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Nutritional and antinutritional characteristics of selected Vicia genotypes
ANIMAL FEED SCIENCE AND TECHNOLOGY
E LS EV I ER
Animal Feed Science and Technology 47 (1994) 125-139
Nutritional and antinutritional characteristics of selected Vicia genotypes V.A. Aletor *'1, A.V. Goodchild, A.M Abd E1 Moneim International Centerfor Agricultural Research in the Dry Areas (ICARDA), PO Box 5466, Aleppo, Syria (Received 30 December 1992; accepted 26 October 1993)
Abstract
Mature seeds of Vicia narbonensis (91 lines), Vicia sativa (23 lines), Vicia ervilia ( 16 lines) and Vicia palaestina ( 16 lines) were evaluated for crude protein (CP), protein precipitable tannin (PPT), vanillin-HC1 catechin equivalent (CE) and trypsin inhibitor activity (TIA). Other chemical and in vitro characteristics measured included ash, organic matter (OM), neutral detergent fibre (NDF), acid detergent fibre (ADF), in vitro organic digestibility (IVOMD) and in vitro dry matter (DM) digestibility (IVDMD). Crude protein content ranged from 264.38 + 6.34 g kg- 1 DM in V. ervilia to 341.87 + 8.55 g kg- 1DM in V. palaestina with all species showing little intraspecies variability. The DM, OM and ash contents of all the lines were similar. However, the ADF and NDF values for V. narbonensis were significantly ( P < 0.05) higher than those of the other species. Mean IVDMD and IVOMD values of the species also differed significantly ( P < 0.05 ). The higher IVDMD (90.95%) and IVOMD (88.30%) values of V. ervilia paralleled the relatively lower ADF and NDF values. PPT was mainly restricted to V. narbonensis while none was detected in any of the lines of either V. sativa or V. ervilia. Tannin expressed as CE was no more than 8.27 g kg- t in any of the species and seven of the 91 lines of V. narbonensis had no detectable CE levels. There was considerable intraspecies variability in CE as indicated by the high coefficients of variation (CV), which ranged from 17.48% in V. palaestina to 68.99% in V. sativa. In comparison with most conventional legumes, TIA values were generally low in all the species, ranging from 0.36 g kg -~ DM in selection IFLVP 2524 to 5.00 gkg -1 DM in IFLVS 2560. Values for TIA in V. palaestina were particularly low (0.51 + 0.13 g kg- ~ DM) and a CV of 25.86% suggests that selection for lower inhibitor levels is possible. Seed weight was significantly (P<0.05) correlated with CE in both V. sativa and V. palaestina, while CP was weakly negatively correlated ( r = - 0.48 ) with TIA among the V. *Corresponding author. tPresent address: Institut fiir Tieremahrung, University of Bonn, Endenicher Allee 15, Bonn 1, Germany. 0377-8401/94/$07.00 © 1994 Elsevier Science B.V. All rights reserved SSD10377-8401 (93) 00568-G
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sativa genotypes. There was no significant relationship between seed weight and TIA in
any of the species investigated.
1. Introduction
The principal agricultural activity in the dry areas of West Asia and North Africa (WANA) is small ruminant (sheep and goat) production with rangeland grazing providing most of the animal feed (Cocks et al., 1986). During periods of high livestock feed prices, feed legumes such as Vicia species, which may be fed to small ruminants in the form of straw and grain, are increasingly attractive to farmers in WANA (Abd E1 Moneim et al., 1988). In view of the overall objectives of The International Center for Agricultural Research in the Dry Areas (ICARDA) of developing sustainable farming systems in the dry areas, there is a clear need for feed legume crops. One of the most attractive legume species for grain and straw production is Narbon vetch, Vicia narbonensis. It is a good source of protein with seeds containing up to 28% protein and yielding about 365 kg protein ha- ~while the straw contains about 9% protein (Abd E1 Moneim, 1992 ). ICARDA currently maintains breeding lines of Vicia species which include V. narbonensis L., Vicia sativa L., Vicia ervilia and Vicia palaestina R. In this study, we present compositional data on selected lines of these species with respect to their crude protein (CP), trypsin inhibitor activity (TIA), catechin equivalents (CE) and protein precipitable tannin (PPT) content. These parameters are of interest because both trypsin inhibitors and tannins are implicated in poor protein digestibility (Liener, 1969, 1989 ), while tannins generally have been associated with poor digestibility and palatability (Menhansho et al., 1987; Hagerman et al., 1992). We hope that this information, along with in vitro characteristics, will arouse greater interest in the exploitation of their potential in human and/or animal feeding.
2. Materials and methods
The Vicia genotypes evaluated were obtained from the breeding programme at ICARDA (Tel Haydia, Syria; 36°40'N, 37°20'E, 390 m elevation). The current breeding procedure uses germplasm evaluation and seed multiplication in nursery rows, and evaluates selected genotypes in microplots and promising genotypes in advanced yield trials. The samples analysed were mature grains comprising 91 lines of V. narbonensis (Narbon vetch), 23 lines of V. sativa (common vetch), 16 lines of V. ervilia (bitter vetch) and 16 lines of V. palaestina. About 50 g each of the dried seeds were ground before use using a UD cyclone sample mill (UD Corporation, Fort Collins, CO, USA) fitted with a 1 mm mesh sieve. The dry matter (DM), CP and ash were determined as described by the Min-
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127
istry of Agriculture, Fisheries and Food (1981), while neutral detergent fibre (NDF) and acid detergent fibre (ADF) were determined by the method of Goering and Van Soest (1970). Some random selections were also evaluated for in vitro organic matter digestibility (IVOMD) and in vitro dry matter digestibility (IVDMD) using the technique of Tilley and Terry (1963). The weight of 100 seeds was estimated using a mechanical seed counter (Numigral, Franken, Netherlands) before weighing. 2. I. Assay for antinutritional factors
2.1.1. Protein precipitable tannin (PPT) and catechin equivalent (CE) All samples for tannin determination were milled just before analysis to prevent the oxidation of phenolic compounds. A 200 mg measure of the flour was defatted in a screw-top test-tube with 5 ml of ethyl ether for 15 min using a GalTable 1 Crude protein (CP), protein precipitable tannin ( P P T ) , tannin measured as vanillin-HC1 catechin equivalent (CE) and trypsin inhibitor activity (TIA) of V. narbonensis seeds selected in microplots Selection no.
Weight per 100 DM seeds (g) (%)
CP (gkg -~ D M )
PPT (gkg - l D M )
CE (gkg - l D M )
IFLVN2376 IFLVN 2377 IFLVN2378 IFLVN 2379 IFLVN 2381 IFLVN 2382 IFLVN2384 IFLVN 2385 IFLVN2386 IFLVN2389 IFLVN 2394 IFLVN2395 IFLVN2396 IFLVN 2397 IFLVN 2398 IFLVN2460 IFLVN 2463 IFLVN 2482 IFLVN2597 IFLVN2598 IFLVN 2599 IFLVN 2600 IFLVN 2601 IFLVN 2602
19.371 21.168 20.868 17.928 19.192 17.664 20.096 20.686 16.968 18.85 15.838 21.24 16.399 19.208 13.507 14.296 18.691 16.371 14.658 20.866 13.129 17.8 18.607 15.329
90.79 90.65 90.65 90.72 90.67 90.59 90.72 90.64 90.77 90.60 90.67 90.81 90.70 90.60 90.53 90.69 90.62 90.70 90.51 90.72 90.78 90.65 90.65 90.71
301.02 294.54 306.56 285.16 303.85 303.34 276.01 277.69 274.43 276,93 285.43 285.87 288.09 288.30 276.15 278.20 290.22 288.31 284.06 295.19 283.98 301.27 325.32 292.25
ND 4.37 4.62 4.62 4.19 4.54 4.44 4.19 4.19 4.28 4.37 4.61 4.44 4.54 4.45 ND 4.11 ND 4.38 4.53 4.36 4.19 ND 4.28
1.38 1.65 1.65 2.48 1.38 1.93 1.38 1.38 1.38 1.38 1.93 2.75 2.48 2.48 2.76 2.76 2.76 1.93 2.49 2.48 3.30 1.93 1.38 1.93
4.13 3.49 3.34 3.85 3.04 3.71 3.20 3.34 3.04 3.41 3.71 4,57 4.13 4,58 3,13 3,20 3.49 3.34 3.35 4.35 2.83 3.34 3.34 3.70
Mean SD CV (%)
17.864 2.428 13.593
90.67 290.09 0.07 11.95 0.08 4.12
4.38 0.16 3.59
2.06 0.58 28.17
3.57 0.47 13.21
SD, standard deviation; CV, coefficient of variation; ND, none detected.
TIA (gkg - 1 D M )
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Table 2 Crude protein (CP), protein precipitable tannin (PPT), tannin measured as vanillin-HCl catechin equivalent (CE) and trypsin inhibitor activity (TIA) of I~. narbonensis seeds multiplied in the nursery Selection no.
Weight per 100 DM seeds (g) (g)
CP (gkg - 1 D M )
PPT (gkg - I D M )
CE (gkg -~DM)
IFLVN 111 IFLVN 112 IFLVN 113 IFLVN 114 IFLVN 123 IFLVN 124 IFLVN 125 IFLVN 126 IFLVN 127 IFLVN 129 IFLVN 130 IFLVN 543 IFLVN 569 IFLVN 580 IFLVN 584 IFLVN 803 IFLVN 1142 IFLVN 1144 IFLVN 1147 IFLVN 1148 IFLVN 1150 IFLVN 1152 IFLVN2272 IFLVN2524 IFLVN2525 IFLVN2528 IFLVN 2529 IFLVN2530 IFLVN2531 IFLVN2532 IFLVN2533 IFLVN2556 IFLVN 2624 IFLVN 2628 IFLV-N 2644 IFLVN 2649 IFLVN 2663 IFLVN 2696 IFLVN 2697 IFLVN 2702 IFLVN 2703 IFLVN2706
11.226 12.411 11.417 12.651 15.252 12.045 12.807 11.901 13.186 11.666 12.404 12.648 14.168 15.746 9.713 9.684 8.344 13.379 7.295 6.518 7.682 6.807 10.675 12.723 12.774 14.031 11.58 12.389 14.282 12.441 12.952 12.371 5.612 6.917 9.198 6.88 8.623 9.508 8.58 8.488 8.55 12.43
90.82 90.75 90.94 90.71 90.68 90.82 90.72 91.12 91.27 91.16 91.21 91.19 90.68 90.71 91.19 90.91 91.06 90.99 91.08 91.04 91.04 91.13 90.87 90.83 90.95 90.56 90.77 91.36 90.92 90.61 90.57 90.79 89.28 91.13 90.93 90.80 91.06 91.15 91.12 90.78 90.85 90.76
297.40 322.09 295.69 301.40 296.87 273.40 307.76 315.30 258.90 275.78 261.92 263.08 309.88 295.78 258.91 286.88 253.02 275.85 282.72 307.12 281.96 288.05 292.73 298.58 291.15 282.13 278.07 304.18 290.59 292.68 257.26 280.65 311.38 298.36 292.09 279.41 247.42 259.13 258.56 272.75 279.91 313.02
4.36 4.44 4.35 4.19 4.53 5.14 4.71 4.77 4.94 5.04 5.46 5.55 4.53 4.53 4.68 5.22 5.73 4.96 4.35 5.04 5.04 4.60 5.23 4.70 4.18 4.11 4.10 4.50 4.78 4.19 5.16 5.45 ND 5.12 4.18 5.23 4.51 4.17 4.08 ND 5.05 ND
4.40 2.48 3.30 2.76 2.48 4.68 2.76 2.47 3.83 4.39 4.66 4.93 1.93 2.76 1.92 3.85 3.29 3.57 3.84 3.57 2.20 4.39 2.75 2.75 2.20 1.93 2.75 1.92 2.75 1.93 3.04 2.20 1.96 1.92 1.37 4.41 0.82 1.92 2.47 1.38 2.20 0.83
3.77 3.12 3.47 3.20 3.77 2.90 3.20 3.25 2.88 3.47 3.32 3.18 3.48 3.91 2.30 3.33 4.48 3.33 3.90 3.39 4.48 3.47 3.70 4.05 3.11 4.36 3.12 3.10 3.04 2.90 2.54 2.83 4.28 4.40 4.05 3.91 2.24 3.10 3.18 3.26 3.26 3.21
Mean SD CV (%)
10.951 2.579 23.547
90.89 285.47 0.32 18.72 0.35 6.56
4.74 0.45 9.51
2.81 1.05 37.48
3.41 0.54 15.84
SD, standard deviation; CV, coefficient of variation; ND, none detected.
TIA (gkg -~ DM)
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Table 3 Crude protein (CP), protein precipitable tannin ( P P T ) , tannin measured as vanillin-HCl catechin equivalent (CE) and trypsin inhibitor activity (TIA) of advanced lines of V. narbonensis seeds Selection no.
Weight per 100 DM seeds (g) (%)
CP (gkg - 1 D M )
PPT (gkg - I D M )
CE (gkg - 1 D M )
IFLVN 2561 IFLVN 2380 IFLVN 2383 IFLVN2387 IFLVN 2388 IFLVN2390 IFLVN 2391 IFLVN2392 IFLVN2393 IFLVN 2461 IFLVN 2462 IFLVN2464 IFLVN 2465 IFLVN 2466 IFLVN 2467 IFLVN2468 IFLVN 2469 IFLVN2470 IFLVN 2471 IFLVN2473 IFLVN 2474 IFLVN2475 IFLVN 2476 IFLVN 2477 IFLVN 2478
10.596 17.425 19.821 18.833 16.035 16.917 17.686 16.533 20.139 21.405 19.914 22.247 18.357 19.954 21.63 21.386 21.001 22.638 24.412 13.735 19.609 23.086 19.144 21.354 19.576
296.82 274.56 295.54 270.18 306.85 294.20 305.38 277.97 305.68 272.59 277.56 281.06 284.52 309.77 311.30 303.85 313.51 293.21 294.34 287.80 304.66 294.88 297.35 292.63 287.50
4.10 ND 4.19 ND ND ND ND ND ND ND ND 4.09 4.09 ND ND ND ND ND ND ND ND ND 4.18 ND 4.17
ND ND ND 0.83 ND 0.83 ND ND ND 1.37 1.92 1.38 1.38 0.55 ND 0.55 0.55 0.55 1.10 0.55 0.55 0.83 1.65 1.38 2.19
3.77 2.68 2.68 2.47 2.89 3.00 2.83 2.32 2.61 3.53 3.69 3.92 4.13 4.34 3.04 2.33 3.48 3.22 2.01 3.21 4.87 3.82 3.39 4.00 4.51
90.83 293.35 0.21 12.42 0.23 4.23
4.14 0.04 1.01
1.07 0.51 48.14
3.31 0.73 22.11
Mean SD CV (%)
19.337 2.977 15.393
90.66 90.69 90.75 90.83 90.89 90.04 90.87 90.91 90.88 91.09 91.15 90.87 90.89 90.97 90.78 90.67 90.81 90.72 90.71 91.00 90.79 90.85 90.87 90.83 91.13
TIA (gkg -~ D M )
SD, standard deviation; CV, coefficient of variation; ND, none detected.
lenkamp Lab Quake followed by centrifugation. The extract was discarded and the air-dry residue was thereafter extracted with 60% methanol; the PPT content of the extract was determined using standard bovine serum albumin (Lot 41H0520; Sigma, St. Louis, MO, USA) as outlined by Hagerman and Butler ( 1978 ). CE, which detects simple flavonoids as well as condensed tannins, was determined by the vanillin-HC1 method of Burns (1971 ) as modified by Price and Butler (1977) and Price et al. (1978). Commercial ( _+ )-catechin (Lot C0774; Sigma) was used as reference standard.
2.1.2. Trypsin inhibitor activity (TIA) The TIA content of the grains was measured as the extent to which an extract of the flour inhibited the action of bovine trypsin (EC 3.4.21.1 ) on the substrate benzoyl-DL-arginine-p-nitroanilide hydrochloride (Lot 110H0329; Sigma) as
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Table 4 Crude protein (CP), protein precipitable tannin (PPT), tannin measured as vanillin-HC1 catechin equivalent (CE) and trypsin inhibitor activity (TIA) in seeds from advanced lines of V. sativa Selection no. IFLVS 545 IFLVS 1134 IFLVS 1135 IFLVS 1136 IFLVS 1437 IFLVS 1448 IFLVS2019 IFLVS 2037 IFLVS 2044 IFLVS 2057 IFLVS 2062 IFLVS 2065 IFLVS 2083 IFLVS 2086 IFLVS2096 IFLVS 2106 IFLVS 2108 IFLVS 2109 IFLVS 2556 IFLVS 2557 IFLVS2539 IFLVS 2603 IFLVS 2560
Mean SD CV (%)
Weightper 100 DM seeds (g) (%) 4.995 4.794 5.534 4.397 4.908 2.08 5.822 2.539 4.227 3.802 6.729 2.103 4.898 5.37 4.711 4.518 5.313 4.86 5.509 2.464 5.716 5.522 4.805 4.592 1.209 26.336
CP (gkg - l DM)
PPT (gkg - 1 D M )
336.53 306.96 302.69 343.21 344.27 307.25 315.81 294.35 355.94 344.88 298.45 315.88 318.85 323.49 328.38 306.34 322.92 301.36 312.95 306.68 292.29 284.71 335.18
ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND
2.76 2.21 1.38 4.41 3.29 5.51 2.20 6.07 1.93 4.97 1.66 8.27 1.93 1.93 1.93 3.30 0.55 1.92 0.83 5.00 0.28 1.39 1.39
3.57 4.36 3.82 4.17 3.98 4.44 4.96 4.88 4.61 4.49 4.88 4.61 4.00 4.09 2.95 3.74 4.88 4.08 4.53 4.65 4.05 4.01 5.00
90.59 317.36 0.33 18.69 0.37 5.89
ND ND ND
2.83 1.95 68.99
4.29 0.50 11.58
90.66 90.63 90.72 90.79 91.12 90.74 90.72 90.54 90.69 90.61 90.60 90.70 90.67 90.73 90.81 90.88 90.55 90.96 90.75 89.93 89.74 89.95 90.07
CE (g kg - l DM)
TIA (gkg -~ DM)
SD, standard deviation; CV, coefficient of variation; ND, none detected.
modified by Smith et al. (1980). The flour was first defatted at room temperature with 50 ml portions of petroleum ether (b.p. 4 0 - 6 0 ° C ) in covered flasks and then mechanically shaken until fat-free. The extract was discarded and the residue air-dried. Extracts were thereafter made from 1 g of the flour with 10 mM NaOH for 3 h at room temperature using an orbital shaker (Gallenkamp, UK). The pH of the resulting slurry was adjusted to 9.5 with 1 M NaOH or 1 M HCI. After extraction, the suspension was shaken and diluted with distilled water such that 1 ml of the diluted extract produced trypsin inhibition of between 40% and 60% at 37 °C. The respective dilutions were noted and, in the present assay, dilutions of 5 or 6 were suitable for all the species except F. palaestina extracts which needed no dilution. The TIA was subsequently determined in terms of mg pure trypsin g - l sample using the equation TIA = 2.632DA/S, where D is dilution factor, A is change in absorbance at 410 nm resulting from trypsin inhibition per cm 3 of diluted sample extract, S is weight of sample (Smith et al., 1980 ).
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Table 5 Crude protein (CP), protein precipitable tannin (PPT)m tannin measured as vanillin-HC1 catechin equivalent (CE), and trypsin inhibitor activity (TIA) in seeds from advanced lines of V. ervilia Selection no.
Weight per 100 DM seeds (g) (%)
CP (gkg -~ D M )
PPT (gkg - ~ D M )
IFLVE2508 IFLVE 2509 IFLVE2510 IFLVE 2511 IFLVE 2512 IFLVE 2513 IFLVE2514 IFLVE 2515 IFLVE 2516 IFLVE2517 IFLVE2518 IFLVE2519 IFLVE2520 IFLVE 2521 IFLVE2522 IFLVE 2563
5.032 4.619 4.384 4.204 4.883 4.891 4.621 4.772 5.042 4.734 4.549 4.381 4.068 5.083 4.878 3.851
90.35 90.27 90.23 90.50 90.40 90.40 90.17 90.30 90.15 90.19 90.23 90.47 90.14 90.24 90.26 90.48
262.65 259.11 261.44 270.28 254.65 259.07 257.85 272.54 255.68 270.54 264.32 267.82 268.69 267.40 260.14 277.96
ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND
1.66 0.83 1.66 1.66 1.66 2.21 2.22 2.21 2.22 1.66 1.66 3.32 2.77 1.39 2.22 2.76
2.71 3.41 3.50 3.40 3.50 3.58 3.59 3.77 3.59 2.89 4.29 3.23 3.77 3.06 3.41 3.58
Mean
4.625 0.353 7.634
90.30 264.38 0.12 6.43 0.13 2.43
ND ND ND
2.01 0.59 29.42
3.46 0.36 10.36
SD CV (%)
CE (gkg -~ D M )
TIA (gkg -~ D M )
SD, standard deviation; CV, coefficient of variation; ND, none detected.
2.2. Data analyses All values (means of duplicate determinations) were analysed statistically and coefficients of variation (CV) within the lines were calculated (Steel and Torrie, 1960). Mean values on the proximate and in vitro parameters in the randomly selected lines were compared using MSTATC software while the correlations between the weight of 100 seeds, CP and the anti-quality factors were computed using SPSS.
3. Results
3.1. Dry matter (DM), seed weight and crude protein (CP) content The weight of 100 seeds and the DM and CP contents of all the species are shown in Tables 1-6. The DM values of all the lines analysed were similar, and ranged from 90.26 _+0.16% in V. palaestina to 90.89 __0.32% in V. narbonensis. The weight of 100 seeds was least in V. palaestina (3.77_+0.28 g; Table 6) and highest in V. narbonensis (19.33 _+2.97 g; Table 3 ). The average weights of the seeds of V. sativa and V. ervilia were similar, and generally much lower than those
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Table 6 Crude protein (CP), protein precipitable tannin (PPT), tannin measured as vanillin-HCl catechin equivalent (CE) and trypsin inhibitor activity (TIA) of seeds from advanced lines of V. palaestina Selection no.
Weight per 100 DM seeds (g) (%)
CP (gkg - l DM)
PPT (gkg - ~ DM)
IFLVP2523 IFLVP2524 IFLVP 2525 IFLVP2526 IFLVP2527 IFLVP 2528 IFLVP2529 IFLVP 2530 IFLVP2531 IFLVP2532 IFLYP2533 IFLVP2534 IFLVP2535 IFLVP 2536 IFLVP2537 IFLVP2538
3.586 3.500 3.543 3.312 3.609 3.730 4.050 4.150 4.033 4.170 3.836 4.310 3.703 3.468 3.658 3.703
90.45 90.42 90.31 90.29 90.35 90,11 90.43 90,39 90,37 90,45 90.18 90.24 90.11 90.01 90.08 89.92
348.70 349.37 355.66 329.60 332.04 340.36 334.29 350.04 352.66 345.94 334.77 346.63 332.93 327.74 345.58 343.53
ND ND ND ND ND ND ND ND ND ND ND ND ND 4.40 4.31 4.40
3.59 3.32 3.60 1.94 2.21 3.61 3.32 3.32 3.32 4.15 3.33 3.32 2.50 2.78 3.33 2.78
0.54 0.36 0.47 0.37 0.51 0.68 0.46 0.48 0.45 0.43 0.51 0.38 0.47 0.84 0.75 0.47
Mean SD CV (%)
3.773 0.280 7.427
90.26 341.87 0.16 8.55 0.18 2.50
4.37 0.04 1.02
3.15 0.55 17.48
0.51 0.13 25.86
CE (gkg -~ DM)
TIA (gkg - 1 D M)
SD, standard deviation; CV, coefficient of variation; ND, none detected.
of V. narbonensis. Intraspecies variabilities in seed weights were generally higher in V. narbonensis than in the other species as shown by their respective CVs. The species with the lowest and highest mean CP values were V. ervilia (264.38 _+6.43 g kg -~ DM; Table 3) and V. palaestina (341.87_+8.55 g kg -1 DM; Table 6), respectively. The CP content of V. sativa (Table 4) was similar to that of V. palaestina. The CV, an indicator of intraspecies variability in CP, was similar and small in all lines.
3.2. Protein precipitable tannin (PPT) and vanillin-HCl catechin equivalent (CE) The PPT levels in K narbonensis lines (Tables I-3 ) were similar to those in K palaestina (Table 6). No PPT was detected in any line of K sativa or K ervilia. Most of the lines from the advance collection of K narbonensis and K palaestina had no detectable PPT levels. Flavonoid content (including condensed tannins), measured as CE, was no more than 8.27 g kg- ~ DM in all the Vicia species, and seven of the 91 K narbonensis lines had no detectable CE. All the lines from the other species contained CE with mean values ranging from 1.07_+0.51 g kg -~ DM in K narbonensis to 3.15 g kg-~ DM in K palaestina. There were large intraspecies variations in CE content as show by the high CVs which ranged from 17.48% in V. palaestina to 68.99% in V. sativa.
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Table 7 Proximate and in vitro characteristics of Vicia seeds DM CP OM Ash ADF NDF (gkg -1) (gkg -1) (gkg - l ) (gkg - t ) (gkg -~) (gkg - l )
IVDMD IVOMD (%) (%)
V. narbonensis (microplo 0 IFLVN 2379 IFLVN 2389 IFLVN 2395 IFLVN 2601 Mean SD
907.20 906.00 908.10 906.50 906.95a 0.79
285.16 276.93 285.87 325.32 293.32a 18.81
968.00 964.60 967.50 963.40 965.88a 1.93
35.21 39.06 35.80 40.37 37.61a 2.17
137.54 187.06 1 2 5 . 7 9 198.31 97.83 198.20 1 1 2 . 2 8 209.55 118.36b 198.28b 14.85 7.95
88.98 89.35 88.54 89.29 89.04a 0.32
85.79 85.57 85.27 85.46 85.52a 0.19
273.40 263.08 272.75 313.02 280.56b 19.18
973.00 964.10 965.60 963.80 966.63a 3.74
29.70 39.47 37.86 39.86 36.72a 4.12
149.17 165.13 176.00 156.74 161.76a 9.97
86.08 87.43 85.92 86.23 86.42b 0.60
83.55 83.43 82.48 82.44 82.98b 0.52
274.56 277.56 287.50 296.82 284.11a 8.76
965.20 967.80 967.40 970.60a 1.70
38.35 35.34 35.88 33.09 35.67a 1.87
137.54 194.07 107.23 149.60 113.91 191.39 1 2 8 . 7 2 249.83 121.85b 196.22bc 11.94 35.62
88.76 89.22 89.76 88.31 89.01a 0.54
85.22 86.48 86.06 85.17 85.73a 0.56
307.25 294.35 322.92 292.29 304.20a 12.23
967.60 967.10 966.80 973.90 968.85a 2.93
35.75 36.37 36.68 28.81 34.40a 3.25
95.00 95.63 75.68 69.88 84.05c 11.45
136.60 135.77 147.83 156.33 144.13bc 8.50
83.53 83.85 86.69 87.66 85.43b 1.78
79.94 80.78 83.72 85.66 82.53abd 2.29
259.11 267.82 268.69 267.40 265.76d 3.86
970.10 972.60 970.20 971.70 971.15b 1.05
32.87 29.97 32.69 31.08 31.65a 1.20
59.25 55.14 58.57 54.14 56.78d 2.18
148.07 156.43 140.24 113.22 139.49c 16.21
90.22 91.92 91.23 90.44 90.95c 0.67
87.29 89.31 88.53 88.05 88.30c 0.73
348.70 329.60 332.04 345.94 339.07c 8.35
965.90 970.00 969.60 967.90 968.35a 1.62
37.35 32.97 33.39 35.00 34.68a 1.72
89.80 101.10 91.38 85.16 91.86c 5.80
181.03 174.51 125.32 120.71 150.39c 27.52
81.48 82.00 83.05 81.40 81.98d 0.66
78.09 79.74 80.66 78.40 79.22d 1.04
V. narbonensis (nursery) IFLVB 124 IFLVN 543 IFLVN 2702 IFLVN 2706 Mean SD
908.20 901.90 907.80 907.60 906.38a 2.59
235.97 234.06 296.75 304.00 267.70a 32.79
V. narbonensis (advance) IFLVN 2380 IFLVN 2462 IFLVN 2478 IFLVN2561 Mean SD
906.90 911.50 906.60 906.58a 3.61
V. sativa (multilocation) IFLVS 1 4 4 8 IFLVS 2037 IFLVS 2108 IFLVS 2559 Mean SD
907.40 905.40 905.50 897.40 903.93a 3.85
V. ervilia (microploO IFLVE 2509 IFLVE 2519 IFLVE 2520 IFLVE 2 5 2 1 Mean SD
902.70 914.70 901.40 902.40 905.30a 5.45
V. palaestina (microplo 0 IFLVP 2523 IFLVP 2526 IFLVP 2527 IFLVP 2532 Mean SD
904.50 902.90 903.50 914.50 906.35a 4.74
Means followed by dissimilar letters in the same vertical column differ significantly (P< 0.05 ). SD, standard deviation.
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V.A. Aletor et al. / Animal Feed Science and Technology 47 (1994) 125-139
Table 8 Correlation coefficients (r) b e t w e e n weight o f seeds, c r u d e p r o t e i n a n d a n t i n u t r i t i o n a l factors PPT
CE
TIA
91 -0.45 *
91 -0.12 NS
91 -0.02 NS
91 -0.21 *
91
91
0.01 NS
0.17 NS
-
23 -0.65 ***
23 -0.31 NS
-
23 -0.04 NS
23 -0.48 *
-
16 -0.41 NS
16 -0.34 NS
16
16 -0.05 NS
V. narbonensis Weight o f 100 seeds n r P C r u d e protein n r P
V. sativa Weight o f 100 seeds n r P C r u d e protein n r P
23
23
V. ervilia Weight o f 100 seeds n r P Crude protein n r P
16
16 -
0.32 NS
V. palaestina Weight o f 100 seeds n r P Crude protein n r P
16 -0.2 NS 16 -0.16 NS
16 0.55
16 -0.27 NS
0.65
16 -0.28 NS
* 16 *
* P < 0.05; **P< 0.01; ***P< 0.001. n, n u m b e r o f observations; NS, n o t significant.
3.3. Trypsin inhibitor activity (TIA) All species contained low levels of TIA with mean values ranging from 0.51 + 0.13 g kg- 1 DM in V. palaestina (Table 6) to 4.29 + 0.50 g kg- 1 DM in V. sativa (Table 4 ). TIA values were highest in IFLVS 2560 (5.00 g kg- ~ D M ) and
V.A. Aletor et al. / A nimal FeedScience and Technology47 (1994) 125-139
135
least in IFLVP 2524 (0.36 g kg-~ DM). All the V. palaestina lines had low TIA, with values ranging from 0.36 g kg -~ DM in IFLVP 2524 to 0.84 g kg -~ DM in IFLVP 2536 with a CV of 25.86%. Mean TIA values in all lines of V. narbonensis, V. sativa and V. ervilia were generally similar, but substantially higher than those of V. palaestina (Table 6). 3.4. Proximate and in vitro studies
Some chemical and in vitro data on randomly chosen lines from each of the species are summarized in Table 7. The OM and ash contents of the samples were generally similar. However, the ADF and NDF values of V. narbonensis lines were significantly ( P < 0.05) higher than those of the other species. The mean IDMD and IOMD values of the species also differed significantly ( P < 0.05 ). The higher IDMD (90.95%) and IOMD (88.30%) values of F. ervilia appeared to parallel the lower ADF ( 56.78 g kg- ~DM) and NDF ( 139.49 g kg- ~DM) values. 3.5. Correlation analysis
Table 8 summarizes the correlation coefficients (r) between seed weight, CP and the different antinutrients. Seed weight was significantly and negatively correlated with PPT only among the V. narbonensis lines ( P < 0.05; r= - 0.45 ). Seed weight was also correlated significantly ( P < 0.05 ) with CE in both V. sativa and V. palaestina. There were no significant correlations between seed weight and TIA in any of the species. Crude protein was positively correlated (r= 0.05 ) with CE only in V. palestina lines. Similarly, there was a significant correlation ( P < 0.05 ); r= - 0 . 4 8 ) between CP and TIA only among the V. sativa genotypes.
4. Discussion
It is well documented (Hove and King, 1978; Farrell and Vohra, 1983; Liener, 1989 ) that the nutritional importance of a given food/feedstuffin a diet depends not only on the nutrient composition of the raw feedstuff, but also on the amount that is consumed as well as the presence of antinutritional constituents. With regard to CP, the present data suggest that Vicia species could be important contributors of plant protein supplements to foods and feeds. For example, the mean CP contents of V. palaestina (341.87+8.55 g kg -~ DM) and V. sativa (317.36 + 18.68 g kg- 1 DM) compare favourably with those reported for the more conventional soya bean and lupins (Hove and King, 1978) and clearly surpass those reported for Pisum, Vicia faba, Cajanus cajan and Phaseolus species by Hove and King (1978), Ologhobo (1980) and Aletor and Aladetimi (1989). Similarly, the CP contents of virtually all the V. narbonensis and V. ervilia lines were much higher than those commonly reported for lentil, Pisum and Vigna species. Given the desirability of the agronomic characteristics and yield potential of Vicia, it is conceivable that it could play a valuable role as a supplemental
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V.A. Aletor et al. / Animal Feed Science and Technology 47 (1994) 125-139
protein source to cereal straw and other low-nitrogen farm byproducts currently fed to ruminants in several parts of WANA. However, appropriate feeding regimes and the necessary processing technique (s), if any, remain to be established to ensure its optimal utilization. In this context, the data on the relative seed sizes could be of value, especially if cooking is envisaged as a mode of processing. This is because earlier studies with chick peas, lentils and faba beans (Williams et al., 1985; Eskine et al., 1985; Singh et al., 1988 ) have shown significant positive correlation between seed size and cooking time. Indeed, Singh et al. (1988) have suggested that selection for seed weight (an adequate predictor of cooking time) could eliminate labour-intensive tests for cooking time, and thus will enable legume quality analysts to concentrate on the more critical aspects of legume quality such as protein digestibility, S-amino acid content and antinutrient constituents. Although the immense contribution of grain legumes to dietary protein supply is well acknowledged, their ability to synthesize myriad antiphysiological factors remains a major drawback to their direct use as food by man and livestock. The present study shows that Vicia species contain tannins and trypsin inhibitors in varying levels. Unlike 1I. narbonensis, in which most of the lines analysed contained PPT and CE, it was of interest that no PPT was detected in any of the lines of 1I. sativa and 1I. ervilia, while only three of the 16 lines of II. palaestina contained detectable levels. The fact that many simple flavonoids (including carechin) do not precipitate proteins (Hagerman and Butler, 1978 ) tends to suggest that, unlike V. narbonensis, most of the 1I. sativa, 1I. ervilia and I1. palaestina lines may contain predominantly low molecular weight phenolics. These, unlike the condensed tannins, may not be deleterious to animals unless consumed in large amounts. However, they generally contribute to poor palatability of rations (Menhansho et al., 1987 ). Although direct comparison of analytical results on antinutritional factors is often made difficult by differences in analytical techniques, using similar analytical methods Ologhobo (1980), Smith et al. (1980), Aletor and Ojo (1989) and Aletor et al. (unpublished data, 1992) reported much higher levels of TIA for Glycine max, Phaseolus, Vigna and Lathyrus species. Trypsin inhibitor levels in 1I. palaestina were particularly low, and were no more than residual levels found in cooked or roasted soya bean. Most legumes contain trypsin inhibitors whose inactivation by heat treatment improves the nutritional value. Consequently, trypsin inhibitor levels are an important quality index, especially for leguminous protein sources. Data on the other chemical and in vitro parameters showed a significant species difference in ADF, NDF, IVDMD and IVOMD. Vicia ervilia generally had the highest IVDMD and IVOMD values, which seemed to parallel the lower CE and NDF values. In general, the ADF and in vitro digestibility data for the species were similar to those reported for the more conventional feed legumes including V. faba (Garfido et al., 1989). The in vitro data corroborate our earlier suggestion that Vicia seeds could be of great value as protein supplement to the vast amount of cereal straw and grains currently fed to animals in regions where they are primarily cultivated. However, wholesale incorporation into animal diets
V.A. Aletor et al. / Animal Feed Science and Technology 47 (1994) 125-139
137
must be avoided, and the potential toxicity of feeding seeds from species with high fl-cyano-L-alanine levels, especially to monogastric animals, recognized. Although sample size in the present study did not permit reliable correlations to be made between tannins and in vitro digestibilities, Buckley et al. ( 1983 ) and Garrido et al. ( 1989 ) reported significant negative correlations between dietary tannins in V. faba and other plant materials and in vitro digestibilities. The inhibition of protein and carbohydrate degradation in vitro by tannins is believed to arise via a combination of several modes of action, including complexation with proteins, polysaccharides, bacterial cell membranes, or with enzymes involved in protein or carbohydrate degradation (Konishi et al., 1987; Muller et al., 1989 ). The correlations between seed size, CP and the various antinutrients were generally poor, suggesting that a selection programme based on seed size and protein may be difficult. With regard to tannins, a selection programme based on matching seed and flower colours is envisaged in our germplasm collection since seed and flower colours are known to be strongly correlated with tannin levels (Cabrera and Martin, 1986; Garrido et al., 1989). 5. Conclusion It is evident that the protein content and in vitro characteristics of these species of Vicia compare quite favourably with those of the more conventional and higherpriced grain legumes. Additionally, their content of antiproteinases, typified by trypsin inhibitors and tannins, appear to be much lower than found in the more conventional legumes. Clearly, much more information is needed on their content of other antiphysiological agents, especially fl-cyanoalanine, and on simple treatments to ensure their safe use as dietary components for monogastrics and ruminants under feed-lot. Identification and development of cultivars with lower levels of these antinutritional factors, especially offl-cyano-L-alanine, should be a major focus of current breeding programmes. The need for more evaluatory tests on Vicia has become compelling in the wake of reported cases of purposeful adulteration, with Vicia, of some of the more conventional and higher-priced grain legumes. Acknowledgements We greatly appreciate the technical assistance of Adil E1 Awad, Ibrahim Said, Mohammed Heilani and other members of staff of the Forage and Legume Quality Laboratories. Our thanks also go to Farouk Shamo for the statistical analyses. References Abd El Moneim, A.M., Cocks, P.S. and Sweedan, Y., 1988. Yield stability of selected forage vetches ( Vicia spp. ) under rainfed conditions in West Asia. J. Agric. Sci., 111: 295-301.
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Abd El Moneim, A., 1992. Narbon vetch ( Vicia narbonensis): a potential feed legume crop for the dry areas in West Asia. J. Agron. Crop Sci., in press. Aletor, V.A. and Aladetimi, O.O., 1989. Compositional evaluation of some cowpeas varieties and some under-utilized edible legumes in Nigeria. Nahrung, 33: 999-1007. Aletor, V.A. and Ojo, O.I., 1989. Changes in differently processed soya bean (Glycine max) and lima bean (Phaseolus lunatus) with particular reference to their proximate, mineral and inherent antinutritional constituents. Nahrung, 33: 1009-1016. Burns, R.E., 1971. Methods for evaluating tannin content in grain sorghum. Agron. J., 63:511-512. Buckley, K.E., Devlin, T.J. and Marquardt, R.R., 1983. Factors affecting in vitro rumen digestion of faba bean cultivar. Can. J. Anim. Sci., 63: 89-96. Cabrera, A. and Martin, A., 1988. Variation in tannin content of Viciafaba L. J. Agric. Sci., 196: 337382. Cocks, P.S., Thomson, E.F., Sonnmel, K. and Abd E1 Moneim, E.M., 1986. Degradation and rehabilitation of agricultural lands in North Syria. ICARDA- 110 Ar, En Aleppo. International Center for Agricultural Research in the Dry Areas, Aleppo, Syria. Eskine, W., Williams, P.C. and Nakkoul, H., 1985. Genetic and environmentalvariation in the seed size, protein yield and cooking quality of lentils. Field Crops Res., 12: 153-161. Farrel, D.J. and Vohra, P., 1983. In: Recent Advances in Animal Nutrition in Australia. University of New England Publishing Unit, Amidale. Garrido, A., Cabrera, A., Gomez, A. and Guerrero, J.E., 1989. Relationship between tannin content and in vitro nutritive value in seeds of 24 strains of V.faba L. In: J. Huisman, T.F.B. Van der Poel and I.E. Liener (Editors), Recent Advances of Research in Anti-nutritional Factors in Legume Seeds. Pudoc, Wageningen, pp. 156-159. Goering, H.K. and Van Soest, P.J., 1970. Forage Fibre Analysis. Agric. Handbook No. 379. Agric. Research Service, USDA, Washington, DC. Hagerman, A.E. and Buffer, L.G., 1978. Protein precipitation method for the quantitative determination of tannins. J. Agric. Food Chem., 26: 809-812. Hagerman, A.E., Robbins, C.T., Weerasuriya, Y., Williams, T.C. and McAuthur, C., 1992. Tannin chemistry in relation to protein digestibility. J. Range Manage., 45: 57-62. Hove, E.L. and King, S., 1978. Composition, protein quality and toxins of seeds of grain legumes, Glycine max, Lupinus spp., Phaseolus spp., Pisum sativum and Vicia faba. NZ J. Agric. Res., 2 l: 457-462. Konishi, K., Adachi, K., Kita, K. and Horikochi, I., 1987. Inhibitory effect of tannic acid on the respiratory chain of Photobacterium phosphoreum. Chem. Pharm. Bull., 35:1169-1175. Liener, I.E., 1969. In: I.E. Liener (Editor), Toxic Constituents of Plant Foodstuffs. Academic Press, New York. Liener, I.E., 1989. Anti-nutritionalfactors research: state-of-the-art. In: J. Huisman, T.F.B. Van der Poel and I.E. Liener (Editors), Recent Advances of Research in Anti-nutritionalFactors in Legume Seeds. Pudoc, Wageningen, pp. 6-13. Menhansho, H., Butler, L.G. and Carlson, D.M., 1987. Dietary tannin and salivary proline-rich proteins: interaction, induction and defence mechanism. Annu. Rev. Nutr., 7: 423-430. Ministry of Agriculture, Fisheries and Food, 1981. The analysis of agricultural materials. Tech. Bull. RB 427. HMSO, London. Muller, H.M., Leimuller, E. and Rittner, U., 1989. Effect of tanniferous plant materials on protein and carbohydrate degradation in rumen fluid in vitro. In: J. Huisman, T.F.B. Van der Poel and I.E. Liener (Editors), Recent Advances of Research in Anti-nutritionalFactors in Legume Seeds. Pudoc, Wageningen, pp. 156-159. Ologhobo, A.D., 1980. Biochemical and nutritional studies ofcowpeas and lima bean with particular reference to some inherent anti-nutritionalfactors. Ph.D Thesis, University of Ibadan, Nigeria. Price, M.L. and Butler, L.G., 1977. Rapid visual estimation and spectrophotometric determination of tannin content of sorghum. J. Agric. Food Chem., 25: 1268-1273. Price, M.L., Scoyov, S.V. and Butler, L.G., 1978. A critical evaluation of the vanillin reaction as an assay for tannins in sorghum grains. J. Agric. Food Chem., 26: 1214-1219. Singh, K.B., Erskine, W., Robertson, L.D., Nakkoul, H. and Williams, P.C., 1988. Influence of pretreatment on cooking quality parameters in dry food legumes. J. Sci. Food Agric., 44:135-142.
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Smith, C., Megen, V.M., Twaalfhoven, L. and Hitchcock, C., 1980. The determination of trypsin inhibitor levels in foodstuffs. J. Sci. Food Agric., 3 l: 341-350. Steel, R.G. and Torrie, J.H., 1960. Principles and Procedures of Statistics. McGraw-Hill, New York. Tilley, J.M.A. and Terry, R.A., 1963. A two-stage technique for the in vitro digestion of forage crops. J. Br. Grassl. Soc., 18:104-111. Williams, P.C., Singh, K.B. and Nakkoul, H., 1985. Relation of some aspects of Kabuli-type chickpeas to cooking time. J. Sci. Food Agric., 34: 492-496.
E LS EV I ER
Animal Feed Science and Technology 47 (1994) 125-139
Nutritional and antinutritional characteristics of selected Vicia genotypes V.A. Aletor *'1, A.V. Goodchild, A.M Abd E1 Moneim International Centerfor Agricultural Research in the Dry Areas (ICARDA), PO Box 5466, Aleppo, Syria (Received 30 December 1992; accepted 26 October 1993)
Abstract
Mature seeds of Vicia narbonensis (91 lines), Vicia sativa (23 lines), Vicia ervilia ( 16 lines) and Vicia palaestina ( 16 lines) were evaluated for crude protein (CP), protein precipitable tannin (PPT), vanillin-HC1 catechin equivalent (CE) and trypsin inhibitor activity (TIA). Other chemical and in vitro characteristics measured included ash, organic matter (OM), neutral detergent fibre (NDF), acid detergent fibre (ADF), in vitro organic digestibility (IVOMD) and in vitro dry matter (DM) digestibility (IVDMD). Crude protein content ranged from 264.38 + 6.34 g kg- 1 DM in V. ervilia to 341.87 + 8.55 g kg- 1DM in V. palaestina with all species showing little intraspecies variability. The DM, OM and ash contents of all the lines were similar. However, the ADF and NDF values for V. narbonensis were significantly ( P < 0.05) higher than those of the other species. Mean IVDMD and IVOMD values of the species also differed significantly ( P < 0.05 ). The higher IVDMD (90.95%) and IVOMD (88.30%) values of V. ervilia paralleled the relatively lower ADF and NDF values. PPT was mainly restricted to V. narbonensis while none was detected in any of the lines of either V. sativa or V. ervilia. Tannin expressed as CE was no more than 8.27 g kg- t in any of the species and seven of the 91 lines of V. narbonensis had no detectable CE levels. There was considerable intraspecies variability in CE as indicated by the high coefficients of variation (CV), which ranged from 17.48% in V. palaestina to 68.99% in V. sativa. In comparison with most conventional legumes, TIA values were generally low in all the species, ranging from 0.36 g kg -~ DM in selection IFLVP 2524 to 5.00 gkg -1 DM in IFLVS 2560. Values for TIA in V. palaestina were particularly low (0.51 + 0.13 g kg- ~ DM) and a CV of 25.86% suggests that selection for lower inhibitor levels is possible. Seed weight was significantly (P<0.05) correlated with CE in both V. sativa and V. palaestina, while CP was weakly negatively correlated ( r = - 0.48 ) with TIA among the V. *Corresponding author. tPresent address: Institut fiir Tieremahrung, University of Bonn, Endenicher Allee 15, Bonn 1, Germany. 0377-8401/94/$07.00 © 1994 Elsevier Science B.V. All rights reserved SSD10377-8401 (93) 00568-G
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V.A. Aletor et al. / Animal Feed Science and Technology 4 7 (1994) 125-139
sativa genotypes. There was no significant relationship between seed weight and TIA in
any of the species investigated.
1. Introduction
The principal agricultural activity in the dry areas of West Asia and North Africa (WANA) is small ruminant (sheep and goat) production with rangeland grazing providing most of the animal feed (Cocks et al., 1986). During periods of high livestock feed prices, feed legumes such as Vicia species, which may be fed to small ruminants in the form of straw and grain, are increasingly attractive to farmers in WANA (Abd E1 Moneim et al., 1988). In view of the overall objectives of The International Center for Agricultural Research in the Dry Areas (ICARDA) of developing sustainable farming systems in the dry areas, there is a clear need for feed legume crops. One of the most attractive legume species for grain and straw production is Narbon vetch, Vicia narbonensis. It is a good source of protein with seeds containing up to 28% protein and yielding about 365 kg protein ha- ~while the straw contains about 9% protein (Abd E1 Moneim, 1992 ). ICARDA currently maintains breeding lines of Vicia species which include V. narbonensis L., Vicia sativa L., Vicia ervilia and Vicia palaestina R. In this study, we present compositional data on selected lines of these species with respect to their crude protein (CP), trypsin inhibitor activity (TIA), catechin equivalents (CE) and protein precipitable tannin (PPT) content. These parameters are of interest because both trypsin inhibitors and tannins are implicated in poor protein digestibility (Liener, 1969, 1989 ), while tannins generally have been associated with poor digestibility and palatability (Menhansho et al., 1987; Hagerman et al., 1992). We hope that this information, along with in vitro characteristics, will arouse greater interest in the exploitation of their potential in human and/or animal feeding.
2. Materials and methods
The Vicia genotypes evaluated were obtained from the breeding programme at ICARDA (Tel Haydia, Syria; 36°40'N, 37°20'E, 390 m elevation). The current breeding procedure uses germplasm evaluation and seed multiplication in nursery rows, and evaluates selected genotypes in microplots and promising genotypes in advanced yield trials. The samples analysed were mature grains comprising 91 lines of V. narbonensis (Narbon vetch), 23 lines of V. sativa (common vetch), 16 lines of V. ervilia (bitter vetch) and 16 lines of V. palaestina. About 50 g each of the dried seeds were ground before use using a UD cyclone sample mill (UD Corporation, Fort Collins, CO, USA) fitted with a 1 mm mesh sieve. The dry matter (DM), CP and ash were determined as described by the Min-
V.A. Aletor et al. / Animal Feed Science and Technology 47 (1994) 125-139
127
istry of Agriculture, Fisheries and Food (1981), while neutral detergent fibre (NDF) and acid detergent fibre (ADF) were determined by the method of Goering and Van Soest (1970). Some random selections were also evaluated for in vitro organic matter digestibility (IVOMD) and in vitro dry matter digestibility (IVDMD) using the technique of Tilley and Terry (1963). The weight of 100 seeds was estimated using a mechanical seed counter (Numigral, Franken, Netherlands) before weighing. 2. I. Assay for antinutritional factors
2.1.1. Protein precipitable tannin (PPT) and catechin equivalent (CE) All samples for tannin determination were milled just before analysis to prevent the oxidation of phenolic compounds. A 200 mg measure of the flour was defatted in a screw-top test-tube with 5 ml of ethyl ether for 15 min using a GalTable 1 Crude protein (CP), protein precipitable tannin ( P P T ) , tannin measured as vanillin-HC1 catechin equivalent (CE) and trypsin inhibitor activity (TIA) of V. narbonensis seeds selected in microplots Selection no.
Weight per 100 DM seeds (g) (%)
CP (gkg -~ D M )
PPT (gkg - l D M )
CE (gkg - l D M )
IFLVN2376 IFLVN 2377 IFLVN2378 IFLVN 2379 IFLVN 2381 IFLVN 2382 IFLVN2384 IFLVN 2385 IFLVN2386 IFLVN2389 IFLVN 2394 IFLVN2395 IFLVN2396 IFLVN 2397 IFLVN 2398 IFLVN2460 IFLVN 2463 IFLVN 2482 IFLVN2597 IFLVN2598 IFLVN 2599 IFLVN 2600 IFLVN 2601 IFLVN 2602
19.371 21.168 20.868 17.928 19.192 17.664 20.096 20.686 16.968 18.85 15.838 21.24 16.399 19.208 13.507 14.296 18.691 16.371 14.658 20.866 13.129 17.8 18.607 15.329
90.79 90.65 90.65 90.72 90.67 90.59 90.72 90.64 90.77 90.60 90.67 90.81 90.70 90.60 90.53 90.69 90.62 90.70 90.51 90.72 90.78 90.65 90.65 90.71
301.02 294.54 306.56 285.16 303.85 303.34 276.01 277.69 274.43 276,93 285.43 285.87 288.09 288.30 276.15 278.20 290.22 288.31 284.06 295.19 283.98 301.27 325.32 292.25
ND 4.37 4.62 4.62 4.19 4.54 4.44 4.19 4.19 4.28 4.37 4.61 4.44 4.54 4.45 ND 4.11 ND 4.38 4.53 4.36 4.19 ND 4.28
1.38 1.65 1.65 2.48 1.38 1.93 1.38 1.38 1.38 1.38 1.93 2.75 2.48 2.48 2.76 2.76 2.76 1.93 2.49 2.48 3.30 1.93 1.38 1.93
4.13 3.49 3.34 3.85 3.04 3.71 3.20 3.34 3.04 3.41 3.71 4,57 4.13 4,58 3,13 3,20 3.49 3.34 3.35 4.35 2.83 3.34 3.34 3.70
Mean SD CV (%)
17.864 2.428 13.593
90.67 290.09 0.07 11.95 0.08 4.12
4.38 0.16 3.59
2.06 0.58 28.17
3.57 0.47 13.21
SD, standard deviation; CV, coefficient of variation; ND, none detected.
TIA (gkg - 1 D M )
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Table 2 Crude protein (CP), protein precipitable tannin (PPT), tannin measured as vanillin-HCl catechin equivalent (CE) and trypsin inhibitor activity (TIA) of I~. narbonensis seeds multiplied in the nursery Selection no.
Weight per 100 DM seeds (g) (g)
CP (gkg - 1 D M )
PPT (gkg - I D M )
CE (gkg -~DM)
IFLVN 111 IFLVN 112 IFLVN 113 IFLVN 114 IFLVN 123 IFLVN 124 IFLVN 125 IFLVN 126 IFLVN 127 IFLVN 129 IFLVN 130 IFLVN 543 IFLVN 569 IFLVN 580 IFLVN 584 IFLVN 803 IFLVN 1142 IFLVN 1144 IFLVN 1147 IFLVN 1148 IFLVN 1150 IFLVN 1152 IFLVN2272 IFLVN2524 IFLVN2525 IFLVN2528 IFLVN 2529 IFLVN2530 IFLVN2531 IFLVN2532 IFLVN2533 IFLVN2556 IFLVN 2624 IFLVN 2628 IFLV-N 2644 IFLVN 2649 IFLVN 2663 IFLVN 2696 IFLVN 2697 IFLVN 2702 IFLVN 2703 IFLVN2706
11.226 12.411 11.417 12.651 15.252 12.045 12.807 11.901 13.186 11.666 12.404 12.648 14.168 15.746 9.713 9.684 8.344 13.379 7.295 6.518 7.682 6.807 10.675 12.723 12.774 14.031 11.58 12.389 14.282 12.441 12.952 12.371 5.612 6.917 9.198 6.88 8.623 9.508 8.58 8.488 8.55 12.43
90.82 90.75 90.94 90.71 90.68 90.82 90.72 91.12 91.27 91.16 91.21 91.19 90.68 90.71 91.19 90.91 91.06 90.99 91.08 91.04 91.04 91.13 90.87 90.83 90.95 90.56 90.77 91.36 90.92 90.61 90.57 90.79 89.28 91.13 90.93 90.80 91.06 91.15 91.12 90.78 90.85 90.76
297.40 322.09 295.69 301.40 296.87 273.40 307.76 315.30 258.90 275.78 261.92 263.08 309.88 295.78 258.91 286.88 253.02 275.85 282.72 307.12 281.96 288.05 292.73 298.58 291.15 282.13 278.07 304.18 290.59 292.68 257.26 280.65 311.38 298.36 292.09 279.41 247.42 259.13 258.56 272.75 279.91 313.02
4.36 4.44 4.35 4.19 4.53 5.14 4.71 4.77 4.94 5.04 5.46 5.55 4.53 4.53 4.68 5.22 5.73 4.96 4.35 5.04 5.04 4.60 5.23 4.70 4.18 4.11 4.10 4.50 4.78 4.19 5.16 5.45 ND 5.12 4.18 5.23 4.51 4.17 4.08 ND 5.05 ND
4.40 2.48 3.30 2.76 2.48 4.68 2.76 2.47 3.83 4.39 4.66 4.93 1.93 2.76 1.92 3.85 3.29 3.57 3.84 3.57 2.20 4.39 2.75 2.75 2.20 1.93 2.75 1.92 2.75 1.93 3.04 2.20 1.96 1.92 1.37 4.41 0.82 1.92 2.47 1.38 2.20 0.83
3.77 3.12 3.47 3.20 3.77 2.90 3.20 3.25 2.88 3.47 3.32 3.18 3.48 3.91 2.30 3.33 4.48 3.33 3.90 3.39 4.48 3.47 3.70 4.05 3.11 4.36 3.12 3.10 3.04 2.90 2.54 2.83 4.28 4.40 4.05 3.91 2.24 3.10 3.18 3.26 3.26 3.21
Mean SD CV (%)
10.951 2.579 23.547
90.89 285.47 0.32 18.72 0.35 6.56
4.74 0.45 9.51
2.81 1.05 37.48
3.41 0.54 15.84
SD, standard deviation; CV, coefficient of variation; ND, none detected.
TIA (gkg -~ DM)
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Table 3 Crude protein (CP), protein precipitable tannin ( P P T ) , tannin measured as vanillin-HCl catechin equivalent (CE) and trypsin inhibitor activity (TIA) of advanced lines of V. narbonensis seeds Selection no.
Weight per 100 DM seeds (g) (%)
CP (gkg - 1 D M )
PPT (gkg - I D M )
CE (gkg - 1 D M )
IFLVN 2561 IFLVN 2380 IFLVN 2383 IFLVN2387 IFLVN 2388 IFLVN2390 IFLVN 2391 IFLVN2392 IFLVN2393 IFLVN 2461 IFLVN 2462 IFLVN2464 IFLVN 2465 IFLVN 2466 IFLVN 2467 IFLVN2468 IFLVN 2469 IFLVN2470 IFLVN 2471 IFLVN2473 IFLVN 2474 IFLVN2475 IFLVN 2476 IFLVN 2477 IFLVN 2478
10.596 17.425 19.821 18.833 16.035 16.917 17.686 16.533 20.139 21.405 19.914 22.247 18.357 19.954 21.63 21.386 21.001 22.638 24.412 13.735 19.609 23.086 19.144 21.354 19.576
296.82 274.56 295.54 270.18 306.85 294.20 305.38 277.97 305.68 272.59 277.56 281.06 284.52 309.77 311.30 303.85 313.51 293.21 294.34 287.80 304.66 294.88 297.35 292.63 287.50
4.10 ND 4.19 ND ND ND ND ND ND ND ND 4.09 4.09 ND ND ND ND ND ND ND ND ND 4.18 ND 4.17
ND ND ND 0.83 ND 0.83 ND ND ND 1.37 1.92 1.38 1.38 0.55 ND 0.55 0.55 0.55 1.10 0.55 0.55 0.83 1.65 1.38 2.19
3.77 2.68 2.68 2.47 2.89 3.00 2.83 2.32 2.61 3.53 3.69 3.92 4.13 4.34 3.04 2.33 3.48 3.22 2.01 3.21 4.87 3.82 3.39 4.00 4.51
90.83 293.35 0.21 12.42 0.23 4.23
4.14 0.04 1.01
1.07 0.51 48.14
3.31 0.73 22.11
Mean SD CV (%)
19.337 2.977 15.393
90.66 90.69 90.75 90.83 90.89 90.04 90.87 90.91 90.88 91.09 91.15 90.87 90.89 90.97 90.78 90.67 90.81 90.72 90.71 91.00 90.79 90.85 90.87 90.83 91.13
TIA (gkg -~ D M )
SD, standard deviation; CV, coefficient of variation; ND, none detected.
lenkamp Lab Quake followed by centrifugation. The extract was discarded and the air-dry residue was thereafter extracted with 60% methanol; the PPT content of the extract was determined using standard bovine serum albumin (Lot 41H0520; Sigma, St. Louis, MO, USA) as outlined by Hagerman and Butler ( 1978 ). CE, which detects simple flavonoids as well as condensed tannins, was determined by the vanillin-HC1 method of Burns (1971 ) as modified by Price and Butler (1977) and Price et al. (1978). Commercial ( _+ )-catechin (Lot C0774; Sigma) was used as reference standard.
2.1.2. Trypsin inhibitor activity (TIA) The TIA content of the grains was measured as the extent to which an extract of the flour inhibited the action of bovine trypsin (EC 3.4.21.1 ) on the substrate benzoyl-DL-arginine-p-nitroanilide hydrochloride (Lot 110H0329; Sigma) as
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Table 4 Crude protein (CP), protein precipitable tannin (PPT), tannin measured as vanillin-HC1 catechin equivalent (CE) and trypsin inhibitor activity (TIA) in seeds from advanced lines of V. sativa Selection no. IFLVS 545 IFLVS 1134 IFLVS 1135 IFLVS 1136 IFLVS 1437 IFLVS 1448 IFLVS2019 IFLVS 2037 IFLVS 2044 IFLVS 2057 IFLVS 2062 IFLVS 2065 IFLVS 2083 IFLVS 2086 IFLVS2096 IFLVS 2106 IFLVS 2108 IFLVS 2109 IFLVS 2556 IFLVS 2557 IFLVS2539 IFLVS 2603 IFLVS 2560
Mean SD CV (%)
Weightper 100 DM seeds (g) (%) 4.995 4.794 5.534 4.397 4.908 2.08 5.822 2.539 4.227 3.802 6.729 2.103 4.898 5.37 4.711 4.518 5.313 4.86 5.509 2.464 5.716 5.522 4.805 4.592 1.209 26.336
CP (gkg - l DM)
PPT (gkg - 1 D M )
336.53 306.96 302.69 343.21 344.27 307.25 315.81 294.35 355.94 344.88 298.45 315.88 318.85 323.49 328.38 306.34 322.92 301.36 312.95 306.68 292.29 284.71 335.18
ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND
2.76 2.21 1.38 4.41 3.29 5.51 2.20 6.07 1.93 4.97 1.66 8.27 1.93 1.93 1.93 3.30 0.55 1.92 0.83 5.00 0.28 1.39 1.39
3.57 4.36 3.82 4.17 3.98 4.44 4.96 4.88 4.61 4.49 4.88 4.61 4.00 4.09 2.95 3.74 4.88 4.08 4.53 4.65 4.05 4.01 5.00
90.59 317.36 0.33 18.69 0.37 5.89
ND ND ND
2.83 1.95 68.99
4.29 0.50 11.58
90.66 90.63 90.72 90.79 91.12 90.74 90.72 90.54 90.69 90.61 90.60 90.70 90.67 90.73 90.81 90.88 90.55 90.96 90.75 89.93 89.74 89.95 90.07
CE (g kg - l DM)
TIA (gkg -~ DM)
SD, standard deviation; CV, coefficient of variation; ND, none detected.
modified by Smith et al. (1980). The flour was first defatted at room temperature with 50 ml portions of petroleum ether (b.p. 4 0 - 6 0 ° C ) in covered flasks and then mechanically shaken until fat-free. The extract was discarded and the residue air-dried. Extracts were thereafter made from 1 g of the flour with 10 mM NaOH for 3 h at room temperature using an orbital shaker (Gallenkamp, UK). The pH of the resulting slurry was adjusted to 9.5 with 1 M NaOH or 1 M HCI. After extraction, the suspension was shaken and diluted with distilled water such that 1 ml of the diluted extract produced trypsin inhibition of between 40% and 60% at 37 °C. The respective dilutions were noted and, in the present assay, dilutions of 5 or 6 were suitable for all the species except F. palaestina extracts which needed no dilution. The TIA was subsequently determined in terms of mg pure trypsin g - l sample using the equation TIA = 2.632DA/S, where D is dilution factor, A is change in absorbance at 410 nm resulting from trypsin inhibition per cm 3 of diluted sample extract, S is weight of sample (Smith et al., 1980 ).
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Table 5 Crude protein (CP), protein precipitable tannin (PPT)m tannin measured as vanillin-HC1 catechin equivalent (CE), and trypsin inhibitor activity (TIA) in seeds from advanced lines of V. ervilia Selection no.
Weight per 100 DM seeds (g) (%)
CP (gkg -~ D M )
PPT (gkg - ~ D M )
IFLVE2508 IFLVE 2509 IFLVE2510 IFLVE 2511 IFLVE 2512 IFLVE 2513 IFLVE2514 IFLVE 2515 IFLVE 2516 IFLVE2517 IFLVE2518 IFLVE2519 IFLVE2520 IFLVE 2521 IFLVE2522 IFLVE 2563
5.032 4.619 4.384 4.204 4.883 4.891 4.621 4.772 5.042 4.734 4.549 4.381 4.068 5.083 4.878 3.851
90.35 90.27 90.23 90.50 90.40 90.40 90.17 90.30 90.15 90.19 90.23 90.47 90.14 90.24 90.26 90.48
262.65 259.11 261.44 270.28 254.65 259.07 257.85 272.54 255.68 270.54 264.32 267.82 268.69 267.40 260.14 277.96
ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND
1.66 0.83 1.66 1.66 1.66 2.21 2.22 2.21 2.22 1.66 1.66 3.32 2.77 1.39 2.22 2.76
2.71 3.41 3.50 3.40 3.50 3.58 3.59 3.77 3.59 2.89 4.29 3.23 3.77 3.06 3.41 3.58
Mean
4.625 0.353 7.634
90.30 264.38 0.12 6.43 0.13 2.43
ND ND ND
2.01 0.59 29.42
3.46 0.36 10.36
SD CV (%)
CE (gkg -~ D M )
TIA (gkg -~ D M )
SD, standard deviation; CV, coefficient of variation; ND, none detected.
2.2. Data analyses All values (means of duplicate determinations) were analysed statistically and coefficients of variation (CV) within the lines were calculated (Steel and Torrie, 1960). Mean values on the proximate and in vitro parameters in the randomly selected lines were compared using MSTATC software while the correlations between the weight of 100 seeds, CP and the anti-quality factors were computed using SPSS.
3. Results
3.1. Dry matter (DM), seed weight and crude protein (CP) content The weight of 100 seeds and the DM and CP contents of all the species are shown in Tables 1-6. The DM values of all the lines analysed were similar, and ranged from 90.26 _+0.16% in V. palaestina to 90.89 __0.32% in V. narbonensis. The weight of 100 seeds was least in V. palaestina (3.77_+0.28 g; Table 6) and highest in V. narbonensis (19.33 _+2.97 g; Table 3 ). The average weights of the seeds of V. sativa and V. ervilia were similar, and generally much lower than those
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Table 6 Crude protein (CP), protein precipitable tannin (PPT), tannin measured as vanillin-HCl catechin equivalent (CE) and trypsin inhibitor activity (TIA) of seeds from advanced lines of V. palaestina Selection no.
Weight per 100 DM seeds (g) (%)
CP (gkg - l DM)
PPT (gkg - ~ DM)
IFLVP2523 IFLVP2524 IFLVP 2525 IFLVP2526 IFLVP2527 IFLVP 2528 IFLVP2529 IFLVP 2530 IFLVP2531 IFLVP2532 IFLYP2533 IFLVP2534 IFLVP2535 IFLVP 2536 IFLVP2537 IFLVP2538
3.586 3.500 3.543 3.312 3.609 3.730 4.050 4.150 4.033 4.170 3.836 4.310 3.703 3.468 3.658 3.703
90.45 90.42 90.31 90.29 90.35 90,11 90.43 90,39 90,37 90,45 90.18 90.24 90.11 90.01 90.08 89.92
348.70 349.37 355.66 329.60 332.04 340.36 334.29 350.04 352.66 345.94 334.77 346.63 332.93 327.74 345.58 343.53
ND ND ND ND ND ND ND ND ND ND ND ND ND 4.40 4.31 4.40
3.59 3.32 3.60 1.94 2.21 3.61 3.32 3.32 3.32 4.15 3.33 3.32 2.50 2.78 3.33 2.78
0.54 0.36 0.47 0.37 0.51 0.68 0.46 0.48 0.45 0.43 0.51 0.38 0.47 0.84 0.75 0.47
Mean SD CV (%)
3.773 0.280 7.427
90.26 341.87 0.16 8.55 0.18 2.50
4.37 0.04 1.02
3.15 0.55 17.48
0.51 0.13 25.86
CE (gkg -~ DM)
TIA (gkg - 1 D M)
SD, standard deviation; CV, coefficient of variation; ND, none detected.
of V. narbonensis. Intraspecies variabilities in seed weights were generally higher in V. narbonensis than in the other species as shown by their respective CVs. The species with the lowest and highest mean CP values were V. ervilia (264.38 _+6.43 g kg -~ DM; Table 3) and V. palaestina (341.87_+8.55 g kg -1 DM; Table 6), respectively. The CP content of V. sativa (Table 4) was similar to that of V. palaestina. The CV, an indicator of intraspecies variability in CP, was similar and small in all lines.
3.2. Protein precipitable tannin (PPT) and vanillin-HCl catechin equivalent (CE) The PPT levels in K narbonensis lines (Tables I-3 ) were similar to those in K palaestina (Table 6). No PPT was detected in any line of K sativa or K ervilia. Most of the lines from the advance collection of K narbonensis and K palaestina had no detectable PPT levels. Flavonoid content (including condensed tannins), measured as CE, was no more than 8.27 g kg- ~ DM in all the Vicia species, and seven of the 91 K narbonensis lines had no detectable CE. All the lines from the other species contained CE with mean values ranging from 1.07_+0.51 g kg -~ DM in K narbonensis to 3.15 g kg-~ DM in K palaestina. There were large intraspecies variations in CE content as show by the high CVs which ranged from 17.48% in V. palaestina to 68.99% in V. sativa.
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Table 7 Proximate and in vitro characteristics of Vicia seeds DM CP OM Ash ADF NDF (gkg -1) (gkg -1) (gkg - l ) (gkg - t ) (gkg -~) (gkg - l )
IVDMD IVOMD (%) (%)
V. narbonensis (microplo 0 IFLVN 2379 IFLVN 2389 IFLVN 2395 IFLVN 2601 Mean SD
907.20 906.00 908.10 906.50 906.95a 0.79
285.16 276.93 285.87 325.32 293.32a 18.81
968.00 964.60 967.50 963.40 965.88a 1.93
35.21 39.06 35.80 40.37 37.61a 2.17
137.54 187.06 1 2 5 . 7 9 198.31 97.83 198.20 1 1 2 . 2 8 209.55 118.36b 198.28b 14.85 7.95
88.98 89.35 88.54 89.29 89.04a 0.32
85.79 85.57 85.27 85.46 85.52a 0.19
273.40 263.08 272.75 313.02 280.56b 19.18
973.00 964.10 965.60 963.80 966.63a 3.74
29.70 39.47 37.86 39.86 36.72a 4.12
149.17 165.13 176.00 156.74 161.76a 9.97
86.08 87.43 85.92 86.23 86.42b 0.60
83.55 83.43 82.48 82.44 82.98b 0.52
274.56 277.56 287.50 296.82 284.11a 8.76
965.20 967.80 967.40 970.60a 1.70
38.35 35.34 35.88 33.09 35.67a 1.87
137.54 194.07 107.23 149.60 113.91 191.39 1 2 8 . 7 2 249.83 121.85b 196.22bc 11.94 35.62
88.76 89.22 89.76 88.31 89.01a 0.54
85.22 86.48 86.06 85.17 85.73a 0.56
307.25 294.35 322.92 292.29 304.20a 12.23
967.60 967.10 966.80 973.90 968.85a 2.93
35.75 36.37 36.68 28.81 34.40a 3.25
95.00 95.63 75.68 69.88 84.05c 11.45
136.60 135.77 147.83 156.33 144.13bc 8.50
83.53 83.85 86.69 87.66 85.43b 1.78
79.94 80.78 83.72 85.66 82.53abd 2.29
259.11 267.82 268.69 267.40 265.76d 3.86
970.10 972.60 970.20 971.70 971.15b 1.05
32.87 29.97 32.69 31.08 31.65a 1.20
59.25 55.14 58.57 54.14 56.78d 2.18
148.07 156.43 140.24 113.22 139.49c 16.21
90.22 91.92 91.23 90.44 90.95c 0.67
87.29 89.31 88.53 88.05 88.30c 0.73
348.70 329.60 332.04 345.94 339.07c 8.35
965.90 970.00 969.60 967.90 968.35a 1.62
37.35 32.97 33.39 35.00 34.68a 1.72
89.80 101.10 91.38 85.16 91.86c 5.80
181.03 174.51 125.32 120.71 150.39c 27.52
81.48 82.00 83.05 81.40 81.98d 0.66
78.09 79.74 80.66 78.40 79.22d 1.04
V. narbonensis (nursery) IFLVB 124 IFLVN 543 IFLVN 2702 IFLVN 2706 Mean SD
908.20 901.90 907.80 907.60 906.38a 2.59
235.97 234.06 296.75 304.00 267.70a 32.79
V. narbonensis (advance) IFLVN 2380 IFLVN 2462 IFLVN 2478 IFLVN2561 Mean SD
906.90 911.50 906.60 906.58a 3.61
V. sativa (multilocation) IFLVS 1 4 4 8 IFLVS 2037 IFLVS 2108 IFLVS 2559 Mean SD
907.40 905.40 905.50 897.40 903.93a 3.85
V. ervilia (microploO IFLVE 2509 IFLVE 2519 IFLVE 2520 IFLVE 2 5 2 1 Mean SD
902.70 914.70 901.40 902.40 905.30a 5.45
V. palaestina (microplo 0 IFLVP 2523 IFLVP 2526 IFLVP 2527 IFLVP 2532 Mean SD
904.50 902.90 903.50 914.50 906.35a 4.74
Means followed by dissimilar letters in the same vertical column differ significantly (P< 0.05 ). SD, standard deviation.
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V.A. Aletor et al. / Animal Feed Science and Technology 47 (1994) 125-139
Table 8 Correlation coefficients (r) b e t w e e n weight o f seeds, c r u d e p r o t e i n a n d a n t i n u t r i t i o n a l factors PPT
CE
TIA
91 -0.45 *
91 -0.12 NS
91 -0.02 NS
91 -0.21 *
91
91
0.01 NS
0.17 NS
-
23 -0.65 ***
23 -0.31 NS
-
23 -0.04 NS
23 -0.48 *
-
16 -0.41 NS
16 -0.34 NS
16
16 -0.05 NS
V. narbonensis Weight o f 100 seeds n r P C r u d e protein n r P
V. sativa Weight o f 100 seeds n r P C r u d e protein n r P
23
23
V. ervilia Weight o f 100 seeds n r P Crude protein n r P
16
16 -
0.32 NS
V. palaestina Weight o f 100 seeds n r P Crude protein n r P
16 -0.2 NS 16 -0.16 NS
16 0.55
16 -0.27 NS
0.65
16 -0.28 NS
* 16 *
* P < 0.05; **P< 0.01; ***P< 0.001. n, n u m b e r o f observations; NS, n o t significant.
3.3. Trypsin inhibitor activity (TIA) All species contained low levels of TIA with mean values ranging from 0.51 + 0.13 g kg- 1 DM in V. palaestina (Table 6) to 4.29 + 0.50 g kg- 1 DM in V. sativa (Table 4 ). TIA values were highest in IFLVS 2560 (5.00 g kg- ~ D M ) and
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135
least in IFLVP 2524 (0.36 g kg-~ DM). All the V. palaestina lines had low TIA, with values ranging from 0.36 g kg -~ DM in IFLVP 2524 to 0.84 g kg -~ DM in IFLVP 2536 with a CV of 25.86%. Mean TIA values in all lines of V. narbonensis, V. sativa and V. ervilia were generally similar, but substantially higher than those of V. palaestina (Table 6). 3.4. Proximate and in vitro studies
Some chemical and in vitro data on randomly chosen lines from each of the species are summarized in Table 7. The OM and ash contents of the samples were generally similar. However, the ADF and NDF values of V. narbonensis lines were significantly ( P < 0.05) higher than those of the other species. The mean IDMD and IOMD values of the species also differed significantly ( P < 0.05 ). The higher IDMD (90.95%) and IOMD (88.30%) values of F. ervilia appeared to parallel the lower ADF ( 56.78 g kg- ~DM) and NDF ( 139.49 g kg- ~DM) values. 3.5. Correlation analysis
Table 8 summarizes the correlation coefficients (r) between seed weight, CP and the different antinutrients. Seed weight was significantly and negatively correlated with PPT only among the V. narbonensis lines ( P < 0.05; r= - 0.45 ). Seed weight was also correlated significantly ( P < 0.05 ) with CE in both V. sativa and V. palaestina. There were no significant correlations between seed weight and TIA in any of the species. Crude protein was positively correlated (r= 0.05 ) with CE only in V. palestina lines. Similarly, there was a significant correlation ( P < 0.05 ); r= - 0 . 4 8 ) between CP and TIA only among the V. sativa genotypes.
4. Discussion
It is well documented (Hove and King, 1978; Farrell and Vohra, 1983; Liener, 1989 ) that the nutritional importance of a given food/feedstuffin a diet depends not only on the nutrient composition of the raw feedstuff, but also on the amount that is consumed as well as the presence of antinutritional constituents. With regard to CP, the present data suggest that Vicia species could be important contributors of plant protein supplements to foods and feeds. For example, the mean CP contents of V. palaestina (341.87+8.55 g kg -~ DM) and V. sativa (317.36 + 18.68 g kg- 1 DM) compare favourably with those reported for the more conventional soya bean and lupins (Hove and King, 1978) and clearly surpass those reported for Pisum, Vicia faba, Cajanus cajan and Phaseolus species by Hove and King (1978), Ologhobo (1980) and Aletor and Aladetimi (1989). Similarly, the CP contents of virtually all the V. narbonensis and V. ervilia lines were much higher than those commonly reported for lentil, Pisum and Vigna species. Given the desirability of the agronomic characteristics and yield potential of Vicia, it is conceivable that it could play a valuable role as a supplemental
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protein source to cereal straw and other low-nitrogen farm byproducts currently fed to ruminants in several parts of WANA. However, appropriate feeding regimes and the necessary processing technique (s), if any, remain to be established to ensure its optimal utilization. In this context, the data on the relative seed sizes could be of value, especially if cooking is envisaged as a mode of processing. This is because earlier studies with chick peas, lentils and faba beans (Williams et al., 1985; Eskine et al., 1985; Singh et al., 1988 ) have shown significant positive correlation between seed size and cooking time. Indeed, Singh et al. (1988) have suggested that selection for seed weight (an adequate predictor of cooking time) could eliminate labour-intensive tests for cooking time, and thus will enable legume quality analysts to concentrate on the more critical aspects of legume quality such as protein digestibility, S-amino acid content and antinutrient constituents. Although the immense contribution of grain legumes to dietary protein supply is well acknowledged, their ability to synthesize myriad antiphysiological factors remains a major drawback to their direct use as food by man and livestock. The present study shows that Vicia species contain tannins and trypsin inhibitors in varying levels. Unlike 1I. narbonensis, in which most of the lines analysed contained PPT and CE, it was of interest that no PPT was detected in any of the lines of 1I. sativa and 1I. ervilia, while only three of the 16 lines of II. palaestina contained detectable levels. The fact that many simple flavonoids (including carechin) do not precipitate proteins (Hagerman and Butler, 1978 ) tends to suggest that, unlike V. narbonensis, most of the 1I. sativa, 1I. ervilia and I1. palaestina lines may contain predominantly low molecular weight phenolics. These, unlike the condensed tannins, may not be deleterious to animals unless consumed in large amounts. However, they generally contribute to poor palatability of rations (Menhansho et al., 1987 ). Although direct comparison of analytical results on antinutritional factors is often made difficult by differences in analytical techniques, using similar analytical methods Ologhobo (1980), Smith et al. (1980), Aletor and Ojo (1989) and Aletor et al. (unpublished data, 1992) reported much higher levels of TIA for Glycine max, Phaseolus, Vigna and Lathyrus species. Trypsin inhibitor levels in 1I. palaestina were particularly low, and were no more than residual levels found in cooked or roasted soya bean. Most legumes contain trypsin inhibitors whose inactivation by heat treatment improves the nutritional value. Consequently, trypsin inhibitor levels are an important quality index, especially for leguminous protein sources. Data on the other chemical and in vitro parameters showed a significant species difference in ADF, NDF, IVDMD and IVOMD. Vicia ervilia generally had the highest IVDMD and IVOMD values, which seemed to parallel the lower CE and NDF values. In general, the ADF and in vitro digestibility data for the species were similar to those reported for the more conventional feed legumes including V. faba (Garfido et al., 1989). The in vitro data corroborate our earlier suggestion that Vicia seeds could be of great value as protein supplement to the vast amount of cereal straw and grains currently fed to animals in regions where they are primarily cultivated. However, wholesale incorporation into animal diets
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must be avoided, and the potential toxicity of feeding seeds from species with high fl-cyano-L-alanine levels, especially to monogastric animals, recognized. Although sample size in the present study did not permit reliable correlations to be made between tannins and in vitro digestibilities, Buckley et al. ( 1983 ) and Garrido et al. ( 1989 ) reported significant negative correlations between dietary tannins in V. faba and other plant materials and in vitro digestibilities. The inhibition of protein and carbohydrate degradation in vitro by tannins is believed to arise via a combination of several modes of action, including complexation with proteins, polysaccharides, bacterial cell membranes, or with enzymes involved in protein or carbohydrate degradation (Konishi et al., 1987; Muller et al., 1989 ). The correlations between seed size, CP and the various antinutrients were generally poor, suggesting that a selection programme based on seed size and protein may be difficult. With regard to tannins, a selection programme based on matching seed and flower colours is envisaged in our germplasm collection since seed and flower colours are known to be strongly correlated with tannin levels (Cabrera and Martin, 1986; Garrido et al., 1989). 5. Conclusion It is evident that the protein content and in vitro characteristics of these species of Vicia compare quite favourably with those of the more conventional and higherpriced grain legumes. Additionally, their content of antiproteinases, typified by trypsin inhibitors and tannins, appear to be much lower than found in the more conventional legumes. Clearly, much more information is needed on their content of other antiphysiological agents, especially fl-cyanoalanine, and on simple treatments to ensure their safe use as dietary components for monogastrics and ruminants under feed-lot. Identification and development of cultivars with lower levels of these antinutritional factors, especially offl-cyano-L-alanine, should be a major focus of current breeding programmes. The need for more evaluatory tests on Vicia has become compelling in the wake of reported cases of purposeful adulteration, with Vicia, of some of the more conventional and higher-priced grain legumes. Acknowledgements We greatly appreciate the technical assistance of Adil E1 Awad, Ibrahim Said, Mohammed Heilani and other members of staff of the Forage and Legume Quality Laboratories. Our thanks also go to Farouk Shamo for the statistical analyses. References Abd El Moneim, A.M., Cocks, P.S. and Sweedan, Y., 1988. Yield stability of selected forage vetches ( Vicia spp. ) under rainfed conditions in West Asia. J. Agric. Sci., 111: 295-301.
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