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SUPPLEMENTAL POLYETHYLENE GLYCOL AND ENERGY INCREASE INTAKE OF MEDITERRANEAN SHRUBS BY SHEEP AND GOATS
Jozo Rogošić
; Department of Ecology, Agronomy and Aquaculture, University of Zadar, Zadar, Croatia
Sažetak
Maquis is an extensive shrubby vegetation type in the Mediterranean region that provides important habitat for wild and domestic herbivores. Although the majority of the shrubs are nutritious, virtually all contain secondary compounds that reduce their forage value. In four trials, we examined the effect of polyethylene glycol (PEG) and a number of of Mediterranean shrubs was offered species to sheep and goats. We offered 6 shrubs in trial 1, three shrubs in trial 2, two shrubs in trial 3, and one shrub in trial 4. Trials were conducted with 12 sheep and 12 goats (6 PEG vs. 6 control). In trial 1, goats ate more total shrub biomass than did sheep (60.7 vs. 45.9 ± 2.6 g/kg BW, respectively). There was a trend (P=0.08) towards a positive PEG effect on total shrub intake, with PEG-supplemented animals consuming more total shrubs than controls (56.7 vs. 50.0 ± 2.6 g/kg BW). In trial 2, both species of animals showed a numerical decrease in total shrub intake with or without supplemental PEG. Sheep receiving PEG ate more (P=0.002) total shrubs than did controls, but no such treatment effect was found for goats. In trial 3, supplemental PEG had a positive effect (P<0.001) on total shrub intake for both sheep and goats when only 2 shrubs (Arbutus and Pistacia) of lower palatability were offered. In trial 4, supplemental PEG had a marked positive effect (P<0.001) on intake of Pistacia lentiscus in both sheep and goats. PEG supplemented goats ate more Pistacia lentiscus (39.6 g/kg BW) than did PEG supplemented sheep (28.1 g/kg BW), whereas control sheep and goats ate similar amounts (12.2 and 15.3 g/kg BW, respectively). Our findings suggest that plant biochemical diversity plays a very important role in herbivore’s diet selection, enabling animals to better meet their nutritional needs and avoid toxicity. In addition, as the number of shrubs in the diet decreased, the impact of PEG on intake of shrubs increased. PEG alone had a greater influence on sheep than on goats, and it had the greatest influence on both sheep and goats when only one or two foods were available.
Ključne riječi
Mediterranean shrubs; biological diversity; sheep; goats; diet selection; secondary compounds; polyethylene glycol
Hrčak ID:
26801
URI
Datum izdavanja:
15.11.2007.
Posjeta: 1.763 *