Resumen:
Sixteen Suffolk lambs with 29 ± 2·0 kg body weight were housed in individual cages for 60 days and allotted to four
treatments in a completely randomized design to determine the effect of administration of Salix babylonica (SB)
extract and/or exogenous enzymes (ZADO®) on lamb performance. Lambs were fed with 300 g/kg concentrate
(160 g crude protein (CP)/kg, 13·4 MJ metabolizable energy (ME)/kg dry matter (DM)) and 700 g/kg maize silage
(80 g/kg CP, 11·7 MJ ME/kg DM) as a basal diet (control). Another three treatments were tested; the SB extract
was administered at 30 ml/day (SB) and exogenous enzymes ZADO® (i.e. an exogenous enzyme cocktail in a
powder form) directly fed at 10 g/day (EZ), while the last treatment contained ZADO® at 10 g/day + SB extract at
30 ml/day (EZSB). Lambs of the treatment EZSB had the greatest average daily weight gain (ADG) and feed conversion
throughout the period of the experiment. However, during the first 30 days SB was more effective for ADG than
EZ and vice versa during the last 30 days of the experiment.Water consumption was greater for SB, followed by EZ
and EZSB compared to the control. Intakes ofDMand organicmatter (OM) were the highest in EZSB followed by EZ,
which had the greatest neutral detergent fibre, acid detergent fibre (ADF) and nitrogen (N) intakes. The EZSB treatment
had the greatest DM and OM digestibilities compared to the other treatments; however, SB had the greatest
ADF digestibility. Combination of EZ and SB had the best N balance. Allantoin, total purine derivatives (PD), allantoin
: -creatinine ratio, and PD: creatinine ratio were increased in EZSB compared to the other treatments. However,
EZ supplementation increased uric acid concentration, whereas the microbial N (g N/day) and metabolizable
protein (g N/day) were increased in EZSB versus the other treatments. It can be concluded that addition of 10 g
ZADO® in combination with S. babylonica extract at 30 ml/day in the diet of lambs increased feed intake, nutrient
digestibility and daily gain, with a positive impact on the use of N and microbial protein synthesis.
Descripción:
In Mexico, there are native trees that
can be used as an alternative feed when forages are
scarce and of poor quality in the dry season (Palma
et al. 1995). However, the use of plants or their
extracts as feed additives is restricted by their secondary
compound content (Salem et al. 2014c): although
the ideal concentrations can modify and support the
utilization of nutrients in the rumen (Salem et al.
2014a, b, c), an inverse relationship between secondary
compound concentration and animal performance
has been observed (Vasta & Luciano 2011; Salem
et al. 2011a, 2013).