β-Mannanase ameliorates viscosity-associated depression of growth in broiler chickens fed guar germ and hull fractions

Abstract

High concentrations of guar meal in broiler chicken diets reduce body weight and feed efficiency. The increased intestinal viscosity that is responsible for reduced measures of performance results from residual guar gum present in guar meal. Two experiments were designed to study the effects of 2 guar meal fractions at 3 different concentrations, germ (0, 5.0, and 7.5%) and hull (0, 2.5, and 5.0%), and the effectiveness of a beta-mannanase at three levels (0, 1x, and 4x; 1x = 1.09 x 10(5) units/ kg) on broiler growth and feed conversion. Growth and performance were measured as a function of intestinal viscosity. Addition of the germ fraction to rations did not reduce body weight, although feed conversion ratio was increased at 7.5% of the diet. Intestinal viscosity also increased significantly at this level. Enzyme addition significantly reduced intestinal viscosity. Due to an interaction that was present between hull and enzyme concentration, each treatment was compared separately. Inclusion of the hull fraction significantly reduced body weight at both levels of inclusion and increased feed conversion ratio at 5% inclusion. Addition of the enzyme significantly increased body weight and reduced feed conversion ratio in diets containing guar hull fractions. Supplementation of beta-mannanase to feeds containing either fraction of guar meal reduced intestinal viscosity and alleviated the deleterious effects associated with guar meal feeding.

Effects of Dietary Inclusion of Guar Meal Supplemented by β-Mannanase on Performance of Laying Hens, Egg Quality Characteristics and Diacritical Counts of White Blood Cells

“…Some studies reported that there was no negative impact on productive performance after adding GM without enzyme to diets at concentrations up to 2.5% in broiler chicks (Lee et al, 2003a;2003b) or 5% in laying hen diets (Gutierrez et al, 2007). Different indigestible polysaccharides, such as pectin, gum Arabic, gum agar, locust bean gum and guar gum, increase intestinal viscosity, which decreases growth and increases feed conversion.…”

Practical Application of Guar (Cyamopsistetragonoloba L. Taub) Meal in Poultry Nutrition

“…Heat treatment and supple- (Patel and McGinnis, 1985;Lee et al, 2003a;2003b;2009) (Table 3). Theenzymes like pectinase in chick feed have also been recommended for overcoming growth-inhibitory properties of GM (Anderson and Warnick, 1964;Rao et al, 2015).…”

“…Flow diagram depicting overall guar meal processing steps of feed mills (Figure 3). Patel and McGinnis, 1985;Lee et al, 2003a;2003b;2009) …”

The Effect of Heat or Heat-Xylose Processing on Nitrogen Fractions and <I>in Situ</I>/<i>In Vitro</i> Ruminal and Post-Ruminal Protein Disappearance of Guar Meal

“…To remove some of the beans odour and gum residual from Guar Meal (GM), it is toasted being subjected to steam and dry heat (Rahman and Leighton, 1968). Feeding characteristics and other properties of GM have been well evaluated in poultry nutrition (Couch et al, 1967;Verma and McNab, 1982;Lee et al, 2003a;2003b;Hassan et al, 2008). However, few experiments have been done to evaluate the chemical composition and nutritive value of different guar meals for ruminant nutrition.…”