Hemp has the greatest economical potential if grown both for seeds and stems as residual agricultural products .Hempseed contains more than 30% oil of which more than 80% is polyunsaturated fatty acids . They are present in a ratio of about 3:1, considered optimal in healthy human adipose tissue , and apparently unique among common plant oils . This preferred omega-6/omega-3 ratio was successfully utilized in animal feed to manipulate the fatty acid pattern in bovine adipose tissue and eggs . There are various benefits attributed to omega-3 and include anti-cancer,anti-inflammatory and anti-thrombosis properties,stimulation of general metabolism and promotion of burning fat .Hempseed oil is commonly extracted by solvents and, the resulting by-product, is known as hempseed meal which has good protein level ranging from 30% to 40% in dry matter of flour depending upon the variety of hemp used .
HSM is a rich source of protein and energy and can represent a nutritious feed supplement for livestock or used for production of a high-protein flour.Identification and characterization of hempseed proteins showed that edestin, rich in valuable amino acids,constituted the main protein component in isolate hempseed protein . Another protein structure, rich in methionine and cystine, was found in hemp seeds and subsequently characterized as an albumin protein family member. Numerous factors are known to influence the nutritional quality of plant proteins, as measured by their amino acid composition and digestibility. The amino acid composition may be affected by genotypic variability or agronomic conditions such as soil fertility and postharvest processing that alters the ratio of seed components. The digestibility of proteins may be affected by protein structure, the presence of antinutritional compounds and high temperature processing.HSM contains antinutritional compounds that need to be considered when feeding this product. In hemp seed,among a vast number of antinutritional compounds, phytate has raised more attention.Phytic acid is the main organic form of phosphorus present in plant seeds.
Its presence reduces protein digestibility and increases the excretion of endogenous nitrogen, amino acids and minerals, in particular bivalent cations. Another nutritionally important group of compounds are the condensed tannins. Tannins are known to negatively affect nitrogenous compounds uptake, absorption of minerals, and reduce weight gain and feed consumption intake in broiler chicks . In the case of sorghum, 1% of increased tannin content reduced the dietary energy value by 10%. Being protein precipitants, the tannins form complexes with feed proteins and endogenous enzymes. Hence, the weight of the pancreas increases if the feed contains high levels of tannins. Other deleterious compounds considered by animal nutritionists are the saponins.These substances consist of a sugar moiety usually containing one sugar , glycosidically linked to a hydrophobic aglycone which may be in nature triterpenoid or steroid.Dietary saponins depressed growth, feed consumption and egg production in poultry.These negative effects have been ascribed to several properties of saponins such as reduced feed intake caused by the astringent and irritating taste of saponins,reduction in intestinal motility and reduction in protein digestibility, probably due to the formation of sparingly digestible saponin-protein complexes.
Moreover,saponins have pronounced haemolytic properties and are responsible for bloat in ruminats. Trypsin inhibitors are considered one of the most important antinutritional factors and are found in many species of graminaceous, cruciferous and leguminosae. In literature, there are few data about the trypsin inhibitor activities in HSM . Lastly, the metabolism of some substances contained in flour may lead to the release of toxic products .In the present study, HSM was evaluated as protein source and for the presence of the main antinutritional compounds . Two groups of hemp varieties were used. The first group was consisting of dioecious varieties and the second group of monoecious varieties . The dioecious and monoecious hemp varieties have strong differences in the flowering time and seed filling. The characterization of these biochemical features will help to better understand the nutritional quality of HSM and its use as feed ingredient. Bioherbicides may offer alternatives to the control of weeds with synthetic compounds including the use of plant pathogens as bioherbicides.
Results from our laboratory demonstrated that the bioherbicidal fungus, Myrothecium verrucaria Ditmar: Fr. , can control several weeds from various families. A substantial portion of this research has been devoted to the potential of MV to control several economically important weeds including, hemp sesbania , sicklepod ,kudzu and glyphosate-resistant and -susceptible Palmeramaranth .Kudzu is an exotic invasive weed in the southeastern US that is difficult to control with current commercial herbicides and this weed has had a devastating impact on forests, rights of ways, etc. . Kudzu, a perennial leguminous vine native to eastern Asia, was introduced into the US in the late 1800’s and now occurs from Florida to New York, westward to central Oklahoma and Texas, with heavy infestations in Alabama, Georgia, and Mississippi.