Effects of Dietary Restriction on the Expression of Lipid Metabolism and Growth Hormone Signaling Genes in the Longissimus dorsi Muscle of Korean Cattle Steers.

H J Kang,M Baik,N H Trang

doi:10.5713/ajas.15.0056

Abstract

This study determined the effects of dietary restriction on growth and the expression of lipid metabolism and growth hormone signaling genes in the longissimus dorsi muscle (LM) of Korean cattle. Thirty-one Korean cattle steers (average age 10.5 months) were allocated to normal (N; n = 16) or dietary restriction (DR; n = 15) groups. The feeding trial consisted of two stages: for the 8-month growing period, the DR group was fed 80% of the food intake of the normal diet, and for the 6-month growth-finishing period, the DR group was fed a DR total mixed ration with 78.4% of the crude protein and 64% of the net energy for gain of the normal diet. The LM was biopsied 5 months (period 1 [P1] at 15.5 months of age) and 14 months (period 2 [P2] at 24.5 months of age) after the start of feeding. The mRNA levels were determined using real-time polymerase chain reaction. Body weight, daily feed intake, average daily gain, and feed efficiency were lower in the DR group compared with the normal group at both P1 and P2. At P1, the lipogenic fatty acid synthase (FASN) mRNA levels were lower (p<0.05) in the DR group compared with the normal group. The DR group tended (p = 0.06) to have higher of levels of growth hormone receptor (GHR) mRNA than the normal group. At P2, the DR group tended to have lower (p = 0.06) androgen receptor (AR) mRNA levels than the normal group. In conclusion, our results demonstrate that dietary restriction partially decreases the transcription of lipogenic FASN and growth hormone signaling AR genes, but increases transcription of the GHR gene. These changes in gene transcription might affect body fat accumulation and the growth of the animals.

Highlights

Gene expression is determined by both genetic and environmental factors, and the optimum environmental factors maximize the genetic potential of animals
Nutritional status exerts a major influence on lipid metabolism and growth hormone (GH) signaling, and the transcriptional regulation of the genes involved in these pathways is important
This study determined the effects of dietary restriction on the growth performance and expression of genes for lipid metabolism and GH signaling in the longissimus dorsi (LM) muscle of Korean cattle

Summary

INTRODUCTION

Gene expression is determined by both genetic and environmental factors, and the optimum environmental factors maximize the genetic potential of animals. Lipid metabolism and adipogenesis are important for body fat deposition, and GH signaling is important for animal growth. Nutritional status exerts a major influence on lipid metabolism and GH signaling, and the transcriptional regulation of the genes involved in these pathways is important. Diet restriction during the early postnatal period in mice delayed growth, altered endocrine. Sci. 28:1187-1193 status affecting energy/lipid metabolism, and altered 9.8% CP/0.72 Mcal/kg NEg. During the growth-finishing expression of the genes involved in the somatotropic axis, stage, the steers in both groups were fed the corresponding including growth hormone-releasing hormone and growth diets ad libitum. Expression of genes for lipid metabolism, adipogenesis, and growth in the muscles of cattle. This study determined the effects of dietary restriction on the growth performance and expression of genes for lipid metabolism and GH signaling in the longissimus dorsi (LM) muscle of Korean cattle. The animals were anesthetized with an i.m. injection of 1 mL of Rompun

MATERIALS AND METHODS

RESULTS AND DISCUSSION

Growth hormone signaling genes