This experiment was performed to evaluate the effect of Non starch polysaccharide (NSP) enzymes product (a mixture of xylanase, cellulase, hemicellulase, β-glucanase, α-amylase, protease, pectinase and β-mannanase), supplemented in cereal based diet on broiler performance. Total 120 day old broiler birds were randomly divided in two experimental groups. Control group received normal cereal based diet and treatment group received NSP enzyme mixed diet (1g/kg of diet). The results showed that NSP supplemented diet improved body weight gain by 5.1% (p<0.05) and also improved feed conversion ratio (FCR) by 5.21% (p<0.05). Nutrient retention also increased significantly (p<0.05) in treatment group as compared to control. No significant difference found in feed intake between groups, however intestinal viscosity and intestinal pH were reduced significantly in treated group. The results suggest that supplementation of NSP enzyme to cereal based diet improves digestibility, reduce the viscosity of gut and improves the performance of birds.
In poultry industry, commercial poultry producers are trying different approaches for better growth and economic broiler production. Different types of growth promoters activate the liver of the birds and helps in better synthesis of amino acids, better utilization of nutrients, minimizing the effect of afflatoxins and intestinal pathogens and there by helps in growth (Roy et al., 2002; Bansal et al., 2011). Cereals and vegetable protein sources are the major ingredients in poultry rations (Nikam et al., 2017). These ingredients contain 10-75% of non-starch polysaccharide (NSP). The major detrimental effect of NSP are associated with the viscous nature of these polysaccharides, their physiological and morphological effect on the digestive tract and the interaction with the micro flora of the gut (Choct and Annison, 1991; Choct et al., 1996). The mechanism includes altered intestinal transit time, modification of intestinal mucosa and changes to hormonal regulation due to varied rate of nutrient absorption (Vahouny, 1982). The primary objective of using enzymes is to enhance nutrient digestibility, focusing primarily on minimizing the anti-nutritive effects of NSP, such as arabinoxylans and β-glucans in broiler diets based on wheat, rye or barley which increase the viscosity of digesta. Soybean meal (SBM) is being used as sole protein source which contains about 29% NSP. Similarly, other major ingredients used in broiler and layer diets i.e., maize and rice bran contain 9 and 25% NSP respectively, half of which is cellulose. The beneficial effect of the NSP degrading enzymes is primarily the reduction in the viscosity in gastrointestinal tract and increase in the availability of sugars. The reduction in viscosity is due to breakdown of NSP into smaller polymers which leads to prevention of formation of viscous networks. Due to breakdown of NSP, their respective monosaccharides; starch present within endosperm are released, digested and this results in release of more glucose The digestibility of carbohydrates contained in cereal based diet is an important determinant of the available energy content which is hindered by many anti nutritional principles like arabinoxylons. Supplementation of cereal based diets with NSP-degrading enzymes (xylanase, glucanases, cellulases) reduces digesta viscosity and increases nutrient availability by breaking down NSP fractions (Simon, 1998; Nilufar et al., 2012). The aim of present research work was to study the comparative effect of non-starch polysaccharide enzymes in cereal based low energy diet on broiler growth performance, nutrient retention, gut health and tissue integrity.
Materials and Methods
120 day old healthy commercial broiler chicks were randomly distributed in two experimental groups (Table 1). Each group consists of six replications and ten birds in each replicate. All the broiler chicks were weighed and wing banded. Treatment group was fed with cereal based diet with NSP enzymes procured from Hester Biosciences Limited, which is a blend of xylanase, β-mannanase, protease, xylanase, β-glucanase and cellulose. Total duration of experiment was 21 days. The control group was fed with normal cereal based diet. Birds were given broiler starter feed (for 7-21 days age) and details of ingredient composition and nutrient level of experimental diet are shown in Tables 2 and 3. The birds were kept in wired 3-level battery cages from 7 to 21 days in environmentally controlled pen house. Diet was fed in mash form and ad libitum access to feed and water. Diets were formulated to meet or nutrient requirements as per ICAR feeding standards. Weekly body weight and feed intake were recorded.
Table 1: Experimental groups
|Control||Cereal based Diet|
|Treatment||Cereal based Diet with NSP enzyme|
Table 2: Experimental Diet
Table 3: Nutrient composition (% dry matter basis) of broiler starter diet
|Nitrogen free extract||62.88||63.2|
At the end of the experiment, metabolic trial of four days duration was conducted to determine the nutrient utilization. The samples of feed, feed residue and feces were collected separately during trial. The samples were analyzed for proximate principles as per the method of AOAC, (2000). After trial 24 birds or 2 birds in each replicate were slaughtered to access the carcass characteristics.
The digesta was collected from distal portion of small intestine during slaughter. 2 g of digesta was collected and centrifuged at 5000 rpm for 10 minutes at 20 °C. An aliquot of supernatant (0.5 to 1 ml) was collected and stored in capped vials for viscosity determination. The digesta collected in centrifuge tubes was utilized for measuring the pH.
Histology of Intestine
The pieces of part of duodenum were collected and preserved with 10% normal saline for histolopathological study. After proper fixation the intestinal tissue was trimmed and subjected to overnight washing, dehydration in various percentages of alcohol, cleaning in xylol and embedding in paraffin wax for preparation of blocks (Clayden, 1962). The paraffin blocks were cut into 5 µm thick sections and stained with routine H and E stain (Culling, 1957) and used for microscopic examination. All data were entered into Microsoft Excel worksheet and analyzed by IBM SPSS 20 software.
Results and Discussion
The growth performance of birds of both groups is presented in Table 4. Non starch polysaccharide enzymes containing diet supplementation increased body weight gain by 5.1% (p<0.05) and also improved FCR by 5.21% (p<0.05). There was significant increase in body weight and feed conversion ratio in treatment group as compared to control. Similar effect was observed in previous study (Jung et al., 2008). There was no significant difference found in feed intake between groups.
Table 4: Effect of Non starch polysaccharide supplementation on performance of animals
|NSP supplemented feed||SEM||p value|
|Initial body weight||126.20||127.02||1.55||0.4533|
|After 21 days|
|Body Weight gain (g/birds)||479.70||505.48||4.47||0.0142|
|Feed intake (g/birds)||763.80||764.23||11.78||0.846|
|Feed conversion ratio||1.63||1.54||0.02||0.046|
Data are represented as Mean ± SEM
There was significant influence observed in nutrient retention with treatment group compared to that of control group (Table 5). Results showed that dry matter (DM), organic matter (OM), crude protein (CP), ether extract (EE), nitrogen free extract (NFE), total ash (TA) and pH were found significantly increased (p<0.05) in NSP enzymes supplemented group. Crude fibre value was found decreased, but not statistically significant (p>0.05). Similar findings were reported by Bhatt et al. (1991), where supplementation of broiler ration with NSP enzyme could improve digestibility of DM and CP.
Table 5: Nutrient retention and intestinal pH of broiler diet supplemented with NSP enzyme and without NSP enzyme
|NSP enzyme supplemented diet||65.92||77.14||69.03||33.33||76||66.56||36.661||4.48||5.2|
Data are represented in percentage unit and Mean ± SEM
The intestinal microbiota plays an important role in the normal nutritional, physiological, immunological and protective functions of the host animals. The composition and metabolic activity of the intestinal microbiota can be influenced by the diet. The present study shows there were changes in the ileal villus of intestinal surface. It became broad in NSP supplemented group as compared to control group (Fig. 1).
Fig.1: Histopathological examination of gut showing effect of NSP enzyme supplemented diet
Wageha et al. (2008) and Narsimba et al. (2013) also studied the effect of combination of enzyme and prebiotics on gut performance, where increase in the villus height and thus, increased surface area for better absorption available.
The current study concluded that supplementation of non starch polysaccharide enzyme in cereal based diet improve digestibility, reduce the viscosity of gut and improve the performance of birds.