injected group) and 0.75% NaCl injected group. The results showed that no significant differences among all groups in serum protein profiles (total protein, albumin, globulin, and albumin/globulin ratio) and creatine kinase were observed. The level of heat shock protein-90 was decreased with Met-Cys In ovo injection. The In ovo injection of Met-Cys also improved the values of total antioxidants capacity and glutathione in examined tissues. At the same time, an increase in fold change mRNA abundance of IGF-I and TLR4 was observed after Met-Cys injection in tested tissues. Finally, an increase of 29% in villus area was found after Met-Cys injection compared to the control group. In conclusion, the In ovo injection of Met-Cys resulted in improved embryonic development, IGF-I and TLR4 gene expression, antioxidant status and jejunum histomorphometry of newly hatched broiler chicks exposed to heat stress during incubation.

Intra-Amnionic Threonine Administered to Chicken Embryos Reduces Salmonella Enteritidis Cecal Counts and Improves Posthatch Intestinal Development

This study assessed the effect of in ovo threonine supplementation on the response of broiler chicks challenged with Salmonella Enteritidis, considering bacterial counts in cecal contents, intestinal morphology, body weight, and weight gain. Fertilized eggs were inoculated in the amniotic fluid with saline (NT) or 3.5% threonine (T) solution at day 17.5 of incubation. At hatch, chicks were individually weighed and cloacal swabs were screened for Salmonella. At 2 days of age, half of the birds from each in ovo treatment were given either 0.5 mL of nutrient broth (sham-inoculated) or nalidixic acid-resistant Salmonella Enteritidis (SE Nal^R) in nutrient broth (8.3 × 10⁷ colony forming units (CFU) SE Nal^R/mL). The birds were distributed using a completely randomized design with four treatments after the Salmonella challenge: no in ovo Thr supplementation and sham-inoculated in the posthatch challenge (NT-SHAM), in ovo Thr supplementation and sham-inoculated (T-SHAM), no in ovo Thr supplementation and SE Nal^R-challenged (NT-SE), and in ovo Thr supplementation and SE Nal^R-challenged (T-SE). In ovo threonine supplementation reduced Salmonella Enteritidis colonization 168-hour postinoculation and reduced the negative effects associated with Salmonella infection on intestinal morphology and performance, with results similar to those of the sham-inoculated birds. In ovo Thr supplementation increased the expression of MUC2 at hatch and the expression of MUC2 and IgA at 2 days of age and 168-hour postinoculation. Our results suggest that providing in ovo threonine promotes intestinal health in broilers challenged with Salmonella Enteritidis in the first days of life.

Comparative effects of in ovo versus subcutaneous administration of the Marek's disease vaccine and pre-placement holding time on the post-hatch performance of Ross 708 broilers1,2,3

Effects of 2 types of methods of administration (moa; in ovo or s.c.) of the Marek's disease (MD) vaccine and 4 and 18 h pre-placement holding times (pht) on the performance of male broilers through 48 d of age were investigated. Ross 708 broiler hatching eggs (3,900) were either in ovo-vaccinated at 18 d of incubation or chicks from eggs that were not in ovo-injected were vaccinated s.c. at hatch, and chicks from each moa group were held for one of the 2 pht. In ovo injections (50 μL) were delivered by a commercial multi-egg injector and s.c. injections (0.2 mL) were delivered by an automatic pneumatic s.c. injector. Sixteen birds were assigned to each of 15 replicate floor pens belonging to each of the 4 moa and pht combination groups. Mortality and BW gain were determined at weekly intervals, and feed consumption and conversion were determined in the zero to 14, 14 to 28, 28 to 42, and 42 to 48 d age intervals. No interactive effects between moa and pht were observed for any variable, and mortality was not significantly affected by moa or pht. The 14 to 28 d feed consumption and 14 to 21 d BW gain of s.c.-vaccinated birds were lower than that of in ovo-vaccinated birds, and the increase in pht from 4 to 18 h decreased feed consumption through 28 d post hatch and BW gain through 35 d post hatch. Overall, the performances of male Ross 708 broilers through 48 d of age in response to in ovo and s.c. injections of the MD vaccine were comparable, and delays in hatchling placement should be less that 18 h in duration. Furthermore, despite the decrease in BW gain through 35 d associated with the reduction in feed consumption through 28 d in response to the 14 h increase in pht, in ovo injection did not exacerbate the effect of the increase in pht.

Response of in ovo administration of zinc on egg hatchability and immune response of commercial broiler chicken

An experiment was conducted to determine the effect of in ovo administration of different forms of zinc with respect to hatchability and performance of commercial broiler chicken. In trial 1, the fertile eggs on day 18 were divided into six treatment groups: Group I as control without any supplementation of zinc, group II to IV were supplemented with 0.5 mg zinc per egg as zinc sulphate, zinc methionine or nano zinc, respectively, and Group V with nano zinc at 0.25 mg zinc per egg. Sixth group received 0.5 ml citric acid per egg as sham control. The results of the first trial indicated that in ovo administration of nano zinc at both levels and zinc methionine resulted in complete failure of hatchability. A second trial to validate the result of trial 1 consisted of Group I control (no administration). Group II and Group III were supplemented with zinc sulphate and zinc methionine, respectively, at 0.5 mg zinc per egg. Group IV and Group V were supplemented with nano zinc at 0.04 and 0.08 mg per egg. In the second trial, again there was a similar pattern for zinc sulphate and zinc methionine. Administration of Zn by nano form had around 80% hatchability on fertile eggs in comparison with the unadministered control eggs (92%). There was no difference (p > .05) in body weight gain, feed intake and FCR. No difference (p > .05) was observed between treatments for cell-mediated immune response and humoral immune response. Nano Zn-administered group showed a non-significant downregulation of MUC2 gene. It could be concluded that in ovo administration of higher levels of zinc has to be with caution for the developing embryo of commercial broiler chicken.

Comparative effect of arginine and/or tryptophan in ovo feeding on hatchability percentage, growth performance and economic importance of commercial broiler

In ovo feeding is the administration of exogenous nutrients into the amnion of the late-term avian embryo so that the avian embryo orally consumes the amniotic fluid (primarily water and albumen protein) prior to pipping the air cell. So the study was carried out to find out the effect of in ovo nutrition on post-hatch performances in broilers. Total 700 fertile eggs of Cobb 400 with uniform egg weight were divided into 5 groups: non-injected control, injected control (0.5 ml of 0.9% normal saline), arginine (0.5 ml of 0.5% arginine), tryptophan (0.5 ml of 0.5% tryptophan) and combination (0.25 ml of 0.5% each of arginine and tryptophan); and injected on 18 d of incubation into amnion. On the 21d, 108 chicks were randomly selected from each treatment in total accounting 540 chicks. The hatchability and hatch weight were studied where arginine had shown a highly significant improved hatch weight and placement weight. There was no significant difference in feed efficiency, but cumulative feed intake was higher in tryptophan and combination groups. Body weight and body weight gain had also resulted significantly in arginine fed in ovo groups up to 21d of age. The broiler farm economy index (BFEI) and broiler feed price ratio (BFPR) were best in tryptophan and arginine in ovo fed groups, respectively.

Physico-chemical properties of late-incubation egg amniotic fluid and a potential in ovo feed supplement

Objective

This study explored the physico-chemical properties of late-incubation egg amniotic fluid and a potential in ovo feed (IOF) supplement.

Methods

Amniotic fluid was collected from broiler breeders (Ross 308, 51 weeks and Cobb 500, 35 weeks) on day 17 after incubation. A mixture of high-quality soy protein supplement – Hamlet Protein AviStart (HPA) was serially diluted in MilliQ water to obtain solutions ranging from 150 to 9.375 mg/mL. The mixtures were heat-treated (0, 30, 60 minutes) in a waterbath (80°C) and then centrifuged to obtain supernatants. The amniotic fluid and HPA supernatants were analysed for their physico-chemical properties.

Results

Only viscosity and K⁺ were significantly (p<0.05) different in both strains. Of all essential amino acids, leucine and lysine were in the highest concentration in both strains. The osmolality, viscosity and pCO₂ of the supernatants decreased (p<0.05) with decreasing HPA concentration. Heat treatment significantly (p<0.05) affected osmolality, pH, and pCO₂, of the supernatants. The interactions between HPA concentration and heat treatment were significant with regards to osmolality (p<0.01), pH (p<0.01), pCO₂ (p<0.05), glucose (p<0.05), lactate (p<0.01) and acid-base status (p<0.01) of HPA solutions. The Ca²⁺, K⁺, glucose, and lactate increased with increasing concentration of HPA solution. The protein content of HPA solutions decreased (p<0.05) with reduced HPA solution concentrations. The supernatant from 150 mg/mL HPA solution was richest in glutamic acid, aspartic acid, arginine and lysine. Amino acids concentrations were reduced (p<0.05) with each serial dilution but increased with longer heating.

Conclusion

The values obtained in the primary solution (highest concentration) are close to the profiles of high-protein ingredients. This supplement, as a solution, hence, may be suitable for use as an IOF supplement and should be tested for this potential.

Impact of thermal stress during incubation on gene expression in embryonic muscle of Peking ducks (Anasplatyrhynchos domestica)

Changes in temperature will influence poultry embryonic muscle development. However, little is known about the changes in molecular processes impacted by incubation temperature in avians. In this study, we investigated the effects of increasing the incubation temperature by 1°C from day 11-20 on the embryonic and posthatch skeletal muscle development of the Peking duck, and identified the differentially expressed genes using RNA-seq of leg muscle tissues. The results showed that altering the incubation temperature had immediate and long-lasting effects on phenotypic changes in the embryonic and post-hatching muscle development. It was shown that expression levels of total 1370 genes were altered in muscle tissues by the thermal treatments. The gene ontology (GO) analyses indicated that cellular processes including metabolism, cell cycle, catalytic activity, and enzyme regulatory activity may have involved in the muscle mass impacted by thermal manipulation. TGF-beta and insulin pathways as two classical muscle development related pathways may also involve in regulating muscle mass. These data may be helpful for understanding the physiological and biochemical processes of muscle development under environmental treatments in embryonic avians.