Forragens taniníferas na produção de caprinos e ovinos

Abstract

Tannins are a complex group of polyphenolic compounds, derived from secondary plant metabolism. The aim of this study was to conduct a survey of information on the effects of using tanninipherous forage on ruminal parameters, intake and digestibility of nutrients, weight gain and carcass traits, milk production and composition, wool production activity and anti- helminth in sheep and goats. At moderate concentrations (20-40 g/kg DM), tannins reduce the ruminal degradation of dietary protein and increase the post-rumen flow of essential amino acids. In tannin rich diets (> 50 g/kg DM) there is formation of insoluble complexes, mainly with the protein diet, which damage the digestibility of nutrients, reduce voluntary intake due to diet astringency, and damage microbial activity and ruminal digestive efficiency. In the presence of soluble tannins, ruminal bacterial species responsible for endoglucanase activity and methanogenic bacteria are affected. To mitigate the effects of tannins and other secondary compounds in tropical and temperate fodder, polyethylene glycol (PEG) has been used. Positive effects are characterized by an increase in milk production, an altered fatty acid profile of milk and meat, wool growth, and weight gain. The parasitic infections are reduced with the tannins presence due to the reduction in the availability of nutrients for nematodes, complexing the tannins glycoprotein cuticle of the worms and toxic effect on the abomasal and intestinal mucosa. It is suggested that tannin concentrations do not exceed 6-7% of the diet dry matter. Therefore, more research is required in order to clarify the issues related to this topic.