The Improvement Of Maternal Zinc And Selenium Supplementation On The Skeletal Muscle Development Of Their Offspring And The Mechanism

Three experiments were conducted to study the effects of different source and dose of maternal zinc supplementation on skeletal muscle development of the offspring, the effects of different source of maternal selenium supplementation and thermal manipulation during hatch on skeletal muscle development and redox status of the offspring. The genes and proteins which were important for the protein synthesis and degradation were measured looking forward to find out the detailed molecular mechanism by maternal zinc and selenium supplementation.To investigate the effects of different source and dose of maternal zinc supplementation on skeletal muscle development of the offspring,1200Ross308broiler breeders at46-week-old were allocated into5treatments with6replicates of40hens each and fed with diets supplemented with zinc at0,50and300mg/kg from MHA-Zn,50and300mg/kg from ZnSO4respectively for6weeks. Hatching eggs laid during53week of age were incubated. The male offspring from each dietary treatment were divided into14cages of10birds each and fed with two commercial diets with supplemental zinc from ZnSO4at20and70mg/kg to avoid the effects of zinc supplementation in broilers’ diets. Results indicated that with the increase of zinc supplementation in hen’s diet, the zinc levels were significantly elevated in the egg yolk and albumen. The breast muscle fiber width were significantly larger in the broilers by treatment of high levels of zinc supplemented in chikcs’diet and maternal organicn and inorganic zinc supplementation at2and5weeks post-hatch. When the broilers were fed the diets supplemented low levels of zinc, the phosphorylation of AKT Ser473, mTOR Ser2448and FOXO Se256in skeletal muscles of the birds from various dietary treatments at two different age post-hatch were significantly increased compared with the control group. The phosphorylation of AKT, mTOR and FOXO was usually related to protein synthesis and degradation. In conclusion, supplemental zinc into the breeders’diet could increase protein synthesis and decrease protein degradation, which, in turn, enhance breast muscle development of the offspring.To investigate the comparative effects of maternal zinc supplementation from organic versus inorganic source on skeletal muscle development of their offspring,720Ross308broiler breeders at24-week-old were allocated into3treatments with6replicates of40hens each and fed with diets supplemented with zinc at0(Zn/C),100mg/kg from organic zinc (Zn/O) and100mg/kg from inorganic zinc (Zn/I) respectively for8weeks. Hatching eggs laid during34week of age were incubated. The male offspring from each dietary treatment were divided into8cages of14birds each and fed with a commercial diet with supplemental zinc from ZnSO4at20mg/kg. Results indicated that the egg production in1,3and4week were significantly increased by maternal organic zinc supplementation. The zinc concentration in egg yolk and albumen from group Zn/O and Zn/I were significantly enhanced, and the egg yolk and albumen from group Zn/O had the highest zinc deposition. Maternal organic or inorganic zinc supplementation promoted breast muscle yield and zinc content in tibia, increased insulin, IGF-1and Cu-Zn SOD concentration in serum, up-regulated AKT, mTOR, P70S6K mRNA levels, improved the phosphorylation of AKT Ser473, mTOR Ser2448and FOXO Se256in skeletal musclesof the birdsat2and5week post-hatch, while the zinc supplemented into hens’ diet reduced uric acid concentration in serum, down-regulated Atrogin-land MuRFl mRNA levels in skeletal muscle of the offspring at2and5week post-hatch. However, no difference effect of skeletal muscle development post-hatch was observed between organic and inorganic zinc. In conclusion, maternal organic zinc supplementation just improved the zinc deposition in egg, but had no difference effect on breast muscle development of the offspring compared with inorganic zinc.To investigate the the effects of maternal selenium supplementation and thermal manipulation during hatchon skeletal muscle development of the offspring,720Ross308broiler breeders at24-week-old were allocated into3treatments with6replicates of40hens each and fed with diets supplemented with selenium at0,0.5mg/kg from organic selenium and0.5mg/kg from inorganic selenium respectively for8weeks.The eggs in34-week was collected and incubated under standard conditions of37.8℃and56%RH while being turned once per hour, and the TM eggs were exposed from E7to E16(inclusive) to39.5℃and65%RH for12h/d. The male offspring from each dietary treatment were divided into8cages of12birds each and fed with a commercial diet with supplemental selenium from Na2SeO3at0.15mg/kg. Results indicated that the selenium concentration in serum, egg yolk and albumen was significantly increased by treatment of maternal organic and inorganic supplementation, and the egg yolk and albumen by treatment of maternal organic selenium supplementation had the highest selenium deposition. Maternal inorganic selenium improved hatchability of eggs and body weight of the offspring at42d post-hatch. Maternal organic and inorganic selenium increased breast muscle yield of the offspring at2and5week post-hatch. The effects of thermal manipulation on broiler chickens post-hatch included increasing GSH-Px concentration in breast muscle on day35and42, decreasing protein carbonyl concentration in serum and breast muscle on day42, promoting mRNA levels of P70S6K in breast muscle on day14and35and Hsp70in breast muscle on E18and day42, inhibiting gene expression of MuRFl in breast muscle on day14and35, up-regulation the phosphorylation of AKT at Serine473residue and FOXO at Serine256residuein breast muscle on day14and35. The influences of maternal organic and inorganic selenium supplementation on broiler chickens post-hatch contained improving IGF-1concentration in serum on day35and42, increasing GSH-Px concentration in serum, breast muscle and liver on day14, promoting total antioxidantcapacity in serum and breast muscle on day35, enhancing gene expression of mTOR and selenoproteins in breast muscle on day14and35, increasing mRNA level of Hsp70in breast muscle on El8and day42, down-regulation Atrogin-1and MuRFl mRNA levels in breast muscle on day14and35, up-regulation the hosphorylation of AKT Ser473, mTOR Ser2448and FOXO Ser256in breast muscle on day14and35. Therefore, maternal selenium supplementation enhanced skeletal muscle development and prmoted the antioxidant capacity of the offspring, and thermal manipulation just increasd the antioxidant capacity of the offspring.In summary, supplemental zinc and selenium into the breeders’ diet could increase protein synthesis and decrease protein degradation, which, in turn, enhance breast muscle development of the offspring. Maternal organic zinc and selenium supplementation just improved the zinc and selenium deposition in egg, but had no difference effect on breast muscle development of the offspring compared with inorganic zinc and selenium.