Effect of variously-processed rubber seed meals on reproductive performance: The use of Sprague-Dawley laboratory rats as model for pigs

The study aimed to determine the potential adverse effects of variously-processed rubber seed meals on the reproductive performance, postnatal growth and offspring survival rate using the Sprague-Dawley laboratory rat as model for pigs. Eighteen Sprague-Dawley female rats with an average initial body weight of 154.0 g were randomly allotted into 6 groups designated as T1 control (no rubber seed meal), T2 raw rubber seed meal, T3 soaked rubber seed meal, T4 sundried rubber seed meal, T5 boiled rubber seed meal and T6 roasted rubber seed meal. The diets were prepared with various types of rubber seed meals incorporated at the level of 0 g kg-1 (control diet, T!) and 100 g kg-1 of each of the five rubber seed meal-containing diets. The study was conducted for 70 days and parameters studied included: feed intake, number of fertile females, pregnancy index, gestation length (length of pregnancy), number of pups born, number of pups born alive, live birth index and number of still births. Upon parturition (day 1), pups were individually counted, weighed and examined for external malformations. Other parameters evaluated were number of pubs weaned and mortality of pups. The inclusion of various types of rubber seed meals in the diets did not alter the general health of all the experimental rats. With the exception of rats on the T6 diet, all other rats recorded successful mating and pregnancies. There were no significant (p>0.05) difference in the gestation length (22 to 23 days) and all the pregnant rats delivered normally. No external malformations were observed in any of the pups delivered. No significant (p>0.05) differences in the maternal body weight (199.8 g), litter size (4.0 to 10), pup birth weight (4.88 to 7.07 g) and number of pups weaned (3.33 to 9.67) were observed. However, dietary treatments significantly (p<0.05) influenced weaning weight (29.60 to 48.25 g) and post-natal mortality of pups, with those on the T1 (control) and the T4 diets having the highest mortalities of 2.67 and 2.33, respectively. Based on the findings of the present study, up to 100 g of the raw and the variously-processed rubber seed meals could be included in 1 kg diets of laboratory rats without compromising on the health and reproductive performance in terms of reproductive toxicity or complications in pregnancy, delivery and other reproductive indices studied.