In ovo feeding of creatine pyruvate modulates growth performance, energy reserves and mRNA expression levels of gluconeogenesis and glycogenesis enzymes in liver of embryos and neonatal broilers

Physiological effects of in ovo delivery of bioactive substances in broiler chickens

The poultry industry has improved genetics, nutrition, and management practices, resulting in fast-growing chickens; however, disturbances during embryonic development may affect the entire production cycle and cause irreversible losses to broiler chicken producers. The most crucial time in the chicks' development appears to be the perinatal period, which encompasses the last few days of pre-hatch and the first few days of post-hatch. During this critical period, intestinal development occurs rapidly, and the chicks undergo a metabolic and physiological shift from the utilization of egg nutrients to exogenous feed. However, the nutrient reserve of the egg yolk may not be enough to sustain the late stage of embryonic development and provide energy for the hatching process. In addition, modern hatchery practices cause a delay in access to feed immediately post-hatch, and this can potentially affect the intestinal microbiome, health, development, and growth of the chickens. Development of the in ovo technology allowing for the delivery of bioactive substances into chicken embryos during their development represents a way to accommodate the perinatal period, late embryo development, and post-hatch growth. Many bioactive substances have been delivered through the in ovo technology, including carbohydrates, amino acids, hormones, prebiotics, probiotics and synbiotics, antibodies, immunostimulants, minerals, and microorganisms with a variety of physiological effects. In this review, we focused on the physiological effects of the in ovo delivery of these substances, including their effects on embryo development, gastrointestinal tract function and health, nutrient digestion, immune system development and function, bone development, overall growth performance, muscle development and meat quality, gastrointestinal tract microbiota development, heat stress response, pathogens exclusion, and birds metabolism, as well as transcriptome and proteome. We believe that this method is widely underestimated and underused by the poultry industry.

Effect of in ovo creatine monohydrate on hatchability, post-hatch performance, breast muscle yield and fiber size in chicks from young breeder flocks

Younger broiler breeder flocks produce smaller eggs containing smaller yolks, with potentially lower energy reserves for the developing chick. Creatine is a naturally occurring energy source and is abundant in metabolically active tissues; providing this to chicks in ovo should provide additional energy to improve hatchability and post-hatch growth. Thus, post-hatch performance of male and female chicks hatched from younger breeder flocks supplemented with creatine monohydrate (CrM) in ovo was investigated. Four hundred eggs from Ross 308 breeder hens aged 27 to 29 wk were collected and at d 14 assigned to a treatment group and received 1) no injection, 2) 0.75% saline injection, or 3) 8.16 mg creatine monohydrate in 0.75% saline. At hatch 72 birds (24/treatment) were euthanized and BW, breast muscle, heart and liver weight were obtained, and breast muscle tissue was placed in 10% buffered formalin. Birds were then placed in raised metal pens (24 pens; 10-11 birds/pen; 8 replicates/treatment) and grown to d 42 with BW and pen feed intake measured once a week. At d 42, ninty-six birds were euthanized (2 male and 2 female/pen) and the process occurred as at hatch. Body composition was obtained for 48 birds (2/pen; 1 male,1 female) with a dual energy X-ray absorptiometry (DXA) scanner. Breast muscle tissue was processed for histological analysis and breast muscle fiber parameters were analyzed by ImageJ. While not statistically significant, the CrM treatment group saw an improved hatch rate (CrM: 93.5%, Saline: 88.6%, Control: 88.8%) and reduced early post hatch mortality. Chicks given in ovo CrM had significantly increased creatine concentrations in both liver and heart tissue at hatch compared to those in the saline and control groups. BW, BW gain, and final body composition parameters were not statistically different between treatments and in ovo CrM did not affect breast muscle fiber number or area. The creatine injection likely improved the energy status of the growing embryo resulting in the improved hatch rate but leaving little reserves for post-hatch growth.

In Ovo Feeding of Creatine Pyruvate Increases the Glycolysis Pathway, Glucose Transporter Gene Expression, and AMPK Phosphorylation in Breast Muscle of Neonatal Broilers

This study aims to investigate in ovo feeding (IOF) of creatine pyruvate (CrPyr) on glucose metabolism, hormone concentration, and the 5'-AMP-activated protein kinase (AMPK) pathway in breast muscle of embryos and neonatal broilers. The three treatments were noninjected control, 0.75% NaCl treatment, and 12 mg CrPyr/egg treatment. The solution was injected on the 17.5 day of incubation. At hatch, 120 male broilers from each treatment were chosen for a 7 day feeding trial. Compared with other treatments, CrPyr treated broilers enhanced insulin and thyroxine levels in plasma, adenosine triphosphate (ATP) concentration, hexokinase and pyruvate kinase activities, glucose transporter protein mRNA expressions, as well as protein abundances of phosphor-liver kinase B1 and phosphor-AMPK in breast muscle at hatch. In conclusion, IOF of CrPyr improved the energy status, increased the gene expression of glucose transporter proteins, and facilitated glycolysis in breast muscle, which may be associated with the activated AMPK pathway.