Evaluation of the seeds of selected lines of three Lathyrus spp for β-N-oxalylamino-L- alanine (BOAA), tannins, trypsin inhibitor activity and certain in-vitro characteristics

Abstract

Sixty eight lines comprising 36 Lathyrus sativus, 16 L cicera and 16 of L ochrus were analysed for crude protein (CP), the neurotoxin β-N-oxalylamino- L-alanine (BOAA), protein precipitable tannin (PPT), catechin equivalents (CE), and trypsin inhibitor activity (TIA). Randomly chosen lines from each of the species were also evaluated for other chemical and in-vitro characteristics including neutral detergent fibre (NDF), acid detergent fibre (ADF), in-vitro dry matter and in-vitro organic matter digestibilities (IVDMD, IVOMD), respectively.

The species with the lowest and highest CP were L cicera(295.39 ± 18.69 g kg−1 DM) and L sativus(324.99 ± 13.40 g kg−1 DM), respectively. BOAA concentration, also, was least in L cicera (1.26 ± 0.18 g kg−1 DM) and highest in L sativus(5.63 ± 0.43 g kg−1 DM). There were higher intraspecies variations in BOAA levels among L sativus and L cicera than in L ochus genotypes. On average, BOAA levels in L ochrus and L sativus were about four to five times higher than those in L cicera. The PPT level in L sativus(4.54 ± 0.31 g kg−1 DM) was similar to that in the other species. However, there were some lines without detectable PPT in all the species. CE, which detects simple flavonoids as well as condensed tannins, was no more than 6.10 g kg−1DM in any accession, except in L ochrus in which CE ranged from 14.07 g kg−1 to 28.50 g kg−1 DM. There were high variabilities between and within species in CE values as shown by the high coefficients of variation. Mean TIA in all the L sativus lines (18.16 ± 2.38 g kg−1 DM) was similar to that in L ochrus and about twice the levels in L cicera. The coefficients of variation ranged from 10.93% in L ochrus to 17.13% in L sativus. The ash, organic matter and NDF content of the lines did not differ significantly. However, the ADF, IVDMD and IVOMD differed significantly (P < 0.05) between the species. The IVDMD and IVOMD of L cicera (88.55 ± 0.80% and 85.53 ± 0.85%, respectively) were significantly lower (P < 0.05) than in the other species. Seed weight correlated significantly (P < 0.05) with CE and TIA in both L sativus and L ochrus while CP correlated significatly (P < 0.01) with TIA in both L sativus and L cicera with respective r values of 0.70 and −0.75.