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Maternal nutrition during gestation is a leading factor of modifying the foetal epigenome and phenotype for mammals. Imprinting genes have important roles in regulating foetal growth, programming and development. There, however, are limited data available on the effects of feed intake restriction on the expression of imprinting genes in pregnant goats. The present study, therefore, was conducted to assess the effects of maternal feed intake restriction on the relative abundance of mRNA for growth imprinting, DNA methyltransferase (DNMT) and epigenetic transcription-related genes in the liver and heart of foetal goats during gestation. A total of 24 Liuyang black goats (2.0±0.3 yr) with similar body weight (BW, 31.22±8.09 kg) and parity (2) were allocated equally to either a control group (CG) or a restriction group (RG) during both early (from 26 to 65 days) and late (from 96 to 135 days) gestation. All goats were fed a mixed diet and had free access to fresh water. The feed of the RG was 40% less than that of the CG. The early and late gestation goats were weighed, bled and slaughtered on days 65 and 135 of gestation, respectively. In early gestation, the foetal weight, body length, the weight of foetal heart and liver were greater (P 0.05) in the RG. The CpG methylation of genomic DNA in the foetal heart was less (P = 0.0001) in the RG. The relative abundance of mRNA of methyl-CpG-binding domain protein 2 (MBD2) and methyl-CpG-binding domain protein 3 (MBD3) genes in the foetal liver were greater (P 0.05) in the RG. During the late gestation, the foetal weight, heart weight and liver weight were less (P 0.05) in the RG. The relative abundance of mRNA for the MBD2 gene (P = 0.043) in the foetal heart, and the ten-eleven translocation protein 1 (TET1) gene (P 0.05) in both the foetal heart and liver were greater in the RG. These results indicate feed intake restriction during gestation influenced foetal development and regulated the relative abundance of mRNA for epigenetic transcription-related genes.

Carcass attributes of steers were examined for influences of selection for residual feed intake (RFI), and exposure to different levels of prenatal nutrition. Heifers characterized for RFI corrected for backfat were mated to bulls with genetic potential for either High-RFI or Low-RFI, such that the progeny were expected to be H/H or L/L RFI (sire/dam). Pregnant heifers were assigned to a low diet (Ldiet; 0.40 kg/d ADG), or moderate diet (Mdiet; 0.57 kg/d ADG), from 30 to 150 days of gestation, after which all heifers were managed similarly. Steer offspring (n = 23) were also managed similarly until slaughter. Dressing percentage of steers from H-RFI dams/sires exposed to Ldiet during gestation was lower than all other groups (P = 0.02). Marbling was greater for steers from H-RFI parents, as was fat content of longissimus thoracis et lumborum and triceps brachii (P ≤ 0.02). Results suggest that parental selection for RFI and prenatal maternal diet can influence carcass characteristics of progeny.

Approximately 70% of the cost of beef production is impacted by feed utilization. Maximizing production efficiency of beef cattle requires not only genetic selection to maximize feeding efficiency (i.e. residual feed intake - RFI), but also adequate nutrition throughout all stages of growth and development to maximize productivity of growth and reproductive capacity, even during gestation. Nutrient restriction during gestation has been shown to negatively affect post-natal growth and development. This, when combined with efforts to minimize RFI, may significantly affect energy partitioning in the offspring and subsequently important performance traits. Therefore, we decided to investigate the impacts of prenatal under-nutrition during the first half of gestation, as well as selection for divergent RFI, upon gene expression in select tissues, including Longissimus thoracis (LT) and semimembranosus (SM) muscles, liver, and testis, in Angus bull progeny. The genes monitored in this study included metabolic drivers of animal growth, especially muscle growth and development, and those that were aspects of detoxification/immune function. The results showed that the mRNA abundance of protocadherin 19 [PCDH19] in liver, and myocyte enhancer factor 2A [MEF2A] in LT muscle, was significantly higher in Low-diet (Ldiet), and Normal-diet (Ndiet) prenatal maternal diet groups, respectively. The results also showed that in all four tissues, expression of MEF2A was significantly higher in the Low-RFI (LRFI) group as compared to its High-RFI (HRFI) counterpart. We also reported correlations between gene expression in these four tissues with phenotypic measures of feed efficiency and body weight.