The effect of roselle (HIBICUS SABDARIFFA LINN.) calyx as antioxidant and acidifier on growth performances and ileal digestibility in postweaning pigs

Abstract

The objectives of this investigation were to study the effect of roselle (Hibicus sabdariffa Linn.) calyx as antioxidant and acidifier on growth performances and ileal digestibility in postweaning pigs. In experiment 1, the suitable level of roselle calyx on growth performance was examined. Twenty four castrated male and twelve female piglets were allocated into 6 treatments : T1, basal diet; T2, T3, T4, basal diet plus crude powder of roselle calyx at the level of 4, 8, 12% feed; T5, basal diet plus acidifier at the level of 4 g/kg feed; T6 basal diet plus antibiotic (chlortetracycline) at the level of 100 mg/kg feed. All diet were calculated to be isocaloric and isonitrogenous. Body weight and feed intake were measured at 7, 9 and 11 weeks of age. The suitable level of roselle calyx on growth performances from expt 1 were used in the experiment 2 to determine the antioxidant and acidifier properties. Thirty two castrated male and female piglets wereallocated into 4 treatments : T1, basal diet ; T2 basal diet plus crude powder of roselle calyx at the level of 8% feed; T3, basal diet plus acidifier at the level of 4 g/kg feed; T4 basal diet plus antibiotic at the level of 100 mg/kg feed. At 5-7 and 7-9 weeks of age, body weight were measured, four pigs in each group were randomly selected, exthanased and the pH of gastrointestinal tract were measured ; stomach mucosa were collected for determination of pepsin activity; pancreas for trypsin activity, ileal digesta for protein and fat digestibility, plasma and liver for malondialdehyde and glutathione concentration. Experiment 1 showed that there was no significant difference in growth performance among (P>0.05): however, it was found that feed conversion ration (FCR) was significantly different at 5-7 weeks of age (P<0.05). Pigs fed 8% Roselle calyx had the lowest FCR: therefore, 8% Roselle calyx was set to be an appropriate level in feed and was used in the experiment 2. Experiment 2 also showed no significant difference in growth performance among groups at all ages (P>0.05). Concerning acidifier property of roselle calyx, the additional of 8% roselle calyx help lower pH in gastrointestinal tract (P>0.05), increase activity of pepsin (P>0.05), increase activity of trypsin at the age of 7 weeks (P<0.05) and increase fat digestibility at the age of 7 weeks (P<0.05) but there was no effect found on protein digestibility. Besides, Roselle calyx act as an antioxidant as well for the results showed that additional 8% Roselle calyx help lower MDA both in plasma and liver (P>0.05) and help increase glutathione in plasma at the age of 7 weeks (P<0.05) and in liver (P>0.05). Significant differences were found in every parameter between basal diet and roselle fed groups except acidifier and antibiotic. In conclusion, Roselle calyx is likely to have properties of being acidifier and antioxidant though the result did not show that significantly. Since this experiment used roselle calyx in form of powder and was conducted in controlled environment to maintain low stress in pigs, there should be further research using the extraction form and conducting in commercial conditions.