Abstract: The oligosaccharides that are present in the feed modulate the development of microflora, which in turn helps the animal performance. Agave tequilana azul Weber plant in primarily use to produce beverage tequila and is a source of the fructo-oligosaccharide inulin. Three levels (0, 1, or 2%) of agave inulin were added to the feed of eighteen male rabbits to assess the performance and organ changes. The addition of the agave inulin reduced the intake but the average daily gain was similar among levels (p>0.05). Digestive tract associated organs were not affected by the level of inulin in the feed (p>0.05). Therefore, using 2% of agave inulin can affect positively the rabbit digestive tract.

INTRODUCTION

Systemic response of the animal reflects the protection of the intestine mucosa against pathogen bacteria and tissue integrity (Kleessen et al., 2001). Some researchers (Campbell et al., 1997; Flickinger et al., 2003; Kleessen and Blau, 2005; Le Blay et al., 1999; Volek et al., 2007) have shown that it can be managed with the use of indigestible nutrients of the ingredients such as oligosaccharides. Oligosaccharides influence the composition of the bacterial populations in the intestine of a number of animal species (Bónai et al., 2008; Falcão-e-Cunha et al., 2007; Flickinger et al., 2003; Grizard and Barthomeuf, 1999; Le Blay et al., 1999; Parks et al., 2001; Rycroft et al., 2001; Van Loo, 2007; Verdonk et al., 2005; Volek et al., 2007; Yalcinkaya et al., 2008; Yusrizal and Chen, 2003).

Inulin is a fructose oligosaccharide that can be found in plants such as wheat, onion, bananas, garlic and chicory (Flickinger et al., 2003). Commercial available inulin is synthesized from sucrose or extracted from chicory (Flickinger et al., 2003; Rycroft et al., 2001; Van Loo, 2007). In México the A. tequilana azul Weber agave plant (31.0-31.5% of dry matter, 1.3-1.4% protein, 1.7-1.9% minerals (ash), 22.3-22.7% of total carbohydrate and 3-10% of fructo-oligomeres, quite similar in the heart of agave and the leaves (Praznik et al., 2002)) is primarily use for tequila production, but also is a source of inulin. Furthermore, no research articles were found on the use of agave inulin in the rabbit performance and organ impact.

MATERIALS AND METHODS

Eighteen New Zealand x California x Rex male rabbits (average initial weight of 350 g) were individually housed in metallic cages (40x40 cm) with plastic floor. Rabbits were given free access to feed formulated to meet daily requirements and was measured daily. Agave inulin was obtained locally (Inulina y Miel de Agave, SA de CV). The inulin treatments were; 0, 1 or 2% addition (dry matter basis) to the feed. Animals were weighted at the start and assigned at random to the three treatments. Environmental conditions were as follows: temperature 16-18°C, relative humidity 60-65%.

On day 66 of the experiment, final body weight was measured using a portables electronic scale. All animals were humanly slaughtered under the supervision of a certified veterinarian. The internal organs and digestive tract were removed immediately and weighted. Digestive tract was thoroughly rinsed with the isotonic solution and died using paper towels. Dry matter of feed was determined by drying samples at 70°C for 24 h. Data were analyzed as a randomized trial using the SAS package and using a 0.05α to declare differences among treatments and when they existed the Duncan procedure was used to separate the means.

RESULTS AND DISCUSSION

The consumption of dry matter by the rabbit use in the trial was reduced (averaged 95.83 g day^-1; p<0.05; Table 1) with the addition of Agave tequilana Weber nulin to the feed. Average daily gain was 28.025 g and with the addition of 1% of inulin it was reduced, but with 2% of the oligosaccharide the gain was higher than control (0, 1 and 2% of agave inulin; g day^-1, respectively; p<0.05).

Table 1:	Rabbit performance and internal organ wet weight variation with agave inulin
Means with the different letter within the row are statistically different (p<0.05)

With 4% of chicory inulin in the feed Volek et al. (2007) reported 33.3 g and Bolai 36 g of daily gain in rabbits, a bit higher to the results observed in the present trial with of agave inulin.

The carcass weight was in average 795.91 g and was reduced with the addition of 1% of inulin (p<0.05) and further increased with the 2% (Table 1). Similar behavior was observed on the stomach, small and large intestine and cecum.

Trautwein et al. (1998) using hamsters reported higher cecum weight with the use of increasing levels of chicory inulin. On the other hand, Volek et al. (2007) using rabbits fed 4% chicory inulin reported that cecum weighed 34.5 g, higher than the observed with 2% agave inulin. There was a lack of effect of the agave inulin on the weight of pancreas, liver kidney, lungs and hart (p>0.05), but increased the spleen weight (p<0.05) of the experimental rabbits.

CONCLUSION

Agave inulin can be use in rabbit feeding at 2% with no adverse effect on performance or internal organs.

ACKNOWLEDGEMENTS

The researchers wish to thank the company Inulina y Miel de Agave S.A. de C.V. for providing the agave inulin needed for the present study.