Growth Performance, Biochemical Blood Indices, and Large Intestine Physiology of Rats Fed Diets with Alfalfa Protein-Xanthophyll Concentrate

The effect of dietary levels of alfalfa protein-xanthophyll concentrate (PXC) was determined in growing rats. Three groups of eight four-week-old male Wistar rats, with an average initial body weight of 61 g, were fed for 28 days either natural-ingredient diets without PXC or supplemented with 1.5% or 3% PXC. Growth performance, blood biochemistry, caecal fermentation, morphology of the large intestine, and mucin gene expression were evaluated. PXC did not affect growth performance but tended to decrease relative liver weight. Among biochemical blood parameters, only bilirubin decreased and uric acid increased in response to 1.5% and 3% PXC, respectively. Caecal fermentation was not affected, with the exception of isovaleric acid concentration, which tended to be higher in rats fed the diet containing 3% PXC. Colonic crypts tended to be deeper in rats fed the 3% PXC diet and the thickness of the colonic mucus layer was reduced by both PXC levels. In conclusion, PXC did not affect growth performance or caecal fermentation but decreased thickness of the protective mucus layer in the colon.

Effect of fibre and digestible energy levels on growth performance, apparent nutrient digestibility and caecal fermentation of growing rabbits

A seventy-day feeding trial was conducted to investigate the effect of dietary fibre and digestible energy (DE) level on growth performance, apparent nutrient digestibility and caecal fermentation of growing rabbits. The experiment was laid out in a 3 × 3 factorial arrangement of 3 levels of fibre (low (249 – 258 g/kg NDF, 149 - 157 g/kg ADF), optimum (349 – 381 g/kg NDF, 188 - 193 g/kg ADF) and high (430 – 456 g/kg NDF, 249 - 253 g/kg ADF)) and 3 levels of DE (low (8 – 8.5 MJ/kg), optimum (10.5 – 11 MJ/kg) and high (12 – 12.30 MJ/kg)). A total of one hundred and thirty five weaner rabbits were allotted to 9 dietary groups of 15 rabbits each. Main effect of fibre showed that the final live weight and weight gain of rabbits increased (P < 0.01) while Ca retention reduced (P < 0.001) with increasing dietary fibre level. Rabbits fed (249 – 258 g/kg NDF, 149 - 157 g/kg ADF), had the worst (P < 0.05) feed to gain ratio. Rabbits fed (349 – 381 g/kg NDF, 188 - 193 g/kg ADF) had the highest apparent dry matter (P < 0.05), ether extract (P < 0.05), NDF (P < 0.001), ADF (P < 0.001) and organic matter digestibility (P < 0.001). Main effect of DE showed that rabbits fed high DE recorded the highest (P < 0.05) weight gain. Highest (P < 0.01) apparent dry matter, crude protein, ash, NDF, ADF, organic matter digestibility and Ca retention were recorded with rabbits fed optimum DE diet. Rabbits(445.70g/kgNDF, 252.10g/kgADF and 8.01MJ/Kg) recorded the highest (P < 0.001) final live weight, weight gain and feed intake (P<0.05) while rabbits fed (249 g/kg NDF, 149 g/kg ADF and 8.17MJ/Kg) had the least (P < 0.001) final live weight, weight gain, apparent dry matter digestibility, NDF and ADF digestibility. Highest (P<0.001) NDF digestibility was obtained with rabbits fed (370.79 g/kg NDF, 189.61 g/kg ADF and 10.84MJ/kg). Not withstanding the DE level of the diets, rabbits fed with (430 – 456 g/kg NDF, 249 - 253 g/kg ADF) recorded the highest (P<0.05) total VFA and acetic acid concentration. Rabbits fed (445.7g/KgNDF, 250.09g/KgADF and 10.52MJ/kg) recorded the best growth performance, improved caecal fermentation with no adverse effect on apparent nutrient digestibility.

Preliminary evaluation of fenugreek (Trigonella foenum-graecum) seed gum as a potential prebiotic for growing rabbits in Tunisia: effects on in vivo faecal digestibility and in vitro fermentation

<p>This study aims to determine the effect of dietary inclusion of fenugreek seed gum (FSG), rich in galactomannans, on nutrient apparent digestibility and caecal environment, as well as on <em>in vitro</em> caecal fermentation of Tunisian growing rabbits. Three experimental diets were formulated, including 0, 0.25 and 0.5% of FSG (FSG0, FSG0.25 and FSG0.5, respectively) for the <em>in vivo</em> trial and 0, 0.125, 0.25, 0.5 and 100% of FSG (FSG0, FSG0125, FSG0.25, FSG0.5 and FSG100, respectively) for the <em>in vitro</em> trial. In the <em>in vivo</em> trial, 45 weaned rabbits 31 d old (15 per treatment) were housed in individual cages until 94 d of age. Apparent digestibility coefficients were determined at two ages, from 38 to 41 and from 56 to 59 d old, and caecal traits were recorded after slaughtering. In the <em>in vitro</em> trial, the five experimental diets were incubated with a rabbit caecal inoculum. Gas production was measured and modelled until 72 h and the fermentation traits were measured. Apparent faecal digestibility coefficients of main nutrients and main caecal environment traits were not significantly affected by the dietary inclusion of FSG (<em>P</em>&gt;0.05). However, animals fed with FSG showed lower caecal pH (–0.15; <em>P</em>&lt;0.05) values. Regarding the in vitro fermentation, FSG100 increased asymptotic gas production (+11.25, <em>P</em>&lt;0.001), sharpness of the switching characteristic of the profile (+1.98, <em>P</em>&lt;0.001) and the maximum substrate degradation rate (RM) (+0.188, <em>P</em>&lt;0.001), but decreasing the time after incubation at which half of the asymptotic amount of gas has been formed (–5.86, <em>P</em>&lt;0.001) and at which RM occurs (–4.53, <em>P</em>&lt;0.01). Likewise, FSG100 significantly decreased caecal pH (–1.035, <em>P</em>&lt;0.001), lactic acid (–9.51, <em>P</em>&lt;0.069) and N-NH₃ concentrations (–12.81, <em>P</em>&lt;0.001). Meanwhile, it increased the total volatile fatty acids (VFA) production (+43.15, <em>P</em>&lt;0.001). Gradual dietary inclusion of FSG from 0 to 0.5% only significantly increased total VFA production in the caecum (+100 mmol/L per percentage point of FSG inclusion; <em>P</em>&lt;0.05). In conclusion, FSG is highly and rapidly in vitro fermented by rabbit caecal bacteria. However, dietary inclusion of FSG up to 0.5%, might be insufficient to affect the apparent digestibility and fermentation profile of growing rabbits to a great extent.</p>