Resumen

COBOS-PERALTA, Mario A. et al. Ground polyethylene terephthalate bottles and its function as fiber sustitute in diets for lambs. Agrociencia [online]. 2011, vol.45, n.1, pp.33-41. ISSN 2521-9766.

The methods used for recycling polyethylene terephthalate (PET) bottles are insufficient and have caused a serious problem of environmental contamination in several countries. An alternative for recycling these bottles is to include them as a source of fiber or inert material in diets for ruminants. With the objective of testing this alternative, 30 lambs (average live weight 23.4 kg; 10 per treatment) were fed diets without (T1 = PET-0) and with 100 (T2=PET-100) and 200 g (T3=PET-200) of ground PET bottles kg^-1 DM in substitution of corn stalks. The diets were formulated to cover the nutritional requirements of growing lambs with an average weight gain of 200 g^-1. The variables feed intake, weight gain and feed conversion were similar (p>0.05) during the experiment (60 d). The concentration of acetate and ruminal propionate was similar (p>0.05) among treatments, whereas the concentration of butyrate was higher (p≤0.05) in the ruminal fluid of the lambs of the treatment PET-200. The ruminal pH varied from 6.54 to 7.2 without differences (p>0.05) among treatments. The concentration of total bacteria had an interval of 2.84X10¹⁰ and 2.97X10¹⁰ mL^-1 and that of cellulolytic bacteria of 1.32X10⁸ to 1.66X10⁸ mL^-1 of ruminal fluid, without differences (p>0.05) among treatments. The concentration of protozoa decreased (p≤0.05) after 45 d in the lambs of treatment PET-200 with respect to treatment PET-0 (1.64 vs 2.49 x 10⁵ mL^-1), although these values are normal in ruminants (10⁴ to 10⁶ protozoa mL^-1 of ruminal fluid). It is concluded that ground PET bottles can substitute corn stalks as a fiber source, without any negative effect on productive efficiency, ruminal fermentation or concentration of ruminal bacteria and protozoa.

Palabras llave : ruminal bacteria; plastic bottles; PET recycling; PET.

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