| 1. |
|
|
| 2. |
- Dullemeijer, Carla, et al.
(författare)
-
Differences in fatty acid composition between cerebral brain lobes in juvenile pigs after fish oil feeding
- 2008
-
Ingår i: British Journal of Nutrition. - 0007-1145 .- 1475-2662. ; 100:4, s. 794-800
-
Tidskriftsartikel (refereegranskat)abstract
- Very long-chain n-3 PUFA from fish are suggested to play a role in the development of the brain. Fish oil feeding results in higher proportions of n-3 PUFA in the brains of newborn piglets. However, the effect of fish oil on the fatty acid composition of specific cerebral brain lobes in juvenile pigs is largely uninvestigated. This study examined the effect of a fish oil diet on the fatty acid composition of the frontal, parietal, temporal and occipital brain lobes in juvenile pigs (7 weeks old). Pigs were randomly allocated to a semipurified pig diet containing either 4% (w/w) fish oil (n 19) or 4% (w/w) high-oleic acid sunflower oil (HOSF diet, n 18) for a period of 8 weeks. The fish oil diet resulted in significantly higher proportions (%) of DHA in the frontal (10.6 (SD1.2)), parietal (10.2 (SD1.5)) and occipital brain lobes (9.9 (SD 1.3)), but not in the temporal lobe (7.7 (SD1.6)), compared with pigs fed the HOSF diet (frontal lobe, 7.5 (SD1.0); parietal lobe, 8.1 (SD 1.3); occipital lobe, 7.3 (SD1.2), temporal lobe, 6.6 (SD1.2). Moreover, the proportion of DHA was significantly lower in the temporal lobe compared with the frontal, parietal and occipital brain lobes in pigs fed a fish oil diet. In conclusion, the brains of juvenile pigs appear to be responsive to dietary fish oil, although the temporal brain lobe is less responsive compared with the other three brain lobes. The functional consequences of these differences are a challenging focus for future investigation.
|
|
| 3. |
- Dussutour, A, et al.
(författare)
-
Noise improves collective decision-making by ants in dynamic environments
- 2009
-
Ingår i: Proceedings of the Royal Society of London. Biological Sciences. - : The Royal Society. - 0962-8452 .- 1471-2954. ; 276:1677, s. 4353-4361
-
Tidskriftsartikel (refereegranskat)abstract
- Recruitment via pheromone trails by ants is arguably one of the best-studied examples of self-organization in animal societies. Yet it is still unclear if and how trail recruitment allows a colony to adapt to changes in its foraging environment. We study foraging decisions by colonies of the ant Pheidole megacephala under dynamic conditions. Our experiments show that P. megacephala, unlike many other mass recruiting species, can make a collective decision for the better of two food sources even when the environment changes dynamically. We developed a stochastic differential equation model that explains our data qualitatively and quantitatively. Analysing this model reveals that both deterministic and stochastic effects (noise) work together to allow colonies to efficiently track changes in the environment. Our study thus suggests that a certain level of noise is not a disturbance in self-organized decision-making but rather serves an important functional role.
|
|
| 4. |
- Dussutour, A., et al.
(författare)
-
The role of multiple pheromones in food recruitment by ants
- 2009
-
Ingår i: Journal of Experimental Biology. - : The Company of Biologists. - 0022-0949 .- 1477-9145. ; 212:15, s. 2337-2348
-
Tidskriftsartikel (refereegranskat)abstract
- In this paper we investigate the foraging activity of an invasive ant species, the big headed ant Pheidole megacephala. We establish that the ants' behavior is consistent with the use of two different pheromone signals, both of which recruit nestmates. Our experiments suggest that during exploration the ants deposit a long-lasting pheromone that elicits a weak recruitment of nestmates, while when exploiting food the ants deposit a shorter lasting pheromone eliciting a much stronger recruitment. We further investigate experimentally the role of these pheromones under both static and dynamic conditions and develop a mathematical model based on the hypothesis that exploration locally enhances exploitation, while exploitation locally suppresses exploration. The model and the experiments indicate that exploratory pheromone allows the colony to more quickly mobilize foragers when food is discovered. Furthermore, the combination of two pheromones allows colonies to track changing foraging conditions more effectively than would a single pheromone. In addition to the already known causes for the ecological success of invasive ant species, our study suggests that their opportunistic strategy of rapid food discovery and ability to react to changes in the environment may have strongly contributed to their dominance over native species.
|
|
| 5. |
|
|
