Reproductive performance and changes in blood lipids in breeding females and in growing Watanabe Heritable Hyperlipidaemic and New Zealand White rabbits

Abstract

The aim of the study was to compare the reproductive performance of homozygous and heterozygous WHHL and NZW females, to record the changes in blood lipids due to gestation and lactation in the heterozygous WHHL and NZW females, and to investigate the changes in blood lipids from 4 to 11 weeks of age in homozygous and heterozygous WHHL and NZW rabbits. The conception rate of homozygous WHHL females was 14% lower than that of NZW and heterozygous WHHL females. The litter size and the weaning rate of homozygous WHHL females were significantly lower than in NZW and heterozygous WHHL females. In heterozygous WHHL and NZW females the total cholesterol was lower during the gestation and lactation while the triglycerides were higher during the gestation and were the lowest during lactation when compared to the levels at mating. In growing homozygous WHHLs of both sexes the total cholesterol did not change from 4 to 11 weeks of age. The triglycerides remained unchanged in males but decreased in females at 11 weeks of age. At this age the triglycerides were significantly lower in females than in males. In growing heterozygous WHHLs of both sexes the total cholesterol and triglycerides decreased with age. At 11 weeks of age the blood lipids were significantly higher in females than in males. The triglyceride levels in homozygous and heterozygous WHHL males and females were comparable at 4 and 6 weeks of age but significantly lower in heterozygous WHHLs at 11 weeks of age. In growing NZW rabbits of both sexes the blood lipids decreased significantly with age but no sex difference was recorded. The blood lipids in the heterozygous WHHLs of both sexes were higher than in NZWs during weaning. At 11 weeks of age the blood lipids of the males and triglycerides of the females of both strains were comparable. Only the total cholesterol remained higher in heterozygous WHHL females. The decrease with age in blood lipids in growing rabbits should be kept in mind when designing experiments beginning in animals younger than 3 months of age.