Effects of diets supplemented by fish oil on sex ratio of pups in bitch

The present study was conducted to evaluate the effect of fish oil supplementation prior to mating on secondary sex ratio of pups (the proportion of males at birth) in bitches. Sixty five bitches (German Shepherd, n = ۳۵; Husky, n = ۳۰) were enrolled in the study. Bitches (۱۴۰-۱۵۰ days post-estrus) were given ۲% per dry matter intake palm oil and fish oil in the control (n = ۳۳) and treatment (n = ۳۲) groups, respectively. To induce estrus, bitches were received equine chorionic gonadotropin (eCG) administration (۵۰ IU kg-۱) ۳۰ days after nutritional supplementation followed by human chorionic gonadotropin (hCG) administration (۵۰۰ IU per dog) seven days later. Bitches were introduced to dogs of the same breed after hCG administration. The weight of bitches was increased over time (p < ۰.۰۵), but their weight change was not different between two groups (p > ۰.۰۵). The mating rate, pregnancy rate and litter size were not influenced by treatment and breed. Secondary sex ratio was higher in the treatment (۱۰۵/۱۶۴; ۶۴.۰۰%) than in the control (۶۸/۱۴۷; ۴۶.۳۰%) group (p < ۰.۰۵; adjusted odds ratio = ۲.۰۶۸). Moreover, secondary sex ratio was higher in Husky bitches (۸۸/۱۴۱; ۶۲.۴۰%) compared to German Shepherd (۸۵/۱۷۰; ۵۰.۰۰%; p < ۰.۰۵; adjusted odds ratio = ۱.۶۶۱). In conclusion, the present study showed that inclusion of fish oil in the diet of bitches prior to mating could increase the proportion of male pups at birth. In addition, it appears that there might be variation among dog breeds with regard to the sex ratio of offspring.

کلیدواژه ها:

Dog ، n-۳ fatty acids ، Secondary sex ratio