Ceramics were subjected to organic residue analysis from two collections: a series of middle Copper Age (Bodrogkeresztúr) vessels hitherto known as ‘milk jugs’, curated in the Magyar Nemzeti Múzeum, Budapest, and a collection of early Baden (Boleráz) vessels from the recently discovered settlement of Gyo”r-Szabadrét-domb, in western Hungary. The aim of the analyses was to establish whether or not these vessels, often associated with milk based on typological criteria, were actually used to process, store or serve dairy products. The results of the analyses revealed that no dairy products could be securely identified in the so-called ‘milk jugs’. Nevertheless dairy products were identified in other vessel types.

Dans le but d'évaluer les perspectives de valorisation de l'algue verte Scenedesmus abundans Chlorophyceae, sa compositionbiochimique a été réalisée sur des cultures soumises à différentes conditions environnementales. Parmi les facteurs retenus, latempérature a le plus d'influence. Les teneurs en protéines sont maximales à 15°C, celles des composés lipidiques et glucidiquesà 25 et 35°C respectivement. L'intensité lumineuse n'affecte pas la composition biochimique globale, si ce n'est une baisse d'environ20 % des substances lipidiques, sous un éclairement de 300 µmol quanta.m-2.s-1. De même, la source azotée a peu d'effetsignificatif sur les teneurs des 3 constituants cellulaires. L'augmentation de la concentration en azote induit un accroissement desteneurs en protéines et en lipides avec cependant une réduction de la production de biomasse, au-delà de 400 mg.l-1 de KNO3.Des modifications de la composition biochimique de Scenedesmus abundans en fonction du stade de croissance ont égalementété observées. En phase de croissance stationnaire, ces modifications se résument en une réduction marquée de la teneur en protéineset, dans une moindre mesure, de la teneur en lipides, accompagnée d'une accumulation importante des hydrates de carbone.Les résultats sont analysés en tenant compte de la notion de rendement de production de chacun des trois types decomposé.

The biochemical composition of Daphnia magna Straus, the dominant planktonic crustacean of the waste stabilisation pond of Differdange (Grand-Duchy of Luxembourg), was quantitatively determined from October 1993 to July 1994. Over the sampling period, the average composition (mean ± S.D.) was 271 ± 64 mg proteins.g-1 dry weight (DW), 100 ± 28 mg lipids.g-1 (DW), 96 ± 58 μg carotenoids.g-1 (DW), 49 ± 14 mg chitin.g-1 (DW) and 125 ± 78 mg ash.g-1 (DW). The seasonal variations of the biochemical composition were related to several ecological variables (water temperature, dissolved oxygen concentration, pH, water transparency, chlorophyll a concentration and D. magna biomass). The chitin content was positively correlated to the water temperature as a result of the strong influence of this later variable on the moulting rate of the daphnids and, subsequently, on the chitin synthesis by these organisms. The carotenoid content was positively correlated to the water transparency as a result of their photoprotective role in daphnids. The fluctuations of the lipid, protein and ash levels in D. magna depended to the food availability. Despite a seasonal variation in the biochemical composition, D. magna appeared to have adequate lipid and protein levels to be used in aquaculture. Its carotenoid content is similar to fish meals used to color salmonid flesh and these organisms could be used for this purpose. The prospect of using D. magna for chitin extraction is worth considering with respect to its significant chitin content, especially if highly valuable applications are aimed.

The influence of gibberellic acid (GA3), a plant growth regulator (PGR), on the protein, total lipid, total carbohydrate, glycogen and trehalose contents of the banana fruit fly, Zaprionus paravittiger (Godbole and Vaidya) (Diptera: Drosophilidae), was investigated by feeding 63-h-old larvae on artificial diet containing 1000, 2000 and 4000 ppm GA3 for 30 and 50 h. The maximum increase in the protein content was recorded for the 1000 ppm GA3 treatment. Significant decreases in the total lipid and total carbohydrate contents were recorded at 1000 and 2000 ppm while the 4000 ppm treatment significantly increased their levels. Glycogen content was significantly decreased by all the tested GA3 concentrations. The possible reasons for the observed changes in these biochemical components are discussed.

Dans une optique de valorisation de l'algue verte Chlorella sorokiniana, la composition biochimique de cette espèce a été déterminée en fonction de la température d'incubation, de l'intensité lumineuse et du stade de croissance. A 35°C, sous un éclairement de 140 µE.m-2.s-1, et en phase exponentielle de croissance, les analyses effectuées ont révélé que la biomasse algale était composée d'environ 40 % de protéines, 30 % de glucides et 18 % de lipides (% de la matière sèche des cellules). Les résultats obtenus ont montré également que les teneurs de ces constituants dépendaient étroitement des conditions de culture. Ainsi, il est possible d'orienter le métabolisme cellulaire de cette espèce vers la production du ou des métabolites souhaités, en choisissant les conditions environnementales appropriées et le moment de la récolte de la biomasse algale.

The channel catfish (Ictalurus punctatus) is the most widely cultured foodfish in the U.S., thus most of the nutrient requirement data are available for this species. Qualitatively, about 40 nutrients have been identified as necessary for the normal metabolic function of the channel catfish with quantitative requirement values available for about 30 nutrients including amino acids, fatty acids, minerals and vitamins. Additional information is available on protein and energy requirements, digestible protein and energy coefficients as well as amino acid availability values. Thus adequate nutritional information is available to formulate high quality practical channel catfish feeds.Only limited nutrient requirement data are available for the other Siluroidei species. Some requirement data have been reported for a few species from Africa (Clarias gariepinus, C. isheriensis, Heterobranchus longifilis and H. bidorsalis), Asia (Clarias batrachus, C. macrocephalus, C. fuscus and Heteropneustes,fossilis) and Europe (Silurus glanis). The available requirement data will be summarized and compared with the requirement data for the channel catfish. Some variation does appear to exist in optimum dictary protein levels, essential fatty acid requirements, and lipid vs carbohydrate utilization.

Reliable data on tilapia nutrition and feeding are scarce. In the best documented field, that of protein requirement, current data show good agreement with available information on coldwater and warmwater fishes. Various feedstuffs have been used to satisfy the protein needs, but the effects of variations of their quality have not been sufficiently studied. The main problem lies in the assessment of the effects of natural food in open rearing structures; thus there are some discrepancies with the results obtained in laboratory. More insight on in situ nutrition of pond fish, as well as the management of the feedstuffs and feeding practices is needed.

Suitable winter wheat cultivars of different degree of resistance to cereal aphids, Sitobion avenae F. and Rhopalosiphum pali L. have been studied in the field conditions. The differences in the chemical composition of possible attractants and repellants have been analysed. The results confirm the inter-pendence between contents of yellow and orange plant pigments in the leaves of the studied varieties and their preference by the aphids. The leaves of the susceptible cultivars also had the highest level of sucrose. The number of the aphids was directly proportional to the total free amino acids content. The higher degree of resistance of the cultivars was related to the contents free phenols in their tissues and was also associated with a high value of ‘toxicity index’, which is the ratio of free phenols content to free amino acids content. Also the contents of structural polysaccharides (cellulose, hemicelluloses and pectins) of the investigated cultivars were inversely proportional to the degree of their infestation.