Cultivar differences and effect of pigeon pea seeds boiling on trypsin inhibitor activity andin vitro digestibility of protein and starch

Utilization and farmers' knowledge on pigeonpea diversity in Benin, West Africa

BACKGROUND

Understanding factors driving farmers' uses of crop genetic resources is a key component not only to design appropriate conservation strategies but also to promote sustainable production. However, in Benin, limited information is available on farmers' knowledge related to pigeonpea uses and conservation. This study aimed at i) identifying and investigating the different uses of pigeonpea in relation with socio-cultural factors, namely age, gender, ethnic group and respondents' residence, ii) assessing pigeonpea varieties richness at household level and iii) evaluating the extent and distribution of pigeonpea varieties.

METHODS

Three hundred and two farmers were surveyed using structured questionnaire. Direct observation, field visit and focus group discussion were carried out. Association between number of varieties maintained at household level and socio-cultural variables was tested. Mann-Whitney test was used to assess whether the number of varieties held by households headed by men and women were different. Distribution and extent of diversity was assessed through four cells analysis.

RESULTS

Farmers in Benin mainly grow pigeonpea for its grains for home consumption. Pigeonpea's stem and leaves are used for medicinal purposes to treat malaria, dizziness, measles, and eye infection. The ethnic group and the locality of residence of farmers influenced on the use of pigeonpea for medicinal purposes (P < 0.01). There was no significant association (P > 0.05) between the number of varieties held by household and the age of the respondent, number of years of experience in pigeonpea cultivation, the size of household, number of family members engaged in agricultural activities and gender. Farmers used criteria including seed colors, seed size, plant height, maturity groups and cooking time to classify their varieties. Varieties with white seed coat color were the most grown while varieties with black, red or mottled seed coat color are being abandoned and deserve to be conserved.

CONCLUSION

Knowledge on medicinal uses of pigeonpea is vertically transmitted within community and pigeonpea varieties maintenance at household level does not depend on socio-cultural factors. This study will contribute to raise awareness on the various utilization of pigeonpea. In addition, it provides the basis for designing conservation strategies of pigeonpea genetic resources.

Toxicity Assessment of Common Beans (Phaseolus vulgaris L.) Widely Consumed by Tunisian Population

This research aimed at assessing the content and the functional properties of phytohemagglutinin (PHA) in different varieties of beans widely consumed in Tunisia through soaking, cooking, autoclaving, germination, and their combinations. This study was carried out on three varieties of white beans grown in different localities of Tunisia, namely Twila, Coco, and Beldia, as well as on imported and local canned beans. All bean samples underwent biochemical and immunological evaluation by employing several techniques such as indirect competitive enzyme-linked immunosorbent assay (ELISA), hemagglutinating assay, Ouchterlony double immunodiffusion, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Biochemical and immunological analyses indicated that raw dry beans contained a considerable amount of proteins and PHAs. ELISA demonstrated that soaking, either in plain water or in alkaline solution, caused an increase in the concentration of PHA. A slight increase of PHA was produced equally by germination during 4 days in all bean varieties. Cooking or autoclaving of presoaked beans resulted in a complete disappearance of PHA. ELISA test also proved that both imported and local canned beans contained fingerprints of PHA. Hemagglutination assays showed that not only cooked and autoclaved presoaked beans lacked the ability to agglutinate red blood cells but also autoclaved unsoaked beans did. In agar gel immunodiffusion using rabbit anti-PHA serum, raw, soaked, cooked unsoaked, and sprouted beans gave precipitin arc reactions, indicating that PHA existed in immunoreactive form in the tested seeds. SDS-PAGE electrophoretograms showed protein isolates of Twila and Beldia beans to have different profiles through soaking, cooking, and autoclaving processes. This work revealed that the combination of soaking and cooking/autoclaving was the best way in reducing PHA content and its activity in all bean varieties when compared with germination.

A maize trypsin inhibitor (ZmTIp) with limited activity against Aspergillus flavus

Infection of maize both pre- and postharvest by Aspergillus flavus is a severe agricultural problem in the southern United States. Aflatoxins are secondary metabolites produced by A. flavus and are carcinogenic to humans and animals upon ingestion. Extensive research has been conducted to identify sources of resistance to A. flavus in maize. Some maize genotypes exhibit greater resistance to A. flavus than others. Many research groups have validated the role of plant trypsin inhibitors (TIs) as a means of plant defense against fungal infection. Research consisting of the cloning, expression, and partial characterization of one previously uncharacterized TI protein has been conducted. The overexpressed protein displayed TI activity, as expected, and some ability to alter germination of conidia (8%) from several fungal pathogens and to inhibit hyphal growth (30%). This effect on fungal growth, although less than that of previously investigated TIs, marks this protein as a potential source of resistance to aflatoxin accumulation in maize.

Digestibility of soybean and pigeon pea seed meals and morphological intestinal alterations in pigs

To compare the nutrient digestibility of soybean meal (SM) and pigeon pea seed meal (PM) as well as morphological intestinal alterations in piglets fed them, three pigs per group were randomly selected at the end of the feeding experiment for ten days. Growth performance was higher in the SM group than in the PM group (p<0.05). The digestibility of crude protein, crude fat and crude fiber was 80.6%, 23.6% and 52.4% in the SM group, while in the PM group, values of 49.8%, 23.6% and 43.2% were observed, respectively. Digestible energy was 3.26 kcal g(-1) in SM and 3.17 kcal g(-1) in PM. It was concluded that the digestibility of PM was lower than that of SM; almost half of the protein in PM was digested. Dietary treatments had no effect on length of each small intestinal segment and weight of visceral organs (small intestine, liver, heart, spleen, kidney, stomach and lung) except the decreased kidney weight in the PM group (p<0.05). The epithelial cells on the jejunal villi showed a dome-like shape in the SM group, but they were a flat shape in the PM group. The present digestion trial and histological intestinal data suggest that the intestinal digestive and absorptive functions are much more atrophied in the PM group than in the SM group, and demonstrate that histological intestinal alterations might be well related with the intestinal functions.