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Summary — The composition and digestibility by sheep of 15 commercial maize varieties and 1 brown mid-rib experimental hybrid was measured over 2 yr in 7 locations, according to earliness as fresh-cut forage from the milky stage of the grain to the glazed stage. This study determined the effect of the main factors causing variations in plant composition and digestibility. Under satisfactory growing conditions, the digestibility of a given maize hybrid increases significantly with growth stage, whereas it changes very little under poor conditions (low temperatures, drought, etc). For a given dry matter content, genotype effects were significant in only 2 locations and were of similar importance to those of environment (location and year) on a given genotype. As for other forage crops, maize digestibility is closely linked (R = 0.98) to its undigestible cell wall content. In contrast, the digestibility of maize cell walls is not only independent of their content in the plant but also lower than that of other forage crops (-10

Phytasic activity and phytic P content, which are important factors in determining the availability of P, were measured in 56 wheat samples. The different agronomic and genetic factors which could have an influence on these two variables were studied, specifically N and/or P fertilisation, date of harvest, preharvest sprouting and variety of French wheat. Phytasic activity ranged from 206 to 775mUg−1, with an average of 508mUg−1 and a standard deviation of 109mUg−1. Only the variety of wheat appeared as a significant factor explaining the endogenous phytasic activity (P=0·006). The phytic P content varied between 0·92 and 2·80gkg−1 DM, with an average of 2·18gkg−1 and a standard deviation of 0·35gkg−1 DM. None of the factors studied significantly affected the phytic P content of the wheat. This content was correlated with the total P content (r=0·56;P<0·05). The activity of the endogenous phytase was independent of the quantity of its substrate, the phytic phosphorus of the kernels of wheat.

Synopsis Oakmoss absolute, an extract of the lichen Evernia prunastri, is known to cause allergenic skin reactions due to the presence of certain aromatic aldehydes such as atranorin, chloratranorin, ethyl hematommate and ethyl chlorohematommate. In this paper it is shown that treatment of Oakmoss absolute with amino acids such as lysine and/or leucine, lowers considerably the content of these allergenic constituents including atranol and chloratranol. The resulting Oakmoss absolute, which exhibits an excellent olfactive quality, was tested extensively in comparative studies on guinea pigs and on man. The results of the Guinea Pig Maximization Test (GPMT) and Human Repeated Insult Patch Test (HRIPT) indicate that, in comparison with the commercial test sample, the allergenicity of this new quality of Oakmoss absolute was considerably reduced, and consequently better skin tolerance of this fragrance for man was achieved.

In order to reduce the P concentration in manure, P availability in different plant feedstuffs should be determined. Wheat P availability has been studied by the digestive balance technique on broilers and pigs. Nineteen wheat samples were tested on broilers, giving a mean P retention of 57% (45–70%). P retention was observed to be linearly associated with the endogenous phytasic activity in wheats (r=0·58;P<0·05). This variability in P retention cannot be satisfactorily explained by the phytic P content of wheat. Four wheat samples were tested on pigs, giving a mean apparent P digestibility of 40%.