The influence of choice feeding and cereal type (corn or triticale) during the finishing period on performance of mule ducks.

The aim of this trial was to study the influence of choice feeding and cereal type (corn or triticale) during the finishing period on performance of ducks. In total, 624 one-day-old male mule ducks (Cairina moschata × Anas platyrhynchos) were divided into 3 groups differing in the diet they received between 56 and 84 d of age: a commercial complete pelleted diet (control group; AMEn 12.1 MJ/kg, CP 15%), or corn whole seeds (AMEn 14.4 MJ/kg, CP 7.3%) and protein-rich pellets (AMEn 9.9 MJ/kg, CP 22.7%) in 2 separated feeders [choice feeding with corn (CFC) group]; or triticale whole seeds (AMEn 13.0 MJ/kg, CP 10.5%) and protein-rich pellets (AMEn 11.2 MJ/kg, CP 19.5%) in 2 separated feeders [choice feeding with triticale (CFT) group]. From 85 to 96 d, 96 birds/group were overfed with corn. Feed intake (complete pellets or cereal and protein-rich pellets) per pen was measured at 60, 62, 65, 69, 78, and 84 d of age. Body weight and body traits were measured at 56 to 84 d of age. Over the entire period, from 56 to 84 d, the feed intake of the CFC group was 7% lower than the control group, and 5% lower than that in the CFT group (P = 0.002). Whatever the diet tested, at 56 and 84 d of age, the BW (4,099 and 4,779 g, P = 0.42 and P = 0.35, respectively) and the carcass traits (P > 0.05) of ducks were similar in the 3 groups. During and after overfeeding, the performances of the ducks were also similar (P > 0.05). The present results suggest that CFC during the finishing period is a solution to reduce the cost of diet destined to ducks. Indeed, using locally grown grains could reduce the economic and environmental impacts of duck feeding, reducing the transportation and crushing processes.

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.

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.

Effect of outdoor grazing-area access time and enrichment on space and pasture use, behaviour, health and growth traits of weaned rabbits.

Providing rabbits with a grassy outdoor area allows them to express a broad variety of specific behaviours such as grazing where grazeable herbage persists. However, rabbits that graze are also exposed to external stressors. Controlled outdoor access time may help preserve the grassland resource, while a hiding place may offer the rabbits a secure space. We focused on rabbit growth, health and behaviour according to outdoor access time and the presence of a hideout on a 30-m2 pasture area. We divided 144 rabbits into four groups (group of rabbits with 8 hours per day (H8) of access to pastures provided with an hideout (Y) (H8Y): n = 36; group of rabbits with 8 hours per day (H8) of access to pastures unprovided with an hideout (N) (H8N): n = 36; group of rabbits with 3 hours per day (H3) of access to pastures provided with an hideout (Y) (H3Y): n = 36; group of rabbits with 3 hours per day (H3) of access to pastures unprovided with an hideout (N) (H3N): n = 36) that differed in access time (H8, four replicates, eight hours a day from 0900 h to 1700 h; and H3, four replicates, three hours a day from 0900 h to 1200 h) and the presence of a hideout (presence of an hideout on the pasture (Y), four replicates, with a roof-shaped wooden hideout; and absence of an hideout on the pasture (N), four replicates, without). Rabbit growth and morbidity were measured weekly for each rabbit from 34 to 76 days of age. Rabbit behaviour was assessed on days 43, 60 and 74 by direct visual scanning. Available grassy biomass was evaluated on days 36, 54 and 77. We also measured the time rabbits took to enter and exit the mobile house and the level of corticosterone accumulated in their hair during the fattening period. There were no between-group differences in live weight (on average, 2 534 g at 76 days of age) and mortality rate (18.7%). The rabbits expressed a broad variety of specific behaviours, with grazing being the most frequent (30.9% of all the observed behaviours). Foraging behaviours including pawscraping and sniffing were more frequently observed in H3 rabbits than H8 rabbits (1.1 vs 0.3% and 8.4 vs 6.2%, respectively; P < 0.05). There was neither an access-time nor hideout presence effect on rabbit hair corticosterone levels or time to exit and enter the pens. Patches of bare ground were more frequent in H8 pastures than in H3 pastures (26.8 vs 15.6%, respectively; P < 0.05). Over the whole growing period, the biomass intake rate was higher in H3 than H8 and higher in N than Y (1.9 vs 0.9 g/rabbit/h and 1.8 vs 0.9 g/rabbit/h, respectively; P < 0.05). In conclusion, restricted access time tended to slow the reduction of the grass resource but had no detrimental effects on rabbit growth or health. Rabbits facing restricted access time adapted their grazing behaviour. A hideout helps rabbits cope with external stressors.

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.

Changes over time in the bacterial communities associated with fluid and food particles and the ruminal parameters in the bovine rumen before and after a dietary change.

This work aimed to study the changes over time in the bacterial communities associated with the fluid and food particle fractions of the cow rumen following a change in diet. Four cannulated cows were fed a hay-based diet for 21 days and were then switched to a corn-silage-based diet for 33 days. The bacterial communities were regularly characterized by capillary electrophoresis - single-strand conformation polymorphism (CE-SSCP) and qPCR, and the main ruminal parameters were determined. The dietary change led to slight reductions in the diversity index, bacterial concentration, pH, and NH(3)-N concentration, and to an increase in the redox potential and volatile fatty acid concentrations. CE-SSCP profiles were not significantly affected by the dietary change but did change over time, with frequent fluctuations in both fluid and food particle fractions before and after the dietary change. The food particle fraction had a higher diversity index of bacterial community (+1.2 points, P < 0.001) and slightly more total bacteria than the fluid fraction of the rumen.

Effect of access to outdoor grazing and stocking density on space and pasture use, behaviour, reactivity, and growth traits of weaned rabbits.

In a context of evolving concern over housing conditions of farmed rabbits, we developed a housing system that allows access to an outdoor area. The aim was to study the health status, growth and behaviour of rabbits raised at two stocking densities with access to a paddock, or not. We distributed 299 weaned rabbits in four groups (YH: 100, NH: 99, YL: 50 and NL: 50) using a 2 × 2 factorial design including access (Y: yes) or not (N: not) to a 23 m2 paddock and the indoor stocking density (H, high: 17 or L, low: 9 rabbits/m2). We measured the growth and health status of each animal weekly for 42 days (from 31 to 73 days of age) and performed reactivity tests to a new environment, a human and new object. We also assessed the rabbits' behaviour at days 26 and 40 by doing a visual scan of each animal at regular time intervals. Our results showed that stocking density had no effect on mortality, but mortality tended to increase with outdoor access from 3.0% to 7.0% (P < 0.10). Although the stocking density had no effect on average daily gain, it was higher in rabbits in the N group than in the Y group (+3.6 g/day; P < 0.05). Rabbits entered the paddocks for the first time in less time at the beginning of the trial (50 s at day 3 vs 10 min at day 31; P < 0.001). The proportion of rabbits outside after 20 min of the new environment test was higher among rabbits in the L group than in the H group (+24% points at day 3 and +11% points at day 20; P < 0.001). Regardless of the stocking density, more rabbits in the N group touched the experimenter's hand (16% vs 27%; P < 0.05) and the new object (34% vs 20%; P < 0.05) than rabbits in the Y group. Inactivity was more frequent in rabbits inside the pens than in the paddocks (70.0% vs 34.2% at days 26 and 40; P < 0.05). Locomotion was more frequent in the paddocks than in the indoor pens (20.0% vs 7.2% at days 26 and 40; P < 0.05). The stocking density did not affect the behavioural traits measured. In conclusion, providing rabbits access to a paddock could allow them to fulfil some natural behaviours but slightly reduced their growth.

Part-time grouping of rabbit does in enriched housing: effects on performances, injury occurrence and enrichment use.

Collective housing is perceived as a possible way to improve rabbit welfare, especially among adult females, which are normally individually housed. Part-time group housing seems to allow a better balance between welfare and health than continuous group housing, but practical implementation and consequences for reproductive performance have not been extensively studied. The aim of this work was to compare weight, feed intake, litter size, injury occurrence, body integrity, and spatial location of female rabbits housed part-time in group housing (PGH group, n = 32) or housed individually (IH group, n = 8). Females were grouped by opening connecting hatches between four individual enriched cages (platform, wood stick and gnawing block). Collective housing started 12 days after artificial insemination and was interrupted at the 10th day (instead of the 15th day later as originally planned) due to high injury rates and severe injuries caused by fighting. The proportion of injured females increased from 25% on the first day of grouping to 63% on the 10th day. Female weight gain during the experiment was similar in the two groups. Litter size at weaning was 9% lower in the PGH group than in the IH group (9.2 vs 10.0, P < 0.01). Platform use was recorded in 32% of the observations and was the highest during the 2 weeks before weaning (46% and 47% of total observations, P < 0.05). During the grouping period, there were at least two females in the same housing unit in 59.4% of the cases, at least two females were located on the same level in 31.3% of the cases. In conclusion, connecting individual cages is an ergonomic solution for part-time group housing, but does not prevent fights for the establishment of a social hierarchy. This is detrimental to the health and body integrity of female rabbits.

Influence of dietary strategy on progression of health and behaviour in mule ducks reared for fatty liver production.

Overfeeding in ducks is questioned because forced introduction of food into the animal and metabolic overload may induce damage to health and discomfort. In this context, the objective of our experiment was to measure the impact of dietary strategy on the progression of animal status evaluated through 28 health and behavioural indicators in ducks reared for fatty liver production. To do this, 320 ducks were forced-fed twice a day from 70 to 90 days of age including 10 days of overfeeding (87 to 96 days). They were divided into two groups differing in the feeding strategy during overfeeding period: a moderate feed intake (MI, an average of 376 g of maize flour per meal, n = 160 ducks) or at high feed intake (HI, 414 g/meal, n = 160 ducks). We evaluated 28 indicators related to Good feeding (n = 3), Good housing (n = 4), Good health (n = 10) and Appropriate behaviour (n = 11) principles, taken from the European Welfare Quality Consortium® at four stages: before overfeeding (BEF; 80 days), at the beginning (88 days), the middle (MID; 92 days) or the end of overfeeding (END; 96 days). Animals were slaughtered at 93 and 97 days to measure fatty liver weight at MID and END stages (n = 80 per group). The results showed that dietary strategy influenced the fatty liver weight at MID (+23% in HI v. MI group; P < 0;05) and END stage (+23%; P < 0.05). Assessment stage influenced 13 of the 28 indicators measured. Among these 13 indicators, (i) BEF differed from END stage for 7 indicators and (ii) the dietary strategy degraded all the indicators chosen to evaluate the Good feeding (2/2) principle, but had no effect on the indicators related to the Good health (0/4) principle while (iii) most of the indicators that evaluated Good housing (2/3) and Appropriate behaviour (2/4) principles were affected by an interaction between both factors. Our results suggest that (i) duck fattening status, including the fatty liver weight, and several welfare indicators progressed during the fatty liver production process; and (ii) feeding strategy influenced or even interacted with this progression.

Evolution of gut microbial community through reproductive life in female rabbits and investigation of the link with offspring survival.

The digestive microbiota plays a decisive role in shaping and preserving health throughout life. Rabbit younglings are born with a sterile digestive tract but then it gets progressively colonised by the microbiota of the nursing mother, by entering in contact with or ingesting the maternal droppings present in the nest. Here we posit that (i) offspring survival and (ii) lifespan of female rabbits are linked to how diverse their microbiota are. To test the hypothesis that maternal microbiota evolves in females having had different levels of offspring survival in their lifetime, we obtained 216 hard faecal samples from 75 female rabbits at ages 19.6, 31.6, 62.6 and 77.6 weeks. The annual mean offspring survival (MOS) at 64 days was calculated for each female then crossed against three alpha-diversity indexes (operational taxonomic units (OTUs), inverse Simpson index and Shannon index). Age was also analysed against these three parameters. The alpha-diversity indexes of the female faecal microbiota did not correlate with MOS, but they did decrease with age (e.g. from 712 OTUs at age 19.6 weeks to 444 OTUs at 77.6 weeks; P < 0.05). The age effect was also found in beta-diversity non-metric multidimensional scaling plots using the Bray-Curtis dissimilarity index and the unweighted UniFrac index but not for MOS. The ability of the microbiota composition from the faecal samples of young females (19.6 weeks old) to predict their lifespan was also evaluated. After subdividing the initial population into two classes (females that weaned a maximum of three litters and females living longer), we found no clear distinction between these two classes. To our knowledge, this is the first long-term study to characterise the gut microbiota of adult female rabbits through their reproductive life, thus laying foundations for using the gut microbiota data and its influence in studies on adult rabbits.

Insights into suckling rabbit feeding behaviour: acceptability of different creep feed presentations and attractiveness for sensory feed additives.

In young rabbit, digestive disorders are frequently observed around weaning. Stimulating the onset of feed intake in the suckling rabbit might be a way to promote gut health. The aim of this study was to determine the rabbit's acceptability for different feed presentations and its preferences for flavours at an early stage of life. Two trials were conducted to evaluate the effects of physical form and flavouring on creep feed attractiveness. All the diets tested were provided in the nest from 3 to 17 days, and the daily intake per litter was recorded as of 8 days of age. In the first trial, five feed presentations were tested separately (n = 60 litters). Three dry presentations were chosen: commercial pellet (P), crumb from commercial pellet (cP) and crumb from beet pulp pellet (cBP). Hydrated feeds were also provided with either raw fodder beetroot (B) or a semi-solid feed in agar gel form produced with fodder beetroot juice and pulp (gB). In the second trial, double-choice tests were performed on four feed gels (n = 72 litters), leading to six comparison treatments. These agar gels were made of pellet mash without or with a sensory additive: one non-odorised control gel and three gels with 0.20% banana flavour, 0.06% red berry flavour and 0.10% vanilla flavour, respectively. In the first trial, kits ate more gB in fresh matter than other feed presentations (P < 0.001), with a total intake of 7.0 ± 1.8 g/rabbit from 8 to 17 days. In DM, the total consumption of pellets P (1.6 ± 0.4 g of DM/rabbit) was the highest together with the gB form (1.4 ± 0.4 g of DM/rabbit), whereas cBP was barely consumed (0.3 ± 0.1 g of DM/rabbit). Gel feed supplemented with vanilla was slightly more consumed than other flavoured and non-odorised gels (relative consumption of 57% when compared to control gel; P = 0.001). The gel feed intake was independent of the milk intake but was correlated with the litter weight at 3 days (r = 0.40, P < 0.001). In both trials, rabbit growth before and after weaning was not affected by the type of creep feed provided. Our results confirmed that providing creep feed promotes the solid intake of rabbits at early stages. Gel feed form motivated rabbits to eat and vanilla flavour supplementation increased the feed palatability. Those creep feed characteristics should be explored further for seeking effective stimulation of the onset of the feed intake in suckling rabbit.

Spatial and temporal variations of the bacterial community in the bovine digestive tract.

AIMS: Improved knowledge of the bacterial community of the digestive tract is required to enhance the efficiency of digestion in herbivores. This work aimed to study spatial and temporal variations of the bacterial communities in the bovine digestive tract and their correlation with gut environmental parameters. METHODS AND RESULTS: Rumen content and faeces of five cows were sampled for 3 weeks. In addition, reticulum content was sampled during the third week. Bacterial communities were assessed by studying capillary electrophoresis single-stranded conformation polymorphism (CE-SSCP) profiles of 16S rRNA genes. The bacterial community structure differed between the forestomach and faecal contents. The abundance of several operational taxonomic units changed from week to week. Bacterial community structure of the rumen was correlated to propionic acid and NH(3)-N concentrations. CONCLUSIONS: The bacterial community of the bovine digestive tract varied in space and time. SIGNIFICANCE AND IMPACT OF THE STUDY: The study of the bacterial communities of the digestive tract in herbivores should be widened from the rumen to the large intestine. The amplitude and origin of the temporal variation of the ruminal bacterial community need to be better understood to improve the control of the fermentative activity in herbivores.

Influence of the corn form in the diet and length of fasting before slaughter on the performance of overfed mule ducks.

The aim of this trial was to study the effect of the corn form fed during the overfeeding period and of the length of the fasting (LF) before slaughter on the performance of overfed mule ducks. A total of 180 ducks were distributed into 9 groups of 20 birds each, according to a 3 × 3 factorial design that differed according to the LF (9, 12, or 15 h) and the ratio of whole corn/corn flour in the overfeeding diet (OD): constant ratio of 30/70 [C diet]; progressive change from 0/100 to 30/70 [P diet]; or constant ratio of 0/100 [F diet]). At the end of the overfeeding period, the birds were slaughtered to measure the weight and chemical composition of the fatty liver. No significant interaction between the OD and LF was observed. The fatty liver weight was higher (+8%; P = 0.031) in the ducks fed the P diet than those fed the F diet. The ones fed the C diet were intermediate (709 g). The fatty liver weight was heavier (+7%) in the ducks slaughtered after 9 h of fasting than in those slaughtered after 15 h of fasting, The weight of fatty liver of birds slaughtered after 12 h was intermediate (711 g; P < 0.05). The foie gras fat loss during cooking (20% vs. 27%; P = 0.003), DM (68.13% vs. 69.3%; P = 0.021), and ash content (0.40% vs. 0.36%; P = 0.010) were lower in the group of ducks slaughtered after 9 h of fasting than in the other 2 groups. In conclusion, the present results suggest that (i) incorporating whole corn in the OD at a constant or increasing rate up to 30% significantly improves the performance of overfed mule ducks, and (ii) the shorter the fasting time is, the greater the weight and the quality of the foie gras will be.

Maturation of the intestinal digestion and of microbial activity in the young rabbit: impact of the dietary fibre:starch ratio.

The developmental changes of intestinal digestive potential and caecal microbial activity were described in suckling and weaned rabbits according to two feeding programmes. Two groups of thirteen litters were fed from 18 to 42 days old a "High" or a "Medium" NDF:starch ratio diet (resp. 2.7 vs 2.0, groups HL and ML) with similar protein and lipid levels, and from 42 to 70 days old the two groups were fed a "Low" NDF:starch ratio diet (1.7). From 25 to 32 days (weaning), the milk and solid feed intake were 22% and 41% higher in ML group (P<0.05), and the mortality by diarrhoea was 4 units lower (P<0.01). The whole tract digestive efficiency increased by 10% before weaning, and remained steady (organic matter) or decreased (lipids, protein) after weaning. Energy digestibility was 0.623 and 0.686 for High and Medium diets respectively. From 25 to 42 days, total enzymatic activity in intestinal content increased for chymotrypsin (5-fold, P<0.001), lipase (10-fold, P<0.001), amylase (17-fold, P<0.01) and maltase (11-fold, P<0.001), while trypsin doubled after weaning. The feeding programme only affected the amylase and maltase activities, that were higher in HL group (P<0.05). The volatile fatty acids concentration in the caecum was not significantly different among the groups, but it increased by 44% 10 days after weaning. The bacterial fibrolytic enzymes, increased by 30% after weaning and were similar among the two groups. The study revealed that the intestinal digestive maturation and the caecal microbial activity of the rabbit evolved markedly between 3 and 5 weeks of age, and was weakly affected when the NDF:starch ratio decreased from 2.7 to 2.0.

The influence of whole-corn feeding method during the finishing stage on the performance of overfed mule ducks.

The aim of this trial was to compare 2 feeding systems based on whole corn, a loose-mix and a free-choice feeding system, during the finishing stage on the performance of ducks. Five hundred sixteen day-old male mule ducks (Muscovy drake × Pekin duck) were divided into 3 groups that differed in the presentation of the diet they received between 58 and 88 d of age: a complete pelleted diet (Control (CON) group; AMEn 12.1 MJ/kg, CP 15.0%) containing 500 g of corn per kg; or whole corn (AMEn 13.9 MJ/kg, CP 7.3%) and protein-rich pellets (AMEn 10.3 MJ/kg, CP 22.7%) in equal quantities mixed in the same feeders (loose-mix feeding [LMF] group) or in 2 separate feeders (free-choice feeding [FCF] group). From 89 to 99 d, 72 birds/group were overfed with a mixture containing mainly corn and water and then slaughtered to determine the weight and commercial value of the fatty liver. Feed intake was measured daily. Body weight (BW) was measured at 58, 88, and 99 d of age. From 58 to 88 d, total feed intake of the FCF group was +7% and +9% (+558 g and +672 g) higher than in the groups CON and LMF, respectively (P = 0.005). At 88 d, the BW was higher in the CON group than in the FCF group (4,959 vs. 4,778 g, P < 0.001), the LMF group being intermediate (4,874 g). During the experimental stage, the feed conversion ratio was higher in the FCF group than in the 2 others (+32%, P = 0.024), but the energy intake was similar between the 3 groups (92.6 MJ/duck, P = 0.353).After overfeeding (99 d), the BW (6,593 g), weight (642 g), and commercial grading of fatty liver were similar (P > 0.05) in the 3 groups. The present results suggest that loose-mix feeding during the finishing stage using whole corn is a solution for reducing feed cost.

Influence of the incorporation mode of sugar beet pulp in the finishing diet on the digestive tract and performances of geese reared for foie gras production.

The aim of this work was to study the effects of incorporating sugar beet pulp (SBP) into the diet of geese in two feeding systems (complete pelleted feed or loose-mix feeding system) on crop development and performance. A total of 480 1-d-old male geese were divided into three groups whose diet differed from d 56 to 90: a complete pelleted diet containing 50% corn (control diet: AMEn 11.5 MJ/kg; CP 161 g/kg), and no SBP; a complete pelleted diet containing 50% corn and 10% SBP (SBPcp diet: AMEn: 11.5 MJ/kg; CP: 161 g/kg); and a mix in the same feeder (SBPlm diet) of 500 g/kg of protein-rich pellets containing 20% SBP (SBPprp: AMEn: 9.0 MJ/kg; CP: 250 g/kg) and 500 g/kg of whole corn (WC: AMEn: 14.0 MJ/kg; CP: 72 g/kg). Body traits, including crop volume, were measured at d 91. From d 91 to 106, 88 birds/group were overfed with a mixture containing mainly corn and water before slaughter to measure fatty liver performance. Feed intake from d 56 to 90 was higher (+10%; P = 0.004) in the SBPcp group than the other two, but at d 90, the body weight (BW) of the birds was higher (+7%; P = 0.002) in the SBPlm group than the other two. At d 91, the volume of the crop was greater in the SBPcp group (80.4 mL/kg of BW, P < 0.001) than in the control group (60.3 mL/kg of BW), the SBPlm group being intermediate (64.1 mL/kg of BW). Feed intake (13,321 g), weight gain (2,733 g), and feed-to-gain ratio (4.9) during the overfeeding period, as well as fatty liver weight (963 g) and commercial grading, were similar (P > 0.05) between the three groups. In conclusion, the use of sugar beet pulp in the diet of finishing geese helps the adaptation of the digestive tract to the overfeeding period, even in a loose-mix feeding system based on whole corn.

Direct and correlated responses to selection in two lines of rabbits selected for feed efficiency under ad libitum and restricted feeding: III. Digestion and excretion of nitrogen and minerals.

Two rabbit lines have been created to result in better feed efficiency: the ConsoResidual line was selected for a lower residual feed intake under ad libitum feeding, and the ADGrestrict line was selected for higher ADG under restricted feeding (-20% of ad libitum). The present study aimed to analyze the digestion and excretion of N and minerals from 29 to 63 d of age of these 2 lines compared with an unselected control line (G0) under 2 feeding levels (ad libitum or restricted). The ADGrestrict line had greater digestibility compared with G0 (+1.3% for OM and N; < 0.05), and the ConsoResidual line had intermediate values. There was no genetic line effect on the digestibility of N and P and on minerals concentrations (P, Zn, and Cu) in the feces and in the urine. The N balance was improved for the 2 selected lines (+5%; < 0.05), leading to a reduced N output through the feces (0.06 g/d compared with G0; < 0.001) and the urine (-0.07 g/d; < 0.05) and to an improved N retention ratio (+3% compared with G0). Over the whole fattening period (d 29-63), significant differences were observed among lines only when fed ad libitum, with 13% greater DM fecal output and 5% greater N fecal output for G0. The N excretion in urine was 2 g less in the 2 selected lines, leading to a reduction of total N release of 4.4 g (compared with G0). The P excretion in feces (12 g) or urine (0.1 g) did not differ among the 3 lines. Over the whole fattening period and for ad libitum-fed rabbits, the 5% improvement in feed efficiency ( < 0.01) for the 2 selected lines corresponded to 400 g less feed intake (-8%) and to 20 g less N intake. The fecal excretion of the ADGrestrict and ConsoResidual lines were reduced by 200 g DM ( < 0.01), corresponding to 417 g fresh matter and 5 g of N. The excretion in minerals (P, Zn, and Cu) was not affected by the line. The feeding level strongly reduced the fecal and urine outputs (-50 and -60%, respectively; < 0.001). Higher digestibility coefficients ( < 0.001) were found in restricted-fed rabbits for OM (+6%), N (+8%), and P (+11%). The N balance was substantially improved by the restriction, with 40% less total (feces + urine) N excretion ( < 0.001). The P balance was improved by the restriction (0.469 vs. 0.360). Over the fattening period, the P fecal output was 37% less (-6 g) with 24% less feed intake and the Zn and Cu outputs were reduced by 27 (-130 mg) and 29% (-30 mg), respectively.

Energy balance and reproductive performance in rabbit does.

The mortality and the culling rates of females are very high in rabbit breeding. In many cases, the dead or culled females show low reproductive performances and poor body conditions. Energy deficit leads to body mobilization and reduced reproductive performance. Consequently, energy balance and lifespan are closely linked. Two in vivo methods to estimate body composition were recently validated for rabbit does. Ultrasounds and TOBEC methods permitted the evaluation of the changes in energy balance and their relationship to reproductive performance of females. Influence of intrinsic (parity, litter size, genetic line, ...) and extrinsic (reproduction rhythm, temperature, ...) factors on the energetic balance of females are discussed. Energy deficit and depletion of body stores occurring during lactation lead to a decrease in reproductive performance and the physiological mechanisms implicated in these effects were presented. Interest and limitations of several strategies to reduce the body energy deficit in reproducing does and to improve their fertility and thus lifespan are discussed: rearing, feeding, management, genetic selection. A multi-facetted approach, combining these various strategies seems to be required to meet these objectives.

Effects of replacing corn with sorghum on the performance of overfed mule ducks.

The aim of this trial was to study the effects of replacing yellow corn (C) with condensed tannin-free sorghum (S) during the finishing period (F period; age 53 to 79 d) and/or overfeeding period (O period; age 80 to 91 d) on the performance of overfed mule ducks. 192 ducks were divided into 4 groups (48 in each) differing in the cereal (yellow corn or sorghum) included in the diet given during the F and/or the O periods, using a 2 × 2 factorial arrangement of treatments : SS, SC, CS, CC. At the end of the O period, the birds were slaughtered after 10 h of fasting to measure foie gras and magret qualities. Mortality (1%; P > 0.05) and weight gain (2,030 g; P > 0.05) during the O period were similar in the 4 groups. At the end of the O period, birds overfed with sorghum had foie gras that was heavier (723 vs. 694 g in CS+SS vs. CC+SC, respectively; P < 0.05) and less yellow (24.40 vs. 38.59 for b* in CS+SS vs. CC+SC, respectively; P < 0.001) than birds overfed with corn. Fat loss during foie gras cooking was similar in the 4 groups (18%; P > 0.05), but the foie gras was less yellow in birds overfed with sorghum (14.84 vs. 26.01 for b* in CS+SS vs. CC+SC, respectively; P < 0.001). Weight of magret was similar in the 4 groups (491 g, P > 0.05) but the color of the breast muscle and skin of magret was less yellow in birds overfed with sorghum compared with corn (12.26 vs. 12.92 and 13.84 vs. 18.30 in CS+SS vs. CC+SC, respectively; P < 0.001). In conclusion, the replacement of yellow corn with sorghum during finishing and/or overfeeding is possible and useful in a mule duck foie gras production system because it increases foie gras weight without decreasing the weight of magret However, it changes the quality of the products, mainly their color.

Influence of feeding strategy and diet for reproductive rabbit does on intake, performances, and health of young and females before and after weaning.

This study aimed to determine the influences of feeding strategy and diet for reproductive females on feed intake, BW, reproductive performances, and milk composition and their effects on kit performances from birth (d 0) to 70 d of age (d 70). A total of 133 does followed for 3 reproductive cycles and their offspring, 2,322 kits from 236 litters, were divided into 3 experimental groups that differed only by the diet offered to the doe. Three experimental diets were used: a reproduction (Repro) diet (11.01 MJ DE/kg, 24.0 g lipids/kg, 161 g starch/kg, and 343 g/kg NDF), a lactation (Lact) diet (11.88 MJ DE/kg, 49.0 g lipids/kg, 161 g starch/kg, and 302 g/kg NDF), and a fattening (Fatt) diet (9.73 MJ DE/kg, 23.0 g lipids/kg, 70 g starch/kg, and 415 g/kg NDF). In group RR, does received feed Repro throughout the study (d 0 to 42 of each cycle). In group RF, does received diet Repro from d 0 to 25 and d 35 to 42 and diet Fatt from d 25 to 35. In group LR, does received diet Lact from d 0 to 25 and diet Repro from d 25 to 42. Kits in all groups received diet F from d 18 to 70, where intake was restricted from d 35 to 63. Doe BW was similar throughout the study (4,495 g; > 0.05). Doe feed intake differed only from weaning to the subsequent kindling (+7.8% in group RF; = 0.042). Reproductive performances were similar, except for litter weight at birth (+3.6% in group LR; = 0.029). From d 0 to 25, a negative energy balance was observed in does yet most markedly in group LR (-8.61 MJ vs. -3.15 and -2.39 for groups RF and RR, respectively; < 0.01). Milk intake per kit was greater in group LR than in the other 2 groups at 17 d (+14.5%; < 0.001) and 23 d (+14.9%; < 0.05). Kit BW was highest in group LR at 18 and 25 d (+10.1% and +8.2%, respectively; < 0.01), but no difference was observed at 35 or 70 d ( > 0.05). Feed intake per kit from d 18 to 25 was greater in groups RR and RF than in group LR (+26%; < 0.001) and greater in group RF than in group LR from d 25 to 35 (+8%; < 0.05). Feed intake, when fed ad libitum (63 to 70 d), was similar in all groups ( = 0.292). Kit mortality before weaning was similar in all groups (8.1%; > 0.05) but was lowest in group RF after weaning compared to groups RR and LR (1.7 vs. 4.8 and 5.8%, respectively; < 0.001). Our results suggest that stimulating milk production through the incorporation of fat at the beginning of lactation offers few benefits for females and had a negative effect on early solid feed intake, which could explain animal health after weaning.