This study was conducted to investigate the effect of weaning age on growth performance, nutrient digestion and metabolism, and serological indicators, and to obtain an optimal weaning age in Hu lambs.Forty-eight newb...This study was conducted to investigate the effect of weaning age on growth performance, nutrient digestion and metabolism, and serological indicators, and to obtain an optimal weaning age in Hu lambs.Forty-eight newborn Hu lambs(birth weight, 2.53 ± 0.14 kg) were randomly divided into 4 groups. The lambs in control group(ER) suckled their dams. The lambs in other three experimental groups were weaned on milk replacer at 10.20, and 30 days of age(EW10, EW20, and EW30 groups),respectively. The results were as follows: 1) lambs in EW10 and EW30 groups had a lower(P < 0.05) ADG than those in ER group within 10 days post-weaning; the weaned lambs began to show a higher(P < 0.05) ADG than those in ER group after 20 days post-weaning. 2) EW10 and EW20 groups had a higher(P < 0.05) creep feed intake than EW30 and ER groups from 15 to 60 days of age. 3) The apparent digestibility of dry matter, organic matter, gross energy, nitrogen, ether extract and phosphorus, and the deposition of nitrogen and phosphorus did not differ(P > 0.05) among groups; however, the apparent digestibility and deposition of calcium in early weaned lambs were lower(P < 0.05) than those in ewe-reared lambs. 4)The albumin content in EW30 group was lower(P < 0.05) than that in ER group; the globulin content in EW30 group was higher(P < 0.05) than that in other groups; the content of serum insulin-like growth factor-1 in weaned lambs tended to increase compared with lambs in ER group. Finally, the growth rate of lambs decreased within 10 days post-weaning, but early weaning boosted creep feed intake, leading to better growth and health later in life. The Hu lambs can be weaned on milk replacer and creep feed at 10 days of age.展开更多
DNA methylation is one of the main epigenetic phenomena affecting gene expression.It is an important mechanism for the development of embryo,growth and health of animals.As a key nutritional factor limiting the synthe...DNA methylation is one of the main epigenetic phenomena affecting gene expression.It is an important mechanism for the development of embryo,growth and health of animals.As a key nutritional factor limiting the synthesis of protein,methionine serves as the precursor of S-adenosylmethionine(SAM) in the hepatic one-carbon metabolism.The dietary fluctuation of methionine content can alter the levels of metabolic substrates in one-carbon metabolism,e.g.,the SAM,S-adenosylhomocysteine(SAH),and change the expression of genes related to the growth and health of animals by DNA methylation reactions.The ratio of SAM to SAH is called ‘methylation index' but it should be carefully explained because the complexity of methylation reaction.Alterations of methylation in a specific cytosine-guanine(Cp G)site,rather than the whole promoter region,might be enough to change gene expression.Aberrant methionine cycle may provoke molecular changes of one-carbon metabolism that results in deregulation of cellular hemostasis and health problems.The importance of DNA methylation has been underscored but the mechanisms of methionine affecting DNA methylation are poorly understood.Nutritional epigenomics provides a promising insight into the targeting epigenetic changes in animals from a nutritional standpoint,which will deepen and expand our understanding of genes,molecules,tissues,and animals in which methionine alteration influences DNA methylation and gene expression.展开更多
It is well known that phenotype of animals may be modified by the nutritional modulations through epigenetic mechanisms. As a key and central component of epigenetic network, DNA methylation is labile in response to n...It is well known that phenotype of animals may be modified by the nutritional modulations through epigenetic mechanisms. As a key and central component of epigenetic network, DNA methylation is labile in response to nutritional influences. Alterations in DNA methylation profiles can lead to changes in gene expression, resulting in diverse phenotypes with the potential for decreased growth and health.Here, I reviewed the biological process of DNA methylation that results in the addition of methyl groups to DNA; the possible ways including methyl donors, DNA methyltransferase(DNMT) activity and other cofactors, the critical periods including prenatal, postnatal and dietary transition periods, and tissue specific of epigenetic modulation of DNA methylation by nutrition and its mechanisms in animals.展开更多
基金supported by the Special Fund for Agro-scientific Research in the Public Interest(201303143)China Scholarship Council Fund(201403250010)
文摘This study was conducted to investigate the effect of weaning age on growth performance, nutrient digestion and metabolism, and serological indicators, and to obtain an optimal weaning age in Hu lambs.Forty-eight newborn Hu lambs(birth weight, 2.53 ± 0.14 kg) were randomly divided into 4 groups. The lambs in control group(ER) suckled their dams. The lambs in other three experimental groups were weaned on milk replacer at 10.20, and 30 days of age(EW10, EW20, and EW30 groups),respectively. The results were as follows: 1) lambs in EW10 and EW30 groups had a lower(P < 0.05) ADG than those in ER group within 10 days post-weaning; the weaned lambs began to show a higher(P < 0.05) ADG than those in ER group after 20 days post-weaning. 2) EW10 and EW20 groups had a higher(P < 0.05) creep feed intake than EW30 and ER groups from 15 to 60 days of age. 3) The apparent digestibility of dry matter, organic matter, gross energy, nitrogen, ether extract and phosphorus, and the deposition of nitrogen and phosphorus did not differ(P > 0.05) among groups; however, the apparent digestibility and deposition of calcium in early weaned lambs were lower(P < 0.05) than those in ewe-reared lambs. 4)The albumin content in EW30 group was lower(P < 0.05) than that in ER group; the globulin content in EW30 group was higher(P < 0.05) than that in other groups; the content of serum insulin-like growth factor-1 in weaned lambs tended to increase compared with lambs in ER group. Finally, the growth rate of lambs decreased within 10 days post-weaning, but early weaning boosted creep feed intake, leading to better growth and health later in life. The Hu lambs can be weaned on milk replacer and creep feed at 10 days of age.
基金supported by the Special Fund for Agro-scientific Research in the Public Interest (Grant No.:201303143) from the Ministry of Agriculture of the People's Republic of China
文摘DNA methylation is one of the main epigenetic phenomena affecting gene expression.It is an important mechanism for the development of embryo,growth and health of animals.As a key nutritional factor limiting the synthesis of protein,methionine serves as the precursor of S-adenosylmethionine(SAM) in the hepatic one-carbon metabolism.The dietary fluctuation of methionine content can alter the levels of metabolic substrates in one-carbon metabolism,e.g.,the SAM,S-adenosylhomocysteine(SAH),and change the expression of genes related to the growth and health of animals by DNA methylation reactions.The ratio of SAM to SAH is called ‘methylation index' but it should be carefully explained because the complexity of methylation reaction.Alterations of methylation in a specific cytosine-guanine(Cp G)site,rather than the whole promoter region,might be enough to change gene expression.Aberrant methionine cycle may provoke molecular changes of one-carbon metabolism that results in deregulation of cellular hemostasis and health problems.The importance of DNA methylation has been underscored but the mechanisms of methionine affecting DNA methylation are poorly understood.Nutritional epigenomics provides a promising insight into the targeting epigenetic changes in animals from a nutritional standpoint,which will deepen and expand our understanding of genes,molecules,tissues,and animals in which methionine alteration influences DNA methylation and gene expression.
基金supported by the Special Fund for Agro-scientific Research in the Public Interest (201303143)the Chinese scholarship council fund (201403250010)
文摘It is well known that phenotype of animals may be modified by the nutritional modulations through epigenetic mechanisms. As a key and central component of epigenetic network, DNA methylation is labile in response to nutritional influences. Alterations in DNA methylation profiles can lead to changes in gene expression, resulting in diverse phenotypes with the potential for decreased growth and health.Here, I reviewed the biological process of DNA methylation that results in the addition of methyl groups to DNA; the possible ways including methyl donors, DNA methyltransferase(DNMT) activity and other cofactors, the critical periods including prenatal, postnatal and dietary transition periods, and tissue specific of epigenetic modulation of DNA methylation by nutrition and its mechanisms in animals.
