NUTRITION ▶▶▶
the diet by breaking down the indigestible fraction. By rais- ing performance to the level of the positive control, a feedase offers feed cost savings.
New evidence A new study looked at the effect of adding a feedase (Rova- bio Advance, Adisseo) to standard or diluted broiler diets in terms of nutrient digestibility and energy utilisation. The trial was carried out at Adisseo’s Center of Expertise in Research and Nutrition (CERN) in France. Broilers were fed one of four dietary treatments between days 12 and 22 – after being fed the same starter formulation (days 1 to 11). The commercial control was compared with this same feed diluted by 3% (us- ing 3% sand) and the diluted feed including the feedase. The digestibility of dry matter, amino acids and gross energy were determined by analysis of feed, excreta and digesta.
Reducing nutrient density Feed intake was not affected by the sand dilution of the di- ets and faecal energy digestibility was similar in the unsup- plemented diets. However, the apparent metabolisable en- ergy (AME) content was significantly lower in the diluted diet compared with the control. This effect was associated with changes in total nutrient content. The addition of the feedase significantly improved energy uptake. This led to an increase in the AME content of the diluted and standard di- ets by 2.8% and 2.9% respectively (Table 1). As a conse- quence, the AME content of the diluted diet plus feedase was similar to that of the standard unsupplemented diet. This demonstrated that the feedase effect fully compensated for the 3% nutrient dilution. At ileal level, amino acid digestibility was around 75% for all treatments. Amino acid digestibility significantly increased by an average of 4.4%, when the feedase was added to the diets (Figure 2). Again showing that nutrient availability was restored in the diluted diet by the feedase effect. The authors of the published study highlighted the importance of consid- ering the entire nutrient matrix when adding enzymes to broiler diets.
Figure 1: Digestibility of amino acids Control diet
Feedase supplemented diets
65 70 75 80 85
Cys His Ile Leu Lys Met Phe Thr Val ▶ POULTRY WORLD | No. 9, 2019 29
Table 1 – Digestibility results Treatments
Standard
Digestibility, % Dry matter AME/GE
Energy values, kcal/kg AME
AMEn
68.7 b 73.4 b
3453 b 3286 b
70.848 a 75.430 a
3551 a 3379 a
Standard + Feedase
Diluted
66.5 c 73.3 b
3348 c 3189 c
Unravelling complex carbohydrate structures Carbohydrases are added to broiler diets to improve feed effi- ciency with the aim of increasing the metabolisable energy. However, energy is not a nutrient as such. It is the amount of energy produced by nutrient combustion. These nutrients in- clude valuable protein. In a world demanding more protein that is both cheaper and more sustainable – feedase could be part of the solution. New research has shown that using a feedase enables broilers to maximise energy utilisation and amino acid digestion from reformulated diets. By adding a feedase to the diluted ration broilers were able to obtain the same level of AME and amino acids as from the unsupplemented control diet. These lower nutrient density diets require less costly raw materials and can include more by-products, hence resulting in feed cost sav- ings.
Ensuring optimum degradation of NSPs potentiates the ef- fects of endogenous enzymes. By considering the overall ef- fect of enzymes on the indigestible dietary fraction, the aim of the feedase is to maintain poultry performance and im- prove gut function, while reducing diet costs. Nutritionists can now formulate diets to meet the needs of broilers, producers and customers alike. The sociological, environmental and eco- nomic impact of feeding broilers a lower nutrient density diet is beyond doubt.
References available on request.
Diluted + Feedase
68.3 b 75.4 a
3444 b 3283 b
PHOTO: POULTRY WORLD
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