The Effects Of In Ovo Feeding On The Energy Metabolism, Hatchability, Protein Status And Perinatal Growth Performance In Ducks

The course of late pre-hatch and early post-hatch growth (perinatal growth) in ducks involves major changes in the energy and protein substrate utilization and may be susceptible to complex metabolic distresses that can adversely affect future growth and developmental potential, both at pre-and stages.The present research was intended to explore the effects of the supplementation of 23 day old duck embryos with carbohydrates and arginine on energy metabolism, hatchability, protein status and perinatal growth in the late-term duck embryos and neonates.For this purpose, six hundred fifty fertile eggs were randomly divided into 5 groups having 130 eggs each:1) Uninjected control;2) sodium chloride (NaCl);3)sucrose+ maltose (CHO);4) arginine (Arg);5)sucrose+maltose+arginine (CHO+Arg).All in ovo feeding solutions were prepared in a 0.35% NaCl.The controls were uninjected and subjected to standard hatchery and laboratory protocols.In ovo feeding of NaCl was purposed to test the effect of the in ovo feeding nutrients CHO, Arg and CHO+Arg, prepared in a 0.35% NaCl solution. At 23 days of incubation,1.2 ml of all the solutions was injected into amniotic fluid of each group using a 22 gauge needle (attached to a 10 mL syringe).Ten eggs/ducklings per treatment were sampled at 25 days of incubation, at hatch,3 and 7 days of age to determine liver and muscle glycogen levels and hepatic glucose-6-phosphatase activity. Relative pectoral muscle p70S6K1 and AMPKa expression was performed with the B-actin activation levels.Hatchability percentages were determined. Body weights of ducklings were measured at hatch,3,7,14,21,28 and 35 days of age.Ducklings were given ad libitum access, throughout the duration of study, to water and efficient diet formulated to meet the nutrient requirements of poultry farming standards NY/T33-2004 in P.R.China. All the experimental procedures involving animals were performed according to the Chinese guidelines on animal experimentation and approved by the Animal Care and Research Ethics Committee of the College of Animal Sciences and Technology, Huazhong Agricultural University, P.R. of China. Furthermore, all biochemical protocols were conducted according to the manufacturer's recommendations in the laboratories of Animal Molecular Nutrition, Department of Animal Nutrition and Feed Science. Experimental data were analyzed using procedures for ANOVA (SAS,1996) probability values of less than 0.05 (P<0.05) were considered statistically significant.Maximal hatchability was found in the treatment (P<0.05) fed with CHO+Arg (93%) followed by Arg(87%),uninjected control (86%), NaCl (74%) and CHO (69%). In ovo feeding Arg and CHO+Arg treatments had enhanced significantly liver glycogen level by 187.85% and 249.42% at hatch (P<0.01) compared to the uninjected treatment. In ovo feeding CHO and CHO+Arg treatments significantly (P<0.01) increased muscle glycogen level by 21.80% and 41.80% at 25 days of incubation over the uninjected treatment, respectively. In ovo feeding of CHO and Arg treatments alone had decreased glucose-6-phosphatase by 40.67% and 29.94% at 25 days of incubation (P<0.01),whereas in ovo feeding NaCl and CHO+Arg increased (P<0.01) glucose-6-phosphatase by 30.2% and 19.79% at hatch in comparison with the uninjected treatment, respectively. At 25 days of incubation, duck embryos in ovo fed Arg and CHO+Arg had 105% and 69.47% greater muscle p70S6Kl activity, while they had 232.87% and 215.06% greater (P<0.01)p70S6K1 phosphorylation than the uninjected treatments, respectively. Similarly, AMPKa activity was significantly increased by 97.22% and 75.92% by in ovo feeding of Arg alone and CHO+Arg treatments over the uninjected treatment at 25 days of incubation, respectively (P< 0.05).At 3 days of age, in ovo feeding of CHO+Arg treatment significantly (P<0.01) increased p70S6K1 activation by 84.74% and phosphorylation 70kDa ribosomal protein S6 kinasel by 81.35% in muscle over the uninjected treatment, respectively. At hatch,3, 7 and 14 days of age, the body weights increased more (P<0.01)in the in ovo feeding treatments if compared with the uninjected. Liver glycogen was positively correlated (r =0.52;P<0.05)with glucose-6-phosphatase activity and (r=0.79;P<0.05) with body weight but negatively correlated (r=-0.63;P<0.05) with muscle glycogen. The results of this study suggest that in ovo supplementation with carbohydrates and arginine may enhance the glycogen and protein reserves, which provide the energy needed for embryo survival and rapid growth, resulting in good duckling performance. Further, this research has established a new technique of perinatal nutrition during the developmental transition from egg yolk to duckling.