Stimulate feed intake before weaning and control intake after weaning to optimise health and growth performance

[EN] Post-weaning feed restriction is a common practice in rabbit farming to reduce mortality, but results in lower growth performance and slaughter weights. This study aimed to assess the influence of 2 diets both rich in fibre and low in starch, with high or low digestible energy (DE) and digestible protein (DP) contents for a constant DP/DE ratio offered from 18 to 70 d of age, on the growth performance and health parameters of rabbits. Eight hundred rabbit kits were divided in 2 experimental groups differing in the feed offered from 18 to 70 d: a high concentrate diet (HC group; 10.37 MJ DE/kg DM and 102 g DP/kg DM) or low concentrate diet (LC group; 9.63 MJ DE/kg DM and 95 g DP/kg DM). Feed was offered ad libitum before weaning (35 d) and from 63 to 70 d, while feed offered from 35 to 63 d was controlled to obtain similar DE intake in both groups. Feed intake, animal weights and health status were recorded weekly. Mortality was recorded daily. Feed intake was similar in both groups before weaning (P=0.204), and consequently the DE intake was higher in the HC group compared to the LC group before weaning (3.91 vs. 3.39 MJ, respectively; P=0.017). Feed intake from 63 to 70 d was lower in the HC than in the LC group (229 vs. 239 g/d/kit, respectively; P<0.001).Total DE ingested after weaning was similar in both groups (45.44 MJ; P=0.143). Kits were heavier in the HC group throughout the study (P<0.05). A higher average daily gain during the periods of 18-28, 35-42 and 56-63 d was seen in the HC group (+8.1%, +16.8% and +4.5%, respectively; P<0.05). Mortality and morbidity rates were similar between groups throughout the study (P=1.0 and P=0.104, respectively). Our results suggest that when the feed intake after weaning is controlled, i) the feeding strategy before weaning determines the weight at weaning and at slaughter age; and ii) rabbits fed a diet more highly concentrated but rich in fibre increase their growth performance without negative consequences on their digestive health.The authors gratefully acknowledge the technical help of C. Bannelier, B. Gabinaud and M. Segura (INRA, UMR 1388 GenPhySE), and the assistance of the staff at the rabbit experimental unit (PECTOUL, Toulouse, France).Read, T.; Combes, S.; Gidenne, T.; Destombes, N.; Grenet, L.; Fortun-Lamothe, L. (2015). Stimulate feed intake before weaning and control intake after weaning to optimise health and growth performance. World Rabbit Science. 23(3):145-153. doi:10.4995/wrs.2015.3977SWORD14515323

Diversity and Co-occurrence Pattern Analysis of Cecal Microbiota Establishment at the Onset of Solid Feeding in Young Rabbits

This study aimed to evaluate how the feeding strategy of rabbit kits at the onset of solid feed intake could affect ecological diversity and co-occurrence patterns of the cecal bacterial community. From birth to 18 days of age kits were exclusively milk-fed, and between 18 and 35 days the young rabbits also had access to solid feed. After weaning at (35 days), young rabbits were exclusively fed solid feed. Three experimental feeds were used: a high concentrate diet [H: 10.16 MJ digestible energy (DE)/kg and 15.3% crude protein (CP)], a low concentrate diet (L: 9.33 MJ DE/kg and 14.7% CP) and a reproductive female diet (R: 10.57 MJ DE/kg and 17.3% CP). The rabbit kits (n = 357) were divided into three groups, differing by the diet received during two periods: from 18 to 28 and from 28 to 49 days of age. In the groups LL and HH, rabbit kits were fed L or H diets, respectively, during both periods. Kits in the group RL received feeds R and L from 18 to 28 and 28 to 49 days of age, respectively. Cecal bacterial communities of 10 rabbits per group were carried out at 18, 28, 35, 43 and 49 days of age by MiSeq Illumina sequencing 16S rRNA encoding genes. Between 18 and 28 days of age, solid feed intake was higher in the group RL compared to the other two groups (+24%; P &lt; 0.01). Overall, 13.4% of the OTUs detected were present in the cecal ecosystem from 18 to 49 days old, whereas 17.4% were acquired with the onset of solid feeding and kept from 28 days on. Exclusive milk consumption constrains the bacterial community toward a similar structure but high phylogenetic beta-diversity. Introduction of solid feed induced a sharp change of microbial community structure and decreased phylogenetic diversity. A strong relationship in bacterial community network occurred only from 43 days on. Our feeding strategy at the onset of solid feed ingestion exhibited only a moderate effect on the microbial community structure (P = 0.072), although the LL group seemed to reach faster maturity compared to the two other groups

Rearing conditions during the force-feeding period in male mule ducks and their impact upon stress and welfare

The aim of the first experiment conducted was to further characterise HPA axis functionality in male mule ducks during the force-feeding period, by measuring corticosterone levels (Exp. 1). The objectives of the two other experiments were to investigate the impact of different rearing conditions on stress response (Exp. 2) and behaviour patterns (Exp. 3) in male mule ducks. The rearing conditions examined comprised individual (Exps. 1–3) and collective battery cages (Exps. 2, 3), as well as collective floor pens (Exps. 2, 3). The ducks were then fed (Exps. 1–3) by force-feeding for foie gras production or ad libitum (Exp. 1). The highest levels of corticosterone (up to 100 ng$\cdot$mL$^{-1})$ were measured after initial capture and handling in a large collective rearing pen, transfer to a different environment, initial placement in a net for 10 min and injection of 5 $\mu$g$\cdot$kg$^{-1}$ BW of 1-24 ACTH agonist. Both force-fed and non-force fed male mule ducks responded to a first physical constraint in a net by a large increase in corticosterone levels. Their HPA axis was therefore functional although the effect quickly vanished, which was interpreted as an indication that habituation took place. Most often, corticosterone levels measured before and after force-feeding during the force-feeding period did not differ significantly ($P > 0.05$) when the ducks were raised in individual cages, even on the first occurrence. A significant increase in corticosterone levels was observed after the first force-fed meal for both groups of ducks raised collectively, i.e. in cages or floor pens, when the practice involved capture and handling. Following the injection of 0.625 and 5 $\mu$g$\cdot$kg$^{-1}$ BW doses of 1-24 ACTH, cortico-adrenal responses were significantly ($P < 0.05$) higher and lower for ducks raised in collective floor pens compared to those raised in individual cages, respectively. This hypersensitivity and lower maximal capacity may result from a chronic stressful state related to repeated acute stress (i.e. capture and handling twice daily). Ducks raised in cages (individual or collective) spent more time standing (less lying) and less time inactive i.e. expressing passive behaviour patterns, which suggest that they were not presenting signs of passive coping or learned helplessness. Behaviour observations did not provide any indication of stereotyped behaviour. From these results, it could have been concluded that placement in individual battery cages the limited period of force-feeding are not detrimental in terms of welfare. However, they cannot achieve full wing stretching or express a full range of social behaviours as required by the European Council recommendation (Scientific Committee on Animal Health and Animal Welfare, Welfare aspects of the production of foie gras in ducks and geese, CEC, DGXXIV/B3/AW/R06, 1998, 94 p.). They may also have more difficulty in thermoregulating as indicated by the fact that they had higher frequencies of both panting and watering. In terms of welfare, since signs of acute and possibly chronic stress were observed when the force-feeding procedure involved capture and handling, there is a need to set up new models of collective cages and better define the optimal group size and density to be used in future rearing conditions.Impacts sur les réponses de stress et le bien-être des conditions d'élevage du canard mulard mâle durant la période de gavage. Dans une première expérience (Exp. 1), la fonctionnalité de l'axe hypothalamus-hypophyse-surrénales (HPA) a été caractérisée durant la période de gavage chez le canard mulard, par mesure de la corticostéronémie (Exp. 1). Les objectifs des autres expériences réalisées étaient d'analyser les effets des conditions d'hébergement sur les réponses de stress (Exp. 2) et les comportements exprimés (Exp. 3). Après avoir été élevés collectivement au sol, les canards ont été transférés en cages batteries individuelles (Exps. 1–3), ou collectives (Exps. 2, 3), ou en loges collectives au sol (Exps. 2, 3). Les canards s'alimentent spontanément ad libitum (Exp. 1) ou reçoivent une alimentation par gavage pour la production de foie gras (Exps. 1–3). Les corticostéronémies les plus élevées (jusqu'à 100 ng$\cdot$mL$^{-1}$ plasma) ont été mesurées avant transfert lors d'une première capture, immédiatement après transfert, après une première contention dans un filet pendant 10 minutes et après l'injection de 5 $\mu$g$\cdot$kg$^{-1}$ PV de 1-24 ACTH. Les canards, gavés ou non, ont répondu par une élévation significative de leur corticostéronémie après une première contention dans un filet pendant 10 minutes. La réponse s'est progressivement estompée en dépit du fait que l'axe HPA était fonctionnel ; résultats qui suggèrent la mise en place d'un processus d'habituation. Au cours de la période expérimentale, l'acte de gavage n'induit généralement pas d'élévation ($P > 0,05$) de la corticostéronémie, chez les canards placés en cage individuelle. Ce résultat suggère que l'acte de gavage n'est pas perçu comme un stress aigu majeur par le canard mulard dans ces conditions expérimentales. Une augmentation significative de la corticostéronémie a été observée après le premier repas de gavage pour les canards des deux groupes élevés collectivement (c.a.d. cage et loge au sol) ; conditions dans lesquelles la pratique de l'acte nécessite une capture et une contention. Les réponses en corticostérone mesurées après injection i.m. de doses de 0,625 ou 5 $\mu$g$\cdot$kg$^{-1}$ PV de 1-24 ACTH, pour ces mêmes groupes de canards, suggèrent un état d'hypersensibilité et une diminution de la capacité de réponse maximale des surrénales, qui caractérisent potentiellement un état de stress chronique. Cet état de fait a pu être engendré par la répétition de stress aigus liés à l'acte de gavage dans ces conditions expérimentales impliquant pour la pratique de l'acte gavage : capture, manipulation et contention deux fois par jour. Les observations comportementales n'ont pas permis de mettre en évidence de comportements stéréotypés chez le canard mulard. Les canards placés en cages batteries ont passé plus de temps debout et sont plus actifs ; résultat qui suggèrent qu'ils n'expriment pas de signes d'adaptation passive ou de passivité acquise. Nous pourrions donc en conclure que le placement en cage individuelle durant la période de gavage n'a pas de conséquence négative en termes de bien-être. Les canards ne peuvent toutefois dans ces conditions expérimentales réaliser l'étirement complet des ailes ainsi que divers comportements sociaux qui sont stipulés dans la recommandation du Conseil de l'Europe (Scientific Committee on Animal Health and Animal Welfare, Welfare aspects of the production of foie gras in ducks and geese, CEC, DGXXIV/B3/AW/R06, 1998, 94 p.). En outre, ils ont sans doute des besoins supérieurs en termes de thermorégulation, comme le suggère l'observation de fréquences supérieures d'halètement et d'abreuvement. Des signes de stress aigu et éventuellement chronique ayant été mis en évidence lorsque la pratique du gavage exige une capture et une contention, il est nécessaire de concevoir de nouveaux modèles de cage collective et aussi de mieux définir les tailles de groupe et les densités optimales à utiliser dans ces conditions d'hébergement

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; P > 0.05). Doe feed intake differed only from weaning to the subsequent kindling (+7.8% in group RF; P = 0.042). Reproductive performances were similar, except for litter weight at birth (+3.6% in group LR; P = 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; P 0.05). Feed intake per kit from d 18 to 25 was greater in groups RR and RF than in group LR (+26%; P 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; P < 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