Abstract

RESENDIZ-HERNANDEZ, Miriam et al. Effect of organic selenium and chromiun and Saccharomyces cerevisiae on in situ diet degradation, rumen fermentation and growth performance of lambs. Agrociencia [online]. 2012, vol.46, n.8, pp.745-755. ISSN 2521-9766.

Chrome (Cr) and selenium (Se) are micro-minerals essential for ruminants, they modify metabolism and their addition to diets can affect feed degradation and fermentation in the rumen and, therefore, the productive response of the animals. The objective of this study was to evaluate the effect of Se (0.90 mg kg^-1) + Cr (1.4 mg kg^-1) both chelated with inert yeast in Biotecap® (organic Se+Cr) and of Saccharomyces cerevisiae (SC, strain 7907) on: 1) in situ degradation of DM, NDF, ADF, and CP; 2) pH, VFA and N-NH₃ in rumen; 3) DM intake, average daily gain (ADG), feed conversion (FC), as well as on carcass fat content of lambs. Treatments were diets: 1) control, without Se+ Cr neither SC; 2) control+ Se+ Cr; 3) control+ SC; 4) control Se+ Cr+ SC. To determine in situ degradation of the diets and ruminal fermentation variables, the experimental design was a Latin Square 4X4, using four criollo lambs (PV=30±2 kg) with a ruminal cannula. To evaluate the productive variables, the experimental design was completely randomized, and 20 criollo lambs were used (PV=29.88±2.98 kg). The data were analyzed with the GLM procedure of SAS, and means of treatments were compared with the Tukey test (p<0.05). In situ degradation was higher (p<0.05) for DM (ISDMD) in the organic Se+ Cr and the SC treatment than in the control and the Se+ Cr+ SC treatments. ADF (ISDFDA) was also higher in the Se+Cr treatment. No differences (p>0.05) for pH, VFA and N-NH₃ were found among treatments. Average daily gain was lower (p<0.05) in the control, while carcass weight was higher (p<0.05) in the treatment with Se+ Cr than in the control, but there was no effect on the other productive variables. It is concluded that the addition of organic Cr+ Se only increased weight gain and carcass weight, but there was no effect from addition of SC.

Keywords : organic minerals; Saccharomyces cerevisiae; in situ degradation; sheep.

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