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Background: Rabbits are well-domesticated animals. As a crucial economic animal, rabbit has been successfully bred into wool-use, meat-use and fur-use breeds. Hair length is one of the most economically important traits affecting profitability in wool rabbits. In this study, to identify selection signatures with the long-hair trait, whole-genomic resequencing of long-haired rabbits (Angora rabbits) and short-haired rabbits (Rex and New Zealand rabbits) was performed. Results: By genome-wide selective sweeping analysis based on population comparison, we identified a total of 5.85 Mb regions (containing 174 candidate genes) with strong selection signals. Six of these genes (Dusp1, Ihh, Fam134a, Map3k1, Spata16, and Fgf5) were enriched in the MAPK signalling and Hedgehog signalling pathways, both of which are closely associated with hair growth regulation. Among these genes, Fgf5 encodes the FGF5 protein, which is a well-established regulator of hair growth. There was a nonsynonymous nucleotide substitution (T19234C) in the Fgf5 gene. At this locus, the C allele was present in all of the tested Angora rabbits, while the T allele was dominant in New Zealand and Rex rabbits. We further confirmed that the C allele was conserved in Angora rabbits by screening an additional 135 rabbits. Moreover, the results of functional predictions and co-immunoprecipitation revealed that the T19234C mutation impaired the binding capacity of FGF5 to its receptor FGFR1. Conclusions: We discovered that the homozygous missense mutation T19234C within Fgf5 might contribute to the long-hair trait of Angora rabbits by reducing its receptor binding capacity. This finding will provide new insights into the genetic basis underlying the genetic improvement of Angora rabbits and benefit the improvement of rabbit breeding in the future. [ABSTRACT FROM AUTHOR]

Plasma lipid and glucose levels are important parameters for evaluating the onset and development of metabolic and cardiovascular diseases. In clinical and experimental studies of humans or mice, fasting is often required before testing plasma lipid and glucose levels. The rabbit is a valuable animal model for cardiovascular disease research. However, whether fasting is necessary for measuring plasma lipid and glucose levels in rabbits remains unclear. In the current study, 12 healthy Japanese white rabbits (males weighing 2.5–3.0 kg) were randomly divided into a chow diet group (n = 6) and a high cholesterol diet group (n = 6). They were fed either a standard chow diet or a chow diet supplemented with 0.5% cholesterol and 3% corn oil for 12 weeks. After 12 weeks, the plasma levels of total cholesterol, triglycerides, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol and glucose were measured before and after various fasting durations (8, 12, 16, 20 and 24 h). The results showed that there were no significant differences in lipid levels between the fasting and non-fasting samples, whereas glucose levels were lower after 8 h of fasting than in the absence of fasting. Moreover, the glucose levels were restored to normal after 8 h of refeeding. These results indicate that fasting does not affect plasma lipid values in rabbits but that fasting is important for determining the glucose level in rabbits. These findings may be helpful for future rabbit experiments and beneficial for animal welfare. [ABSTRACT FROM AUTHOR]

Rabbits (Oryctolagus cuniculus) are one of the most widely used animal models for the study of human lipid metabolism and atherosclerosis because they are more sensitive to a cholesterol diet than other experimental animals such as rodents. Currently, two hypercholesterolemic rabbit models are frequently used for atherosclerosis studies. One is a cholesterol-fed wild-type rabbit and the other is the Watanabe heritable hyperlipidemic (WHHL) rabbit, which is genetically deficient in low density lipoprotein (LDL) receptor function. Wild-type rabbits can be easily induced to develop severe hypercholesterolemia with a cholesterol-rich diet due to the marked increase in hepatically and intestinally derived remnant lipoproteins, called β-very low density lipoproteins (VLDL), which are rich in cholesteryl esters. WHHL rabbits are characterized by elevated plasma LDL levels on a standard chow diet, which resembles human familial hypercholesterolemia. Therefore, both rabbit models develop aortic and coronary atherosclerosis, but the elevated plasma cholesterol levels are caused by completely different mechanisms. In addition, cholesterol-fed rabbits but not WHHL rabbits exhibit different degrees of hepatosteatosis. Recently, we along with others have shown that there are many differentially expressed genes in the atherosclerotic lesions and livers of cholesterol-fed rabbits that are either significantly up- or down-regulated, compared with those in normal rabbits, including genes involved in the regulation of inflammation and lipid metabolism. Therefore, dietary cholesterol plays an important role not only in hypercholesterolemia and atherosclerosis but also in hepatosteatosis. In this review, we make an overview of the recent progress in genomic and transcriptomic analyses of hypercholesterolemic rabbits. These transcriptomic profiling data should provide novel insight into the relationship between hypercholesterolemia and atherosclerosis or hepatic dysfunction caused by dietary cholesterol. [ABSTRACT FROM AUTHOR]