With a growing population, feeding competition between human and animals is increasing. Because major ingredients used in animal feeds, especially in poultry diets are now being used in human nutrition, there is a decreased availability of quality feed resources and poultry feeds are becoming costly. Guar meal is an easily available and economical feed ingredient and may be helpful in alleviating this problem. A large quantity of guar is processed in the world for gum extraction and residue left over from processing is converted into guar meal. It has a good amino acid profile with crude protein contents of about 33-45%. However, anti-nutritional components like guar gum (β-mannan), saponins and trypsin inhibitors limit the use of guar meal in broiler diets. These anti-nutritional factors have been reported to depress growth in birds but at lower levels some of these (β-mannan and saponins) have positive effects on bird health and performance. β-mannan is considered a major anti-nutritional factor when higher levels of guar meal are used in poultry. To improve the utilisation of such feeds, β-mannanases are used. This paper reviews some benefits and drawbacks regarding the use of guar meal in poultry diets and how to improve its feeding value.

An increase in the production of palm kernel meal (PKM) coupled with the concern for continued availability of conventional feedstuffs in some parts of the world has led to research to establish the maximum inclusion level of palm kernel meal in broiler diets. The results suggested that palm kernel meal has no anti-nutritional properties and thus its inclusion is safe up to at least 40% in the diet, provided the diet is balanced in amino acids and metabolisable energy. Although feed digestibility is decreased due to high dietary fibre when PKM is included in the diet, the feed intake is increased. This makes total digestible nutrient intake relatively high. β-mannan is the main component of palm kernel meal non-starch polysaccharide (NSP). Both mannose and manno-oligosaccharides have been reported to act as prebiotics. The inclusion of palm kernel meal in the diet improves the immune system of birds and reduces pathogenic bacteria and increases the population of non-pathogenic bacteria in the intestine. These two benefits should be considered as strong recommendations for using palm kernel meal in broiler diets, particularly in palm kernel meal producing countries, not only forincreasing bird productivity but also to improve chicken health. Selective enzyme addition increases feed efficiency and digestibility as well as decreasing the moisture content of faeces.