Fatty acid composition of the seed oils of selected Vicia L. taxa from Tunisia

Whole mature seeds of eight selected varieties, subspecies and accessions of three Vicia L. species grown in Tunisia were investigated for their fatty acid (FA) profile. The FA composition ranged from lauric (C12:0) to lignoceric (C24:0) acids. The total FA content was 1235.14 to 1580.34 mg 100 g–1 dry matter (DM). Linoleic acid (C18:2 c9c12; 647.87 to 801.93 mg 100 g–1 DM, i.e. >50% of total FA), oleic acid (C18:1 c9; 181.32 to 346.79 mg 100 g–1 DM, i.e. 13.2 to 24.6% of total FA) and a-linolenic acid (C18:3 c9c12c15; 42.01 to 97.72 mg 100 g–1 DM, i.e. 3.4 to 7.1% of total FA) were the most abundant unsaturated FA. Palmitic acid (C16:0; 189.86 to 281.07 mg 100 g–1 DM, i.e. 15.4 to 17.8% of total FA) and stearic acid (C18:0; 24.35 to 52.75 mg 100 g–1 DM, i.e. 2.0 to 4.0% of total FA) were the major saturated ones. The sum of all other FA did not exceed 3.0% of TFA. The favourable FA profile of the studied vetch seeds makes them interesting cheap diet components to be used in the nutrition of ruminants and non-ruminants reared in the dryland agricultural regions of Mediterranean countries

In vitro fermentation of diets incorporating carob pulp using inoculum from rabbit caecum

The aim of this work was to evaluate the nutritive value of carob pulp for rabbits using the in vitro digestibility and gas production techniques with inocula from caecal content of rabbits. Experimental diets contained 0% (D1), 10% (D2), 20% (D3) and 100% (D4) carob pulp on a dry matter (DM) basis and were incubated in glass syringes for 72 h at 39ºC. Carob pulp contained 313 g neutral detergent fibre/kg DM with a high acid detergent fibre (263 g/kg DM) content, resulting in a low hemicellulose content of 50 g/kg DM. Potential gas production ranged from 123 (D1) to 179 (D4) mL/g DM and was similar for the D1 (123 mL/g DM), D2 (126 mL/g DM) and D3 (130 mL/g DM) treatments. The lowest pH value of 6.47 and the highest organic matter degradation (OMD, 64.3%) were observed in the 100% carob pulp (D4) treatment, while its inclusion at 10% and 20% tended to improve the OMD of the diets. These results show that carob pulp is well fermented by the caecal micro-organisms of rabbits. Although its inclusion at 20% did not improve in vitro fermentation and degradation of the commercial concentrate, it was concluded that carob pulp has potential as an unconventional feed resource for rabbits. Its utilization could have a positive effect on intestinal microbiota owing to its high content of soluble fibre.Keywords: Ceratonia siliqua, by-product, chemical composition, gas production, organic matter degradatio

Browser selectivity alters post-fire competition between Erica arborea and E. trimera in the sub-alpine heathlands of Ethiopia

Mammalian herbivores have the potential to alter the competitive relations of woody species, if consumption is unevenly distributed between species. At elevations above 3500 m in the southern Ethiopian highlands, vegetation is dominated by Erica arborea and Erica trimera. Both species can potentially grow into short trees, but are burnt on a rotation of 6 to 10 years, and regenerate by re-sprouting from belowground lignotubers. The regenerating scrub is heavily browsed by cattle. We set up browsing exclosures at three burnt sites to quantify the impact of browsing over a three-year period. When protected from browsing, E. trimera had similar or better height growth than Erica arborea, but in browsed vegetation, Erica arborea instead grew taller. Browsing was more intense on E. trimera in the first years after fire, indicating a difference in palatability between the species. We checked if browse quality differed, by analysing shoot contents of acid detergent fibre, protein, phenolics and tannins. Contrary to expectations the preferred E. trimera contained more acid detergent fibre, less protein and had a higher tannin activity than E. arborea. Although the vegetative growth of E. arborea is favoured relative to E. trimera under high browsing pressure, rapid change in abundance would not be expected, since short-interval fire will repeatedly eradicate any gains in vegetative growth. However, within the typical fire return interval of less than 10 years, E. trimera barely reach a reproductive state, whereas E. arborea flower profusely. Under the current regime of fire and browsing this may in the long run be more important than differences in height growth, leading to a gradual increase in the proportion of E. arborea