No abstract

The aim of this study was to examine whether the combination of dietary soluble fiber and cellobiose exerts a synergistic effect on growth performance, health status, fermentation traits, and immune response in rabbits. Six treatments in a 3 × 2 factorial arrangement were used: 3 cellobiose concentrations in drinking water (0.0, 7.5, and 15.0 g/L) × 2 dietary levels of soluble fiber (84.0 and 130 g/kg DM, for the low soluble fiber [LSF] and high soluble fiber [HSF] diets, respectively). A total of 318 young rabbits (53/treatment) were weaned at 34 d of age and had ad libitum access to feed and water. At 46 d of age, 9 rabbits/treatment were slaughtered and ileal and cecal digesta were collected to analyze VFA profile and the immune response in the cecal appendix mucosa. At 48 d of age, the cellobiose supplementation was withdrawn and the experimental diets were replaced by a standard commercial diet until 61 d of age. From 34 to 48 d of age, there was a linear increase of mortality with the level of cellobiose in the HSF group (0% vs. 17.1%; P = 0.017). In contrast, a quadratic effect of cellobiose level on mortality was observed in the LSF group, the rabbits offered 7.5-cellobiose showing the lowest mortality (5.7% vs. 21.4%; P = 0.030). Cellobiose level had a quadratic effect on ADFI, ADG, and G:F in this period (P ≤ 0.047), with the 7.5-cellobiose groups having the best growth performance. In contrast, only minor changes on these traits were observed from 48 d of age onwards. Cellobiose level influenced quadratically the ileal VFA concentrations (P = 0.014), showing the maximal value in the 7.5-cellobiose groups. In rabbits fed 7.5-cellobiose-LSF, a change of acetate to propionate, butyrate, and valerate was observed in the ileum. Increasing cellobiose levels reduced linearly cecal VFA concentrations in HSF fed rabbits, but no effect was detected in LSF groups (P = 0.046). The level of soluble fiber increased VFA concentrations in both the ileum (by 22%; P < 0.001), and the cecum (by 11%; P = 0.005). The relative gene expression of IL-6, IL-10, TNF-α, iNOS, MUC-1, and toll-like receptors (TLR-2 and TLR-4) in the cecal appendix increased linear and quadratically with increasing levels of cellobiose (P ≤ 0.063). In conclusion, in rabbits fed LSF diets, a dose of 7.5 g cellobiose/L drinking water would be recommended, whereas these levels of cellobiose supplementation should be avoided in rabbits fed HSF diets.

No abstract

The aim of this work was to study whether the dietary supplementation with arginine (Arg) and glutamine (Gin) or the combination of both influence the digestibility, body composition, and reproductive performance of rabbit does during the first three parturitions. A Control diet containing 29.8 g nitrogen (N), 313 g aNDFom per kg DM and 1.85 g digestible N/MJ digestible energy (DN/DE) was formulated, and another 3 diets were obtained by adding (gAg) 4 Arg, 4 Gin and a mixture of 4 Arg and 4 of Gin to the Control diet. Eighty nulliparous rabbit does were randomly assigned to the diets (20/diet) before the first insemination. After each parturition litter size were homogenized within each treatment and does inseminated lid later. Chemical composition and energy content of rabbit does and their performance, litter growth and milk production were measured between birth and weaning (25 d) along three parturitions. Amino acid supplementation increased the DN content (P = 0.015) and tended to increase the DN/DE ratio compared to Control group {P = 0.077) leading to an increase of digestible N intake during lactation (P = 0.004). In this period, Gin group had a higher DE intake compared to Control and Arg + Gin groups {P = 0.038). Total number kits born per litter tended to increase in rabbit does supplemented with Arg and Gin, compared to Control and Arg + Gin groups {P = 0.095), but no effect of treatments on the number of weaned rabbits was observed (P = 0.15). Single supplementation of Arg and Gin increased the weight of the litters at 20 and 25 d respect to Control and Arg + Gin groups {P < 0.021). Amino acid supplementation did not affect the milk production (P = 0.16), although it was positively correlated with the DE and DN intake (P < 0.001). There were no significant effects of treatments on body weight, chemical composition and energy content of rabbit does, but does supplemented with Arg or Gin tended to have a higher body energy content at the third insemination and at weaning than those from Control and Arg + Gin groups (P < 0.099). Amino acid supplementation did not modify the replacement rate of rabbit does. In conclusion, the single supplementation of Arg and Gin had a positive effect on the weight of litters at weaning and litter size at birth, but no additive effect was observed for the combined supplementation of Arg and Gin.

Background The purpose of the present study was to assess if the exposure to glutamine (Gln), arginine (Arg) or their combination from pregnancy, through the maternal diet, to a post weaning supplemented diet, can stimulate litter performance, gut development and immune function. To this end does and their litters were fed the same basal diet no supplemented (control C), or supplemented with 0.4% Gln, 0.4% Arg, or 0.4 Gln + 0.4 Arg. Rabbits were weaned at 25 d of age and fed the same experimental diet as their mothers for 10 additional days (35 d of age). Bacterial translocation to mesenteric lymph nodes (MLN) at 6 d of age and intestinal histology, enzymatic activity, phenotypical and functional analysis of intraepithelial lymphocytes (IEL) from the appendix were determined at 6, 25 and 35 d of age. Results No significant differences on animal performance or mortality rates were observed among dietary treatments. However, kits from rabbit does supplemented with Gln tended ( P ≤ 0.10) to reduce the translocation of total number of both aerobic and facultative anaerobic bacteria to the MLN. Also, rabbits fed the Gln supplemented diets maintained intestinal villous height at weaning compared to the non-supplemented diets ( P < 0.05). The proportions of CD45 + CD4 + and CD45 + CD8 + IEL in the appendix were not affected by dietary means. However, in rabbits IEL at weaning dietary Gln significantly upregulated IL-2 and downregulated IL-6 expression. Conclusions Despite a lack of effect on performance and mortality the inclusion of 0.4% Gln has a positive effect by maintaining intestinal villous height and modulating the cytokine profile at weaning. The supplementation with Arg or Arg + Gln at the selected doses in this study did not exert positive effects on rabbit intestinal health.