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Doctoral; To answer research questions related to spontaneous liver steatosis in geese, individual measurement of ingestion and feeding behavior of batch-fed animals is essential. In this way, single place electronic feeder dedicated to ducks is being adapted to geese by testing two feeders, one fitted with doors at the entrance of the corridor and the other not. Two groups of 34 geese were reared on each of these two feeders according to the same breeding protocol promoting hyperphagia and spontaneous liver steatosis. The first analyses show that the doors allow better isolation of the animal within the feeder and increase the number of recordings attributable to a single animal. Moreover, with a density of 34 geese per feeder, the single place electronic feeder with doors is not saturated, the occupancy limits of this feeder being 10.25 h. Fitted with doors, the feeder allows the daily individual recording of growth, ingestion and description of feeding behavior during feed restriction and ad libitum feeding periods. With a relatively low average daily gain during the feed restriction period, geese visit nearly 3.5 times less the feeder, these visits last 99 s longer and consumptions are 1.7 times higher than during the ad libitum feeding. Correlations between liver weight and these innovative phenotypes were calculated for each of the two periods. Total and daily food consumptions as well as total and daily duration of visits appear to be predicting variables of liver weight at any time scale studied (week or period). Despite the low number of animals raised in this trial, these first conclusions enable to identify ways to improve this feeder and give firsts elements of discussion for future spontaneous steatosis trials.; Pour répondre aux questions de recherche liées à la stéatose spontanée chez l’oie, la mesure individuelle de l’ingestion et du comportement alimentaire d’animaux élevés en lot est indispensable. Ainsi, un distributeur automatique de concentré (DAC) dédié aux canards est en cours d’adaptation aux oies en testant deux distributeurs, l’un équipé de portes à l’entrée du couloir et l’autre non. Deux lots de 34 oies ont été élevés sur chacun de ces deux DAC selon un même protocole d’élevage favorisant l’hyperphagie et l’engraissement hépatique. Les premières analyses montrent que les portes permettent un meilleur isolement de l’animal devant la mangeoire et limitent l’enregistrement de consommations non attribuables à un seul individu. De plus, avec une densité de 34 oies par distributeur, le DAC avec portes n’est pas saturé, le temps maximal d’occupation du distributeur étant de 10,25 h. Equipé de portes, le distributeur permet également le suivi individuel de la croissance et de l’ingestion et la description du comportement alimentaire sur les périodes de rationnement et de relâchement. Avec un GMQ relativement faible en période de rationnement, les oies visitent près de 3,5 fois moins le DAC, ces visites durent 99 s de plus et les consommations sont 1,7 fois supérieures qu’en période de relâchement. Les corrélations entre le poids de foie et ces phénotypes innovants ont été calculées pour chacune des deux périodes. Les consommations totale et journalière d’aliment ainsi que les durées totale et journalière des visites semblent être des variables explicatives du poids de foie que ce soit à l’échelle de la semaine ou de la période. Malgré un faible effectif d’animaux mis en place dans le cadre de cet essai, ces premières conclusions ont permis d’identifier des pistes d’améliorations du distributeur mais aussi d’apporter des premiers éléments de discussion pour les futurs essais portant sur la stéatose spontanée.

National audience; Livestock provides many services in the territories in which it is established and it is interesting to be able to perceive them in their entirety. The objective of this study was to qualify the multiple contributions of agroforestry fatty liver production systems, taking as an example the association of geese/walnuts in Périgord. The conceptual framework used was that proposed by Ryschawy et al (2015). The data came from 1) biological measurements (tree growth or fruit production, animal behavior, biodiversity) or soil data (soil fertility) carried out on adult geese raised on outdoor areas of walnut trees aged between 7 and 11 years and 2) data from the literature, for the other dimensions. Our analysis shows that the breeding of geese for foie gras production on outdoor walnut areas is of mutual benefit since the shade provided by walnut trees is very appreciated by animals, while the droppings of the geese fertilize the trees, which increases their growth and their fruit production without altering their sanitary quality. This association provides services by i) of suppling the production of relative moderate amounts of foie gras, goose meat, walnut wood, walnuts and co-products (goose down and fat, walnut stain and shell); ii) preserving environmental quality by upgrading co-products in animal feed (77 t/year) and preserving soil fertility; iii) improving heritage and life quality through high added value products (AOC Noix du Périgord, goose of Périgord brand) and preserving gastronomic and cultural heritage iv) favoring territorial vitality through employment and a contribution to agro-tourism. It also has negative aspects (environmental impacts, social acceptability of gavage and health risks).This work shows that the benefits of the goose/walnut association are much broader than the technical and economic interests that justified them.; L’élevage rend de nombreux services dans les territoires dans lesquels il est implanté et il est intéressant de pouvoir les appréhender dans leur globalité. L’objectif de cette étude est de réaliser une qualification du bouquet de services rendus par les systèmes de production de foie gras agroforestiers en prenant comme exemple l’association oies / noyers en Périgord. Le cadre conceptuel utilisé a été adapté de Ryschawy et al (2015). Les données proviennent 1) de mesures biologiques (croissance des arbres ou production de fruit, comportement des animaux, biodiversité) ou pédologiques (fertilité des sols) réalisées sur des oies adultes élevées sur des parcours contenant des noyers âgés de 7 à 11 ans et 2) des données de la littérature pour les autres dimensions. Notre analyse montre que l’élevage des oies pour la production de foie gras sur des parcours implantés de noyers est à bénéfices réciproques puisque l’ombre apportée par les noyers est très appréciée des animaux, et que les déjections des oies fertilisent les arbres ce qui augmente leur croissance et leur production de fruits sans altérer leur qualité sanitaire. Cette association rend des services i) d’approvisionnement par la fourniture en quantité relative modérée de foie gras, de viande d’oie, de bois de noyers, de noix et de coproduits (duvets et graisse d’oie, coques et brou de noix); ii) de préservation de la qualité environnementale en valorisants des coproduits dans l’alimentation des animaux (77 t/an) et en préservant la fertilité du sol ; iii) patrimoniaux et de qualité de vie par le biais de produits labellisés et à haute valeur ajoutée (AOC Noix du Périgord, marque Oie du Périgord) et le maintien du patrimoine culturel et gastronomique; et iv) de vitalité territoriale par la création d’emplois et la contribution à l’agrotourisme. Il a aussi des externalités négatives (impacts environnementaux, acceptabilité sociale du gavage et risques sanitaires). Ce travail permet de montrer que les bénéfices de l’association oies/noyers sont beaucoup plus larges que les intérêts techniques et économiques qui les ont justifiés.

Diplôme : Mémoire de stage

The domestic goose is hyperphagic after a fast resulting in a 40% decrease in body mass (a decrease similar to that during breeding anorexia). Food intake is maximum on the 8th day of refeeding. As it is then an average of 2.5 times higher than before the fast, food intake may thus reach the value during forced-feeding for "foie gras". Since nitrogen assimilation rate also increases 2.5 times, nitrogen fixation is increased 6.8 times, suggesting a high level of protein synthesis.

This study shows the apparent role of the ventromedial nucleus of the hypothalamus (VMH) in regulating food intake in the goose. The feeding pattern of normal animals has been compared with that of animals made hyperphagic by destruction of the VMH. Lesioning of the VMH modified the circadian pattern of intake. All the geese tended to equalize their intakes between the light and dark periods. The overall effect of lesioning was considerable hyperphagia resulting from an increase in the number of meals and of their amplitude and duration, as well as in the rate of ingestion. We have emphasized the importance of defining the meal when interpreting changes in the correlations between the amount of food ingested during the meal and the length of pre or postprandial intervals after destruction of the VMH. Although it is important, the fatty liver syndrome induced after hyperphagia is not sufficient to produce fatty livers which can compete with those obtained by traditional cramming.

The endocrine pancreas of birds contains 3 islet types and releases glucagon, insulin, somatostatin and avian pancreatic polypeptide (APP). Interactions between these hormones, and pancreatic hormone-plasma metabolite feedback mechanisms, are the main regulators of these secretions. In birds, total pancreatectomy induces a fatal hypoglycaemia associated with the disappearance of circulating glucagon, and an impaired glucose tolerance ascribed to the lack of insulin. Normoglycaemia can be restored in depancreatized birds by infusion of glucagon and insulin, provided that the G/I ratio is close to normal. Subtotal pancreatectomy provokes a diabetes characterized by a basal hyperglycaemia and an impaired glucose tolerance. However, while a transient diabetes is observed in most species, in the goose a permanent diabetes is obtained. These results point out the importance of the pancreas and especially of glucagon, in birds. This importance can also be detected in the protein metabolism, since total or subtotal pancreatectomy markedly increases the concentration of plasma aminoacids. As for lipid metabolism, in vivo and/or in vitro experiments have shown the sensitivity of the adipose tissue and liver cells to glucagon. Finally, contrary to the general opinion, insulin seems to be antilipolytic, as in mammals.

In fed geese, plasma levels of glucose and alanine were 1.9 g.l-1 and 560 mumol.l-1, respectively. During a long fast (40 days), plasma glucose and alanine were maintained at a high level (1.5-1.8 g.l-1 and 370-540 mumol.l-1, respectively). Plasma level of acetoacetate was very low (40 mumol.l-1); by contrast, plasma level of beta hydroxybutyrate reached very high values (20 mmol.l-1) after about 20 days of fasting, then it decreased. Plasma levels of lactate and pyruvate decreased along the course of the fast, from 2 500 to 2 000 mumol.l-1 and 220 to 170 mumol.l-1, respectively.

The effects of induced hypothalamic hyperphagia and forced-feeding were studied in 30 geese of the Landes breed. They were housed in individual cages under a dark-light cycle of 12 hrs light-12 hrs darkness. Eleven geese with ventromedian hypothalamic (VMH) lesions and 8 controls were fed ad libitum. A third lot of 11 force-fed animals was pair-fed with the operated geese. The study lasted 4 weeks after an adaptation period to the new environmental conditions. The daily food intake of the geese and their weekly liveweight gain were monitored. After VMH lesions, the mean food intake of the geese increased by 169 p. 100 so that after each treatment their liveweight increased and they became obese (P less than 0.001). The tissue distribution of the group with lesions showed a higher amount of subcutaneous fat (P less than 0.05), while the mesenteric fat (P less than 0.05) was more abundant after forced-feeding. The liver weight was much higher in all cases; its increment reached 311 p. 100 in geese with VMH lesions and 193 p. 100 in the force-fed. However, those values were too low when compared to the means obtained by traditional forced-feeding. Hyperphagia in the geese was very marked as compared to that in rats, but it was insufficient to produce a considerable hepatic steatosis.

Utilising the homology between goose alpha chain hemoglobin and chicken, the primary arrangement of the amino acid residues of the alpha chain (major component) of goose hemoglobin is presented. Data were obtained from amino acid analysis of the isolated alpha chain and of tryptic peptides of the chain. Their chemical structure was established by Edman degradation, carboxypeptidase A and B and leucineaminopeptidase digestion.

This is a study of the comparative physiology of the feeding sequence in 24 Landes geese fed ad libitum. The relative parameters of feeding behavior and the apparatuses used have been described. We found that the 24-hour light/dark cycle, corresponding to maximal ingestion, was not the same in all the animals studied. Two groups were distinguished: those tending to be diurnal and those tending to be nocturnal. The feeding pattern of the animals in each group and from day to day was constant. The correlation between the amount ingested during the meal and the length of pre or post-prandial intervals showed great variation, and the choice of meal definition considerably affected the results.

An abrupt decrease of the mitotic index occurs between the 15th and the 18 day of incubation. This decrease is concomitant withthe appearance of glycogen first and of lipids later. The differenciation implicated by this biochemical specialisation is correlative of a lowering of cellular multiplication ability, according to A. Prenant's general law.

The author who has been observing and shooting geese on the Belgian coast near the estuary of the Scheldt, during more than twenty years, kept careful records of his observations. His conclusions are:1. The number of greylag and beangeese seen in this area did not change.2. The number of pink-feet remained more or less static, but during the last six years there is a notable decrease compared with the years between 1930 and 1940.3. The number of white-fronted geese increased tremendously. Between 1928 and 1933 not a single one was shot. After 1933 a fewwere seen and the first real invasion took place in the severe winter of 1939-1940. Since 1944 the white fronted became far the commonest goose in this area.4. Barnacle geese appear only when the winter is severe. They do not seem to diminish in number.5. Brent geese were common in cold winters in the past. A huge invasion took place in 1937 after a heavy snowfall in the North. Since about ten years the brent disappeared completely. Not a single one has been seen since 1942, not even during the very severe frost in 1946-1947.