PSXV-16 Plasma and tissue abundance of Retinol Binding Protein 4 and body composition of crossbred bulls

• Published in: Journal of animal science 2018-12, Vol.96 (suppl_3), p.239-239
• Main Authors: Albrecht, E, Liu, Y, Yang, R, Maak, S
• Format: Article
• Language: English
• Subjects: Abstracts
• ISSN: 0021-8812; 1525-3163
• DOI: 10.1093/jas/sky404.521

Abstract Retinol deficiency in concentrate rich diets is known to increase body fat deposition in cattle. Retinol is carried through the blood stream to different organs and tissues by retinol binding proteins (RBP), synthesized and secreted primarily in the liver. The current study investigated whether RBP4 abundance in circulation, liver and adipose tissues is also related to fat deposition in cattle. Blood samples of 246 F2-generation bulls of a Charolais x Holstein cross were taken at 250 days of age and at slaughtered with 18 months of age. Fat related traits were determined after slaughter and two groups of 20 bulls each with either high (HCF) or low carcass fat (LCF) were retrospectively assigned. Western blotting and immunohistochemistry were used for detection and quantification of RBP4 in skeletal muscle, adipose and liver tissue, as well as in plasma. Significant correlations between plasma RBP4 abundance at 250 days of age and fat related carcass traits were detected (e.g. r = 0.3; P < 0.001 to carcass fat). Furthermore, plasma RBP4 levels were higher (P < 0.05) in HCF compared to LCF bulls at 250 days of age and at slaughter. Protein and mRNA abundance were increased (P < 0.05) in subcutaneous fat of HCF bulls. Liver, perirenal and omental adipose tissue had similar (P > 0.05) RBP4 expression in both groups. In muscle tissue, RBP4 mRNA abundance was similar (P = 0.33) in both groups, but the protein was not detectable with western blot. It was localized in or close to adipocytes within muscle and in stellate cells in the liver with immunohistochemistry. Our results indicate that the plasma RBP4 level is to some extent predictive for the developing amount of carcass fat of crossbred bulls. Thus, circulating and tissue RBP4 is probably involved in determination of body composition.