Abstract

Awide range of biological and pharmacological activitiesof lasia (Lasia spinosa (L.)Thwaites) are well established. However, little attention has been paid to the growth-promoting effects of lasia on aquatic animals. This study was aimed at elucidating the effects of dietary lasiaextract (LE) on growth performance and physiological indices of common lowland frog (Rana rugulosa). Lasia leafextract was prepared and phytochemical screening showed the presence of flavonoids, terpenoids, phenolic compounds, tannins, steroids, coumarins, glycosides, and anthraquinones. Four treatments of male frog (initial weightsof 14.00±1.00 g) were fed for 8 weekswith dietssupplemented with 0 (control), 1, 3, and 5 g LE/kg diets. The results revealed that growth performance parameters weresignificantlyimproved in frog fed with LE-supplemented diets compared with the control (P<0.05). The survival rate, hepatosomatic index,intestinosomatic index, splenosomatic index,cardiosomatic index, and renosomatic index did not change among the treatments (P>0.05). An increase in intraperitoneal fatweight was noticed in frog fed with LE-supplemented diets compared with the control (P < 0.05). DietaryLE significantly improved villi height, villi width, and the absorptive surface areaof the frog intestine compared to control (P < 0.05). Hemoglobin was markedly increased in frog fed with 5 g LE/kg diet compared with the other treatments (P<0.05). There were no significant differences in hematocrit, white blood cells, and red blood cells among all treatments (P> 0.05). Dietary LE did not affect the levels of serum total protein, albumin, alkaline phosphatase, aspartate transaminase, triglyceride, high-density lipoprotein cholesterol, and low-density lipoprotein cholesterol (P>0.05). Decreased cholesterol levels were detected in frog fed with LE-supplemented diets compared with the control (P<0.05). Glucose value was significantly enhanced in frog fed with 5 g LE/kg diet compared with the other treatments (P<0.05). Taken together, thesefindingssupport the beneficial effects of dietary LEon the growth and physiological indices of the frog. The suitable level of LE observed by using the second-order polynomial regression analysis was 3.60 g LE/kg diet.

Keywords:Raniculture, Natural feed additives, Growth promoters, Intestinal histology