Planta Med 2013; 79 - SL64
DOI: 10.1055/s-0033-1351889

Effects of saponin fractions from fenugreek and the soap bark tree in the diet on performance of Nile tilapia, Oreochromis niloticus (L.)

T Stadtlander 1, WK Khalil 2, B Levavi-Sivan 3, Z Kerem 4, H Dweik 5, M Qutob 5, S Abu-Lafi 6, U Focken 7, K Becker 8
  • 1*Research Institute of Organic Agriculture, Dept. of Animal Science, Frick, Switzerland; University of Hohenheim, Dept. of Aquaculture Systems, Stuttgart, Germany
  • 2Cell Biology Department, Genetic Engineering and Biotechnology Division, National Research Centre, Giza, Egypt
  • 3Department of Animal Sciences, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University, Rehovot, Israel
  • 4Institute of Biochemistry, Food Science and Nutrition, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University, Rehovot, Israel
  • 5Department of Earth and Environmental Sciences, Faculty of Science and Technology, Al-Quds University, Abu Deis, Palestine
  • 6Faculty of Pharmacy, Al-Quds University, Abu-Deis, Palestine
  • 7Johann Heinrich von Thünen Institut, Institute of Fisheries Ecology, Ahrensburg, Germany; University of Hohenheim, Dept. of Aquaculture Systems, Stuttgart, Germany
  • 8University of Hohenheim, Dept. of Aquaculture Systems, Stuttgart, Germany

Saponins are generally regarded as anti-nutritional factors in aquaculture diets. However, previous experiments have shown that low dietary levels of saponins derived from Quillaja saponaria Molina do have growth promoting effects on common carp and Nile tilapia. Based on these experiments, we conducted an experiment in which we fed eluated saponin fractions from Q. saponaria and Trigonella foenum-graecum L. (fenugreek) to Nile tilapia in a respirometric system allowing for continuous measurement of oxygen consumption. Saponins were eluated with consecutive methanol/water concentrations (v/v, 40/60, 60/40, 80/20) resulting in three different eluates for each plant. Fractions chosen were the 80% methanol eluate from Q. saponaria (80QS) and all three eluates from T. foenum-graecum (40TS, 60TS and 80TS). Three fish each were fed with low levels (150 mg kg-1 diet) of saponins in the diet and a control diet without saponins. Growth, feed and nutrient utilization, proximate composition, oxygen consumption and metabolic performance were evaluated.

The fish grew between 224% (40TS) and 266% (Control) over the eight week period. Feed conversion ratios were between 0.94 (80TS) and 1.15 (40TS) and protein efficiency ratios between 2.54 (80TS) and 2.16 (40TS). Due to low sample sizes, no statistical differences were found between control fish and saponin fed fish. However, numerically one of the tested saponin fractions (40TS) showed inferior performance (Table 1).

It is concluded that the tested saponins in the tested concentrations are no potential growth promoter for Nile tilapia. On the contrary, one fraction appears to be a growth inhibitor.

Tab. 1: Growth performance, feed conversion and nutrient utilization of the tilapia.

Control

40TS

60TS

SOTS

SOQS

Initial body mass (g)

31.3 ± 8.25

39.0 ± 3.86

33.4 ± 8.21

35.8 ± 8.37

35.1 ± 2.52

Final body mass (g)

81.9 ± 14.5

86.3 ± 9.88

82.0 ± 5.13

92.5 ± 182

89.6 ± 14.0

Body mass gain (g)

50.7 ± 6.29

47.3 ± 11.9

48.6 ± 4.11

56.8 ± 102

54.5 ± 12.3

Growth (%)

266 ± 21.6

224 ± 41.4

253 ± 43.4

260 ± 15.0

255 ± 30.6

SGR (% day-1)

1.74 ± 0.15

1.42 ± 0.33

1.64 ± 0.32

1.71 ± 0.10

1.66 ± 022

MGR (g kg-0.8 day-1)

7.01 ± 0.34

5.82 ± 1.44

6.60 ± 1.21

7.05 ± 0.36

6.85 ± 1.06

Feed conversion ratio

0.96 ± 0.04

1.15 ± 0.30

1.03 ± 0.20

0.94 ± 0.05

0.98 ± 0.15

Protein efficiency ratio

2.49 ± 0.11

2.16 ± 0.55

2.36 ± 0.42

2.54 ± 0.13

2.47 ± 037

Protein productive value (%)

41.4 ± 4.40

36.8 ± 9.40

38.0 ± 4.14

42.1 ± 0.61

413 ± 3.92

Apparent lipid convers. (%)

62.1 ± 4.56

56.2 ± 25.0

52.2 ± 172

672 ± 7.44

61.6 = 14.6

Feed intake (g DM)

48.7 ± 8.23

52.2 ± 2.71

49.7 ± 5.80

53.3 ± 9.02

52.3 ± 5.05

Values are expressed as mean ± SD: n = 3, TS =Trigonella foenum-graecum saponins, QS = Quillaja saponaria saponins, SGR = specific growth rate, MGR = metabolic growth rate