THE EFFECT OF ACTIVATED CHARCOAL AND NUMBER OF SPECIES OFFERED ON INTAKE OF MEDITERRANEAN SHRUBS BY SHEEP AND GOATS

Authors: ROGOSIC, J - U OF SPLIT; Pfister, James; PROVENZA, F. - USU; GRBESA, D - U OF ZAGREB

Submitted to: Applied Animal Behaviour Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/31/2006
Publication Date: 2/28/2006
Citation: Rogosic, J., Pfister, J.A., Provenza, F.D., Grbesa, D. 2006. The effect of activated charcoal and number of species offered on intake of mediterranean shrubs by sheep and goats pp. 305-317. Available online 02/28/2006

Interpretive Summary: Maquis and garrigues are shrubland vegetation types in the Mediterranean region that provide important habitat for wild and domestic herbivores. Although the majority of these shrubs are nutritious, virtually all contain secondary compounds that reduce their forage value. Activated charcoal given as a supplement may reduce negative effects of secondary compounds like terpenes and tannins, and enable animals to eat more shrubs, Further, offering a variety of different shrubs may have a similar effect on increasing intake. These trials were conducted in Croatia using native animals adapted to shrubs. Goats always ate more shrubs than did sheep. Activated charcoal had a positive effect on shrub intake for both sheep and goats. Our findings support the hypothesis that plant biochemical diversity plays an important role in diet selection, thus enabling animals to better meet their nutritional needs and avoid toxicity. In addition, as the number of shrubs in the diet decreased, and supplemental energy was reduced, activated charcoal had a greater impact on shrub intake. Finally, activated charcoal had the same influence on sheep and goats throughout the trials, even though goats always ate more shrubs than did sheep.

Technical Abstract: Maquis and garrigues are extensive shrubland vegetation types in the Mediterranean region that provide important habitat for wild and domestic herbivores. Although the majority of these shrubs are nutritious, virtually all contain secondary compounds that reduce their forage value. Understanding how animals cope with ingesting secondary compounds is vital for increasing consumption of shrubs and for enhancing and maintaining biodiversity of these shrublands. Ingesting compounds such as activated charcoal can ameliorate the negative effects of secondary compounds and enable animals to eat more shrubs, but offering a variety of shrubs may have a similar effect on increasing intake. Thus, our objectives were to determine if supplemental charcoal and numbers of shrub species offered influenced intake of shrubs by sheep and goats. We conducted two trials each with 12 sheep and 12 goats (6 activated charcoal vs. 6 controls). In Trial 1, we offered 6 shrubs. In Trial 2, we initially offered 3 shrubs (Period 1: Juniperus phoenicea, Helichrysum italicum and Juniperus oxicedrus), then 2 shrubs (Period 2: Juniperus phoenicea and Helichrysum italicum), and finally 1 shrub (Period 3: Juniperus phoenicea). In Trial 1, goats ate more total shrub biomass than did sheep (45.7 ± 1.0 g/kg b.w. vs. 27.2 ± 0.7 g/kg body weight (b.w.), respectively), and there was no difference in shrub intake (P = 0.39) between charcoal-treated animals and controls (mean 37.5 ± 0.8 g/kg b.w.). In Trial 2, supplemental charcoal had a positive effect on total shrub intake for both sheep and goats in all 3 periods (Period 1, P < 0.001; Period 2, P < 0.001 and Period 3, P < 0.03), and goats ate more shrubs than did sheep in all 3 periods (P < 0.01). Regardless of period, both species of animals showed a numerical decrease in total shrub intake, with or without supplemental charcoal, as the number of shrub species on offer decreased.