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Nutritional Differences (nutritional + difference)

Distribution by Scientific Domains
Life Sciences75%

Selected Abstracts

Survivorship and growth in the larvae of Luehdorfia japonica feeding on old leaves of Asarum megacalyx

ENTOMOLOGICAL SCIENCE, Issue 4 2007
Aya HATADA
Abstract Although the papilionid butterfly Luehdorfia japonica, usually lays eggs on new leaves of the host plant (Asarum sp.; Aristolochiaceae), eggs of the butterfly were frequently found on old leaves of Asarum megacalyx in Suyama, Tokamachi, Niigata prefecture. Larvae hatched on new leaves and those hatched on old leaves did not show significant differences in their survival rate in the field. In laboratory breeding, about 90% of larvae that were fed old leaves survived and developed normally to the pupal stage. Their growth rate, however, was slightly lower than those that were fed new leaves. No nutritional differences were found between the old and new leaves. The reason why oviposition on the old leaves was so frequent and why larvae that hatched on old leaves could survive in the study area is discussed. [source]

Subacute effects of transgenic Cry1Ab Bacillus thuringiensis corn litter on the isopods Trachelipus rathkii and Armadillidium nasatum

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 10 2006
Bryan W. Clark
Abstract Laboratory studies were conducted to investigate the subacute effects of transgenic Cry1Ab corn leaf material containing Bacillus thuringiensis (Bt) protein on the terrestrial isopods Trachelipus rathkii and Armadillidium nasatum. Survival and growth were measured for eight weeks in isopods fed leaf material of two Bt11 corn varieties, two Monsanto 810 (Mon810) corn varieties, and the isolines of each. Total lipid and protein content of the organisms was measured to examine effects on energetic reserves. Armadillidium nasatum individuals in all treatments responded similarly. For T. rathkii, no statistically significant effect of Bt was observed, but statistical differences were observed in growth between hybrids. Protein and sugar content of the food were found to be correlated with the differences in growth for T. rathkii. Total protein content was higher in T. rathkii and A. nasatum fed material with higher protein and sugar content. A trend toward less growth in T. rathkii on Bt corn varieties versus their isolines triggered a concentration-response assay with purified Cry1Ab protein. No adverse effects of purified Bt protein were observed. These results indicate that little hazard to T. rathkii and A. nasatum from Bt corn leaf material from these hybrids exists. However, nutritional differences in corn hybrids contributed to differences in isopod growth. [source]

Reproductive success of the rotifer Brachionus calyciflorus feeding on ciliates and flagellates of different trophic modes

FRESHWATER BIOLOGY, Issue 10 2002
Silvia Mohr
SUMMARY 1. The nutritional value of the bacterivorous ciliate Tetrahymena pyriformis and the algivorous ciliate Coleps sp., as well as the heterotrophic flagellate Chilomonas paramecium and the autotrophic flagellate Cryptomonas ovata, were investigated in population growth experiments using the rotifer B. calyciflorus. The two ciliates, both flagellates, which were of similar size, shape and mobility, were each offered as a sole diet and as a supplement to the alga Monoraphidium minutum, known to support reproduction of B. calyciflorus. 2. To further test nutritional differences between the prey organisms, prey selection experiments were conducted in which B. calyciflorus was able to select between the bacterivorous and algivorous ciliate, and between the heterotrophic and autotrophic flagellate. 3. The results demonstrated that both ciliates and the heterotrophic flagellate were not sufficient to support reproduction of B. calyciflorus when offered as a sole diet. They were, however, a good supplement to algal prey (except for the bacterivorous ciliate T. pyriformis). In the prey selection experiments, B. calyciflorus positively selected for the algivorous Coleps sp. and the autotrophic C. ovata. 4. Overall, ciliates and heterotrophic flagellates may enhance survival of B. calyciflorus, but reproduction of the rotifer is likely to rely on algal prey. Both higher population growth of B. calyciflorus when fed the algivorous Coleps and the autotrophic Cryptomonas, along with their positive selection, give evidence for prey specific differences in nutrition, with algivorous or autotrophic prey species tending to be of higher nutritional value. [source]

Demonstration of salmon farming as a net producer of fish protein and oil

AQUACULTURE NUTRITION, Issue 4 2010
V.O. CRAMPTON
Abstract To date aquaculture's reliance on dietary marine sources has been calculated on a fish weight-to-weight basis without considering the absolute amounts of nutrients but this approach neglects the often considerable differences in the nutritional value of fish. We propose simple nutrient-to-nutrient-based dependency measures that take into account these nutritional differences. In the first study reported here, individually tagged Atlantic salmon (Salmo salar) were reared in seawater supplied tanks with feed collection facilities. In the second, commercial net pens were used to grow over 200 000 fish. For both studies, a low marine ingredient feed containing approximately 165 g kg,1 fishmeal was compared to a control feed (approx 300 g kg,1 fishmeal) whilst fish oil inclusion was less markedly reduced. The low marine feeds supported similar growth and feed efficiency compared to the control feeds. With the low marine ingredient feeds, the weight of salmon protein and lipid produced through growth exceeded the weight of marine protein and lipid consumed by the fish meaning that salmon farming can be a net producer of fish protein and oil. The amount of n-3 long-chain polyunsaturated fatty acids deposited was sufficient to meet current recommendations from human health organizations. [source]