The composition and nutritive value of bracken

Abstract

Samples of bracken were taken at regular intervals between June and October from a hill grazing where losses of cattle from ‘bracken poisoning’ had occurred in previous years. These were separated into leaf and stem for analysis. Dry, mature bracken cut in October was examined for digestibility and nutritive value, and in the following season the digestibility of fresh, green bracken was determined for both cattle and sheep.Chemical composition. Analyses of the fresh bracken fed in the digestibility trials were in line with those of the samples collected in the previous year. Crudeprotein content was high in June and July, but fell markedly in August and September, whilst the crude fibre varied in the opposite direction, increasing markedly in August. An increase in the tannin content was observed in September but this was not comparable with the increases reported by Shearer. An attempt to elucidate the significance of tannin in the in vitro digestion of bracken-leaf protein was unsuccessful. The potassium content was found to be rather lower than in good pasture grass, confirming the findings of Ferguson & Armitage. The potassium was highly soluble in water but the soluble part was not entirely in the form of chloride.

Seasonal and interspecific variation in the biochemical composition of some British fern species and their effects on Spodoptera littoralis larvae

“…A seasonal change in tannin concentrations, from high levels in the young fronds to lower levels in the mature fronds, was evident in four out of the five species tested but these results are contrary to the seasonal pattern for bracken (PteTidium aquilinum L.) observed by Moon & Pal (1949) and Cooper-Driver et al (1977). Milton (1979) detected higher concentrations of condensed tannins in young leaves of some tropical tree species than in the mature leaves but tannin levels have been reported to increase with leaf maturity in most temperate angiosperms (Hillis & Swain, 1959;Feeny, 1970;Rhodes & Cates, 1976).…”

“…The effects of a low nitrogen content are further accentuated for phytophagous insects by the presence of indigestible fibre. The limited published data on the nutritional value of ferns (Moon & Pal, 1949;Smith & Agiza, 1951 ;Hunter, 1953;Buckingham et al, 1978) suggest that their nutrient content may be high compared with angiosperms. There are, however, few analyses of cell wall components.…”

Phosphorus speciation by 31P NMR spectroscopy in bracken (Pteridium aquilinum (L.) Kuhn) and bluebell (Hyacinthoides non-scripta (L.) Chouard ex Rothm.) dominated semi-natural upland soil

“…The P content in the different plant parts agreed with previous studies on bluebells (Blackman and Rutter, 1949;Merryweather and Fitter, 1995a,b) and bracken (Ferguson and Armitage, 1944;Moon and Pal, 1949). The amount of P varied according to the different plant parts, with higher values in the above-ground parts (leaves, scapes, flowers for bluebell, stipes and blades for bracken) and with bluebells showing the highest concentrations.…”

Chemotaxonomy and phytochemical ecology of bracken

“…We have found that bracken also contains larger amounts of proanthocyanins estimated by the methods of Hillis & Swain (1959) towards the end of the growing season (Cooper-Driver, Swain & Zantovska, 1974: unpubl.). Earlier workers (Shearer, 1945;Moon & Pal, 1949) had noted an increase in 'tannins' in bracken as the season progressed, using non-specific analytical methods. Bracken grown in shade contained much lower quantities of tannins.…”