Feed Enzymes

An in vitro procedure that simulated digestion in growing broilers was tested to predict phosphorus availability and arabinoxylan hydrolysis in samples of nine wheat varieties and in a wheatbased diet. Amounts of dialysable phosphorus freed from wheat samples correlated with activities of endogenous phytase (R = 0.913; p`0.0001), whereas amounts of pentoses released were correlated with viscosities of the digested samples (R = 0.899; p`0.0001). Differences in phosphorus release resulting from graded levels of microbial phytase added to feeds that were either autoclaved or not autoclaved revealed a decreasing role of endogenous phytase in dephosphorylation as levels of microbial phytase supplementation grew. Amounts of pentoses released from feeds containing two different xylanase preparations re¯ected literature data on different in vivo ef®cacies of those preparations. Simultaneous addition of phytase and xylanase affected phosphorus release in a manner that depended upon the form of xylanase preparation used (liquid or powder). There was a positive in¯uence of acid protease on both phytate and arabinoxylan hydrolysis in feeds supplemented with phytase. Effects observed by the in vitro procedures corresponded to in vivo phenomena described in the literature.

Distillers dried grains with solubles (DDGS), a co-product of the ethanol industry, is often used as feed material in livestock and poultry nutrition. Results of many experiments have indicated, however, that a high dietary level of DDGS can negatively affect the digestibility of nutrients and the performance of monogastric animals due to their high content of non-starch polysaccharides (NSP). Nevertheless, using high levels of DDGS as a protein source in livestock diets can be still economically justifiable in view of the rising prices of soybean meal and other protein sources. The aim of some recent experiments with poultry and pigs was to improve the nutritional efficacy of high-NSP diets through the addition of feed enzymes. As presented and discussed in this review article, the efficacy of feed enzymes added to poultry and pig diets containing DDGS is not consistent and depends on many factors. However, NSP-hydrolysing enzymes generally seemed to be more efficient than phytases in terms of the digestibility of nutrients and the growth performance of poultry and pigs fed high-DDGS diets. For this reason, supplementation with NSP-hydrolysing enzymes could be an efficient way to enable the use of increased levels of DDGS in poultry and pig diets.

1. A total of 192 ISA Brown hens were given diets containing a high concentration of maize dried distiller's grains with solubles (DDGS) and the effect of selected feed additives on laying performance and egg quality was determined.
2. Birds were allocated to 8 treatment groups with 12 replicates (cages) of two hens and were given, from week 26 to 55, iso-caloric and iso-nitrogenous experimental diets with or without a high concentration of DDGS (200 g/kg). The diet containing DDGS was not supplemented or supplemented with enzymes (xylanase and phytase), sodium butyrate, probiotic bacteria (Lactobacillus salivarius) and a mixture of herbal extracts (Taraxaci siccum, Urticae siccum and Salviae siccum), inulin or chitosan.
3. The inclusion of DDGS in the diet had no effect on number of eggs produced, total egg mass, mean egg weight, feed intake or feed conversion ratio. Egg and eggshell quality parameters were also unaffected by dietary DDGS. The yolk colour score (points in Roche scale) was significantly increased by DDGS inclusion. DDGS in the diet caused some changes in the yolk lipid profile that were rather unfavourable from a dietary perspective (an increase of cholesterol content, and PUFA n-6/PUFA n-3 ratio).
4. During the experimental period (26–55 weeks of age) supplementation of the diet containing a high concentration of DDGS with enzymes, inulin as well as chitosan, increased number of eggs produced and daily egg mass. In older hens (50 weeks of age) inulin positively affected eggshell quality parameters, i.e. shell percentage, thickness and density. Diet supplementation with herb extracts, inulin or chitosan, decreased the content of cholesterol in yolks.
5. The results of this study suggest that DDGS may be incorporated up to a concentration of 200 g/kg in the diet of laying hens without any negative effects on egg performance. Moreover, supplementation of xylanase and phytase, as well as inulin and chitosan, can positively affect the performance of layers given diets with a high concentration of DDGS.

In a 2 week study with broilers, graded levels of phytase added to feeds containing 6.70 g kg−1 of Ca, 4.80 g kg−1 of total phosphorus along with the recommended xylanase dosage (400 FXU kg−1) improved body weight gains quadratically (R2 = 0.55; p < 0.0001). Xylanase supplementation to feeds containing 0, 600 or 1000 units kg−1 of phytase significantly improved gains (p = 0.0072) and decreased viscosities of intestinal contents (p < 0.0001). High phytase concentrations in feeds (1000 FTU kg−1) increased intestinal viscosities, whereas, in the presence of xylanase, graded levels of phytase linearly reduced viscosities below the levels attained with xylanase fed as a sole supplemental enzyme (p = 0.033). Contents of ash in the toes were increased by phytase supplementation (p = 0.0011), the effect being more pronounced in birds consuming feeds that also contained xylanase. Improvements in performance and in bone mineralisation resulting from phytase and xylanase supplementation were lower than those observed in the control diets containing 4.50 g kg−1 of available phosphorus. The in vitro dialysable phosphorus predicted 71% of the variability observed in body gains, whereas amounts of pentoses freed from feed samples in vitro were highly correlated (R = 0.919) with feed efficiencies when the data were subjected to Hanes transformation.© 1999 Society of Chemical Industry

In an experiment on 84 Lohman Brown hens (from 26 to 68 weeks of age), the effect of the different dietary levels of maize distillers dried grains with solubles (DDGS) on laying performance and egg quality was studied. Experimental diets were isocaloric and isonitrogenous and contained 0, 5, 10, 15 or 20% DDGS. The diet with 20% DDGS was also supplemented with NSP-hydrolizing enzymes or with enzymes and additional amounts of ly sine and methionine. In the first phase of the laying cycle (26-43 weeks of age) the dietary level of DDGS did not significantly affect the laying rate, daily weight of laid eggs, feed intake and feed conversion. In the second phase of the cycle (44-68 weeks of age), there were no differences in egg production parameters between groups fed diets with 0, 5, 10 and 15% DDGS. A dietary level of 20% DDGS negatively affected laying rate and daily weight of eggs, however, addition of NSP-hydrolizing enzymes to the diet reduced in part this negative influence. The level of DDGS in the diet had no effect on albumen height, Haugh units, eggshell thickness, density and breaking, or sensory properties of boiled eggs. Yolk colour score significantly increased when DDGS was included in the diet.

An in vitro procedure that simulated digestion in growing broilers was tested to predict phosphorus availability and arabinoxylan hydrolysis in samples of nine wheat varieties and in a wheat-based diet. Amounts of dialysable phosphorus freed from wheat samples correlated with activities of endogenous phytase (R = 0.913; p < 0.0001), whereas amounts of pentoses released were correlated with viscosities of the digested samples (R = 0.899; p < 0.0001). Differences in phosphorus release resulting from graded levels of microbial phytase added to feeds that were either autoclaved or not autoclaved revealed a decreasing role of endogenous phytase in dephosphorylation as levels of microbial phytase supplementation grew. Amounts of pentoses released from feeds containing two different xylanase preparations reflected literature data on different in vivo efficacies of those preparations. Simultaneous addition of phytase and xylanase affected phosphorus release in a manner that depended upon the form of xylanase preparation used (liquid or powder). There was a positive influence of acid protease on both phytate and arabinoxylan hydrolysis in feeds supplemented with phytase. Effects observed by the in vitro procedures corresponded to in vivo phenomena described in the literature.© 1999 Society of Chemical Industry

An in vitro procedure that simulated digestion in growing broilers was tested to predict phosphorus availability and arabinoxylan hydrolysis in samples of nine wheat varieties and in a wheatbased diet. Amounts of dialysable phosphorus freed from wheat samples correlated with activities of endogenous phytase (R = 0.913; p`0.0001), whereas amounts of pentoses released were correlated with viscosities of the digested samples (R = 0.899; p`0.0001). Differences in phosphorus release resulting from graded levels of microbial phytase added to feeds that were either autoclaved or not autoclaved revealed a decreasing role of endogenous phytase in dephosphorylation as levels of microbial phytase supplementation grew. Amounts of pentoses released from feeds containing two different xylanase preparations re¯ected literature data on different in vivo ef®cacies of those preparations. Simultaneous addition of phytase and xylanase affected phosphorus release in a manner that depended upon the form of xylanase preparation used (liquid or powder). There was a positive in¯uence of acid protease on both phytate and arabinoxylan hydrolysis in feeds supplemented with phytase. Effects observed by the in vitro procedures corresponded to in vivo phenomena described in the literature.

An in vitro procedure that simulated digestion in growing broilers was tested to predict phosphorus availability and arabinoxylan hydrolysis in samples of nine wheat varieties and in a wheatbased diet. Amounts of dialysable phosphorus freed from wheat samples correlated with activities of endogenous phytase (R = 0.913; p`0.0001), whereas amounts of pentoses released were correlated with viscosities of the digested samples (R = 0.899; p`0.0001). Differences in phosphorus release resulting from graded levels of microbial phytase added to feeds that were either autoclaved or not autoclaved revealed a decreasing role of endogenous phytase in dephosphorylation as levels of microbial phytase supplementation grew. Amounts of pentoses released from feeds containing two different xylanase preparations re¯ected literature data on different in vivo ef®cacies of those preparations. Simultaneous addition of phytase and xylanase affected phosphorus release in a manner that depended upon the form of xylanase preparation used (liquid or powder). There was a positive in¯uence of acid protease on both phytate and arabinoxylan hydrolysis in feeds supplemented with phytase. Effects observed by the in vitro procedures corresponded to in vivo phenomena described in the literature.