Effects of substituting yellow corn for sorghum in geese diets on magret and foie gras quality.

The aim of this trial was to study the effects of substitution of yellow corn with sorghum during the growing-finishing (G period), overfeeding (O period), or both periods on magret and foie gras quality in geese. In total, 260 ganders were divided into 4 groups (65 birds in each) differing in the cereal (yellow corn or sorghum) included in the diet given during the G and the O periods, using a 2 × 2 factorial arrangement of treatments. The groups differed in the nature of the cereal in the diet offered to birds between 44 and 104 d of age (G period: a diet containing 500 g of sorghum/kg (SS and SC groups) or a diet containing 500 g of yellow corn/kg (CS and CC groups). The groups differed also in the diet offered to birds between 105 and 120 d of age (O period): 967 g of yellow corn/kg (SC and CC groups) or 965 g of sorghum/kg (SS and CS groups). At the end of the O period, the birds were slaughtered after 10 h of fasting to measure foie gras and breast muscle weight, color, and chemical composition. The mortality in the SC group was higher (P < 0.05) than in the other 3 groups (14.29 vs. 3.58%, average of the 3 groups). After overfeeding, birds fed with sorghum had foie gras that were heavier 984 vs. 885 g, in CS+SS vs. CC+SC groups, respectively; P < 0.001) and less yellow (18.03 vs. 23.97 for b*, in CS+SS vs. CC+SC groups, respectively, P < 0.001) than birds fed with corn. The substitution of yellow corn with sorghum during the G and O periods (SS group) increased the weight of the foie gras, but altered its color to a paler yellow. In contrast, a substitution during the G period only (SC group) resulted in increased mortality during the O period.

The influence of loose-mix feeding on behavior, feed intake, and body weight of growing geese.

The aim of this trial was to study the influence of loose-mix feeding on behavior, feed intake, and BW of growing geese. In total, 252 one-day-old geese (Anser anser) were divided into 2 groups differing in the form of diet they received between 42 and 98 d of age (AMEn 11.55 MJ/kg, CP 16%): a complete pelleted diet containing 500 g of sorghum/kg (control group) or a mixture containing 500 g of protein-rich pellets and 500 g of sorghum whole seeds/kg (mixed group). Feed intake was measured daily from 42 to 48 d and every 3 d from 49 to 98 d. Individual BW was measured weekly from 42 to 98 d. Goose behavior was monitored by the scan sampling method throughout the experiment, which was divided into 5 periods according to the timing of access to feed: period 1 from 42 to 55 d (ad libitum feeding access), period 2 from 56 to 62 d (2 + 2 h feeding access), period 3 from 63 to 70 d (2 h feeding access), period 4 from 71 to 94 d (1 h feeding access), and period 5 from 95 to 97 d (3 h feeding access). Over the whole period, the feed intake (13,968 and 14,480 g) and the feed conversion ratio (8.53 and 8.15) were similar in both groups (P = 0.112 and P = 0.168; respectively). Body weight was similar in both groups from 42 to 91 d of age, but at 98 d of age, BW was 3.7% lower in the control than in the mixed group (P = 0.006). Goose behavior was influenced by period, because the percentage of birds feeding increased when the daily access time to the feed decreased (P < 0.001), but not by group (P > 0.05). The results suggest that a loose-mix feeding could be recommended in feeding of growing geese because it weakly influences their feed behavior but slightly increases their weight at the end of the growing period.

Influence of feeding sorghum on the growth, gizzard development and carcass traits of growing geese.

The aim of this trial was to study the influence of feed form on the performance, gizzard development and carcass traits of growing geese. Between 42 and 98 days of age, 360 geese (type Maxipalm(®)) were fed a diet containing 500 g sorghum/kg (nitrogen-corrected apparent metabolizable energy 12.6 MJ/kg, 15.1 g/kg CP). Birds were divided into three groups differing in feed form: complete pellets (Control group, n = 120); a coarse-ground meal (CG group, n = 120); or a mixture containing protein-rich pellets and sorghum whole grains (M group, n = 120). Feed intake per pen (40 birds/pen) was measured weekly between 42 and 98 days of age, and individual live weight (LW) was measured every 2 weeks. At 84 and 98 days of age, 12 birds were slaughtered in each group to measure the gizzard development and body traits. Irrespective of the goose sex, LW at 98 days was lower for the CG group than for the Control group (5555 v. 5888 g, P < 0.05 for males and 5039 v. 5215 g, P < 0.05 for females). The feed intake over the entire period was 5.5% higher in the M group (P < 0.05) than in the Control and CG groups but the feed conversion ratio (6.91, P > 0.05) was similar in the three groups. The gizzard development (as % of LW) was higher in birds of the CG group than those of the Control and M groups at 84 days of age (+13.98% and +13.51%, respectively; P < 0.05) but was similar in all three groups at 98 days of age (4.01%, P > 0.05). The relative liver development was lower in the birds of the CG group than those of the other two groups at 84 and 98 days of age (-20%, P < 0.001 and -10%, P < 0.05, respectively). The other body traits were similar in the three groups at both 84 and 98 days of age. The present results suggest that a simplified diet presented in the form of a mixture of sorghum whole grains and protein-rich pellets did not reduce the performance of growing geese.

Effects of presentation and type of cereals (corn or sorghum) on performance of geese.

The aim of this trial was to study the effects of cereal (corn or sorghum) and of the presentation of the diet (pelleted diet or a mixture with cereal) on the performance of geese. In total, 480 one-day-old geese were divided into 4 groups differing in the diet they received between 52 and 102 d of age: a pelleted diet containing 500 g of sorghum/kg (CS group; AMEn 11.29 MJ/kg, CP 16.70%); a mixture containing 500 g of protein-rich pellets and 500 g of sorghum whole seeds/kg (MS group; AMEn 11.61 MJ/kg, CP 14.30%); a pelleted diet containing 500 g of corn/kg (group CC; AMEn 11.33 MJ/kg, CP 16.40%); and a mixture containing 500 g of protein-rich pellets and 500 g of corn mash/kg (group MC; AMEn 11.48 MJ/kg, CP 14.50%). From 102 to 117 d, 33 birds/sex/group were force-fed with corn. Between 52 and 102 d of age, individual BW and collective feed intake (40 birds/pen) were measured weekly. Body traits were measured at 69, 96, and 117 d and the volume of the crop was measured at 102 d of age. The cereal had no significant effect on total feed intake (15,028 g, NS) or BW (5,811 g, NS) but the breast development at 102 d was less in birds fed sorghum compared with corn (-4.9%; P<0.05). Feed intake (+8.4% between 69 and 102 d; P<0.001), BW (+3.9%; P<0.001) and gut development (+9.3%; P<0.001) were higher when the diet was offered as a mixture compared with a complete pelleted diet. The birds fed the complete pelleted diets had a larger crop (+10.1%; P<0.05) than others. The cereal and the presentation of the diet had no effect on the body traits at the end of the force feeding. The results suggest that the use of sorghum whole seeds is interesting for feeding geese.

The effects of stunning methods on product qualities in force-fed ducks and geese. 1. Carcass downgrading and meat quality.

This study investigated the effects of various stunning methods on the quality of carcass and meat in ducks and geese force-fed for the production of French 'foie gras'. The ducks (n = 30 per group) were stunned with one of the following techniques: electrical stunning in a water bath (50 Hz AC, 130 mA, 4 s), head-only electrical stunning (50 Hz AC, 600 mA, 4 s), mechanical stunning (captive bolt) and controlled atmosphere stunning (CAS: phase 1, CO2 (40%)-O2 (30%)-N2 (30%), for 2 min followed by phase 2, CO2 > 85% in air, for 2 min). The same methods (except head-only stunning which was not applied) were used in geese (n = 40 per group). During the first 5 min after slaughter, the stunning techniques that did not kill the animals were associated with a high incidence of head movements (mechanical and electrical head-only stunning), convulsions and convulsive wing flapping (mechanical stunning), in both species. Consequently, the rate of post-mortem pH fall in breast muscle was enhanced and the meat was paler when measured at 24 h or 6 days post mortem (L*, a*, b* coordinates). In ducks, the animals stunned in the water bath showed the lowest bleeding efficiency, compared to the three other procedures. In geese, the mechanical stunning allowed the highest recovery of blood compared to the CAS and the water-bath methods. Meat texture assessed instrumentally and fluid losses during storage and processing were not affected by the stunning method in any species. Sensory analysis showed a higher score for bloody appearance of raw meat in ducks stunned with the methods that kill before neck cutting (water-bath and CAS). This effect was, however, not linked to the rate of bleeding. The sensory properties of cooked meat were not affected by the stunning method. In both ducks and geese, CAS was associated with the lowest rate of fractures of humeral bone but CAS-stunned geese showed the most engorged wing veins. Overall, these results show the positive effect of CAS on the appearance defects of carcass and meat of ducks and geese, and, on the contrary, they confirm the detrimental effects of water-bath stunning on these criteria. However, the incidences on meat sensory qualities were scarce.

The effects of stunning methods on product qualities in force-fed ducks and geese. 2. Fatty liver quality.

This study investigated the effects of various stunning methods on the quality of French 'foie gras' in ducks and geese. The ducks (n = 30 per group) were stunned with one of the following techniques: electrical stunning in a water bath (50 Hz AC, 130 mA, 4 s), head-only electrical stunning (50 Hz AC, 600 mA, 4 s), mechanical stunning (captive bolt) and controlled atmosphere stunning (CAS: phase 1, CO2 (40%)-O2 (30%)-N2 (30%), for 2 min followed by phase 2, CO2 >85% in air, for 2 min). The same methods (except head-only stunning which was not applied) were used in geese (n = 40 per group). The weight of the liver at slaughter was not affected by the stunning techniques, neither was its colour (L*, a*, b* coordinates), despite the differences in bleeding rate between the stunning treatments. The loss of fat during the cooking of canned fatty liver did not depend upon stunning treatment. Some appearance defects of raw fatty livers were significantly affected by the treatment: mechanical and head-only stunning induced higher incidence of petechial haemorrhages in duck liver, whereas in geese, incidence of superficial haemorrhages was significantly higher after CAS and water-bath stunning. The calculation of an overall score based on the incidence and severity of the different appearance defects observed in the present experiment showed that CAS was associated with the least favourable position in ducks as well as in geese, compared to the other treatments. The commercial grading of ducks and geese fatty livers, carried out by an expert from the industry, clearly showed the detrimental effect of CAS on the commercial value of raw livers. CAS, under the conditions applied in the present work cannot be recommended, because of its drastic effect on liver quality. The underlying mechanisms deserve further investigations.

Serum sphinganine and the sphinganine to sphingosine ratio as a biomarker of dietary fumonisins during chronic exposure in ducks.

Sphinganine concentration (Sa) and sphinganine to sphingosine ratio (Sa/So) are sensitive biomarkers of fumonisin B1 (FB1) exposure in animals and have been proposed to reveal FB1 exposure in humans. They correlate with liver and kidney toxicity and often precede signs of toxicity. However, the use of Sa and Sa/So is confusing during chronic exposure. Indeed, some authors report altered sphingolipids metabolism, whereas others fail to demonstrate significant effect. The aim of this study was to investigate the kinetics of Sa and Sa/So in the serum of ducks over a 77-day exposure to 0, 2, 8, 32 and 128 mg FB1/kg feeds. Serum biochemistry was also investigated to reveal hepatotoxicity. The results obtained indicate that the kinetics of sphingolipids and serum biochemistry are closely linked with the duration of the exposure. After a strong and rapid increase Sa and Sa/So decrease then stabilize. The lowest investigated dose able to determine a detectable effect is 2 mg/kg feeds, the Sa/So ratio being the most sensitive biomarker of FB1 exposure.

Effects of fumonisins on liver and kidney sphinganine and the sphinganine to sphingosine ratio during chronic exposure in ducks.

Sa and the Sa/So ratio are very sensitive biomarkers of exposure to fumonisins in several species. We previously demonstrated that increases in Sa and in the Sa/So ratio in serum were less pronounced when ducks ingested fumonisins for more than 7 weeks than when animals were exposed for only 1-2 weeks [S.T. Tran, D. Tardieu, A. Auvergne, J.D. Bailly, R. Babilé, S. Durand, G. Benard, P. Guerre, Serum sphinganine and the sphinganine to sphingosine ratio as biomarker of dietary fumonisins during chronic exposure in ducks, Chem. Biol. Interact., in press]. The aim of this study was to investigate the kinetics of Sa and of the Sa/So in both liver and kidney of ducks that have been previously tested for Sa and the Sa/So ratio in serum. Analysis were performed on treatment days 0, 7, 14, 28 and 77 in five groups of ducks fed fumonisins obtained from an extract of Fusarium verticillioides culture material by daily gavage to obtain an exposure equal to 0, 2, 8, 32 and 128 mg FB1/kg feed. Sa and the Sa/So ratio in tissues were then correlated with Sa and the Sa/So ratio previously obtained in serum. The amounts on sphinganine 1-phosphate (Sa1P) and sphingosine1-phosphate (So1P) in the liver were also investigated. On day 7 of treatment, 2mg/kg FB1 in the feed were sufficient to increase Sa and the Sa/So ratio in liver (by 165 and 148%, respectively) and kidney (by 193 and 104%, respectively). At a rate of 128 mg/kg FB1 in the feed, a very high increase in Sa concentration was observed in both liver and kidney without mortality and/or signs of necrosis (respective increase of 2034 and 3768%). Although the precise mechanism of the resistance of ducks to fumonisin-induced hepatotoxicity is still uncertain, it might be linked to the rate at which the sphingoid bases sphinganine and sphingosine are converted to their 1-phosphate or other metabolite and eliminated from target tissues.

Changes in lipid composition of hepatocyte plasma membrane induced by overfeeding in duck.

This experiment was carried out to examine the influence of overfeeding ducks with corn on the lipid composition of hepatocyte plasma membrane. Seventy-day-old male Mule ducks (Cairina moschata x Anas platyrhynchos) were overfed with corn for 12.5 days in order to induce fatty livers. The cholesterol and phospholipid contents were approximately 50% higher in hepatocyte plasma membranes from fatty livers compared to those of lean livers obtained from non-overfed ducks. However, the cholesterol/phospholipids molar ratio did not differ between both groups. Overfeeding induced a significant change in phospholipid composition of hepatocyte plasma membrane with a decrease in phosphatidylcholine proportion and conversely an increase in phosphatidylethanolamine. The fatty acid profile of phospholipids was also altered. In fatty hepatocyte plasma membrane, the overall proportion of polyunsaturated fatty acids (PUFA) was decreased and this was due to the decrease of some of, but not all, the PUFA. In addition, the proportions of oleic acid and n-9 series unsaturated fatty acids were higher in fatty than in lean liver membranes. This study provides evidence that overfeeding with a carbohydrate-rich corn-based diet induces a de novo hepatic lipogenesis in Mule duck which predominates over dietary lipid intake to change the lipid composition of the hepatocyte plasma membrane.

Chronic effects of fumonisin B1 on ducks.

Partially purified fumonisin B1 (FB1) was orally administrated for 77 d to 5 groups of 8 mule ducks starting at 7 d of age; the concentrations corresponded to 5 diets containing 0, 2, 8, 32, and 128 mg of FB1/kg of feed. No mortality was observed, and no effects on feed consumption and body weight gain were observed at the end of the treatment period. But, surprisingly, FB1 ingested at 32 and 128 mg/kg led to decreased body weight from d 28 to 63 and from d 7 to 63, respectively. FB1 had no effect on the relative weight of heart and breast muscle, whereas a significant increases in the relative weights of gizzard, spleen, and liver were measured in ducks receiving 32 and 128 mg of FB1/kg of feed without evidence of detectable microscopic modification of these organs. FB1 had no significant effect of the serum aspartate aminotransferase and gamma-glutamyltransferase levels but increased serum total protein, cholesterol, alanine aminotransferase, lactate dehydrogenase, alkaline phosphatase levels when 128 mg of FB1/kg of feed was given. Serum, liver, and kidney sphinganine to sphingosine ratio was significantly increased in ducks fed 8 to 128 mg of FB1/kg of feed. The biggest increase was observed in kidneys, suggesting that this organ is the most sensitive to detect FB1-induced disruption of sphingolipid metabolism.

Lipid composition of hepatocyte plasma membranes from geese overfed with corn.

Twelve-week-old Landes male geese were overfed with corn for 21 d in order to induce liver steatosis (fatty liver). Lipid composition of hepatocyte plasma membranes from fatty livers was compared to that of lean livers obtained from geese fed a normal diet. The ratio cholesterol/phospholipids was higher in fatty hepatocyte plasma membranes (0.63 vs. 0.47), whereas the phospholipid/protein ratio was less than half. Overfeeding induced changes in fatty acid composition of hepatocyte plasma membranes, including a greater than twofold increase in the percentage of oleic acid (29.7 vs. 13.8%) and a somewhat lesser increase in lauric, palmitic, and palmitoleic acid contents of plasma membrane lipids of fatty livers. A concomitant reduction in the proportion of stearic acid (18.4 vs. 25.1%) was also observed. In fatty livers, the increased ratio of saturated to polyunsaturated fatty acids (PUFA) (1.5 vs. 1.0) was related to a significant decrease in PUFA content. Among all the PUFA, only the eicosatrienoic acid (20:3n-9) percentage was increased by liver steatosis. Overfeeding with corn appeared to induce competition between de novo synthesized and dietary fatty acids incorporated in hepatocyte plasma membranes. This resulted in an accumulation of de novo synthesized monounsaturated and derived fatty acids in plasma membranes from overfed birds. A defect in the incorporation of linoleic acid and linoleic- and linolenic-derived PUFA was observed despite the high proportion of these essential fatty acids in the diet. It was concluded that in overfed palmipeds, de novo hepatic lipogenesis prevails over dietary lipid intake to modulate lipid composition of the fatty liver plasma membrane.

[Relationship between digestive repletion state and hepatic composition in gavaged mule ducks]. / Relation entre l'état de réplétion digestive et la composition hépatique du canard mulard en gavage.

Two batches of male mule ducks were constituted on the basis of the filling state of the crop at slaughter, after being over-fed twice a day for 5 days: no corn in the crop defined 'OV' birds, and corn in the crop defined 'OP' birds. 'OP' animals presented significantly lower daily consumption during the last 3 days of force-feeding. They had a lighter liver weight than 'OV' ducks (178 versus 197 g), lower hepatic lipid percentages (25.0 versus 33.0%), and enhanced hepatic glycogen rates (4.7 versus 2.4%). Metabolic state of animals might explain these variations in hepatic composition. Unadaptation to force-feeding modifies the metabolic inbalance of the overfed animals and consequently induces higher levels of carbohydrate. These results suggest that similar differences between crude fatty livers could be reflected in the quality of the cooked products.

[Diet type, grinding size and anatomo-functional characteristics of the proximal digestive tract in the rabbit]. / Nature de l'aliment, finesse de mouture et données anatomo-fonctionnelles du tube digestif proximal du lapin.

Two diets containing either dehydrated lucerne (40%) or dehydrated beet pulp (50%) both being coarsely (4 mm) of finely (1 mm) ground before pelleting, were fed to 120 rabbits after weaning. Feed intake and weight gain were estimated. After 79 days, 11 rabbits in each group were slaughtered between 14.00 and 17.00 h. The parameters measured were stomach and ileal weights, dry matter, fibre and nitrogen contents, volatile fatty acid concentrations. Gastric emptying and intestinal transit time were estimated in each group. Rabbits fed the beet pulp diet had a better feed conversion ratio associated with a higher solid matter gastric retention and also a longer jejuno-ileal transit time. Finely ground diet further increased the transit time, particularly in the ileum, which was also associated with a higher concentration of fermentation by-products.

[Physico-chemical stimulation of dietary origin and digestive motility in the rabbit]. / Stimulation physico-chimique d'origine alimentaire et motricité digestive chez le lapin.

The effects on gastrointestinal motility of two different diets, one containing dehydrated lucerne and the other dehydrated beet pulp (both being either coarsely or finely ground before pelleting) were studied in 16 unanesthetized 50-60-day old rabbits fed ad libitum. The rabbits fed with lucerne had better antroduodenal and ileo-caecal coordination, a higher level of electrical activity on the duodenum, and more frequent migrating myoelectric complexes on the jejunum and ileum than those fed with beet pulp. Furthermore, the rabbits fed the finely ground pellets showed weak electrical activity on the ileum and poor ileo-caecal coordination irrespective of fiber source, suggesting a unique effect of size per se on these portions of the digestive tract.